Online Dictionary of Invertebrate Zoology: Complete Work - Best Text

Copyright © 2005 Armand R. Maggenti and Scott L. GardnerDesigned and set in Verdana type by Paul RoysterVersion 1.0, posted September 6, 2005Version 1.01, posted September 14, 2005Version 1.02, posted September 22, 2005Version 2.0, posted October 20, 2005Version 2.1, posted July 31, 2008

In memory ofMary Ann Maggenti,a good friend and teacher.This book is dedicated to Mary Ann’s sons,Timothy and Peter Maggenti.

The roots and origins of the terms presented in this dictionarywere taken from textbooks and from the original literature.Wherever possible the original first reference was located sothat the original meaning was preserved. Original use, subsequentor current usage, and common acceptable uses ofterms are also presented. Many of the terms were taken fromCharles T. Brues and A. L. Melander, Key to the Families ofNorth American Insects (1915) and their Classification of Insects:A Key to the Known Families of Insects and Other TerrestrialArthropods (1932).The authors wish to acknowledge the dedication to thisproject given by Mr. Gaylen Paxman.

Jump to:A ..............1B .......... 109N .......... 595O .......... 620C .......... 151P........... 650D .......... 272E........... 311Q .......... 768R .......... 771F........... 352S........... 799G .......... 381TT........... 888H .......... 416U .......... 927I ........... 463V .......... 937J ........... 492W ......... 953K .......... 495L........... 500X .......... 956Y........... 958M ......... 527Z........... 959

Aabactinal a. [L. ab, from; Gr. aktis, ray] (ECHINOD) Of or pertainingto the area of the body without tube feet that normallydoes not include the madreporite; not situated on theambulacral area; abambulacral. abactinally adv.abambulacral see abactinalA-band That zone of the sarcomere composed of both actinand myosin filaments.abapertural a. [L. ab, from; apertura, an opening] (MOLL:Gastropoda) Refers to being away from any shell aperture.abapical a. [L. ab, from; apex, top] 1. Pertains to the oppositeof apical and thus the lower pole of spherical organisms. 2.(MOLL: Gastropoda) Away from the shell apex toward basealong axis or slightly oblique to it.abaxial a. [L. ab, from; axis, axle] Refers to being situatedoutside of or directed away from the axis or central line.see adaxial.abbreviate fascia (ARTHRO: Insecta) A fascia extending lessthan half the wing.abcauline a. [L. ab, from; caulis, stalk] (CNID: Hydrozoa) Pertainingto polyps that extend outwards from the commonstem. see adcauline.abdomen n. [L. abdomen, belly] 1. (ARTHRO) The posterior ofthe three main body divisions of insects; not homologouswith chelicerate opisthosoma. 2. (ARTHRO: Crustacea) Thetrunk somites (with or without limbs) between the thoraxand telson; the pleon.abdomere n. [L. abdomen, belly; Gr. meros, part] An abdominalsegment.abdominal feet see prolegsabdominal filament see cercus

2Maggenti and Gardnerabdominal ganglia (ARTHRO) Ganglia of the ventral nervecord that innervate the abdomen, each giving off a pair ofprincipal nerves to the muscles of the segment; locatedbetween the alimentary canal and the large ventral muscles.abdominal process (ARTHRO: Crustacea) In Branchiopoda,fingerlike projections on the dorsal surface of the abdomen.abdominal somite (ARTHRO: Crustacea) Any single division ofthe body between the thorax and telson; a pleomere; apleonite.abduce v. [L. abducere, to lead away] To draw or conductaway.abduct v. [L. abducere, to lead away] To draw away from positionof median plane or axis.abductin n. [L. abducere, to lead away] (MOLL: Bivalvia) Rubber-likeblock of protein of the inner hinge ligament ofPecten.abductor muscle The muscle that draws an appendage or partaway from an axis of the body. see adductor muscle.aberrant a. [L. aberrans, wandering] Pertaining to a deviationfrom the normal type or form; abnormal; anomalous variations;different.abient a. [L. abire, to depart] Avoiding or turning away from asource of stimulation. see adient.abiocoen n. [Gr. a, without; bios, life; koinos, common] Thenon-living components of an environment.abiogenesis n. [Gr. a, without; bios, life; genesis, beginning]The theoretical concept that life can arise from non-livingmatter; spontaneous generation; archebiosis; archegenesis,archigenesis. see biogenesis, neobiogenesis.abiology n. [Gr. a, without; bios, life; logos, discourse] Thestudy of inanimate objects; anorganology.abiotic a. [Gr. a, without; bios, life] Pertaining to, or characterizedby the absence of life.abjugal furrow (ARTHRO: Chelicerata) In Acari, the line sepa-

Online Dictionary of Invertebrate Zoology 3rating the aspidosoma (prodorsum) and the podosoma ofmites.ablation n. [L. ablatus, taken away] Removal of a part as byexcision or amputation.aboral a. [L. ab, from; os, mouth] 1. Pertaining to, or situatedaway from the mouth; surface opposite the mouth. 2.(ECHINOD: Asteroidea) The surface opposite that bearingthe mouth and ambulacral grooves; abactinal; apical; dorsal.see oral.aboriginal a. [L. aborigineus, ancestral] 1. Of or pertaining toan aborigine, the first, original. 2. Native fauna and flora ofa geographic region.abortion n. [L. abortus, premature birth] Arrest or failure ofdevelopment of any entity or normally present part or organrendering it unfit for normal function.abranchiate a. [Gr. a, without; branchia, gills] Pertains to beingwithout gills.abreptor n. [L. ab, from; reptere, to crawl] (ARTHRO: Crustacea)The postabdomen of water fleas terminating in twoclaws.abscised n. [L. abscissus, cut off] Cut off squarely; with astraight margin.abscission n. [L. abscissus, cut off] The separation of parts.absolute a. [L. absolutus, finished, perfect, complete] Any entityexisting in and of itself free from impurities or imperfections.absorption n. [L. ab, from; sorbere, to suck] The passage ofwater and dissolved substances into a living cell or tissue.see adsorption.abterminal a. [L. ab, from; terminus, limit] Passing from theend toward the center.abullate a. [Gr. a, without; L. bulla, bubble] Lacking a bulla.abyss n. [Gr. abyssos, the deep sea] Bottomless, sometimesused to denote very deep.

6Maggenti and Gardnercore of nonlaminated calcite, with sheath laminae usuallystrongly deflected toward the zoarial surface as spines;usually larger than paurostyle. 2. (PORIF) A monactinal spiculecovered with thorny processes.acanthozooid n. [Gr. akantha, thorn, spine; zoon, animal; eidos,form] (BRYO) A specialized zooid that secretes smalltubules that project as spines above the colony's surface.Acari n. [Gr. akari, mite or tick] (ARTHRO: Chelicerata) Subclassof the most diverse and species-rich group of arachnidscontaining the mites and ticks; formerly the orderAcarina.acariasis n. [Gr. akari, mite or tick; -iasis, diseased condition](ARTHRO: Chelicerata) Infestation with ticks or mites, orany diseased condition resulting therefrom.Acarina see Acariacarinarium n.; pl. -aria [Gr. akari, mite or tick; L. -arium,place for] 1. (ARTHRO: Chelicerata) Any surface or anatomicalfeature, enclosed or not, internal or external, thatregularly serves as an abode for mites. 2. (ARTHRO: Insecta)In Hymenoptera, variously placed and constructedintegumental cavities that serve as abodes for mites incertain eumenine wasps; originally defined as the enclosedacarid chambers of xylocopid bees.acarocecidium n.; pl. -ia [L. akari, mite or tick; Gr. kekis,gallnut] (ARTHRO: Chelicerata) Any plant gall caused by amite.acarology n. [Gr. akari, mite or tick; logos, discourse] Thatbranch of zoology that studies mites and ticks.acarophily n. [Gr. akari, mite or tick; philos, loving] Symbiosisof mites and plants.acaryote see akaryoteacaudal, acaudate, ecaudate a. [Gr. a, without; L. cauda,tail] Without a tail.acceleration n. [L. acceleratare, to hasten to] The speeding upof a development so that a feature appears earlier in theontogeny of a descendant than in an ancestor.

Online Dictionary of Invertebrate Zoology 7accentuation n. [L. ad, to; canere, to sing] Intensify; increasedistinctness.accessory a.; pl. -ries [L. ad, to; cedere, move] Contributingto the effectiveness of a principal design; secondary; supplemental.accessory appendages (ARTHRO: Insecta) In Odonata, thegenital appendages (intromittent organs) on the venter ofthe second and third abdominal segment.accessory bodies Argyrophil particles obtained from Golgibodies in spermatocytes. see chromatoid bodies.accessory boring organ (MOLL: Gastropoda) A glandularstructure (in naticaceans on the lower lip, and in muriaceanssole of the foot) that aid the radular rasping processby acidic secretions so mechanical removal by the radula ismade easy.acessory cell (ARTHRO: Insecta) A cell in the wing not normallypresent in the group, or definite location.accessory circulating organs see accessory pulsatile organsaccessory claws (ARTHRO: Chelicerata) In Araneae, clawlikebundles of setae or bristles below the true claws.accessory genitalia see accessory appendagesaccessory glands (ARTHRO: Insecta) 1. A pair of glands openingprimarily on the venter or the eighth or ninth abdominalsegment of females that secrete an adhesive substance ormaterial forming a cover or case (ootheca) for the eggs. 2.In males, secretion glands opening into the ejaculatoryduct.accessory lamellae (MOLL: Bivalvia) In Pholadinae, accessoryperiostracal coverings or shelly plates along the dorsalmargin, over the anteroventral pedal gape, or along theposteroventral margin encircling the siphons.accessory lobes (ARTHRO) Ventral lobes of the protocerebrum.accessory nidamental gland (MOLL: Cephalopoda) Smallpaired glands subordinate to the nidamental gland.

8Maggenti and Gardneraccessory pigment cells (ARTHRO: Insecta) As many astwenty-four cells that surround the retinulae of a compoundeye; in superposition eyes the pigment granules assumedifferent positions in light and darkness; also knownas secondary pigment cells, secondary iris cells, iris pigmentcells and outer pigment cells.accessory pulsatile organs (ARTHRO) Pulsating structuresconnected with the hemocoel that are concerned withmaintaining a circulation through the appendages, but pulsatingindependently from the heart.accessory sac (PLATY: Cestoda) A sac in the proglottid wallthat opens into the genital atrium.accessory spicule (PORIF) A category of megasclere, supplementalto the primary skeleton, may be located anywhere.accessory stylets (NEMER) Replacement stylets that arestored in reserve stylet sacs or pouches.accessory subcoastal vein (ARTHRO: Insecta) In Perlidae, thevein given off from the subcosta, branching toward theapex of the wing.accessory testis (ARTHRO: Insecta) In Coleoptera, the coiledmiddle section of the vas deferens serving as a reservoirfor mature sperm.accidental evolution A condition that occurs as a consequenceof mutation, but does not appear to improve survivalvalue.accidental host A host in which a pathogenic parasite is notcommonly found.accidental myiasis (ARTHRO: Insecta) In Diptera, the presencewithin a host of a fly larva that is not normally parasitic;pseudomyiasis.accidental parasite A parasite in other than its normal host;an incidental parasite.accidental transport Unintentional movement of a pathogenfrom one location to another by an animal not normally associatedwith the parasite or disease. see phoresis.

Online Dictionary of Invertebrate Zoology 9acclimation n. [L. ad, to; Gr. klima, climate] The habituationof an organism to a foreign or different climate or environment;acclimatization.acclivous a. [L. acclivis, ascending] Pertaining to an upwardslope. see declivous.accretion n. [L. accrescere, to increase] Growth or increase byexternal addition. see intussusception.acelomate see acoelomateacentric a. [Gr. a, without; kentrol, center] Pertaining to notbeing centered; lacking a centromere when referring to achromosome or chromosome fragment.acentric inversion An inversion of any part of the chromosomenot involving the centromere.Acephala (MOLL) Former name for Class Bivalvia.acephalocyst n. [Gr. a, without; kephale, head; kystis, bladder](PLATY: Cestoda) A hydatid larval stage; bladderworm;cysticercus.acephalous a. [Gr. a, without; kephale, head] (ARTHRO: Insecta)Pertains to the absence of any structure comparableto a head, as in certain dipteran larvae; acephalic. seeeucephalous, hemicephalous.acerata n. [Gr. a, without; keratos, horn] 1. Without true antennae.2. (ARTHRO) In former classifications, the nameAcerata comprised a class combining Merostomata andArachnida.acerate a. [L. acer, sharp] Of or pertaining to needle-shaped;acerose; acicular.acerose a. [L. acer, sharp] Having a sharp, rigid point; acerate;acicular.acerous a. [Gr. a, without; keras, horn] Lacking horns, antennaeor tentacles.acervate a. [L. acervare, to heap] Pertaining to heaped orgrowing in heaps or clusters. see coacervate.acervuline a. [L. acervare, to heap] Resembling small heaps.

10Maggenti and Gardneracescence n. [L. acesceres, to turn sour] Acetic acid fermentation.acetabular caps (ARTHRO: Insecta) The coxal cavity ofHemiptera.acetabuliform a. [L. acetabulum, cup; forma, shape] Resemblingthe shape of a shallow cup or saucer.acetabulum n.; pl. -la [L. acetabulum, cup] 1. A cup-shapedsocket or cavity. 2. (ANN: Hirudinoidea) In leeches, thelarge posterior sucker. 3. (ARTHRO: Chelicerata) In Acari,the genital sucker. 4. (ARTHRO: Insecta) a. Any cavity intowhich an appendage is articulated; the coxal cavity. b. Theconical cavity at the anterior of some larvae; in Diptera,the cavity in the sucking mouth. c. In dytiscid water beetles,stalked cuplets or sucker discs on the anterior tarsi, insome, also the second tarsi, thought to act as adhesive organsduring copulation; a pallette. 5. (ECHINOD: Echinoidea)The cavity located on the proximal end of a spine. 6.(MOLL: Cephalopoda) The sucker on the arm. 7. (PLATY:Cestoda) The sucker on the scolex. 8. (PLATY: Trematoda)The ventral sucker.achaetous, achetous a. [Gr. a, without; chaite, hair] Withoutsetae, bristles, or chaetae.achatine, achatinus a. [L. achates, agate] Pertaining to linesresembling those of an agate; in bands of more or lessconcentric circles.achelate a. [Gr. a, without; chele, claw] Lacking pincherlikeorgans or claws.achilary a. [Gr. a, without; cheilos, lip] Lacking a lip.achlamydate a. [Gr. a, without; chlamys, mantle] Lacking amantle.achroacyte n. [Gr. a, without; chroa, colored; kytos, container]A colorless cell; a lymphocyte.achroglobin n. [Gr. a, without; chroa, colored; L. globus,sphere] (MOLL) A colorless respiratory pigment.achroic see achroous

Online Dictionary of Invertebrate Zoology 11achromasia, achromasie n. [Gr. a, without; chroma, color]Lacking the usual reaction to stains. see chromasia.achromatic a. [Gr. a, without; chroma, color] Being achroous;stains not permeating readily; uncolored.achromatic apparatus/figure Pertaining to mitosis, thosestructures (spindle fibers and cell centers) that do not stainreadily.achromatin n. [Gr. a, without; chroma, color] Those parts ofthe cell nucleus that do not absorb color of the basic stains.achromatinic a. see chromatin.achromic a. [Gr. a, without; chroma, color] Free from color;unpigmented.A-chromosome Any of the chromosomes of the normal chromosomecomplement, as opposed to the B-chromosomes.achroous a. [Gr. a, without; chros, complexion] Colorless; unpigmented;achromatic.acia n. [L. acia, thread] (ARTHRO: Insecta) A thin cuticular plateof the mandible.acicle n. [L. dim. acus, needle] (ARTHRO: Crustacea) A thornshapedscaphocerite of hermit crabs.acicula n.; pl. -lae [L. dim. acus, needle] A slender needle-likeprocess; a spine or bristle; something larger than a seta orchaeta. acicular, aciculate a.aciculiform see aciculaaciculum n.; pl. -lums, -la [L. dim. acus, needle] (ANN: Polychaeta)A chitinous stiff basal seta or rod supporting theparapodial lobes.acid gland, poison gland 1. Any of numerous glands secretingacid in many invertebrates. 2. (ARTHRO: Chelicerata) InAraneae, the poison gland. 3. (ARTHRO: Diplopoda) TheHCN-secreting glands. 4. (ARTHRO: Insecta) Gland ofstinging Hymenoptera. 5. (MOLL: Gastropoda) The salivarygland.acidic a. [L. acere, to be sour] Acid forming; having the propertiesof an acid.

12Maggenti and Gardneracidobiontic a. [L. acere, to be sour; Gr. bion, life] Living inan acid environment. see oxyphilic.acidophil a. [L. acere, to be sour; Gr. philein, to love] Growingin an acid media. see oxyphilic.acidophilic, acidophilous a. [L. acidus, sour; Gr. philein, tolove] 1. Tolerating acid; aciduric. 2. Staining readily in anacid stain.acidophobic a. [L. acere, to be sour; Gr. phobos, fear] Pertainingto the intolerance of an acid environment; oxyphobic.acidotheca n. [L. acere, to be sour; Gr. theke, case] (ARTHRO:Insecta) The pupal sheath of the ovipositor.aciduric a. [L. acere, to be sour; durus, hardy] Tolerating anacid medium. see acidophilic.acies n. [L. acies, sharp edge or point] (ARTHRO: Insecta) Theextreme termination of a margin.aciform a. [L. acus, needle; forma, shape] Pertaining to beingshaped like a needle; acicular.acinaciform, acinacicate a. [L. acinaces, short sword; forma,shape] Scimitar-shaped; having one edge thick and slightlyconcave, the other thin and convex; curved and growingwider toward a curve with a truncate apex.acinarious a. [L. acinarius, pert. to grapes] Having globosevesicles resembling grape seeds.aciniform a. [L. acinus, berry or grape; forma, shape] Resemblinga cluster of berries; having small kernels like grapes.acinus n.; pl. -ini [L. acinus, berry or grape] A small sac oralveolus in a multicellular gland or lung. acinose a.aclid organ (ACANTHO) A spined invagination located at theanterior end of an acanthor; sometimes referred to as arostellum.acline see orthoclineaclitellate a. [L. a, without; clitella, packsaddle] (ANN: Oligochaeta)Lacking a clitellum; an adult earthworm, but still

14Maggenti and Gardnerzoa) In former classifications, a group of jellyfish having amedusa without a velum.acraspedote a. [Gr. a, without; kraspedon, border] 1. (CNID:Hydrozoa) Refers to medusae without a velum. 2. (PLATY:Cestoda) Pertaining to tapeworm segments that do notoverlap.acrembolic proboscis (MOLL) Having a completely invaginableproboscis. see pleurembolic proboscis.acridophagus n. [Gr. akridion, locust, grasshopper; phagein,to eat] (ARTHRO: Insecta) The act of preying and feeding onmembers of the Acrididea.acroblast n. [Gr. akros, tip; blastos, bud] In spermatogenesis,Golgi material giving rise to an acrosome.acrocentric a. [Gr. akros, tip; kentron, center] Pertaining tochromosomes with the centromere at or near one of theends; rod-shaped chromosomes. see telocentric.acrocercus see cercusacrocyst n. [Gr. akros, tip; kystis, sac] (CNID: Hydrozoa) Achitinous sac containing a planula in which development iscompleted; may protrude from the gonangium.acrodendrophily a. [Gr. akros, tip; dendron, tree; philein, tolove] Inhabiting the tree-tops.acron n. [Gr. akros, tip] 1. (ARTHRO) The anterior unsegmented,or indistinguishably fused, body segments. a. InCrustacea, ophthalmic somite; presegmental region. b. InInsecta, the prostomium. 2. (MOLL) The prostomal regionof trochophore larva.acronematic a. [Gr. akros, tip; nema, thread] Referring tosmooth, whip-like flagella.acroneme n. [Gr. akros, tip; nema, thread] The slender sectionof a flagellum.acroparia n.; pl. -ae [Gr. akros, tip; pareion, cheek] (ARTHRO:Insecta) In Coleoptera, the anterior part of the paria bearingthe bristles of scarabaeoid larvae.acroperiphallus n.; pl. -li [Gr. akros, tip; peri, around; phal-

Online Dictionary of Invertebrate Zoology 15los, penis] (ARTHRO: Insecta) In Protura, the distal part ofthe periphallus, sometimes retractable into basiperiphallus.acrophilous a. [Gr. akros, tip; philein, to love] Preferring regionsof high altitude.acrorhagus n.; pl. -gi [Gr. akros, tip; rhax, berry] (CNID: Anthozoa)A marginal tubercle of sea anemones containingspecialized nematocysts.acroscopic a. [Gr. akros, tip; skopein, to view] Looking towardsthe apex. see basiscopic.acrosome n. [Gr. akros, tip; soma, body] A cap-like structureinvesting the front part of the sperm head allowing penetrationof the cover of the egg cell; formed from Golgi material.acrosternite n. [Gr. akros, tip; sternon, chest] (ARTHRO: Insecta)That part of the narrow marginal flange anterior tothe antecosta of a definitive sternal plate, including thepreceding primary intersegmental sclerotization; normallyfound on abdominal sterna, but absent on thoracic sterna.acrostical see acrostichal area, bristles, scalesacrostichal area (ARTHRO: Insecta) In Diptera, the medianlongitudinal area of the scutum between the anterior promontoryand prescutellar area, bearing bristles or scales.acrostichal bristles (ARTHRO: Insecta) In Diptera, setae occurringin a median longitudinal row on the acrostichal areaof the scutum.acrostichal hairs/seta/setulae see acrostichal bristlesacrostichal scales (ARTHRO: Insecta) In Diptera, scales occurringin one or two lines on the acrostichal area.acrosyndesis n. [Gr. akros, tip; syndesai, to bind together]Incomplete end-to-end pairing of two chromosomes duringmeiosis; telosyndesis.acrotergite n. [Gr. akros, tip; L. tergum, back] (ARTHRO: Insecta)The anterior precostal part of the tergal plate of asecondary segment usually in the form of a narrow flange,varying in size or sometimes obliterated.

16Maggenti and Gardneracroteric a. [Gr. akros, tip; -terion, place for] Relating to oraffecting the extremities.acrotroch n. [Gr. akros, tip; trochos, hoop] (ANN: Polychaeta)The band of cilia anterior to the prototroch (preoral band)of a larval stage.acrotrophic ovariole see telotrophic ovarioleacrydian a. [Gr. akridion, locust, grasshopper] (ARTHRO: Insecta)Pertaining to grasshoppers or grasshopper-like.actin n. [Gr. actus, move] A muscle protein that combines withmyosin to form a contractile protein complex, actomyosin;the chief constitutent of the I and Z-band myofilaments ofeach sarcomere.actinal a. [Gr. aktis, ray] 1. Star-shaped; pertaining to thatarea of a radiate organism from which arms or tentaclesradiate. 2. (CNID: Anthozoa) Oral area of sea anemones.actine n. [Gr. aktis, ray] (PORIF) The single ray of a starshapedspicule.actinenchyma a. [Gr. aktis, ray; en, in; chyma, to pour] Cellulartissue resembling a star.actinic a. [Gr. aktis, ray] Pertaining to wave lengths betweenthose of visible violet and X-rays, having certain chemicaleffects.actiniform a. [Gr. aktis, ray; forma, shape] Having a radiatedform; star-shaped. actinoid a.actinobiology n. [Gr. aktis, ray; bios, life; logos, discourse]The study of effects of radiation upon living organisms.actinoblast n. [Gr. aktis, ray; blastos, bud] (PORIF) The rudimentarycell of a spicule.actinochitin n. [Gr. aktis, ray; chiton, tunic] Chitin that is anisotropicor birefringent (double refracting).actinodont a. [Gr. aktis, ray; odous, tooth] (MOLL: Bivalvia)With teeth radiating from the beak of the shell.actinogonidial a. [Gr. aktis, ray; gonos, seed] Having genitaliaarranged in a radial pattern.

Online Dictionary of Invertebrate Zoology 17actinoid, actiniform a. [Gr. aktis, ray; eidos, shape] Raylike;star-shaped; stellate.actinology n. [Gr. aktis, ray; logos, discourse] 1. The study ofradially symmetrical animals. 2. The study of the activity ofradiation.actinomere n. [Gr. aktis, ray; meros, part] A segment of a radiallysegmented organism.actinopharynx n. [Gr. aktis, ray; pharynx, gullet] (CNID: Anthozoa)Gullet of the sea anemone.actinostome n. [Gr. aktis, ray; stoma, mouth] The mouth of aradially symmetrical animal.actinotrocha, actinotroch n. [Gr. aktis, ray; trochos, wheel](PHORON) A free-swimming, elongate, ciliated larva of thephylum Phoronida, bearing tentacles attached to a girdleimmediately posterior to the preoral lobe.actinula n. [Gr. dim. aktis, ray] (CNID: Hydrozoa) A larvalstage that looks like either a polyp or medusa, dependingupon whether the mouth is turned upward or downward.action current The flow of electric current between a region ofexcitation and neighboring unexcited regions.action potential A temporary change in potential that occursacross the surface membrane of a muscle or nerve cell followingstimulation.activator n. [L. agere, to act] Any substance that renders anothersubstance active.active a. [L. agere, to act] Pertaining to movement; given toaction; alert.active center The site on an enzyme molecule that interactswith the substrate molecules; where activation and reactiontake place.active transport The transportation or movement of substancesthrough differentially permeable cell membranesagainst a concentration or electrical gradient with the expenditureof energy.actomyosin n. [Gr. aktis, ray; mys, muscle] Actin and myosin

18Maggenti and Gardnerlinkage in myofilaments that shortens when stimulated resultingin muscle contraction.acuate a. [L. dim. acus, needle] Sharpened; needle-shaped;sharp pointed.aculea n.; pl. -eae [L. dim. acus, needle] (ARTHRO: Insecta) 1.In Diptera, one of the minute spines comprising the tomentumthat covers the cuticula (except the wing membrane),usually dense in adults but sparse or absent in immatures.2. In Lepidoptera, one of the minute spines onthe wing membrane.aculeate a. [L. dim. acus, needle] 1. Pertaining to being armedwith a sting or short, sharp points. 2. Furnished with aculeae.aculeate-serrate Armed with saw-like teeth inclined towardone direction.aculei pl. of aculeusaculeiform a. [L. dim. acus, needle; forma, shape] Formedlike a thorn.aculeus n.; pl. -lei [L. dim. acus, needle] (ARTHRO: Insecta) 1.In Hymenoptera, an ovipositor in the form of a sting. 2. InDiptera, a sharp spine projected from the margin of theeighth sternite of Tipulidae.acumen n. [L. acumen, point] 1. (ARTHRO: Crustacea) In Decapoda,the pointed tip of the rostrum. 2. (ARTHRO: Insecta)The pointed tip of genitalia.acuminate a. [L. acumen, point] Terminating in a long taperingpoint.acuminose a. [L. acumen, point] Nearly acuminate.acuminulate a. [L. acumen, point] Minutely acuminate.acupunctate a. [L. acus, needle; punctus, a pricking] Pertainingto fine superficial punctures as if made with a needle.acutangular a. [L. acutus, sharpened; angulus, angle] Formingor meeting at an acute angle.acute a. [L. acutus, sharpened] Pointed; forming an angle of

Online Dictionary of Invertebrate Zoology 21adductor n. [L. ad, near; ducere, to lead] A muscle that drawsparts together or toward the median axis. see adductormuscles.adductor coxae (ARTHRO: Insecta) The second muscle of thecoxa.adductor mandibulae (ARTHRO) The muscle that retracts orcloses the mandible.adductor muscles 1. Any muscle that adducts or bring partsinto apposition. 2. (ARTHRO: Crustacea) In bivalves, musclesattached to the carapace that pull it to the body, orconnect the carapace. a. In Barnacles, any transverse muscle,especially those attached to the scutum for closing theaperture. 3. (MOLL: Bivalvia) A single posterior or an anteriorand posterior muscle connecting the two valves. a. Inoysters, the crescent shaped "catch" muscle that holds thevalves in a set position, or the "quick" muscle, the mainopening and closure muscle.adductor muscle scar (ARTHRO: Crustacea) In Ostracoda, animpression of the adductor muscles on the valve interior,serving for closure of valves.adductor pit (ARTHRO: Crustacea) Depression on the innersurface of the scutum between the adductor ridge and theoccludent margin for the attachment of the adductor muscleof certain barnacles.adductor ridge (ARTHRO: Crustacea) In sessile barnacles, thelinear elevation on the inner surface bounding the adductorpit on the tergal side.adecticous a. [Gr. a, without; dektikos, able to bite] (ARTHRO:Insecta) Pertaining to pupae without articulated mandibles.see decticous.adelocerous, adelaceratous a. [Gr. adelos, concealed; keras,horn] (ARTHRO: Insecta) Having antennae concealed in acavity or groove.adelocodonic a. [Gr. adelos, concealed; kodon, a bell] (CNID:Scyphozoa) Refers to degenerate attached medusae lackingan umbrella (bell).

Online Dictionary of Invertebrate Zoology 23adenosine monophosphate (AMP) A compound of importancein the release of energy for cellular activity, composedof adenine, d-ribose and phosphoric acid; also calledAMP, adenylic acid, adenine ribotide.adenosine triphosphate (ATP) A major energy contributor inbiokinetic systems that upon hydrolysis yields adenosinediphosphate (ADP).adenotaxy n. [Gr. aden, gland; taxis, arrangement] (ARTHRO:Chelicerata) In Acari, the number and distribution of theopenings of the tegumentary glands of mites.adenotrophic viviparity Reproduction characterized by fullydeveloped, shelled eggs passing to and retained in theuterus, where the egg hatches and the larva is nourishedby special maternal glands until fully developed.adeoniform a. [L. Adeona, Roman goddess; forma, shape](BRYO: Gymnolaemata) Pertaining to a lobate, bilamellarcolony; resembling the fossil Adeona.adermata n. [Gr. a, without; derma, skin] (ARTHRO: Insecta)Transparent cuticle in pupa allowing the wings and otherparts of the forming imago to be seen.adesmatic a. [Gr. a, without; desmos, ligament] Pertaining toa segment of an appendage, or to the articulation betweensegments of an appendage, lacking its own tendons andmuscles. see eudesmatic.adetopneustic a. [Gr. adetos, free; pnein, to breathe] (ECHI-NOD) Dermal gills occurring beyond the abactinal surface.adfrontal areas/plates (ARTHRO: Insecta) A pair of narrowoblique plates on the head of Lepidoptera larvae, extendingupwards from the base of the antennae and meeting mediallyabove.adfrontal setae (ARTHRO: Insecta) Setae borne on the adfrontalareas of immature insects, usually numbered accordingto their proximity to the vertex.adfrontal sutures (ARTHRO: Insecta) In immature insects,sutures separating the adfrontal sclerites or areas from theepicranium.

24Maggenti and Gardneradherent a. [L. ad, near; haerere, to stick] Referring to beingattached, clinging or sticking fast.adhesion n. [L. ad, near; haerere, to stick] 1. Act or state ofadhering. 2. Attraction between two molecules of differentsubstances.adhesion organs 1. Any of numerous invertebrate organsused for adhesion to various surfaces. 2. (ARTHRO: Insecta)Abdominal suckers, tarsal suckers and ventral tube. 3.(NEMATA) The spinneret. 4. (PLATY: Cestoda) Suckers,bothria and bothridia. 5. (PLATY: Trematoda) Oral and ventralsuckers. 6. (ROTIF) Pedal glands in the toes.adhesion tubes (NEMATA) Specialized hollow, tubelike structures,that may be supplied with muscles, associated withglands presumed to secrete a sticky substance; sometimesreferred to as tubular setae, adhesive bristles or ambulatorysetae.adhesive bristles see adhesion tubesadhesive capsule (CNID) A type of nematocyst used for attachingto objects.adhesive cells Various glandular or specialized cells capable ofcausing adhesion in cnidarians and tubellarians; sometimesreferred to as colloblasts, glue cells, or lasso cells.adhesive gland Various invertebrate glands that secrete asticky substance.adhesive pad (CNID: Hydrozoa) In some medusae, an adhesivesucker near tip of the tentacles utilized for clinging tosea weed.adhesive papillae (PLATY: Turbellaria) In triclads, the protuberantstructures for the purpose of attachment at the endsof the marginal adhesive glands.adiabatic a. [Gr. a, without; dia, through; bainein, to go]Without gaining or losing heat.adiaphanous, adiaphanus a. [Gr. a, without; diaphanes,transparent] Impervious to light; opaque.adient a. [L. adire, to approach] Turning toward or approach-

Online Dictionary of Invertebrate Zoology 25ing a source of stimulation. see abient.adipocytes n.pl. [L. adeps, fat; Gr. kytos, container] (ARTHRO:Insecta) Cells that form the fat-bodies of insects; adipohemocytes;trophocytes.adipogenesis n. [L. adeps, fat; Gr. gennaein, to produce] Theformation of fat or fatty tissue.adipohemocytes n.pl. [L. adeps, fat; Gr. haima, blood; kytos,container] (ARTHRO: Insecta) Hemocytes characterized byrefringent fat droplets and other inclusions; spheroidocytes.see adipoleucocytes.adipoleucocytes n.pl. [L. adeps, fat; Gr. leukos, white; kytos,container] 1. Leucocyte blood cells with fat inclusions. 2.(ARTHRO: Insecta) In Hemiptera, large cells containing fatdroplets, often thought to be hemocytes.adipose a. [L. adeps, fat] Pertaining to fat.adipose tissue see fat bodyA-disc see A-bandadiscota n. [Gr. a, without; diskos, circular plate] (ARTHRO:Insecta) Adult development without forming imaginal discs.see discota.aditus n.; pl. aditus, adituses [L. aditus, entrance] Anatomicalpassage or opening to a part or structure.adiverticulate a. [Gr. a, without; L. divertere, to turn away]Without diverticula.adjustor n. [L. ad, near; justus, just] 1. Any central nervousorgan of an animal that links receptors with effectors. 2.(BRACHIO) The muscle linking stalk and valve.adjustor neuron A neuron that is neither sensory nor motor,but which correlates the activities of both.admedial, admedian a. [L. ad, near; medial, middle] 1. Nearthe median plane. 2. (MOLL) The lateral teeth of a radulabetween central and marginal.adminiculum n.; pl. -ula [L. adminiculum, support] 1. A supportor prop. 2. (ARTHRO: Insecta) a. Minute hairs, spines

26Maggenti and Gardneror teeth on the dorsal abdominal surface of certain pupaethat aid in locomotion. b. Elevated or indented lines onsome larvae.adnate a. [L. ad, near; natus, born] Pertaining to being unitedor fused to another organ or structure, normally of unlikeparts.adneural a. [L. ad, near; Gr. neuron, nerve] 1. Adjacent to anerve. 2. (POGON) Term used instead of dorsal. see antineural,subneural.adnotale a. [L. ad, near; Gr. notos, back] (ARTHRO: Insecta) InLepidoptera, having fused median and postmedian notalprocesses; median notal process.adolescaria n.; pl. -iae [L. adolescens, young; Gr. kerkos,tail] (PLATY: Trematoda) Cercaria or metacercaria stage.see marita, parthenita.adoption society A group of one or more organisms living together,free to dissociate, and to neither does the continuedassociation bring any apparent advantage.adoption substance (ARTHRO: Insecta) Any secretion put forthby a social parasite that induces the potential host to acceptit as a member of their colony.adoral a. [L. ad, near; os, mouth] Near or toward the mouth.ADP see adenosine diphosphateADPP see adenosine triphosphateadpressed a. [L. ad, near; pressus, pressed] 1. Refers to beingpressed close to or laying flat against. 2. (MOLL: Gastropoda)Condition of whorls that overlap in such a mannerthat their outer surfaces converge very gradually.adradius n. [L. ad, near; radius, ray] (CNID) The midradiusbetween perradius and interradius; a radius of the third order.adrectal a. [L. ad, near; rectus, straight] Associated with therectum. see adanal.adrostral a. [L. ad, near; rostrum, snout] Adjacent to or connectedwith a beak or rostrum.

Online Dictionary of Invertebrate Zoology 27adsorption n. [L. ad, near; sorbere, to suck in] Adhesion ofdissolved substances, liquids or gases, to the surfaces ofsolid bodies with which they come into contact.adsperse, adspersus a. [L. adspursus, a sprinkling] Havingclosely spaced small spots.adsternal a. [L. ad, near; Gr. sternon, chest] Being situatedadjacent to the sternum.adtidal a. [L. ad, near; A.S. tid, time] Referring to organismsliving in the littoral zone just below the low tide mark.adult n. [L. adultus, grown up] 1. A fully grown, sexually matureindividual. 2. (ARTHRO: Insecta) The imago. 3.(NEMATA) That stage following the 4th (juvenile) and finalmolt.adultation n. [L. adultus, grown up] The appearance of adultancestral characters in the larvae of descendants.adultoid a. [L. adultus, grown up; Gr. eidos, shape] (ARTHRO:Insecta) A nymph having imaginal characters more developedthan in the normal nymphs.adultoid reproductive (ARTHRO: Insecta) In higher termites, areplacement reproductive following the disappearance ofthe primary reproductive, that is an imaginal already present,or a nymph reared to an imago stage and morphologicallyindistinguishable from the primary. see primaryreproductive, nymphoid reproductive, ergatoid reproductive.adult transport (ARTHRO: Insecta) The conveying of an adultsocial insect by carrying or dragging during colony emigrations;frequent behavior among ants.aduncate, aduncous a. [L. ad, near; uncus, hooked] Inwardlycurved; hooked; hamate.adust a. [L. ad, near; urere, to burn] Burnt; scorched; driedup.advehent see afferentadventitia n. [L. adventitius, extraordinary] The connectivetissue covering of an organ (mainly fibroelastic in nature),

28Maggenti and Gardnersuch as the heart, or blood vessels.adventitious a. [L. adventitius, extraordinary] Acquired; accidental;additional; occurring in abnormal places; ectopicfoci.adventitious bud (BRYO: Phylactolaemata) The small bud primordiumon the dorsal side of the main bud near the parentalpolypide.adventitious vein (ARTHRO: Insecta) A secondary wing vein,neither accessory nor intercalary, usually the result of crossveins lined up to form a continuous vein.adventive a. [L. advenire, to arrive] Referring to an organismthat has been accidentally introduced to a new area; notnative.adventral line (ARTHRO: Insecta) A line that extends along theunderside of caterpillars between the middle and the baseof the legs.adventral tubercle (ARTHRO: Insecta) In caterpillars, a smallpimple, sometimes bearing setae, located on each of theabdominal segments on the inner base of the leg and apodalsegment.advolute n. [L. ad, near; voluta, spiral] (MOLL: Gastropoda) Acondition of whorls that barely touch one another, not distinctlyoverlapping.aedaeagus, aedagus, aedoeagus see aedeagusaedeagal fulcrum see juxtaaedeagus n.; pl. -agi [Gr. aidoia, genitals; agein, to lead] (AR-THRO: Insecta) In males, the intromittent organ; distal partof the phallus: penis plus parameres. see penis, telopod.aedoeotype n. [Gr. aidoia, genitals; typos, type] The firstspecimen in which the genitalia are studied.aeneous, aeneus a. [L. aeneus, of bronze] Bright brassy orgolden green in color.aerate v.t. [Gr. aer, air] To combine or charge with air; tosupply or impregnate with common air.

Online Dictionary of Invertebrate Zoology 29aeration n. [Gr. aer, air] 1. Exposure to air. 2. Impregnation ofa liquid with air or oxygen. 3. Oxygenation of blood inlungs.aerial a. [Gr. aer, air] Living or occurring in air.aeriduct, aeriductus n. [L. aer, air; ducere, to lead] (ARTHRO:Insecta) Tubes concerned with respiration, such as internaltrachea or breathing tubes.aeriform a. [Gr. aer, air; L. forma, shape] Of the nature orform of air; gaseous.aerobe, aerobiont n. [Gr. aer, air; bios, life] An organismutilizing air. aerobiotic a. see anaerobe.aerobic respiration That which requires oxygen.aerobiology n. [Gr. aer, air; bios, life; logos, discourse] Thestudy of aerial organisms.aerobiosis n. [Gr. aer, air; biosis, manner of life] Life in air oroxygen.aerophore n. [Gr. aer, air; phorein, to bear] (ARTHRO: Insecta)In caterpillars, a hollow hair on the body containing liquid.aeropyle n. [Gr. aer, air; pyle, orifice] (ARTHRO: Insecta) 1.Rings of cells. 2. In the follicular epithelium, functioning insecretions for chorion formation. 3. Small pores betweenplastron and spiracles in spiracular gills.aeroscepsin, aeroscepsy n. [Gr. aer, air; skepsis, observe]The theoretical power possessed by certain organisms ofobserving the quality of air by means of special sense organs.aeroscopic plate (ARTHRO: Insecta) The air-containing part ofthe chorion of an egg.aerostat n. [Gr. aer, air; statos, placed] (ARTHRO: Insecta) Airsacs in the body.aerostatic a. [Gr. aer, air; statos, placed] Said of any organismor object that is, by certain means, supported chieflyby buoyancy derived from surrounding air.aerotaxis n. [Gr. aer, air; taxis, arrangement] Movement of

30Maggenti and Gardnerorganisms toward or away from oxygen.aeruginous, aeruginose, aeruginus a. [L. aerugo, copperrust] Nature or color of copper rust or verdigris (green).aesthacyte, esthacyte n. [Gr. aisthetes, perceiver; kytos,container] A sensory cell of certain primitive organisms.aesthesia, esthesia n. [Gr. aisthetes, perceiver] Sensibility;sense-perception.aesthetasc, aesthetask, esthestasc n. [Gr. aisthetes, perceiver;askos, bag] (ARTHRO: Crustacea) Sensory seta coveredby a delicate cuticular membrane, often projectingfrom an antenna or antennule; an olfactory hair.aesthete, esthete n. [Gr. aisthetes, perceiver] 1. Any invertebratesense organ. 2. (ARTHRO) Usually applied as sensorynerve endings, but also used for sensory hairs and bristles.3. (MOLL: Polyplacophora) Sensory organs terminating inthe tegmentum. see megalaesthetes, micraesthetes.aestivate, estivate v. [L. aestas, summer] To pass the summerin a quiet, torpid condition.aestivation, estivation n. [L. aestas, summer] A form ofdormancy during the summer months in high temperatures,or dry seasons. see hibernestivation.aetiology see etiologyafference n. [L. ad, near; ferre, to bear] Impulses from theexternal sense organs of an animal because of events inthe environment. see reafference.afferent a. [L. afferre, to bring] Refers to a structure or vesselthat leads to or toward a given position. see efferent.afferent channel (ARTHRO: Crustacea) The opening throughwhich water passes to the gills.afferent fiber A nerve fiber carrying impulses from a receptorto the central nervous system.afferent nerve A nerve that conducts impulses from the peripherytoward a nerve center; the axon of a sensory neuronbetween a receptor and the central nervous system.afferent neuron (neurone) A sensory neuron that conveysinward impulses received or perceived by a sense organ

Online Dictionary of Invertebrate Zoology 31from external sources.affinity n.; pl. -ties [L. affinis, related to] Relationship; sometimesmisleadingly employed as synonym for pheneticsimilarity.aflagellar a. [Gr. a, without; L. flagellum, whip] Without flagella.afterbody a. [A.S. aefter, behind; bodig, body] (ARTHRO: Insecta)In Coleoptera, the body area behind the pronotum.after-discharge 1. The continuing discharge of impulses afterstimulation has ceased in sensory receptors. 2. The continuationof the motor response (reflexes) after discontinuanceof stimulation. see after-sensation.afternose a. [A.S. aefter, behind; nosu, nose] (ARTHRO: Insecta)Pertaining to the triangular area below the antennaeand above the clypeus.after-sensation Continuation of nerve impulses after cessationof external stimulation of sensory apparatus.agameon n. [Gr. a, without; gamos, marriage; on, being] Aspecies reproducing exclusively by apomixis. see apomictic(ameiotic) parthenogenesis.agamete n. [Gr. a, without; gamos, marriage] Any product ofreproductive multiple fission that develops directly into theadult form without sexual union.agamic a. [Gr. a, without; gamos, marriage] Parthenogenetic;reproduction without mating, may be either mitotic or meiotic.agamobium n. [Gr. a, without; gamos, marriage; bios, life]The asexual form in alternation of generations. see gamobium.agamodeme n. [Gr. a, without; gamos, marriage; demos,people] A population mainly consisting of asexual organisms.agamogenesis n. [Gr. a, without; gamos, marriage; genesis,beginning] Asexual reproduction; parthenogenesis; reproductionwithout fertilization by a male gamete. agamogenetica. see gamogenesis.agamospecies n. [Gr. a, without; gamos, marriage; L. spe-

32Maggenti and Gardnercies, kind] A species without sexual reproduction; an asexualspecies.agamous see agamicagar n. [Malay agar-agar, substance from seaweed] A nonnitrogenous,gelatinous hydrophilic substance obtained fromcertain seaweeds used in the preparation of culture mediain microbiology and as a stabilizer of emulsions.agastric a. [Gr. a, without; gaster, stomach] Lacking a digestivetract or cavity.age n. [L. aevum, lifetime] 1. The period of time any living individualhas existed. 2. A particular period of life or development.age and area theory The older a species, the more extensiveits area of distribution.agenesis, agenesia n. [Gr. a, without; genesis, beginning] 1.Lacking development. see aplasia. 2. Inability to produceoffspring. see agennesis.agennesis n. [Gr. a, without; gennesis, an engendering] Impotent;sterile. agennetic a.age polyethism (ARTHRO: Insecta) In social insects, the regularchanging of labor specialization as they grow older. seepolyethism.aggenital a. [L. ad, to; genitalis, genitalia] (ARTHRO: Chelicerata)In Acari, pertaining to that area on both sides of thegenital region.agglomerate n. [L. ad, to; glomerare, to form into a ball] Togroup or gather into a mass or cluster; clustered densely;piled or heaped together.agglutinate v. [L. ad, to; glutinare, to glue] To join by adhesion;to unite as with glue; to collect in masses.agglutinated a. [L. ad, to; glutinare, to glue] 1. Sticking together.2. (ARTHRO: Insecta) Used by entomologists to describea larva with an unusually heavy chitinous covering.see obtect pupa.agglutinin n. [L. ad, to; glutinare, to glue] A substance or specificantibody causing clumping of cells.

Online Dictionary of Invertebrate Zoology 33aggregate a. [L. ad, to; gregare, to collect] Clustering orcrowding together to form a dense mass.aggregation n. [L. ad, to; gregare, to collect] 1. Collection orgrouping into a mass or sum. 2. A group of individualscomprised of more than a mated pair or family, collectingin the same place, that do not construct nests or rear offspringin a cooperative manner. see colony.aggressin n. [L. aggressus, attacked] A substance produced inthe body of a host by a pathogenic organism that paralyzesthe defense mechanisms of the host.aggression n. [L. aggressus, attacked] The behavior of an organisminvolving threats or attack of another organism orobject.aggressive mimicry A method of mimicry of one species byanother that is hostile to it.agigeriate a. [Gr. a, without; gigerium, gizzard] Gizzardless;without a gizzard.Aglossa see Bivalviaaglossate n. [Gr. a, without; glossa, tongue] Lacking atongue.agminate a. [L. agminis, crowd] Grouped together; aggregated.see cluster.agnathous a. [Gr. a, without; gnathos, jaw] Lacking a jaw.agnotobiotic culture Any population with one or more kindsof organisms present. see gnotobiotic culture.agonist n. [Gr. agonistes, contestant] A primary muscle responsiblefor the movement of a part or appendage.agonistic a. [Gr. agonistes, contestant] Behavior signaling aggressiveattitude.agriotype n. [Gr. agrios, wild; typos, type] Ancestral type.agriotypiform a. [Gr. agrios, wild; typos, type; L. forma,shape] (ARTHRO: Insecta) In Hymenoptera, referring to thepeculiar form of larval Agriotypidae, with the first instarhaving a heavily sclerotized, mandibulate head, rows ofspiniform setae on the succeeding segments, and a slender,bifurcate caudal appendage.

34Maggenti and Gardnerahermatype corals (CNID) Non-reef building species of corals.ahermatic a. see hermatype corals.aileron n. [F. dim. aile, wing] (ARTHRO: Insecta) A large scaleor structure in front of the base of the fore wing; sometimesused as synonymous with alula.air chamber (MOLL: Cephalopoda) The gas-filled cavity of anautilus shell that was previously occupied by that organism.air sacs 1. (ARTHRO: Insecta) Pouch-like enlargements of trachealtubes in winged forms, usually lacking taenidia, capableof inflation and thought to function as an aid in flightand to lessen specific gravity. 2. (CNID: Hydrozoa) In Siphonophora,that portion of a pneumatophore that containsgas.air stores (ARTHRO: Insecta) The covering of bubbles of aircarried by hydrofuge structures of certain aquatic forms.air tube A respiratory tube or siphon.aitiogenic a. [Gr. aitios, causing; gennaein, to produce] Referringto the resultant reaction from stimulation.akanth see acanthakaryote, acaryote n. [Gr. a, without; karyon, nut] 1. Lackinga nucleus. 2. A non-nucleated cell.akinesis, akinesia n. [Gr. a, without; kinesis, motion] Loss ordisturbance of motion, as in certain insects, resulting fromloss of antennae.ala n.; pl. alae [L. ala, a wing] Any wing-like process or structure;a thin, cuticular projection or fin, running longitudinally,usually lateral or sublateral, frequently paired.alabastrine a. [Gr. alabastros, alabaster box] Pertaining to, orlike alabaster; smooth and white.alacardo n. [L. ala, a wing; cardo, hinge] (ARTHRO: Insecta)The distal sclerite of the cardo.alacercus n. [L. ala, a wing; Gr. kerkos, tail] (ARTHRO: Insecta)The caudal filament; the middle cercus when threeare present.alacoxasuture n. [L. ala, a wing; coxa, hip; sutura, seam]

Online Dictionary of Invertebrate Zoology 35(ARTHRO) The suture that appears to divide the coxa intoan anterior and posterior part; found on only one side ofthe coxa.alacrious a. [L. alacer, lively] Brisk; active; lively.alacrista n.; pl. -ae [L. ala, a wing; crista, ridge] (ARTHRO: Insecta)In Coleoptera, a ridge on each side of the anteriorscutal area that converges posteromesally.alae pl. of alaalaglossa n. [L. ala, a wing; Gr. glossa, tongue] (ARTHRO: Insecta)Glossae fused into a single plate.alar a. [L. alaris, of the wing] Pertaining to a wing, or wingshaped.alar area (ARTHRO: Insecta) In certain coleopteran scarabaeoidlarvae, an integral area immediately above the epipleuralarea, separated in the thorax by an oblique suture.alar frenum (ARTHRO: Insecta) 1. In Diptera, a ligament dividingthe supra-alar cavity into anterior and posterior areas.2. In Hymenoptera, a ligament crossing the supra-alargroove toward the wing base.alaria n. [L. alaris, of the wing] (ARTHRO: Insecta) The notalwing processes.alarima n. [L. ala, wing; rima, cleft] (ARTHRO: Insecta) Theopening between the two paraglossae.alarm pheromone A chemical released into the environmentinducing a fright response in other members of the samespecies.alar squama (ARTHRO: Insecta) In Diptera, one of three membranouslobes in the region of the wing base that representsthe jugum. see alula, thoracic squama.alary a. [L. alaris, of the wing] Wing-like; aliform.alary muscles see aliform musclesalary polymorphism (ARTHRO: Insecta) Two or more shapesof wings in the same species, not necessarily correlated tosex.alassostasy n. [Gr. allassein, to alter; stasis, standing] (AR-THRO: Chelicerata) An orthostasic stage in the life cycle in-

36Maggenti and Gardnervolving secondary changes in number and/or shape of stasesand number of molts. see orthostasy.alatae n. [L. ala, wing] (ARTHRO: Insecta) Winged forms ofAphidae.alatate a. [L. ala, wing] Possessing lateral wing-like expansions.alate a. [L. ala, wing] 1. Winged, or wing-like expansions, auriclesor alae. 2. (MOLL: Gastropoda) Commonly refers toouter lip.alavertex see occiputalbinism n. [L. albus, white] The congenital deficiency of pigmentation,and particularly of melanin. see melanism.albinistic a. [L. albus, white] Affected with albinism; tendingtoward whiteness of normally dark forms.albumen n. [L. albumen, white of an egg] Egg white, containingseveral proteins, but consisting principally of albumin.albumen gland (MOLL: Gastropoda) A gland that produces theperivitelline fluid that connects to a hermaphroditic gland.albumin n. [L. albumen, white of an egg] One of a group ofproteins present in blood serum, muscle, and other tissue.albuminoid a. [L. albumen, white of an egg; Gr. eidos, form]Like or of the character of albumin, including collagen andkeratin.albuminoid spheres (ARTHRO: Insecta) Eosinophilic bodiesthat are liberated into the blood during molting and metamorphosis,formed by extruded chromatin granules of fatcells.aleatory a. [L. alea, chance] Pertaining to organs that are existingor lacking, depending on chance. see vertition.aletocyte n. [Gr. aletes, wanderer; kytos, container] A wanderingcell; a phagocyte.aleuritic acid (ARTHRO: Insecta) One of the organic acidscontained in lac that is produced by certain scale insects.algicolous a. [L. alga, seaweed; colere, to inhabit] Pertainingto an organism living on or around seaweed.algophagous a. [L. alga, seaweed; Gr. phagein, to eat] Refer-

Online Dictionary of Invertebrate Zoology 37ring to any algae eating organism.alienicola n.; pl. -colae [L. alienus, foreign; colere, to dwell](ARTHRO: Insecta) In aphids, the parthenogenetic, viviparousfemale that mostly develops on the secondary host.see fundatrix, migrante.alifer n. [L. ala, wing; ferre, to bear] (ARTHRO: Insecta) Thepleural fulcrum of the wing.alifera n.; pl. aliferae [L. ala, wing; ferre, to bear] (ARTHRO:Insecta) The projections of the pleuron, against which thepteralia of a wing articulates.aliferous a. [L. ala, wing; ferre, to bear] Bearing or possessingwings.aliform a. [L. ala, wing; forma, shape] Shaped like or resemblinga wing; alary.aliform apophyses (BRACHIO) Incurved anterior and posteriorextremities of the growth line.aliform muscles (ARTHRO: Insecta) Muscles closely associatedwith the heart, usually fan-shaped; sometimes also associatedwith the abdominal as well as the thoracic muscles.alima n. [Gr. halimos, pert. the sea] (ARTHRO: Crustacea) Thelast larval stage of a mantis shrimp of the family Squillidae;a megalopa stage larva.alimentary a. [L. alimentum, food] Pertaining to food or nutrition.alimentary canal (tract) The food tube traversing the bodyfrom mouth to anus; generally divided into three main regions:the ectodermal foregut or stomodeum, the endodermalmidgut or mesenteron and the ectodermal hindgutor proctodeum.alimentary castration Pertaining to an individual deprived ofsufficient nourishment in the larval form leading to suppressionof gonadal development. see nutricial castration.alinotum n. [L. ala, wing; Gr. noton, back] (ARTHRO: Insecta)The notal plate of the mesothorax or metathorax of wingedforms.aliphatic a. [Gr. aleiphos, fat] Refers to compounds having an

38Maggenti and Gardneropen-chain structure, and those cyclic compounds that resemblethe open-chain structure.aliquant a. [L. alius, other; quantus, how great] In mathematics,dividing a smaller number into a larger numberwith a remainder; in biology, taking equal quantities of asolution with unequal numbers of organisms in suspension.see aliquot.aliquot a. [L. alius, other; quantus, how great] In mathematics,dividing a smaller number into a larger number evenly;hence, in biology, dividing a population of organisms evenlyor into equal parts. see aliquant.alitrunk n. [L. ala, wing; truncus, trunk] (ARTHRO: Insecta)Thorax to which the wings are attached, including the firstabdominal segment in certain Hymenoptera; mesosoma.alivincular hinge (MOLL: Bivalvia) A somewhat flattened cordfrom one bivalve umbo to another, having the long axistransverse to the planes of the margins and the axis ofmotion.alizarin, alizarine n. [F. alizari, the juice] A transparent orange-redstain or dye.alkaline gland (ARTHRO: Insecta) In Hymenoptera, the Dufour'sgland; an accessory gland that discharges at thebase of the sting; function unknown, but thought to beconcerned with lubrication of the sting.alkanes n.pl. [OF. al qualiy, ashes of salt wart] A group ofsaturated hydrocarbons found in Pre-Cambrian geologicalstrata presumed to be fossils.allaesthetic, allesthetic a. [Gr. allos, other; aisthetes, perceiver]Recognition of characteristics of an organism, asperceived by another.allantoin n. [Gr. allas, sausage] The resultant of purine andpyrimidine metabolism occurring in allantoic fluid and urineof various invertebrates.allatectomy n. [L. allatum, brought; Gr. ektemnein, to cutout] (ARTHRO: Insecta) Total excision of the endocrineglands, corpora allata.allatum hormone see juvenile hormone

Online Dictionary of Invertebrate Zoology 39Allee's principle The concept of an optimal population levelwhere organisms flourish.allele n. [Gr. allelon, one another] Genes occupying the samelocus in homologous chromosomes, that segregate fromeach other at the reduction division. see dominant allele,pseudoallele, isoallele, recessive allele, multiple allele.allelism n. [Gr. allelon, one another] The relationship betweentwo characters that are alleles; alleomorphism; alternativeinheritance.allelochemic, allelochemical n. [Gr. allelon, one another;chemeia, pert. chemistry and chemical terms] 1. A chemicalagent of natural origin involved in interaction betweenspecies or individuals; sometimes divided into four subgroupsbased on whether the emitter, the receiver, or bothbenefit in the interaction: allomones, kairomones, synomonesand apneumones. 2. Xenomone.allelomimetic a. [Gr. allelon, one another; mimikos, imitative]Referring to imitation of behavioral habits of another animal,usually of the same species.allelomorph n. [Gr. allelon, one another; morphe, form] 1.Two contrasting, although closely parallel genetic characters.2. A member of a Mendelian pair.allelopathy n. [Gr. allelon, one another; pathos, suffer] Thechemical effect of plants on other organisms in the environment.allelotropism n. [Gr. allelon, one another; tropein, to turn]The mutual attraction between two cells or organisms.allelotype n. [Gr. allelon, one another; typos, type] The repeatedoccurrence of alleles in a given population.allesthetic see allaestheticalligate v.t. [L. alligare, to tie] To unite, fasten or suspend.alliogenesis see alloiogenesisallobiosis n. [Gr. allos, other; biosis, manner of life] Differentiationfrom the normal; a changed environment.allochore n. [Gr. allos, other; chorein, to spread] Any organismoccurring in two different habitats in the same geo-

40Maggenti and Gardnergraphic region.allochroic a. [Gr. allos, other; chroia, color of the skin]Changeable in color, or variation of color.allochronic a. [Gr. allos, other; chronos, time] Not occurringat the same period of time; not contemporary.allochronic speciation Speciation that does not occur at thesame period of time, thus causing morphological discontinuity.see synchronic speciation.allochthonous a. [Gr. allos, other; chthon, earth] Exotic; importedor migrated from another area; peregrine. seeautochthonous.allocryptic a. [Gr. allos, other; kryptos, conceal] Concealing;said of organisms that conceal themselves with coveringsof other organisms or with inanimate materials.allogamy n. [Gr. allos, other; gamos, marriage] Cross-fertilization.see autogamy.allograft n. [Gr. allos, other; OF. greffe, graft] A piece of tissueor organ from one individual grafted to another of thesame species.alloheteroploid n. [Gr. allos, other; heteros, different; aploos,onefold; eidos, form] Heteroploid individuals whose chromosomesderive from various chromosome sets. see autoheteroploid.alloiogenesis n. [Gr. alloios, of another kind; genesis, beginning]Alternation of sexual and parthenogenetic generations:alternation of generations.alloiometron n. [Gr. alloios, of another kind; metron, measure]Measurable variability in the physical developmentwithin a species or race.allokinesis n. [Gr. allos, other; kinesis, movement] Passive orreflex movement. allokinetic a. see autokinesis.allomeristic a. [Gr. allos, other; meros, part] Refers to anyorganism differing in the number of parts of any organfrom that which is customary in the group.allometric coefficient The slope of the logarithmic growthcurve of the measurement of an organ or part against thatof the whole remainder or another part; sometimes re-

Online Dictionary of Invertebrate Zoology 41ferred to as the heterogonic or heteroausecic coefficient.allometric growth The growth rate of one part of an organismdiffering from that of another part or of the body as awhole. see heterauxesis.allometrosis n. [Gr. allos, other; metros, mother] Having differentspecies or races living in an organized group.allometry n. [Gr. allos, other; metron, measure] The study ofrelationship of growth. allometric a.allomixis see cross-fertilizationallomone n. [Gr. allos, other; hormaein, to instigate] Anychemical secreted by an organism that causes another organismof different species to react favorably to the emitter.allomonal a.allomorphic evolution A rapid increase in specialization.allomorphosis n. [Gr. allos, other; morphe, form] Rapid developmentof specialized organs or increase of specializationin an organism. see aromorphosis.alloparalectotype n. [Gr. allos, other; para, beside; lektos,chosen; typos, type] A specimen from the original collection,a sex other than that of the holotype, and describedlater than the original publication.allopatry n. [Gr. allos, other; patrios, father land] Populationsseparated by spatial barriers preventing gene flow. allopatrica. see sympatry.allopelagic a. [Gr. allos, other; pelagos, sea] Referring toopen water; marine or freshwater organisms found at variousdepths.alloplasm n. [Gr. allos, other; plassein, to mold] Cell organellesthat serve a special purpose and are not of regular occurrence,such as the neuro- and myofibrils, cilia and flagella.alloplast n. [Gr. allos, other; plassein, to mold] A cell organellecomposed of more than one kind of tissue. see homoplast.allopolyploid n. [Gr. allos, other; polyploos, many fold; eidos,form] A polyploid produced by the chromosome doubling ofa species or genus hybrid, that is, of an individual with two

42Maggenti and Gardnerunlike chromosome sets.alloscutum n. [Gr. allos, other; L. scutum, shield] (ARTHRO:Chelicerata) In Acari, the dorsal part of the exoskeletonposterior to the scutum of larval ticks.allosematic color Having protective coloration resembling thatof dangerous or inedible species; aposematic color; Batesianmimicry. see sematic.allosomal inheritance The inheritance of characters producedby genes in an allosome.allosome n. [Gr. allos, other; soma, body] A chromosome deviatingin size, form or behavior from other chromosomes,usually a sex-chromosome; heterochromosome. see autosome.allosynapsis see allosyndesisallosyndesis n. [Gr. allos, other; syndesis, a binding together]In polyploids, pairing of completely or partially homologouschromosomes that were introduced into the zygote by thesame gamete at fertilization. see autosyndesis.allotetraploid n. [Gr. allos, other; tetraploos, fourfold; eidos,form] A tetraploid produced when a hybrid derived from agenetically different parent doubles its chromosome number;amphidiploid.allotherm n. [Gr. allos, other; therme, heat] Any organismdependent on environmental temperature for its own bodytemperature. see poikilothermal, ectotherm.allotopotype n. [Gr. allos, other; topos, place; typos, type] Anallotype obtained from the original locality.allotriomorphic a. [Gr. allotrios, abnormal; morphe, shape]Displaying an abnormal or unexpected shape.allotriploid n. [Gr. allos, other; triploos, threefold; eidos,form] A triploid with two similar and one dissimilar chromosomesets. see autotriploid.allotrophic a. [Gr. allos, other; trophe, nourishment] Referringto organisms dependent upon other organisms for nutrition;heterotrophic.allotropism n. [Gr. allos, other; tropos, turn] The propensityof attraction of certain cells or structures; allotropy.

Online Dictionary of Invertebrate Zoology 43allotropous a. [Gr. allos, other; tropos, turn] (ARTHRO: Insecta)Refers to insects that are not limited to or adaptedto visiting certain kinds of flowers.allotropy see allotropismallotype n. [Gr. allos, other; typos, type] A paratype of theopposite sex to the holotype.allozygote n. [Gr. allos, other; zygotos, yoked] A homozygotewith only recessive characters.alluring coloration (ARTHRO: Insecta) Patterns or coloringsadapted by predators that attract other species; aggressivemimicry.alluring glands Glandular structures that disperse an odor attractiveto the opposite sex; sex pheromones.allux n. [L. ad, to; luxus, dislocated] (ARTHRO: Insecta) In Curculionidae,the next to the last joint of the tarsus.alpha-chlorophyll n. [Gr. alpha, a; chloros, green; phyllon,leaf] (ARTHRO: Insecta) Chlorophylic properties producingcoloration. see beta-chlorophyll.alpha-female n. [Gr. alpha, α Α; L. femina, female] (ARTHRO:Insecta) In Formicidae, the intermediate form between theteratogyne and normal female.alpha taxonomy That level of taxonomy involved with thecharacterization and naming of species. see beta taxonomy.alpine a. [L. alpinus, of or like high mountains] Applied to organismsoccurring in high mountain meadows; also referredto as alpestrine.altaceratubae n. [L. alter, the other; Gr. keras, horn; tuba,trumpet] (ARTHRO: Insecta) In certain scale insects,ceratubae shaped like large broad cylinders with obliqueopenings, located at or near the margin of the pygidium.alteration theory Explanation of the phenomenon of electromotiveforces of nerve and muscle by changes in chemicalcomposition of tissue in cross-section.alternate host One that alternates with another in the life cycleof a parasite. see intermediate host.

44Maggenti and Gardneralternating cleavage see spiral cleavagealternation of generations The alternation of two or moregenerations reproducing in different ways; an alternation ofsexual and asexual, or parasitic with a free-living cycle. seealloiogenesis, digenesis, heterogamy, heterogenesis,heterogony, metagenesis.alternative inheritance see allelismaltitude see heightaltricial a. [L. altrix, nourisher] Having young at hatching orbirth that require care for sometime.altruism n. [L. alter, the other] Behavior disadvantageous tothe individual, but benefits other individuals of the species.alula n.; pl. -lae [L. dim. ala, wing] (ARTHRO: Insecta) 1. Insome Diptera, one of the membranous lobes in the regionof the wing base, thought to be part of the vannal region.see thoracic squama, alar squama. 2. In some Coleoptera,the alula is folded beneath the elytron/jugum.alulet n. [L. dim. ala, wing] (ARTHRO: Insecta) In Diptera, alobe at the basal posterior part of the wing; wing appendage;posterior lobe. see alula.alutaceous a. [L. alutaceus, soft leather] Pertaining to brownor brownish-yellow; leathery; covered with, or appearinglike, minute cracks.alveator n. [L. alveatus, hollowed out] (ECHINOD) A form ofpedicellaria; usually two valved and recessed into an alveolusor depression in the endoskeleton.alveola n.; pl. -lae [L. alveolus, small cavity] A small pit ordepression on the surface of an organ; faveolus; alveolus.alveolar a.alveolar hydatid cyst (PLATY: Cestoda) A larval form of Echinococcusmultilocularis comprised of many compartmentscontaining many protoscolices that infiltrate body tissues.alveolate a. [L. alveolus, small cavity] Deeply pitted or havingthe appearance of a honeycomb.alveolus n.; pl. -eoli [L. alveolus, small cavity] Any small cavity,pit or depression; alveola.

Online Dictionary of Invertebrate Zoology 45amacrine a. [Gr. a, without; makros, long; inos, fiber] (AR-THRO: Insecta) Pertaining to a unipolar nerve cell within asynaptic region of the brain, i.e., the antennal lobes or themedulla. amacrinal a.amalgamated lips (NEMATA) Lips combined together giving asmooth contour, not discernibly separated from each other.amastigophore n. [Gr. a, without; mastix, whip; pherein, tobear] (CNID) A nematocyst with no tube beyond thehempe; in microbasic types , the hempe is not more thanthree times the capsule length; in macrobasic types , thehempe is more than four times the capsule length. seemastigophore.amber n. [Ar. anbar ambergris, a fossilized resin] A transparent,clear, pale yellow-brown gummy resin of coniferoustrees in which insects and spiders were trapped and fossilizedin the hard transparent state as much as 30 millionyears ago.ambient a. [L. ambire, to go around] Moving around; surrounding.ambient vein (ARTHRO: Insecta) 1. The vein that partially encirclesthe wing close to the margin. 2. The vein-likestructure that serves to stiffen the margin of a wing.ambifenestrate a. [L. ambo, both; fenestra, window](NEMATA) A term used to describe two semifenestrae in thevulval cone formed by a narrow vulval bridge, but not surroundingthe vulva. see bifenestrate.ambiguous a. [L. ambigere, to wander about] Vague ordoubtful in meaning; having more than a single meaning.ambilateral a. [L. ambo, both; latus, side] Pertaining to or affectingboth sides; bilateral.ambisexual see monoecious, hermaphroditeambital see ambitusambitus n. [L. ambitus, going around] The periphery or outeredge of an organism. ambital a.amblychromatic a. [Gr. amblys, dull; chroma, color] Stainingonly slightly, as opposed to trachychromatic.ambosexous see hermaphrodite

46Maggenti and Gardnerambrosia n. [Gr. ambrotos, immortal] (ARTHRO: Insecta) Fungicultures cultivated by scolytid beetles to feed their larvae;sometimes used to designate that part of the fungus thatgrows out into the burrows and is eaten by the beetles. seebee-bread, fungus garden.ambulacral areas (ECHINOD: Asteroidea) The radially arrangedarms (typically 5) bearing the tube feet or podia.see interambulacral areas.ambulacral groove (ECHINOD: Asteroidea) A groove or furrowbordered by large spines extending along the oral surfaceof each arm of sea stars, that contain two to four rows ofsmall tubular projections called feet or podia.ambulacral ridge (ECHINOD: Asteroidea) The internal ridge ofthe external ambulacral groove.ambulacriform a. [L. ambulare, to walk; forma, shape] Resemblingor having the form of an ambulacrum.ambulacrum n.; pl. -lacra [L. ambulare, to walk] 1. (ARTHRO:Chelicerata) The adhesive disc of hooks that terminate thetarsus of ticks. 2. (ARTHRO: Insecta) The walking leg. 3.(ECHINOD) Plates with pores forming the test, arranged in 5or more rows, where the podia of the water-vascular systemproject to the exterior.ambulate v.i. [L. ambulare, to walk] To walk or move about.ambulatory a. [L. ambulare, to walk] Having the power ofwalking or moving from place to place.ambulatory leg see pereopodambulatory rosette (ARTHRO: Insecta) In Neuroptera, a prehensile"holdfast" organ located at the tip of the abdomenthat aids in locomotion of larval snakeflies.ambulatory setae 1. (ARTHRO: Insecta) Hairs or bristles onthe ventral segments of the abdomen. 2. (NEMATA: Adenophorea)Hollow tubelike projections used for locomotion.see adhesion tubes.ambulatory wart see ampullaame- see amoe- for words not found hereameiosis n. [Gr. a, without; meiosis, to make smaller] Failureof meiosis that is replaced by a form of nuclear division not

Online Dictionary of Invertebrate Zoology 47involving the reduction of the chromosome number.ameiotic a. [Gr. a, without; meiosis, to make smaller] Pertainingto maturation division of a gamete without the diploidnumber of chromosomes being reduced to the haploid.ameiotic parthenogenesis Parthenogenesis without meiosis.amensalism n. [Gr. a, without; L. mensa, table] A form ofsymbiotic relationship in which one of the organisms is inhibitedand the other is not.ametabolic a. [Gr. a, without; metabole, change] Withoutmetamorphosis; ametamorphic.ametabolous metamorphosis (ARTHRO: Insecta) Insectswhose eggs hatch into nymphs closely resembling the adultform, differing only in size and life stages; without metamorphosis.ametamorphic a. [Gr. a, without; meta, after; morphe, form]Having no metamorphosis.amethystine a. [Gr. amethystos, not drunk] Pertaining to, orresembling amethyst, a bluish-violet color.amicron n. [Gr. a, without; mikros, small] One of the smallestparticles detectable with the electron microscope; smallerthan one (1) nm and can only be seen as a diffuse illuminationin the track of the beam.amicroscopic a. [Gr. a, without; mikros, small; skopein, toview] Too small to be seen with either the light microscopeor the electronmicroscope; less than about one (1) nanometerin diameter.amictic egg Eggs that do not undergo a meiotic division andare therefore diploid producing females parthenogenetically.see mictic egg.aminosugar n. [prefix names of chemical compounds containingone of the amino groups; Gr. sakcharon, sugar] Amonosaccharide with an amino or substituted amino groupin place of a nonglycosidic hydroxyl group.amitosis n. [Gr. a, without; mitos, thread] Cellular divisionwithout the appearance of chromosomes or any mitotic figure.amitotic a. see mitosis.amixia, amixis n. [Gr. a, without; mixis, a mixing] Absence of

48Maggenti and Gardnerinterbreeding between members of the same species orraces due to morphological, geographical or physiologicalisolation.ammochaeta n.; pl. -tae [Gr. ammos, sand; chaite, long hair](ARTHRO: Insecta) In Hymenoptera, specialized hairs orbristles on the head or lower lip of desert ants, used forremoving sand from the strigils on the forelegs.ammonite n. [Gr. Ammon, Jupiter] (MOLL: Cephalopoda) Anyfossil ammonean shell curved into a spiral like a ram'shorn, common in Paleozoic and Mesozoic rocks of all partsof the world.ammonitiferous a. [Gr. Ammon, Jupiter; ferre, to carry] Saidof rocks containing ammonites.ammonoid a. [Gr. Ammon, Jupiter] (MOLL: Cephalopoda) Pertainingto a shell covered cephalopod.ammonotelic a. [Gr. ammoniakon, temple of Jupiter Ammon;telos, end] The excretion of nitrogen principally as ammonia.see uricotelic.ammophilous a. [Gr. ammos, sand; philos, loving] Sand-loving;living in or frequenting sand.amnion n.; pl. -nions, -nia [Gr. amnion, membrane aroundthe fetus] (ARTHRO) The inner cellular, membranous embryoniccovering of various insects and other arthropods.amniotic a.amnios n. [Gr. amnion, membrane around the fetus] (ARTHRO:Insecta) Cuticular covering of an embryo that is shed beforeor very shortly after hatching.amniotic cavity The cavity between the amnion and the embryoin the developing egg of various invertebrates.amniotic fluid Liquid surrounding the embryo while in the egg.amniotic folds Lateral folds of the amnion that meet to enclosethe germ band in the ovum.amniotic pore (ARTHRO: Insecta) An opening to the amnioticcavity during embryonic development.amoeba, ameba n. [Gr. amoibe, change] Any amoeba-like cellor corpuscle of the blood or other parts of an organism.

Online Dictionary of Invertebrate Zoology 49amoebocyte n. [Gr. amoibe, change; kytos, container] 1.Certain body cells or tissues capable of independentamoeba-like movement. 2. (PORIF) Any mesohyl cell whereno special activity is evident. see plasmatocyte.amorph n. [Gr. a, without; morphe, form] An inactive allelethat acts as a genetic block to biosynthesis.amorpha n. [Gr. a, without; morphe, form] (ARTHRO: Insecta)Those pupa that share no resemblance with the imago.amorphous a. [Gr. a, without; morphe, form] Lacking distinctiveform or structure; shapeless.AMP Adenosine monophosphateampherotoky see amphitokyamphiapomict n. [Gr. amphi, on both sides; apo, away;miktos, mixed] Biotypes that propagate facultatively, i.e.amphimictally and parthenogenetically.amphiasters n.pl. [Gr. amphi, on both sides; aster, star] 1.The two asters in cell division, one at each end of the cell,from which the spindle fibers diverge. 2. (PORIF) Streptastersstellate at each end.amphibiotic a. [Gr. amphi, on both sides; biotikos, pert. tolife] Being aquatic during one period of the life history andterrestrial during the rest.amphibious a. [Gr. amphi, on both sides; bios, life] Capable ofliving both on land and in the water.amphiblastula n. [Gr. amphi, on both sides; dim. blastos,bud] A blastula in which the cells of one pole are markedlydifferent in size or shape from the other pole.amphiblastula larva (PORIF: Calcarea) A type of free-swimminglarva possessing a central cavity, and two morphologicallydistinct types of cells, one anterior and the otherposterior.amphicoelous a. [Gr. amphi, on both sides; koilos, hollow]Being biconcave.amphicyrtic a. [Gr. amphi, on both sides; kyrtos, curved]Having both sides curved, said of angles between curves;biconvex.

50Maggenti and Gardneramphid n. [Gr. amphi, on both sides] (NEMATA) One of a pairof lateral chemosensory organs opening on or near the lipregion; variable in size and shape according to taxa.amphid aperture see amphidial apertureamphidelphic a. [Gr. amphi, on both sides; delphys, womb](NEMATA) Pertaining to uteri opposed; position and directionof the uteri, not the ovary. see didelphic.amphidetic a. [Gr. amphi, on both sides; detos, bound] (MOLL:Bivalvia) Refers to the ligament extending both before andbehind the umbo or beak. see opisthodetic, parivincular.amphidial aperture (NEMATA) The amphid opening pore ororifice through which stimuli are received.amphidial duct (NEMATA) The passage connecting the amphidialaperture and the amphidial pouch.amphidial gland (NEMATA) A gland originating posterior to thenerve ring that connects with the anterior lateral amphids.amphidial nerve (NEMATA) The nerve originating posterior tothe nerve ring that extends anteriorly, connecting to theamphid.amphidial pouch or pocket (NEMATA) The anterior cavity orchamber of the amphid; a fovea.amphidial tubes (NEMATA) Passages containing the amphidialnerves connecting the fibrillar terminals and the sensilla.amphidiploid see allopolyploid, allotetraploidamphidiscs, amphidisks n.pl. [Gr. amphi, on both sides;diskos, round plate] (PORIF: Hexactinellida) Small spiculeswith hooks at both ends, grapnel shape; no six rayed spicules.amphigean, amphigaean a. [Gr. amphi, on both sides; gaia,the earth] Pertaining to both the Old and New Worlds.amphigenesis n. [Gr. amphi, on both sides; genesis, beginning]Development induced by the fusion of two unlikegametes; amphigony.amphigonic a. [Gr. amphi, on both sides; gonos, seed] Referringto sperm and ova being produced in separate gonadsin different individuals; biparental reproduction. see di-

Online Dictionary of Invertebrate Zoology 51gonic; syngonic.amphigony n. [Gr. amphi, on both sides; gonos, seed] biparentalor bisexual reproduction. amphigonus a.amphihaploid n. [Gr. amphi, on both sides; haploos, simple;eidos, form] Said of haploid types produced from amphidiploids.amphikaryon n. [Gr. amphi, on both sides; karyon, nut] Thenucleus of the zygote produced in the course of fertilizationcontaining two haploid genomes. see diplokaryon.amphimict n. [Gr. amphi, on both sides; miktos, mixed] Reproductionby amphimixis.amphimixis n. [Gr. amphi, on both sides; mixis, mingling] Theunion of two gametes in sexual reproduction, as opposed toautomixis.amphimorula n. [Gr. amphi, on both sides; L. morum, mulberry]A morula derived from an amphiblastula.Amphineura, amphineuran see Polyplacophoraamphiodont a. [Gr. amphi, on both sides; odous, tooth] (AR-THRO: Insecta) In Coleoptera, male stag beetles bearingmandibles only intermediate in size; mesodont. see telodont,priodont.amphion larva (ARTHRO: Crustacea) In Malacostraca, larva ofAmphionidacea, zoea and megalopa types; telson is narrowwith spines in first stage and pointed with no spines in laststage.amphiploid see allopolyploidamphipneustic a. [Gr. amphi, on both sides; pneustikos,breathe] (ARTHRO: Insecta) Refers to aquatic larva havingthe first and last pairs of spiracles open and functioning.see metapneustic; peripneustic.amphipyrenin n. [Gr. amphi, on both sides; pyren, fruitstone] The substance of the nuclear membrane of cell nuclei.amphisternous a. [Gr. amphi, on both sides; sternon, breastbone](ECHINOD: Echinoidea) Used to describe the sternumstructure in certain sea urchins; two equal plates that meetthe labrum.

52Maggenti and Gardneramphistome a. [Gr. amphi, on both sides; stoma, mouth](PLATY: Trematoda) Having a ventral acetabulum located atthe posterior end.amphistomous a. [Gr. amphi, on both sides; stoma, mouth](PLATY: Trematoda) Bearing a sucker at each extremity.amphitelic a. [Gr. amphi, on both sides; telos, end] In mitosis,pertaining to orientation of the two chromatids of eachchromosome to different spindle poles at the first meioticdivision as opposed to syntelic.amphitoky, ampherotoky n. [Gr. amphi, on both sides; tokos,birth] Parthenogenesis in which unfertilized eggs developinto either sex; deuterotoky; gametotoky.amphitriaene n. [Gr. amphi, on both sides; triaina, trident](PORIF) A spicule with three divergent rays at each extremity.amphitrocha n. [Gr. amphi, on both sides; trochos, wheel](ANN) Larva bearing two rings of cilia that function in locomotion.amphocyte see amphophilamphodynamous a. [Gr. ampho, both; dynamis, power] Pertainingto an organism that may or may not enter a diapausephase, according to circumstances.amphogenous a. [Gr. ampho, both; gennaein, to produce]Refers to females producing male and female offspring at aratio of 1:1.amphophil, amphophile, amphophilic a. [Gr. ampho, both;philos, love] Certain cells and tissues that have an affinityequally for acid and for basic dyes.amphoteric a. [Gr. amphoteros, in both ways] 1. Possessingopposite characters. 2. Capable of acting either as a baseor an acid.amphoterotoky see amphitokyample a. [L. amplus, large] Large in size, capacity, volume orscope.amplected a. [L. amplexus, embracing] (ARTHRO: Insecta)Having the head set into a hollow or recess of the prothorax.

Online Dictionary of Invertebrate Zoology 53amplexiform wing coupling (ARTHRO: Insecta) Lepidopterouswing coupling by virtue of an extensive area of overlapbetween the fore and hind wing.ampliate a. [L. ampliatus, made wider] To enlarge; to makegreater.amplification n. [L. amplificare, to enlarge] An enlargement orextension; expanding a statement or description.anamorphosis n.; pl. -ses [Gr. ana, backwards; morphosis,forming] 1. A process of slow, steady evolution without apparentgross mutant variation. 2. (ARTHRO: Insecta) a. Theincrease of number of segments after hatching. b. Developmentin which the young gradually become more like theadult in body form after each ecdysis, as opposed tometamorphosis. anamorphic a. see ametabolous, metamorphosis,epimorphosis.anandric a. [Gr. an, without; aner, man] (ANN: Oligochaeta)Designating earthworms without testes.anaphase n. [Gr. ana, up; phasis, appearance] The period ofmitotic division in which the daughter chromosomes movetoward opposite poles.anaphylaxis n. [Gr. ana, again; phylax, guard] A state of excessivesensitivity to a serum or foreign protein that canresult in a state of shock, that may develop with markedcirculatory disturbances and possible death. anaphylactica.anaplasis n. [Gr. ana, up; plassein, to form] Progressive ontogeneticdevelopment.anapleurite n. [Gr. ana, up; pleuron, side] (ARTHRO: Insecta)A dorsal sclerite of the thoracic pleural region.anapolysis n. [Gr. an, without; apo-, separate; lysis, loosen](PLATY: Cestoda) The detachment of a spent proglottid afterit has shed its eggs. anapolytic a. see apolysis.anapterygote a. [Gr. an, not; a, without; pterygotos, winged](ARTHRO: Insecta) Designates apterous insects that are derivedfrom winged ancestors.anaptychus n. [Gr. an, without; apo-, away from; ptychos,fold] (MOLL: Cephalopoda) A shelly plate found in some fos-

54Maggenti and Gardnersil cephalopods, thought to function as an operculum. seesynaptychus.anarsenosomphic a. [Gr. an, without; arsen, male; somphos,porous] (ANN: Oligochaeta) Designates earthworms withoutmale terminalia, such as parthenogenetic morphs, cephalicregenerates, or abnormal individuals.anarthrous a. [Gr. an, without; arthron, joint] Lacking a distinctjoint or joints.anascan n. [Gr. an, without; askos, sac] (BRYO: Gymnolaemata)Cheilostomata in which the autozooids have a hydrostaticsystem including the flexible part of the frontal wall,thus lacking an ascus.anastomosing colony (BRYO) A branching erect colony wherebranches join and rebranch to form an open network.anastomosis n.; pl. -ses [Gr. anastomosis, formation of anetwork] A union or joining between two or more structuresforming a network.anastral a. [Gr. an, without; aster, star] Lacking an aster, withreference to mitosis.anastrophic a. [Gr. ana, backwards; strephein, to turn] (MOLL:Gastropoda) In Prosobranchia, as in Architectonica , pertainingto a heterostrophic shell with the protoconch coiledabout the same axis as the teloconch and the nucleus directedtoward the base of the shell.anatomy n. [Gr. ana, again; temnein, to cut] The science ofinternal morphology, as revealed by dissection. see zootomy.anatoxin n. [Gr. ana, backwards; toxikon, poison] A toxinmodified by heat or chemical treatment eliminating its toxicproperties, but retaining its antigenic properties; toxoid.anatrepsis n. [Gr. anatrepein, to turn over] 1. Increase ofmovement during blastokinesis. 2. (ARTHRO: Insecta) Inblastokinesis, a term used to describe the movement of theembryo inside the egg from one pole to another; refers todifferent activities in different groups of insects, i.e., ventralto dorsal, dorsal to ventral. see katatrepsis.anatriaene n. [Gr. ana, up; triaina, trident] (PORIF) A tetracti-

Online Dictionary of Invertebrate Zoology 55nal megasclere with three short recurved rays and a singlelong shaft.anautogeny a. [Gr. an, without; autos, self; genes, producing](ARTHRO: Insecta) Refers to the necessity of a blood mealof certain Diptera before eggs can develop within the female.see autogeny.anaxial a. [Gr. an, without; L. axis, axle] Lacking a distinctaxis; asymmetrical.anaxon, anaxone n. [Gr. an, without; axon, axis] A nerve cellhaving no apparent axon.ancestral a. [L. antecedere, to go before] Referring to derivationfrom an earlier form or ancestor; primitive.ancestrula n. [L. antecedere, to go before] (BRYO) The firstformed colony founding zooid. a. In Stenolaemata andmost Gymnolaemata, the zooid formed by metamorphosisof a sexually produced larva. b. In Phylactolaemata, thezooid formed from a statoblast.anchialine a. [Gr. anchi, near; hals, salt] Pertaining to landlockedpools or cave lakes that have subterranean connectionsto the ocean.anchor n. [L. ancora, anchor] 1. (ARTHRO: Crustacea) In Copepoda,enlarged first thoracic segment of an anchor worm.2. (ARTHRO: Insecta) In Ephemeroptera, a distal fibrousknob of the egg, terminating an elongate adhesive threadcoiled around the base. 3. (ECHINOD: Holothuroidea) Ananchor-shaped ossicle or spicule of sea cucumbers. 4.(PLATY: Cestoda) In Monogenea, large curved hooks on theopisthaptor; hamuli.anchorate a. [L. anchora, anchor] (PORIF) Pertaining to a chelawith four clads at each end.anchor process (ARTHRO: Insecta) An anterior process ofsome dipterous larvae; sternal spatula. see breastbone.anchylosis see ankylosisanci see ankoancipital a. [L. anceps, double-headed] 1. Having two oppositeedges or angles. 2. (MOLL) A two-edged, double-faced,double-formed shell having two varices that are continu-

56Maggenti and Gardnerous.ancistroid a. [Gr. ankistron, a hook; eidos, shape] Hookshaped;barbed.ancyloid a. [Gr. ankylos, hooked; eidos, shape] (MOLL) Shapedlike the patelliform shell of the fresh-water limpet-likeAncylus , with the apex strongly directed anteriorly.andric a. [Gr. aner, male] Male. see gynic.andrium n. [Gr. aner, male] (ARTHRO: Insecta) In male Diptera,the posterior part of the postabdomen comprising abdominalsomites 9 and 10, and including the copulatoryapparatus.androconia n.pl. [Gr. aner, male; konia, dust] (ARTHRO: Insecta)Specialized scales associated with aphrodisiacpheromone glands, on the wings of male butterflies; comparablescales may occur on legs or abdomen; scentscales.androecium n. [Gr. aner, male; oikos, house] (ECHI) In somefemale bonellids, a specialized part, usually basal, of thenephridium where the male may be found.androgamete n. [Gr. aner, male; gametes, husband] A spermatozoan;a male germ cell or gamete.androgenesis n. [Gr. aner, male; genesis, beginning] Maleparthenogenesis; the development of a haploid embryofrom a male nucleus.androgenic gland (ARTHRO: Crustacea) A gland located nearthe vas deferens responsible for development of male secondarysexual characteristics.androgenous a. [Gr. aner, male; genes, producing] Pertainingto the production of males or male gametes.androgynous see hermaphroditeandrogyny n. [Gr. aner, male; gyne, woman] Having male organsdevelop before female during maturation; protandroushermaphrodite.android n. [Gr. aner, male] Resembling a male.androsperm n. [Gr. aner, male; sperma, seed] A male-producingspermatozoan; containing a Y-chromosome, limited

Online Dictionary of Invertebrate Zoology 57to one sex.androsynhesmia n. [Gr. aner, male; syn, with; hesmos,swarm] A group of males gathered together during matingseason. see synhesmia, gynosynhesmia.androtype n. [Gr. aner, male; typos, type] The male typespecimen of a species.andry n. [Gr. andros, a man] (ANN: Oligochaeta) Pertaining toa testis containing segments.anecdysis n. [Gr. an, without; ekdysis, molt] 1. Ecdysis inwhich successive molts are separated by long intermoltphases. 2. Terminal anecdysis when maximum size isreached and no further ecdyses occur.anecic n. [Gr. anekas; upward] (ANN: Oligochaeta) Deepdwelling worms that come to the surface to feed or breed.see endogean; epigean.anellifer n. [L. anellus, little ring; ferre, to bear] (ARTHRO: Insecta)In male Lepidoptera, the lateral parts of the anelluswhen joined to the inner surface of the valvae; sometimesa distinct structure.anellus n. [L. anellus, little ring] (ARTHRO: Insecta) In maleLepidoptera, a sclerotization of the inner wall of the phallocrypt,forming a funnel-like cone around the aedeagus;penis funnel; ring wall.anelytrous a. [Gr. an, without; elytron, sheath] Lacking elytra.anemochorous a. [Gr. anemos, wind; chorein, to spread] Dispersedby the wind.anemoreceptor n. [Gr. anemos, wind; L. recipere, to receive]A sensory receptor of air currents; trichobothrium.anemotaxis n. [Gr. anemos, wind; taxis, arrangement] Orientationof an animal in response to air currents.anenteric a. [Gr. an, without; enteron, gut] Lacking an alimentarytract.anepimeron n. [Gr. ana, up; epi, upon; meros, part] (ARTHRO:Insecta) The upper portion of an epimeron above a distinctsuture.anepisternite see mesopleuron

58Maggenti and Gardneranepisternum n. [Gr. ana, up; epi, upon; sternon, breastbone](ARTHRO: Insecta) The upper division of the episternum.see infraepisternum.aner n. [Gr. aner, male] (ARTHRO: Insecta) Male, especially inFormicidae.anestrus, anoestrus n. [Gr. an, without; oistros, desire] Aperiod of sexual inactivity; a non-breeding period.aneucentric translocation One that involves the centromereof a chromosome; one daughter chromosome is acentricand the other dicentric.aneuploid a. [Gr. an, without; eu, well; aploos, onefold] Refersto cells or individuals having one, two or a few wholechromosomes, more or less than the basic number of thespecies in question. see heteroploid, euploid.aneuronic a. [Gr. an, without; neuron, nerve] Absence of innervation.aneurose a. [Gr. an, without; neuron, nerve] 1. Withoutnerves. 2. (ARTHRO: Insecta) Term used for a wing withveins near the costa only.anfractuose a. [L. anfractus, circuitous] Wavy, winding, turnings,sinuous.angiogenesis n. [Gr. angeion, vessel; genesis, beginning] Thedevelopment of blood vessels.angiostomatous a. [Gr. angeion, vessel; stoma, mouth] Havinga non-distensible mouth.angstrom n. [after A. J. Angstrom] One hundred-millionth of acentimeter, or one-tenth of a nanometer (nm); a unit usedin measuring the length of light waves.angulate a. [L. angulare, to make angular] Having angles orsharp corners.angulation n. [L. angulus, angular] An angular formation oredge where two surfaces meet at an angle.anguli frontales (ARTHRO: Insecta) In immatures, the anteriorprojections from the frons situated laterad to a medianprojection, the nasale; may or may not be symmetrical.angustate antenna (ARTHRO: Insecta) An antenna in which

Online Dictionary of Invertebrate Zoology 59the intermediate and terminal joints are thinner.angusticorn trumpet (ARTHRO: Insecta) In Diptera, a respiratorystructure of Culicidae pupae bearing the longest axisvertically and approximately in line with the stem, funnelshapedwhen closed, with a split (meatal cleft) down oneside allowing it to open widely at the water surface.angustirostrate a. [L. angustus, narrow; rostrum, beak]Having a narrow rostrum or snout. see latirostrate.anholocyclic a. [Gr. an, without; holos, whole; kyklos, circle]Having only parthenogenetic reproduction. see holocyclic.anhydrobiosis n. [Gr. an, without; hydor, water; biosis, mannerof life] A state of dormancy in various invertebratesdue to low humidity or desiccation.anhydrous a. [Gr. an, without; hydor, water] Being withoutwater; completely lacking in water.animal n. [L. animalis, a living being] Any member of a groupof living organisms distinguished from plants by a definitebody form, absence of rigid cell walls of cellulose, locomotionresponses to external stimuli, and inability to manufacturefoods from inorganic substances.Animalia n. [L. animalis, a living being] A kingdom of organismsthat contains the animals.animal starch see glycogenanion n. [Gr. ana, up; ienai, to go] Any ion bearing a negativecharge. see cation.anisochela n. [Gr. anisos, unequal; chele, claw] 1. (ARTHRO) Achela with two unlike parts. 2. (PORIF) A diactinal microsclerewith unlike, recurved hooks, plates or flukes at eachend. see isochela.anisocytic a. [Gr. anisos, unequal; kytos, container] Havingcells in the intestinal epithelium unequal in height in agiven cross section.anisogametes n.pl. [Gr. anisos, unequal; gametes, spouse]Outwardly dissimilar male and female gametes; heterogamete.anisogamy n. [Gr. anisos, unequal; gamos, marriage] Gameteswhen fusing during fertilization vary in size, shape and

60Maggenti and Gardnerbehavior. see heterogamy.anisoglottid a. [Gr. anisos, unequal; glottis, mouth of thewindpipe] (NEMATA: Secernentea) Having a glottoid apparatuswith metarhabdions at different levels. see isoglottid.anisognathous a. [Gr. anisos, unequal; gnathos, jaw] Bearingunequal jaws.anisomorpha n. [Gr. anisos, unequal; morphe, form] (AR-THRO: Insecta) Insects whose metamorphosis differ in variousways.anisomorphic a. [Gr. anisos, unequal; morphe, form] Varyingin form, size or structure. see isomorphic.anisomyarian a. [Gr. anisos, unequal; myos, muscle] 1. Havingunequal muscles. 2. (MOLL: Bivalvia) Having the anterioradductor muscle reduced or absent. see monomyarian.anisotropic a. [Gr. anisos, unequal; tropein, to turn] Doublyrefracting, such as dark bands in the sarcomere of a musclefiber. see isotropic.ankistroid see ancistroidankylosis, anchylosis n. [Gr. angcheein, to press tight] 1.The union or fusion of parts into one structure. 2. A stiffnessor immobility of a joint.anlage n.; pl. -en, -es [Ger. anlage, predisposition] A primordiumor cell group that constitutes identification of a part ororgan. see blastema.annectent a. [L. annectere, to bind together] Linking; an intermediate;connecting together.annelet n. [L. dim. annellus, little ring] (ARTHRO: Insecta) InHymenoptera, a small ring-joint between the basal scapeand the funicule of the antenna.Annelida, annelids n.; n.pl. [L. annulus, ring; Gr. eidos, form]A phylum of segmented or cylindrical ringed worms, encompassingthe Polychaeta, mainly free-living and marine,the Oligochaeta, mainly free-living, either terrestrial(earthworms), fresh water, or marine, and the Hirudinoideaor leeches, that are ectoparasitic, fresh water, marine, or

Online Dictionary of Invertebrate Zoology 61rarely terrestrial.annidation n. [Gr. an, without; L. nidus, nest] Describing amutant organism existing in a deme because of an ecologicalniche the normal organism is unable to utilize.annotinate n. [L. annus, year] (MOLL: Bivalvia) Depressedlines placed at varying distances across some shells,marking their yearly growth; annual ring; growth ring.annual a. [L. annus, year] Occurring once a year, or lasting forone year.annual colony A deme that lasts only one season and diesout.annual ring see annotinateannular a. [L. annulus, ring] 1. Pertains to being ring-shaped;marked with rings or bands. 2. (ANN: Oligochaeta) Referringto the clitellum of earthworms encircling the body andcontinuing ventrally. see saddle.annular lamina (ARTHRO: Insecta) In Hymenoptera, the laminaor sternal plate situated in front of the genitalia of Formicidae.annular spiracle (ARTHRO: Insecta) 1. In immature Lepidopteraand Hymenoptera, simple, ring-like spiracles with asingle opening with no accessory chambers. 2. In otherimmature insects, may be biforous, having two small orlarge accessory or secondary chambers usually adjacent tothe margin; uniforous, when opening occurs on the margin,or multiforous if three or more openings are present.annulate a. [L. annulus, ring] Composed of, or furnished withring-like bands or annuli; may refer to structural bands orcolored bands.annulates n.pl. [L. annulus, ring] A group of segmented invertebratesincluding the arthropods, annelids and relatedforms.annulations n.pl. [L. annulatus, ringed] Deep, transverse cuticularstriae occurring at intervals (usually regular) givingthe body a segmented appearance.annulet n. [L. annulus, ring] A small ring into which a segmentis divided by complete transverse constrictions, crenula-

62Maggenti and Gardnertions, or plicae.annuli pl. of annulusannulose a. [L. annulus, ring] Bearing rings.annulus n.; pl. -li -luses [L. annulus, ring] 1. Any ring-likecircling of a joint, segment, spot or mark. 2. (BRYO: Phylactolaemata)The outer epidermal layer of a statoblast thatencircles the protective capsule. 3. (NEMATA) The intersticearea between the transverse striae of the body cuticle.annulus antennalis (ARTHRO: Insecta) The encircling scleriteinto which the basal segment of the antenna is inserted;antennal sclerite.annuluses pl. of annulusannulus ventralis (ARTHRO: Crustacea) In Decapoda, theseminal receptacle of a female crayfish.anodontia n. [Gr. an, without; odontos, tooth] 1. Lackingteeth; edentate. 2. (MOLL: Bivalvia) Lacking hinge teeth.anodont a.Anodontoda see Bivalviaanoestrus see anestrusanomalous a. [Gr. anomalos, irregular] Deviating from thecommon or usual rule, form or type. anomaly n.anomoclad n. [Gr. anomoios, dissimilar; blados, branch] (PO-RIF) A subglobular microsclere spicule produced by theswelling of the middle part of the spicule.anomphalous a. [Gr. an, without; omphalos, navel] (MOLL:Gastropoda) Without an umbilicus.anoprocess n.; pl. -ses [L. anus; processus, process] (AR-THRO: Insecta) In Neuroptera, the uppermost process ofeach half of the anal segment.anorganology see abiologyanorthogenesis n. [Gr. an, without; orthos, straight; genesis,beginning] Adaptive changes of evolutionary significancebased on preadaptations; zigzag evolution.anosmatic a. [Gr. an, without; osme, smell] Lacking or impairmentof the sense of smell.

Online Dictionary of Invertebrate Zoology 63anoxybiont n. [Gr. an, without; oxys, sharp; bios, life] An organismincapable of using oxygen as opposed to one that isaerobic.ansa n. [L. ansa, handle] A loop or loop-like structure.ansiform a. [L. ansa, handle; forma, shape] Looped, or looplikein shape.antafossa see antennal fossaantagonism n. [Gr. antagonistes, competitor] 1. Inhibition orinterference in growth of an organism due to unfavorableconditions created by the presence of another species. 2.Opposing action by two different muscles or structures. 3.Neutralizing ability of one drug or hormone upon another;chalone.antagonistic symbiosis A symbiotic association in which onesymbiont seeks to establish domination over the other. seeparasitism.anteal a. [L. ante, before] Being in front or forward.antealar a. [L. ante, before; ala, wing] (ARTHRO: Insecta)Pertaining to being positioned anterior to the front wing.antealar sinus (ARTHRO: Insecta) In Odonata, the transversegrooved area in front of the base of the front wings.anteapical a. [L. ante, before; apex, summit] Proximal of theapex.anteapical cell (ARTHRO: Insecta) A cell in the distal part ofthe wing.anteclypeus n. [L. ante, before; clypeus, shield] (ARTHRO: Insecta)The anterior division of the clypeus when differentiatedfrom the postclypeus by a sulcus or suture. seeclypeus.antecosta n. [L. ante, before; costa, rib] (ARTHRO: Insecta)The anterior marginal or submarginal interior tergal orsternal plate, on which the longitudinal muscles are attached.antecostal sulcus/suture (ARTHRO: Insecta) The groove ofthe intersegmental sclerite that marks the base of the antecosta.

64Maggenti and Gardnerantecoxal piece (ARTHRO: Insecta) An inner sclerite betweenthe trochantin and the episternum; the lateral sclerites ofthe clypeus.antecoxal sclerite (ARTHRO: Insecta) A part of the metasternumjust anterior to the hind coxae.antecubital see antenodal cross veinsantecurrent see prosoclineantefrons n.pl. [L. ante, before; frons, forehead] (ARTHRO: Insecta)Frons situated anterior to the antennal base lines.antefurca n.; pl. -furcae [L. ante, before; furca, fork] (AR-THRO: Insecta) The internal chitinous forked process projectinginto the thoracic cavity from the anterior thoracicsegment.antehumeral a. [L. ante, before; humerus, shoulder] (AR-THRO: Insecta) Designating the area immediately anteriorto the basal portion of the wing.antelabrum n. [L. ante, before; labrum, lip] (ARTHRO: Insecta)The anterior part of the labrum when differentiated.antemarginal process (ARTHRO: Insecta) In Scarabaeoidea, aprocess distad of the lateroproximal marginal region of thephallobase.ante mortem a. [L. ante, before; mors, death] Before death.see post-mortem.antenna n.; pl. -nae [L. antenna, feeler] 1. Analogous, unsegmentedstructures in mollusks, polychaete worms androtifers. 2. (ARTHRO) A movable sensory appendage ofvarious arthropods; usually segmented and located on thehead above the mouth parts; most arthropods bear antennae,although some are greatly reduced; missing in allarachnids. 3. (ARTHRO: Crustacea) The second antennaeproper; the second pair of appendages posterior to antennules;primarily sensory in function, but often adapted forother functions; derived from appendages on primitivethird preoral somite; postantennal appendages; no homologousappendage in insects. see antennua, antennule.antennal appendage (ARTHRO: Insecta) In Anoplura, protu-

Online Dictionary of Invertebrate Zoology 65berance on the first or third antennal segment of male bitinglice.antennal carina (ARTHRO: Crustacea) A prominent ridge extendingposteriorly from a decapod antennal spine.antennal club (ARTHRO: Insecta) The enlarged distal segmentof a clubbed antenna.antennal fossa (ARTHRO: Insecta) A cavity or depression inwhich the antenna is located; antennal groove; antafossa.antennal fovea see antennal grooveantennal gland 1. (ARTHRO: Crustacea) In Malacostraca, acomplex excretory gland with ducts opening on the secondantenna; green gland. 2. (ARTHRO: Insecta) One of a pairof glands that open on the antenna.antennal groove (ARTHRO) A groove or depression in the headof many arthropods, extending posteriorly from the basalsegment of the antenna.antennal lobes see deutocerebrumantennal muscle scar (ARTHRO: Crustacea) In Ostracoda, animpression of the antennal muscle on the inner surface of avalve, situated in front of the adductor muscle scar, usuallyabove the mandibular scar.antennal organs (ARTHRO: Insecta) In Collembola, sensorystructures of springtails situated on the distal segment ofthe antenna.antennal region (ARTHRO: Crustacea) In Decapoda, the anteriormarginal part bordering orbital region laterally, adjoininghepatic, pterygostomial, and occasionally also thefrontal regions of the carapace.antennal scale see scaphoceriteantennal sclerite (ARTHRO: Insecta) The sclerotic rim of thebasal antennal socket. see annulus antennalis.antennal segment (ARTHRO) That segment of an arthropodhead from which the antennae arise, usually second segment;deuterocerebral segment.antennal spine (ARTHRO: Crustacea) A decapod spine situatedon the anterior margin of the carapace, slightly below the

66Maggenti and Gardnerorbit.antennal support (ARTHRO: Insecta) In Coleoptera, ringshapedcranial projections of scarab larvae, to which theantennae are appended; the proximal, nonarticulated firstantennal segment.antennal suture (ARTHRO: Insecta) The external groove in thecranial wall surrounding the antennal socket. see circumantennalsulcus.antennaria n. [L. antenna, feeler] (ARTHRO: Insecta) In immatures,an annular sclerite forming the periphery of eachantennal sclerite.antennation n. [L. antenna, feeler; suff. denoting act] (AR-THRO: Insecta) The act of touching with the antennae thatfunction as a sensory probe or tactile signal to another insect.antennifer n. [L. antenna, feeler; ferre, to carry] (ARTHRO)The single marginal point into which the basal scape of theantenna is inserted, allowing it freedom to move in all directions.antenniform a. [L. antenna, feeler; forma, shape] Appearinglike or shaped like an antenna.antennomere n. [L. antenna, feeler; Gr. meros, part] (AR-THRO: Diplopoda) An antennal segment.antennua n. [L. dim. antenna, feeler] (ARTHRO: Crustacea) Thesecond antennae, when there are two pair.antennular fosette (ARTHRO: Crustacea) A depression, pit orsocket containing the basal portion of the antennule.antennular region see deutocerebral regionantennular scale see styloceriteantennule n. [L. dim. antenna, feeler] (ARTHRO: Crustacea)The first antenna; anteriormost appendage, primarily sensoryin function, but often adapted for other functions indifferent species; derived from appendages on the primitivesecond preoral somite; homologous to antennae of insects.see antenna.antenodal a. [L. ante, before; nodus, knob] Preceding a nodeor nodes.

Online Dictionary of Invertebrate Zoology 67antenodal cross veins (ARTHRO: Insecta) In Odonata, wingveins along the costal border between the base and thenodus, extending from the costa to the radius.anteocular a. [L. ante, before; oculus, eye] Before the eye.antepectus n. [L. ante, before; pectus, chest] (ARTHRO: Insecta)The underside of the prothorax.antepenultimate a. [L. ante, before; paene, almost; ultimus,last] Pertaining to the second from the last segment ofvarious invertebrates.antepleuron see episternumantepronotum n. [L. ante, before; Gr. pro, before; notos,back] (ARTHRO: Insecta) In Diptera, the anterior division ofthe pronotum.antepudendum n. [L. ante, before; pudenda, external genitals,vulva] (NEMATA) Genital tube proceeding anterior fromthe vulva in monovarial amphidelphic descendants. antepudendica.antepygidial bristle (ARTHRO: Insecta) In Siphonaptera, oneor more large bristles on the apical margin of the seventhtergum.anteriad adv. [L. ante, before; ad, toward] Directed towardthe anterior part of the body; directed forward, as opposedto posteriad.anterior a. [L. ante, before] 1. Before or toward the front. 2.Pertaining to the direction in which the head tends to pointwhen an animal is active. 3. (MOLL: Gastropoda) In acrawling gastropod, pertaining to the head being closest tothat part of the apertural margin lying farthest from theshell apex; in high-spired conispiral shells, and some others,anterior is equivalent to abapical.anterior apophyses (ARTHRO: Insecta) In female Lepidoptera,a pair of slender chitinized internal rods extending anteriorlyfrom the ninth abdominal segment.anterior canal see siphonal canalanterior cardiac chamber see proventriculusanterior hard plate (ARTHRO: Insecta) In Diptera, an irregularplatelike anterior area of the clypeopalatum of Culicidae.

68Maggenti and Gardneranterior keel (MOLL) The high point of the whorl next to thesuture at the lower edge of the shell nearest to the anteriorend.anterior lateral tooth (MOLL: Bivalvia) A lateral tooth in frontof the beak.anterior promontory (ARTHRO: Insecta) In Diptera, the medianarea of the mesonotum, at the anterior end of theacrostichal area.anterior setae see ventral setaeanterior stigmatal tubercle (ARTHRO: Insecta) Prominence onthe thoracic and abdominal segments of caterpillars.anterior tentorial arms (ARTHRO: Insecta) An apodeme arisingfrom the anterior tentorial pits, meeting the posteriortentorial arm at a visible fusion point; sometimes bearing asmall dorsal or ventral tentorial arm.anterior tentorial pits (ARTHRO: Insecta) External depressionsin the epistomal suture marking the base of the anteriortentorial arm(s).anterior tubercle (ARTHRO: Crustacea) A swelling or smallprojection in the anterior region of the carapace of archaeostracans;polygenetic, sometimes including the optictubercle.anterobiprostatic a. [L. antero, anterior; bis, twice; Gr. prohistanai,to set before] (ANN: Oligochaeta) Pertaining to themale terminalia of parthenogenetic earthworm morphs inwhich the posterior prostates of an acanthodrilin set areabsent.anterodorsal a. [L. antero, anterior; dorsum, back] Towardthe front and the top or upper side.anterolateral region (ARTHRO: Crustacea) The lateral part ofthe carapace bordering the subhepatic or hepatic regions.anteromesal a. [L. antero, anterior; mesos, middle] In thefront and along the midline of a body.anteroposterior axis The longitudinal axis, from head to tail.anteroventral a. [L. antero, anterior; venter, belly] In thefront on the lower side.

Online Dictionary of Invertebrate Zoology 69antesternite n. [L. ante, before; Gr. sternon, breastbone] (AR-THRO: Insecta) The anterior ventral plate or spicule; basisternum;eusternum.anthelmintic, anthelminthic a. [Gr. anti, against; helmins,worm] Pertaining to therapeutic agents used against intestinalhelminths causing death or expulsion. see vermicide,vermifuge.anthobian n. [Gr. anthos, flowers; bios, life] Feeding on flowers.anthoblast n. [Gr. anthos, flower; blastos, bud] (CNID: Anthozoa)In stony corals, a young sessile polyp producing ananthocyathus.anthocaulus n. [Gr. anthos, flower; kaulos, stalk] (CNID: Anthozoa)The stalk of a solitary coral after the separation ofthe disklike anthocyathus.anthocodium n.; pl. -ia [Gr. anthos, flower; kodeia, head](CNID: Anthozoa) The distal end of an alcyonarian coral;the upper tentacular part of the polyp that can be retractedinto the calyx.anthocyanins n.pl. [Gr. anthos, flower; kyanos, blue] Importantplant pigments (flavones) that may contribute to theblue or red coloration of insects. see anthoxanthins.anthocyathus n.; pl. -ia [Gr. anthos, flower; kyathos, cup](CNID: Anthozoa) The disklike crown portion of solitary coralsthat separates from the stalk (anthocaulus).anthogenesis n. [Gr. anthos, flower; genesis, beginning] Theproduction of both males and females by parthenogenesis.anthophilous a. [Gr. anthos, flower; philein, to love] Designatingattraction to or feeding on flowers; anthobian.anthostele n. [Gr. anthos, flower; stele, column] (CNID: Anthozoa)The stiff proximal part of certain stoloniferan polypsinto which the tentacular portion is retracted.anthoxanthins n.pl. [Gr. anthos, flower; xanthos, yellow]Plant pigments (flavones) responsible for the ivory to yellowcolor of some true bugs and Lepidoptera. see anthocyanins.Anthozoa, anthozoans n.; n.pl. [Gr. anthos, flower; zoon,

70Maggenti and Gardneranimal] Any coelenterate of the class Anthozoa, phylumCnidaria, including the sea anemones and corals.anthracene, anthracine n. [Gr. anthrax, coal] Coal black;shiny black with a bluish tint.anthraquinones n.pl. (ARTHRO: Insecta) A group of orange orred pigments found in certain insects.anthropochorous a. [Gr. anthropos, man; chorein, to spread]Refers to any disease or organism transported by man,usually unintentionally; peregrine.anthropogenic a. [Gr. anthropos, man; genes, producing]Caused by, or resulting from, the influence of man.anthropomorphic a. [Gr. anthropos, man; morphe, form] Attributinghuman attributes to animals.anthropophilous a. [Gr. anthropos, man; philein, to love]Used to describe insects that prefer human blood.anthropozoic a. [Gr. anthropos, man; zoe, life] Designatingthat period of time since man appeared upon the earth.anthropozoonosis n. [Gr. anthropos, man; zoon, animal;nosos, disease] A disease of humans transmissible to otheranimals. see zooanthroponosis, zoonosis.antiaposematic a. [Gr. anti, against; apo, away; sema, signal]Referring to coloration that disguises a predator. seeparasematic, aposematic.antibiosis n. [Gr. anti, against; biosis, manner of life] An associationbetween two organisms in which one secretes asubstance destroying or inhibiting the other.anticlinal a. [Gr. anti, against; klinein, to bend] Radial; incliningin opposite directions; at right angles to the surface ofa part.anticlypeus see anteclypeusanticoagulant a. [Gr. anti, against; L. coagulare, to curdle]Pertaining to any substance that prevents or delays the coagulationof blood.anticoagulin n. [Gr. anti, against; L. coagulare, to curdle](ARTHRO) The secretion of certain parasitic species thatprevents or delays the coagulation of the host's blood.

Online Dictionary of Invertebrate Zoology 71anticrista n.; pl. -ae [Gr. anti, against; L. crista, crest] (MOLL:Cephalopoda) A cartilaginous outgrowth of the statocystwall that protects the macula and crista from sudden inertialmovements of the endolymph.anticryptic color A color or color pattern used for concealmentby a predator in order to facilitate attack on its prey. seecryptic color, homochromy.anticus a. [L. anticus, foremost] Anterior; belonging to or towardthe front; frontal.antidiuretic hormone (ARTHRO: Insecta) A diuretic regulatoryhormonal mechanism that enhances the rate at which fluidis secreted via the Malpighian tubules, and in certain insects,reduces resorption in the rectum.antidromic a. [Gr. anti, against; dromos, running] Moving in adirection contrary to normal. see orthodromic.antigeny a. [Gr. anti, against; genes, producing] Pertaining tosexual dimorphism.antilysin n. [Gr. anti, against; lyein, to dissolve] Any substancethat can counteract lysin.antimere n. [Gr. anti, against; meros, part] Left and righthalves of a bilaterally symmetrical object, or a homologouspart repeated in segments arranged around an axis, as inradially symmetrical animals.antimetabolite n. [Gr. anti, against; metabole, change] Anycompound that interferes with normal cellular metabolism.antimitotic a. [Gr. anti, against; mitos, thread] Refers to theaction of physical or chemical agents that produce a consistentdeviation in the mitotic cycle.antimorph n. [Gr. anti, against; morphe, form] A mutant allelethat inhibits the production of the ancestral allele.antineural a. [Gr. anti, against; neuron, nerve] 1. Distal to anerve. 2. Term used instead of ventral for certain invertebrates,such as Pogonophora. see adneural, subneural.antiperistalsis n. [Gr. anti, against; peri, around; stalsis,contraction] Peristalsis occurring in reverse; reversed muscularcontractions in the digestive tract.antipodal a. [Gr. anti, against; pous, foot] Diametrically oppo-

72Maggenti and Gardnersite; located on the opposite side.antipygidial bristles (ARTHRO: Insecta) In Siphonaptera, bristleslocated on the seventh abdominal segment.antirostrum n. [Gr. anti, against; L. rostrum, beak] (ARTHRO:Chelicerata) Terminal segmental appendages of somemites.antispadix n. [Gr. anti, against; L. spadix, palm branch](MOLL: Gastropoda) Four modified tentacles opposite thespadix of the male Nautilus, sp.antisquama n.; pl. -mae [Gr. anti, against; L. squama, scale](ARTHRO: Insecta) In Diptera, the upper lobe (alula) thatmoves with the wing; antitegula. see squama.antistyle n. [Gr. anti, against; stylos, pillar] (ARTHRO: Insecta)The basal segment of the stylifer.antitegula see antisquamaantithetic generation Alternation of generations in which thealternates are very different in appearance and origin.antitoxin n. [Gr. anti, against; toxikon, poison] Any substancethat neutralizes a toxin.antitype n. [Gr. anti, against; typos, type] 1. An oppositetype; a countertype. 2. A corresponding specimen of a typespecies, obtained at the same time and location of thetype. This definition has no standing in the ICZN.antizoea n. [L. anti, against; zoe, life] (ARTHRO: Crustacea)The first larval stage of the large, carnivorous marine mantisshrimps of the superorder Hoplocarida, that lack theraptorial claws. see pseudozoea.antlered larvae (ARTHRO: Insecta) In some newly hatchedLepidoptera larvae, antler-like horns on the first thoracicsegment and other horns (scoli) on the abdominal segments.antlia n. [Gr. antlia, pump] (ARTHRO: Insecta) The spiral, tubularproboscis.antrorse a. [L. antero, anterior; versus, turned] Directed orleaning upward or forward. see detrorse, retrorse.antrum n. [L. antrum, hollow] 1. A hollow space or cavity. 2. A

Online Dictionary of Invertebrate Zoology 73sinus.anucleate a. [Gr. an, without; L. nucleus, kernel] Lacking anucleus.anural a. [Gr. an, without; oura, tail] Lacking a tail.anuria n. [Gr. an, without; ouron, urine] Absence of or inabilityto excrete urine.anus n. [L. anus] The terminal orifice of the alimentary canal,through which unabsorbed food and waste products arevoided; in some groups it is associated with the cloaca. seeuropore.aorta n. [Gr. aorte, the great artery] The main vessel carryingblood from the heart; the dorsal blood vessel.aortal chamber The thoracic expansion of the aorta.aortic valve The closure mechanism of the dorsal vessel,separating the aorta and the heart proper.apatetic color Those colors that enable an organism to mimiceither its environment or another species.apertum n. [L. aperire, to open] (ARTHRO: Insecta) In Coleoptera,a basal cell opening on the hind wing.apertural a. [L. aperire, to open] Pertaining to or on the sameside as the aperture.apertural muscle (BRYO: Gymnolaemata) One of either twopairs of muscles of cheilostomate autozooids, the occlusormuscle of the operculum or the diaphragmatic dilator muscle.aperture n. [L. aperire, to open] 1. An opening or hole, cleft,or gap. 2. (ARTHRO: Crustacea) The postero-ventral openinginto the mantle cavity of barnacles. see orifice. 3.(BRYO: Stenolaemata) The terminal skeletal opening of azooid. 4. (MOLL) An opening at the last-formed margin of ashell, providing the outlet for the head-foot mass.apex n.; pl. apexes, apices [L. apex, tip] 1. That portion ofany structure opposite the base of attachment; the tip. 2.(ARTHRO: Crustacea) The upper angle of the scutum or tergumof certain barnacles. 3. (ARTHRO: Insecta) Wing tip. 4.(MOLL) a. In Polyplacophora, the beak or umbo of a valve.b. In Gastropoda, the first-formed end of a shell.

74Maggenti and Gardneraphagia n. [Gr. a, not; phagein, to eat] Unable to ingest.apharyngeate cercariae (PLATY: Trematoda) Larvae that developin daughter sporocysts in pulmonate or prosobranchsnails.Aphasmidia see Adenophoreaaphelenchoid bursa see bursaaphideine see aphidiluteinaphidicolous a. [NL. aphis, plant-louse; L. colere, to dwell](ARTHRO) Pertaining to associating with aphid colonies, ascertain ants.aphidilutein n. [NL. aphis, plant-louse; L. luteus, yellow] Theyellowish liquid found in plant lice. see aphins.aphidivorous a. [NL. aphis, plant-louse; L. vorare, to devour]Feeding on aphids.aphins n.pl. [NL. aphis, plant-louse] Fat soluble pigments derivedfrom various aphids that impart a purple or blackcolor to the whole insect.aphodus n.; pl. aphodi [Gr. aphodos, departure] (PORIF:Desmospongiae) The short channel connecting the flagellatedchamber with the excurrent canal. see prosodus.aphorism n. [Gr. aphorizein, to define] The concise definitionof a principle.aphotic zone That zone of ocean water that lies below 800meters and which receives little or no light.aphototropic a. [Gr. an, without; phos, light; tropein, to turn]Turning away from light.aphrodisiac pheromone (ARTHRO: Insecta) A pheromone thatfacilitates copulation.aphytal zone Those waters in which the penetration of light istoo poor to support photosynthesis.apian a. [L. apianus, of bees] Of or pertaining to bees.apiary n.; pl. -ies [L. apiarium, beehive] The area where beesare kept; a collection of hives maintained for honey production.apicad adv. [L. apex, tip; ad, toward] Toward the apex.

Online Dictionary of Invertebrate Zoology 75apical a. [L. apex, tip] Refers to the apex or top, as of a conicalor spherical structure.apical angle 1. (ARTHRO: Insecta) The angle of a wing at itsapex. 2. (MOLL: Gastropoda) In a plane through the axis,that angle subtended between two straight lines that touchadjacent whorls on opposite sides near the apex; identicalwith the spire angle if whorls increase at a regular rate.apical area 1. (ARTHRO: Insecta) see petiole. 2. (MOLL: Polyplacophora)The short part of the periostracum and tegmentumon the head and intermediate valves that is adjacentto the posterior dorsal edge of a valve and which extendsover the edge and onto the ventral side.apical carina (ARTHRO: Insecta) In ichneumonid Hymenoptera,the posterior transverse carina.apical cell 1. A cell situated at the apex of a structure distinguishedby location, shape, size and function. 2. (ARTHRO:Insecta) Apical testicular cell of Orthoptera, Dictyoptera,Diptera and Homoptera, and some Lepidoptera, that suppliesmitochondria to the spermatogonial cytoplasm duringspermatogenesis; Verson's cell; Versonian cell. 3. (NEMATA)An epithelial cell that forms the gonoduct wall.apical chamber (ARTHRO: Insecta) Pertaining to the germariumin the acrotrophic egg tubes.apical cross vein (ARTHRO: Insecta) A cross vein near theapex of the wing.apical field (ROTIF) The central anterior unciliated area of thecorona.apicalia n. [L. apex, tip] (GNATHO) Paired sensory cilia on thehead.apical lip notches (NEMATA) Indented lip margins at the junctionof the lips.apical margin (ARTHRO: Insecta) The outer margin of thewing. see costal margin, anal margin.apical organ A sensory organ located at the apex of trochophorelarvae and some cestodes.apical orifice (MOLL) An opening at the top or apex of a shell.apical plate An external sensory organ of a primitive nervous

76Maggenti and Gardnersystem or cluster of nerve cells at the anterior pole of thebody of certain arthropods and annelids.apical scutellars (ARTHRO: Insecta) In Diptera, the apical pairof marginal bristles on the scutellum; sometimes refers tothe sub-apical scutellars, when the true apicals are absent.apical spur 1. (ARTHRO: Insecta) The short bristles on theventral surface of the tibia. 2. (MOLL) The initial pointedplug forming a posterior septum in truncate shells.apical system (ECHINOD: Echinoidea) Plates surrounding thebody organs of sea-urchins, found at the dorsal or aboralpole of the test. see coronal system.apices pl. of apexapicobasal ridge or furrow (ARTHRO: Crustacea) A longitudinalfeature of barnacles, dividing the tergum from the remainingvalve.apiculate a. [L. dim. apex, tip] Pertaining to a short, abruptpoint or points.apiculture n. [L. apis, honeybee; cultura, cultivation] (ARTHRO:Insecta) The culturing of bees; beekeeping.apiculus n. [L. dim. apex, tip] Any small apical tip or point.apid venom gland (ARTHRO: Insecta) A type of venom glandin which the single venom gland is widened into a saclikereservoir that contains glandular elements, but no muscles.see braconid venom gland.apisthognathous see opisthognathousapitoxin n. [L. apis, honeybee; Gr. toxikon, poison] The maintoxic constituent of bee venom.apivorous a. [L. apis, honeybee; vorare, devour] Refers tofeeding on bees.aplasia n. [Gr. an, without; plasma, formed or molded] 1. Theentire failure of organs or tissue to develop. 2. Incompleteor faulty development. aplastic a. see agenesis.apneumone n. [Gr. an, without; pneuma, air] A substanceemitted by a nonliving material that envokes a behavioralor physiological reaction favorable to the receiving organism,but detrimental to another species that may be found

Online Dictionary of Invertebrate Zoology 77in or on the nonliving material. see allelochemic.apneustic a. [Gr. an, without; pneustos, breath] 1. Lackingexternal breathing organs. 2. (ARTHRO: Insecta) Lackingspiracles, or supplied with nonfunctional spiracles, as inaquatic forms.apobiotic a. [Gr. apo, away; biotikos, of life] Of or pertainingto any change leading to diminished cells or tissues.apocentric a. [Gr. apo, away; kentron, center] Deviating fromthe original type. see archecentric.apochete n. [Gr. apo, away; cheo, pour] (PORIF) An exhalantcanal that extends from the apopyles to apopore.apocrite a. [Gr. apo, away; krinein, to separate] (ARTHRO: Insecta)Pertaining to Hymenoptera in which the first abdominalsegment is fused to the reduced metathorax toform a narrow waist.apodal a. [Gr. a, without; pous, foot] Lacking feet or legs;apodous.apodeme, apodema n. [Gr. apo, away; demas, body] An invaginationof the cuticle that serves for muscle attachmentand for strengthening of the body wall. see apophysis,apodome.apoderma n. [Gr. apo, away; derma, skin] (ARTHRO: Chelicerata)The membrane developed during resting stage of instarsof certain Acari.apodictic, apodeictic, apodictal a. [Gr. apodeiktos, provingfully] Being evident beyond contradiction; clearly proving.apodome n. [Gr. apo, away; L. domus, roof] (ARTHRO) Theinternal portions of a skeleton, consisting of both apodemeand apophysis; sometimes used as synonymous with apodeme.apodous see apodalapodous larvae (ARTHRO) Larvae without legs and with reducedhead, that require maternal deposition in or on afood source.apoenzyme n. [Gr. apo, away; en, in; zyme, yeast] The proteinportion of an enzyme that cannot function without acoenzyme. see holoenzyme.

78Maggenti and Gardnerapogamete n. [Gr. apo, away; gamete, spouse] A gameteformed by apomixis.apogamy see apomixisapolar a. [Gr. an, without; polos, pivot pole] Lacking a pole;without radiating processes.apolegamic a. [Gr. apolegein, to choose; gamos, marriage]Pertaining to sexual selection.apolysis n. [Gr. apo, away; lysis, loosen] 1. (ARTHRO) The firstprocess of molting, characterized by the detachment of theold cuticle from the underlying hypodermal (epidermal)cells. see ecdysis. 2. (PLATY: Cestoda) The detachment ofa gravid proglottid in tapeworms. apolytic a. see anapolysis.apomict n. [Gr. apo, away; miktos, mixed] Any organism producedby apomixis.apomictic (ameiotic) parthenogenesis No reduction divisionoccurs, so that the offspring have the same genetic constitutionas the mother and all are female.apomixis n. [Gr. apo, away; mixis, mixing] Botanical termsometimes used in invertebrates. see parthenogenesis.apomorph n. [Gr. apo, away; morphe, form] A derived character.apomorphy n. [Gr. apo, away; morphe, form] A term pertainingto derived characters, normally used in cladistic taxonomy.apomorphic a. see plesiomorphy.apophysary see apophysisapophysis n.; pl. -ses [Gr. apo, away; phyein, to grow] 1. Aninternal or external tubercular or elongate process of thebody wall; a prominence, swelling or expansion. see apodeme,apodome. 2. (ARTHRO: Insecta) see pleuralapophysis, sternal apophyses. 3. (MOLL) a. In Bivalvia,a large, styloid projection, one in each valve, extendingfrom beneath the umbos to which the foot muscles are attached.b. In Polyplacophora, see sutural laminae.apophystegal plates (ARTHRO: Insecta) In Orthroptera, plateorblade-like sclerites covering the gonapophyses.apopore n. [Gr. apo, away; poros, passage] (PORIF) An aper-

Online Dictionary of Invertebrate Zoology 79ture forming an exit from the apochete; may be equivalentto an oscule.apopyle n. [Gr. apo, away; pyle, gate] (PORIF) An exhalentaperture from a choanocyte chamber.aporrhysa n.pl. [Gr. aporrhyein, to flow away] (PORIF) The exhalentcanals. see epirrhysa.aposematic a. [Gr. apo, away; sema, signal] Warning colorationor structures that repel predators, also includingmovements, sounds, smells, etc. see allosematic color,sematic.aposeme n. [Gr. apo, away; sema, signal] A population inwhich all the individuals, even though taxonomically distinct,share the same aposematic coloration.apostatic a. [Gr. apostates, deserter] Widely departing fromthe norm; said of a phenotype that differs strikingly fromthe search image of a predator.a posteriori weighting The weighting of taxonomic characterson the basis of their proved contribution to the establishmentof sound classifications. see a priori weighting.aposymbiotic a. [Gr. apo, away; syn, together; bios, life] Referringto an organism separated from its symbiotes; symbiote-free;usually refers to mutualistic symbiotes. seemutualism.apotele n. [Gr. apo, away; telos, end] (ARTHRO: Chelicerata)The terminal eudesmatic segment of the appendages ofmites, generally constituting two tendons and two articulation-points.apotelic a. see pretarsus.apotome n. [Gr. apo, away; tomos, a cut] A part or subdivisionappearing as if separated from the whole.apotorma n.; pl. -mae [Gr. apo, away; tormos, socket] (AR-THRO: Insecta) In Scarabaeoidea larvae, a process thatextends forward from the torma between the pternotormaand the interior end of the torma.apotype see hypotypeapotypic a. [Gr. apo, away; typos, type] Varying from a type.apparatus n.; pl. -ratus, -ratuses [L. apparatus, equipment]Any group of structures or parts that unite together in a

80Maggenti and Gardnercommon function.apparition n. [L. appareo, manifest] Something appearing.appeasement behavior That which follows after the attack ofone animal on another of the same species with the loserassuming a submissive attitude.appeasement substance The secretion by a social parasite ofattractive substances that reduce aggression in a host insectand aid the parasite's acceptance by the host colony.appendage n. [L. ad, to; pendere, to hang] A structure attachedor appended to a larger structure, as parts or organsthat are attached to the body of various invertebrates.appendicle n. [L. ad, to; pendere, to hang] A small appendageor appendix. appendicular a.appendiculate a. [L. ad, to; pendere, to hang] Bearing orforming small appendages.appendiculate cell (ARTHRO: Insecta) In Hymenoptera, asmall cell just beyond the apex of the marginal cell of thewing.appendicule n. [L. ad, to; pendere, to hang] (NEMATA) A large,single, ventral, extensible preanal supplementary male organ.appendiculum n. [L. appendicula, small appendage] (CNID:Scyphozoa) The remainder of the partial veil on the pileusrim of jellyfish.appendifer n. [L. ad, to; pendere, to hang; ferre, to carry](ARTHRO: Trilobita) A ventral projection for the attachmentof thoracic muscles.appendix n.; pl. -dixes, -dices [L. ad, to; pendere, to hang]Any supplementary or additional piece or part appended toa regular structure.appendix interna (ARTHRO: Crustacea) In Malacostraca, themedian process of the pleopodal endopod uniting membersof each pair; stylamblys.appendix masculina (ARTHRO: Crustacea) In Isopoda, themodified second (sometimes first also) pleopod(s) in theform of a long, often grooved, rodlike organ that functions

Online Dictionary of Invertebrate Zoology 81as a copulatory organ or gonopod.appendotomy n. [L. appendix, appendage; Gr. tome, a cutting]The loss of appendages. see autospasy, autotilly,autotomy.appose v.t. [L. ad, to; ponere, to put] To place opposite orbefore; to put, apply, or add one thing to another, to placein juxtaposition.apposition n. [L. ad, to; ponere, to put] 1. Juxtaposition. 2.The growth of a structure by the successive deposition oflayers on its outside. see intussusception.apposition eye (ARTHRO) The compound eye of diurnal insectsand crustaceans in which the rhabdom reaches the crystallinecone, it absorbs oblique rays of light in the pigmentedwalls of the ommatidium and, produces a mosaic image.see superposition eye.apposition image A mosaic image.appressed a., adv. [L. ad, to; premere, to press] Pressed orclosely applied against something; adherent.approximate a. [L. ad, to; proximare, to come near] Situatednear or close together.a priori weighting The weighting of taxonomic characters onthe basis of preconceived criteria. see a posterioriweighting.aprostatic a. [L. an, without; pro, before; stare, to stand](ANN: Oligochaeta) Lacking prostates.aptera n.pl. [Gr. an, without; pteron, wing] (ARTHRO: Insecta)Insects without wings; formerly an ordinal term includingthe fleas, lice and other wingless forms.apterergate n. [Gr. an, without; pteron, wing; ergate, worker](ARTHRO: Insecta) A wingless worker in vespid wasps, thatare normally winged.apterodicera a. [Gr. an, without; pteron, wing; dikeros, twohorned](ARTHRO: Insecta) A wingless insect bearing twoantennae.apterogyne n. [Gr. an, without; pteron, wing; gyne, female](ARTHRO: Insecta) A wingless female social insect that isnormally winged.

82Maggenti and Gardnerapterous a. [Gr. an, without; pteron, wing] (ARTHRO: Insecta)Wingless, without wings or winglike expansions; exalate.apterous neoteinic see ergatoid reproductiveapterygogenea n.pl. [Gr. an, without; pteryx, wing; genos,race] (ARTHRO: Insecta) Insects that are wingless in allstages and assumed to be descended from wingless ancestors.see ptergogenea.Apterygota, apterygote n. [Gr. an, without; pterygion, wing]A subclass of primitively wingless insects containing thebristletails, silverfish and rock jumpers. see Pterygota.aptychus n. [Gr. an, without; ptychos, fold] (MOLL) A doublecalcareous plate found in many fossil ammonites, assumedto be an operculum.apyrase n. [Gr. an, without; pyr, fire; -ase, enzyme] An enzymethat functions in the utilization of energy.apyrene a. [Gr. an, without; pyren, kernel] (MOLL) Designatesnonfunctional sperm with no flagella or chromatin. see eupyrene,oligopyrene.aquamarine n. [L. aqua marina, sea water] Blue, blue-greenor green in color.aquatic a. [L. aqua, water] Pertaining to living or growing inwater.aqueous a. [L. aqua, water] Of or of the nature of water; watery.aqueous humor The fluid in the anterior chamber of the eye.see vitreous humoraquiferous a. [L. aqua, water; ferre, to bear] (MOLL) Supplyingwater or watery fluid, as the aquiferous canals.arachnactis n. [Gr. arachne, spider; aktis, ray] (CNID: Anthozoa)The larval stage of anemone-like cerianthids.Arachnida, arachnid n. [Gr. arachne, spider] A class of thephylum Arthropoda that includes the scorpions, mites, spiders,harvestmen and ticks, etc.arachnidism n. [Gr. arachne, spider; ismos, denoting condition](ARTHRO: Chelicerata) Envenomation by an arachnid,such as a spider, tick or scorpion. see arachnism.

Online Dictionary of Invertebrate Zoology 83arachnidium n. [Gr. arachne, spider] (ARTHRO: Chelicerata)The spinning apparatus of spiders, consisting of the spinningglands and their ducts and the spinnerets. arachnidiala.arachnism n. [Gr. arachne, spider; ismos, denoting condition](ARTHRO: Chelicerata) Poisoning, or poisoned condition dueto envenomation by a spider. see arachnidism.arachnoid, arachnoideal a. [Gr. arachne, spider; eidos, form](ARTHRO: Chelicerata) 1. Resembling a member of theArachnida. 2. Resembling a spider's web, thin and fine,filmy.arachnologist n. [Gr. arachne, spider; logos, discourse] Onewho studies the arachnids.aragonite n. [fr. Aragon, in Spain] 1. A calcium carbonate, dimorphouswith calcite. 2. The innermost layer of a shell. 3.(CNID: Anthozoa) The skeleton of coral, produced by thecalicoblastic epithelium.arakoderan a. [Gr. arake, bowl; deros, skin] (NEMATA: Secernentea)Pertaining to a caudal ala that completely surroundsthe cloacal area. see leptoderan; peloderan.araneiform a. [L. aranea, spider; forma, form] Spiderlike inappearance.araneology n. [L. aranea, spider; Gr. logos, discourse] Thatbranch of zoology that treats only of spiders.arboreal a. [L. arbor, tree] Pertaining to or living in or amongtrees.arborescent a. [L. arbor, tree] Tree-like in character or appearance;branching like a tree, as some species of mollusksand corals.arborizations n.pl. [L. arbor, tree] A tree-like branching ofterminal fibers of axons or collaterals.arbovirus n. Any of a group of (ar)thropod-(bo)rne (virus)es,including the causative agents of yellow fever, viral encephalitisand certain febrile infections, that are transmittedto man by various mosquitoes and ticks.arc n. [L. arcus, bow] Any object having a bowlike curvature.arcade n. [L. arcus, arch] (NEMATA: Secernentea) Lateral col-

84Maggenti and Gardnerlecting tubules of the excretory system of Ascaris.arcade cells (NEMATA) The nine anteriormost cells that are believedto form the lips, two opposite each esophageal lumenradius and one opposite each sector.archaeocytes n.pl. [Gr. arche, beginning; kytos, container] 1.(PORIF) Large, wandering amoebocytes with multiplephagosomes in the mesenchyme; nurse cells; trophocytes.2. A totipotent amoeboid cell.archaestomatous a. [Gr. arche, beginning; stoma, mouth](ANN) Describing a group, Archaeostomata of former classifications,with a mouth derived directly from the blastoporeof the embryo.archebiosis n. [Gr. arche, beginning; biosis, manner of life]Abiogenesis.archecentric a. [Gr. arche, beginning; kentron, center] Designatingor pertaining to an original type. see apocentric.archedictyon n. [Gr. arche, beginning; diktyon, net] (ARTHRO:Insecta) The irregular network of cuticular ridges on thewings of many fossils.archegenesis n. [Gr. arche, beginning; genesis, beginning]Abiogenesis.archencephalon see archicerebrumarchenteric pouch One of the paired, segmented, dorsoventralprominances of the archenteron from which the mesodermderives.archenteron n. [Gr. arche, beginning; enteron, intestine] Theprimitive digestive cavity of many invertebrates, formed bygastrulation; the gastrocoele; precursor to the gut.archeocyte see archaeocytesarchetype, architype n. [Gr. arche, beginning; typos, type] Ahypothetical ancestral type arrived at by the elimination ofspecialized characters of known later forms. see phylogeny.Archiacanthocephala n. [Gr. arche, beginning; akantha,thorn; kephale, head] A class of Acanthocephala that areparasites of predacious birds and mammals; insects andmyriapods are the intermediate hosts.

Online Dictionary of Invertebrate Zoology 85archibenthic a. [Gr. arche, beginning; benthos, depths of sea]Refers to the continental deep-sea zone, extending fromthe edge of the continental shelf (200-400 m.) to depths ofabout 800-1100 m. see abyssal.archicephalon n. [Gr. arche, beginning; kephale, head] Theprimitive annelid-arthropod head; the prostomium.archicerebrum n.; pl. -bra [Gr. arche, beginning; L. cerebrum,brain] 1. (ANN) The ganglionic nerve mass of aprostomium. 2. (ARTHRO) The primitive suprastomodealnerve mass of a prostomium; the primitive brain.archidictyon see archedictyonarchigastrula n. [Gr. arche, beginning; gaster, stomach] Atype of gastrula in which the endoderm is produced by invagination;emboly.archigenesis see abiogenesisarchinephridium n. [Gr. arche, beginning; nephros, kidney]An excretory organ of many invertebrate larvae; a solenocyte.archiplasm n. [Gr. arche, beginning; plasma, formed ormolded] A former name for the substance of the spindle fibersand astral rays; was thought to exist during the entirecell cycle, but to only become visible after aggregation atmitosis.Archiptera see Pseudoneuropteraarchitomy n. [Gr. arche, beginning; tome, cut] (ANN) Designatingreproduction by fission, with regeneration afterseparation of heads and/or tails. see paratomy.architype see archetypearchoophorans n.pl. [Gr. arche, beginning; pherein, to carry](PLATY: Turbellaria) 1. Individuals with modified cleavage inwhich yolk is stored in the oocytes; entolecithal eggs. seeneophorans. 2. Archoophora A former division of theTubellaria; a superorder.arciform a. [L. arcus, bow; forma, shape] Being arcuate;shaped like a bow or arch.arctic a. [Gr. arktos, bear] 1. Pertaining to the region of theNorth Pole within the Arctic Circle. 2. Pertaining to the high

86Maggenti and Gardnerlatitude regions, that may or may not be inside the geographicalArctic Circle, from which tree growth is normallyabsent, but with plants and animals.arcticoid teeth (MOLL: Bivalvia) Heterodont teeth intermediatebetween corbiculoid and lucinoid types.arctogaea n. [Gr. arktos, bear; gaia, the earth] One of theprimary zoogeographic zones comprising North America(except Central America), Europe, Asia and Africa.arcuate a. [L. dim. arcus, bow] 1. Pertaining to being shapedlike an arc; arch-like. 2. (MOLL: Bivalvia) Referring to theventral edge in some pelecypods. 3. (PORIF) Referring tothe chelate microsclere in the form of one to three curvedplates; commonly three plates.arcuate vein (ARTHRO: Insecta) The first jugal vein.arculus n. [L. dim. arcus, bow] (ARTHRO: Insecta) A basalcross vein between the radius and the cubitus.are n. [L. area, open place] A metric area measurement of asquare, with each side 10 meters in length.area n. [L. area, open place] (BRYO: Gymnolaemata) In anascans,the space occupied by the frontal membrane.arenaceous a. [L. arena, sand; -aceus, having the nature of]Sandy, or the nature of sand.arenicolous a. [L. arena, sand; colere, to inhabit] Burrowing inor inhabiting sand. see psammophilous.areocel see accessary cellareola, areole n.; pl. -lae, -las (areoles) [L. dim. area, smallopen place] 1. (ARTHRO: Crustacea) In crayfish, the longitudinalstrip between the brachiocardiac grooves and posteriorto the cervical groove on the dorsum. 2. (ARTHRO:Insecta) a. An accessory wing cell of Lepidoptera. seebasal cell. b. In ichneumonid Hymenoptera, the pentagonalor hexagonal area on the propodeum enclosed by carinae.3. (BRYO: Gymnolaemata) In cheilostomes, a smallopening in the frontal wall connecting the endocyst with theectocyst. 4. (ECHINOD) see scrobicula. 5. (NEMATA) A smallarea within longitudinal striae delimited by transverse annuli.6. (NEMATOM) Round or polygonal cuticular plates,

Online Dictionary of Invertebrate Zoology 87sometimes containing pores, that may exude a lubricantonto the cuticle surface, aiding tight-coiling behavioralmovements. areolar, areolate a.areolation n. [L. area, open space] 1. Any small space,bounded by some part differing in color or structure. 2.(ARTHRO: Insecta) Spaces founded by nervures in thewings. 3. (NEMATA) Transverse body striae extending intothe lateral field.areole see areolaareolet n. [L. dim. area, small open space] (ARTHRO: Insecta)A small cell in a wing.argentaffin a. [L. argentum, silver; affinis, related] Of or pertainingto the taking of a silver stain; an argyrophil.argentaffin(e) cell Any cell that stains readily by silver techniques.argenteous a. [L. argentum, silver] Silver-like, silvery, white,shinning.argentophilic cells (ARTHRO: Insecta) In aquatic larvae, specializedcells for ion uptake in the anal papillae or rectalgill.argillaceous a. [L. argilla, white clay] Containing or consistingof, or like clay; clayey.argyrophil a. [Gr. argyros, silver; philein, to love] Pertains tostaining readily with silver dyes; argentaffin.arista n.; pl. -tae [L. arista, awn] A bristlelike appendage.aristate a. [L. arista, awn] Having an arista; aristate antenna.aristopedia n. [L. arista, awn; podos, foot] (ARTHRO: Insecta)A developmental deviation in which the arista may matureas a leg.Aristotle's lantern (ECHINOD: Echinoidea) A complicated masticatingapparatus consisting of several ossicles surroundingthe mouth of sea urchins; called Aristotle's lantern becauseit resembles an early Greek lantern.aristulate a. [L. dim. arista, awn] Bearing a short bristle.ark n. [L. arca, chest] (MOLL: Bivalvia) A marine arcoid bivalvewith an equivalve shell; a heavy box-like shell; an ark-

88Maggenti and Gardnershell.arm n. [A.S. arm, forelimb] 1. Anything resembling or correspondingto an arm. 2. (ECHINOD) a. In Asteroidea, the radialextension of the body surrounding the axis; the ambulacra.b. In Crinoidea, the radial evagination of the bodyextending from the theca; undivided distal branches. 3.(ECHI) The forked section of the proboscis. 4. (MOLL:Cephalopoda) a. In squids and cuttlefish, eight of the tenshort and heavy appendages around the head, the othertwo larger dorsal appendages being tentacles. b. The tentaclesof an octopod.armate cercaria (PLATY: Trematoda) A larva of the xiphidiocercariaegroup with oral and ventral suckers unequal,without a virgula organ and with a Y-shaped excretorybladder.armature n. [L. armare, to arm] Defensive or protectivestructures of invertebrates, such as spinous or chitinousprocesses in the form of hooks, horns, teeth, spines andclaws on various parts of the body.armilla n.; pl. -lae [L. armilla, bracelet] Bearing a bracelet-likering or annulus. armillate a.arolium n.; pl. -ia [Gr. arole, protection] (ARTHRO: Insecta) Amedium lobe or pad-like cushion of the foot. a. Betweenthe claws of Orthoptera. b. The base of each tarsal claw ofHemiptera. c. Between the tarsal claws and comprising partof the pretarsus of Hymenoptera. see pseudarolium.aromorphosis n.; pl. -ses [Gr. airein, to raise; morphosis,shaping] An advancement in organization of an organism,without a marked increase in specialization; an aromorph.see allomorphosis.arrhenogeny n. [Gr. arrhen, male; genos, offspring] The conditionof producing only male offspring. see monogeny,thelygeny.arrhenoidy n. [Gr. arrhen, male; eidos, form] (NEMATA: Secernentea)Sex reversal from female to male; recognizedby males having two testes, instead of one. arrhenoid a.arrhenoplasm n. [Gr. arrhen, male; plasma, formed ormolded] The male element of idioplasm.

Online Dictionary of Invertebrate Zoology 89arrhenotoky n. [Gr. arrhen, male; tokos, birth] The haplodiploidparthenogenesis in which males arise from unfertilized,haploid egg cells. see thelyotoky.arsenosomphic a. [Gr. arsen, male; somphos, porous] (ANN:Oligochaeta) Pertaining to earthworms with male terminalia.artatendon n. [L. artus, joint; tendere, to stretch] (ARTHRO:Insecta) The tendon articulating the post-tarsus.artefact see artifactartenkreis see superspeciesarterial a. [L. arteria, artery] Pertaining to an artery.arteriole n. [L. dim. arteria, artery] A small artery.artery n. [L. arteria, artery] A vessel conveying blood from theheart to the tissues.arthral a. [Gr. arthron, joint] Pertaining to a joint.arthrium n. [Gr. arthron, joint] (ARTHRO: Insecta) In Coleoptera,minute tarsal joints, trimera (3 tarsal joints) andtetramera (4 tarsal joints).arthrobranchia n.; pl. -iae [Gr. arthron, joint; branchia, gills](ARTHRO: Crustacea) In Decapoda, a gill attached to thearticulating membrane between the appendage and body;arthrobranchiata.arthroderm n. [Gr. arthron, joint; derma, skin] (ARTHRO) Theouter covering of skin, or the outer body-wall.arthrodial membrane (ARTHRO) Articular membranes thatpermits unrestricted motion; flexible joints.arthromere n. [Gr. arthron, joint; meros, part] (ARTHRO) Asegment, somite or metamere.arthrophragm see endophragmarthropleure n. [Gr. arthron, joint; pleura, side] (ARTHRO)That portion of the body that bears the limbs.Arthropoda, arthropod n. [Gr. arthron, joint; pous, foot] Aphylum of invertebrates that contains the chitinous segmented,exoskeletoned, jointed-legged animals, such ascentipedes, millipedes, insects, crustaceans, spiders, scorpions,and many other less well-known types.

90Maggenti and Gardnerarthropodin n. [Gr. arthron, joint; pous, foot] (ARTHRO) Aprotein constituent part of the chitinoproteinic structures.arthropodization n. [Gr. arthron, joint; pous, foot] (ARTHRO)Evolutionary development of the combination of characteristicsassociated with arthropods, including the chitinousexoskeleton.arthrostracous a. [Gr. arthron, joint; ostrakon, shell] (AR-THRO: Crustacea) Having the thorax and abdomen segmented,and bearing seven pairs of thoracic legs.article n. [L. dim. artus, joint] 1. A distinct segment or jointedpart or structure. 2. (ARTHRO) a. In Chelicerata, the serratedprocess on the chelicera of a tick. b. In Crustacea, asubdivision of the antennal or antennular flagella or appendage.c. In Insecta, a segment of a leg. see segbment.articulamentum n. [L. articulare, to divide] (MOLL: Polyplacophora)The shell layer between the tegmentum and hypostracum,that is composed of several separate componentsof crystalline shell structure; formerly the hard,semiporcellaneous shell layer projecting past the tegmentumforming the insertion plates and the sutural laminae.articular a. [L. articulare, to divide] Pertaining to a joint.articular area (ARTHRO: Insecta) The basal portion of a wing.articular corium see articular membrane, coriumarticular furrow (ARTHRO: Crustacea) A groove near the tergalmargin of the scutum, or scutal margin of the tergum,forming part of articulation between the two valves of barnacles.articularis n. [L. articulare, to divide] The pre-tarsus.articular membrane (ARTHRO) The nonsclerotized, flexiblemembrane between the segments of arthropods, and thejoints of arthropod appendages.articular pan A cup or dish-like impression into which an articulationis fitted; frogga.articular ridge (ARTHRO: Crustacea) In barnacles, a linearelevation on the scutum or tergum bordering the articularfurrow and together forming an articulation between thetwo valves.

Online Dictionary of Invertebrate Zoology 91articular sclerite (ARTHRO: Insecta) A sclerite between an insectbody and its appendage.Articulata n. [L. articulus, joint] 1. (BRACHIO) A class of thePhylum Brachiopoda, having the valves articulated by teethon the ventral (pedicle) valve and sockets on the dorsal(brachial) valve. 2. (BRYO) A division of Bryozoa containingtubular bryozoans in which colonies are erect, branchedand attached by rhizoids. 3. (ECHINOD) A subclass of echinodermatancrinoids comprising sea lilies and feather stars.articulate a. [L. articulare, to divide] Jointed; formed of segments;connected by a joint.articulated apex see clasp filamentarticulate fascia A band of contiguous spots.articulation n. [L. articulare, to divide] A movable point ofcontact between two sclerotic parts of a structure.artifact, artefact n. [L. ars, art; facere, to make] An appearance,or structure, produced by preparation of materialthat was not present in the original material before themanipulation.artificial classification A classification based on convenientand conspicuous diagnostic characters, ignoring charactersindicating relationship; often a classification based on asingle character instead of an evaluation of all of the characters.see classification, phylogeny.ascaridin, ascaridine n. [Gr. askaris, an intestinal worm](NEMATA) A protein in the sperm.ascarylic acid Material making up the refringent bodies orcrystalloids in the oocytes of nematodes, that presumablyform the vitelline membrane of the egg.Aschelminthes, aschelminths n.pl. [Gr. askos, bag; helmins,worm] A taxon (phylum) of the animal kingdom, when recognized,that includes the (classes) Rotifera, Gastrotricha,Kinorhyncha or Echinodera, Nematomorpha or Gordiacea,and Nemata (=Nematoda).ascon n. [Gr. askos, bag] (PORIF) 1. A simple sponge with unfoldedpinacoderm and choanoderm. 2. Sometimes used todescribe the small, simple, most primitive sponge Leu-

92Maggenti and Gardnercosolenia .asconoid grade (PORIF) A grade of construction in which thechoanocytes line thin, short tubes. see syconoid grade,leuconoid grade or type.ascopore n. [Gr. askos, bag; poros, channel] (BRYO: Gymnolaemata)In some Cheilostomata, a small opening in thefrontal wall connecting the ascus to the external environment.ascus n.; pl. asci [Gr. askos, bag] (BRYO: Gymnolaemata) Inascophoran cheilostomates, the exterior-walled, flexiblefloored,sac beneath the frontal shield of an autozooid. seeanascan.ascus sac (MOLL: Gastropoda) In Sacoglossa, a storage areafor the holder of outgrown teeth usually retained in a spiralor jumbled heap in the pharynx; ventral sac.asemic a. [Gr. asemos, without mark] Pertaining to beingwithout markings.aseptate a. [Gr. an, without; L. septum, partition] Pertainingto being without a septa.aseptic a. [Gr. an, without; sepsis, decay] Refers to being freeof microorganisms, especially those causing decay, putrefaction,or poisoning.aseptic culture A maintained population of organisms containinga single species and free of contamination by allother organisms.asetal a. [Gr. an, without; L. seta, bristle] (ANN: Oligochaeta)Pertaining to being without setae; as in the peristomiumand pygomere of earthworms.asexual a. [Gr. an, without; sexus, sex] Not related to sex.asexual reproduction Any method of reproduction not involvingfertilization, as that by fission, fragmentation, sporeproduction, budding, vegetative reproduction, and gemmuleformation.asiphonate a. [Gr. an, without; siphon, tube] Lacking a siphon.aspect n. [L. aspicere, to look at] The general appearance, directionor view with respect to seasons, species or popula-

Online Dictionary of Invertebrate Zoology 93tions, an object or individual.aspection n. [L. aspicere, to look at] Seasonal succession ofecological phenomena.asperate a. [L. asperare, to roughen] Referring to having arough and uneven surface.asperity n.; pl. -ties [L. asperare, to roughen] 1. Roughnessof surface. 2. (ARTHRO: Insecta) Spinelike structures arrangedin rows or confined to specific areas; sculpturings ordotlike elevations.asperous a. [L. dim. asper, rough] (MOLL) Used to denote verydistinct elevated dots, more uneven than scabrous; roughto the touch.asperulous a. [L. dim. asper, rough] Slightly rough.asphyxia n. [Gr. an, without; sphyzein, pulse, respiration]Suffocation; suspended animation or apparent death resultingfrom a deficiency of oxygen. asphyxial a.asphyxiation n. [Gr. an, without; sphyzein, pulse, respiratrion;L. -tion, denotes act] Act of causing axphysia; suffocation.aspidium n. [Gr. aspidion, a little shield] A drug used for theexpulsion of tapeworms obtained from male Dryopterisfilix-mas ferns from which it is extracted as oleoresin of aspidium.aspidosoma n. [Gr. aspis, shield; soma, body] (ARTHRO: Chelicerata)In Acari, the dorsal region bordered laterally by theabjugal furrow that may be indistinct or incomplete, posteriorlyby the disjugal furrow, and anteriorly by the circumcapitularfurrows.asplanchnic a. [Gr. an, without; splanchnon, entrail] Pertainingto the lack of an alimentary canal.asporogenic a. [Gr. an, without; spora, seed; genes, producing]Pertaining to not producing or bearing spores. asporousa.assemblage n. [L. assimulare, to bring together] A collectionof organisms, or particular things.assembly n.; pl. -lies [L. assimulare, to bring together] Anassemblage of organisms; the smallest community recog-

94Maggenti and Gardnernized in ecology.assimilation n. [L. ad, near; similis, like] The basic nature ofliving matter to convert other substances into its own components.see genetic assimilation.association n. [L. ad, near; sociare, to join] 1. A group assemblageof organisms in a specific geological area withone or two dominant species. 2. A climax plant communitydominated by a particular species and named according totheir characteristics.association neuron An internuncial neuron, that connectssensory and motor neurons, or other association neurons ofthe central nervous system; a connector neuron.associes n.pl [L. ad, near; sociare, to join] 1. A transitory orintermediate stage in the development of an association. 2.A developmental unit of a consocies.assortment n. [L. ad, near; sors, lot] 1. To distribute or classify.2. The normal separation of genes at meiosis.assurgent a. [L. assurgens, to arise] Curving upward; ascending.astacene, astacin n. [L. astacus, lobster] A carotenoid redpigment of some invertebrates.astaxanthin n. [L. astacus, lobster; xanthos, yellow] (ARTHRO)A carotenoid biochrome of certain ingested vegetationfound in certain insects and marine crustaceans.astegasimous a. [Gr. an, without; stege, roof] (ARTHRO: Chelicerata)Referring to mites when the prodorsal scleritedoes not project over the chelicerae. see stegasimous.astelocyttarous a. [Gr. an, without; stele, pillar; kyttaros, cellof a honeycomb] (ARTHRO: Insecta) Pertaining to nests, especiallyof social wasps, in which the brood comb is directlyattached to a support and lacking pillars. see stelocyttarous.aster n. [Gr. aster, star] 1. Star-shaped figures that developduring mitosis. 2. (PORIF) A type of microsclere with severalrays originating from the same center. see chiaster.asteriform a. [Gr. aster, star; forma, shape] Of or pertainingto starlike or star-shaped.

Online Dictionary of Invertebrate Zoology 95asteroid a. [Gr. aster, star; eidos, form] 1. Refers to starlikeor resembling a star. 2. (ECHINOD) A stellate echinoderm ofthe subclass Asteroidea.Asteroidea n. [Gr. aster, star; eidos, form] A subclass of Somasteroideaof the phylum Echinodermata, containing thestellate sea stars and star fish; characterized by havingfive-radiate to multi-armed rays, usually not sharply offsetfrom the central disk.asthenia n. [Gr. asthenes, feeble] Muscle weakness; debility.asthenobiosis n. [Gr. asthenes, feeble; biosis, manner of life](ARTHRO: Insecta) Hibernation or aestivation in certaingenerations of insects induced by non-elimination of uremicproducts by previous active generations.astichous a. [Gr. an, without; stichos, row] Not arranged in arow or rows.astigmatic a. [Gr. an, without; stigma, mark] Lacking stigmata;without a spiracle or breathing pore.astogenetic differences (BRYO) Differences in the morphologyof an asexual generation of zooids, and thereby restrictedto zones of astogenetic change in the colony.astogeny n. [Gr. asty, town; genos, descent] (BRYO) The developmentof a colony through a sequence of asexual generationsof zooids with any extrazooidal parts.astomate a. [Gr. a, without; stoma, mouth] 1. Lacking amouth. 2. (ANN: Oligochaeta) In earthworms, a closednephridium, without a nephrostome. 3. (NEMATA) Referringto a stoma lacking the cheilostome, but retaining an unexpandedesophastome.astragal n. [Gr. astragalos, vertebra] (MOLL: Gastropoda) Thestep-sided, rounded elevations of a shell, that extend spirallyaround the whorls giving added strength.astral ray 1. A ray seen in the cytoplasm that radiates fromeach centriole to the asters during cell division, thus formingthe spindle. 2. A polar ray.astral sphere see astrosphereastrocenter see centrosomeastrocyte n. [Gr. aster, star; kytos, container] 1. A star-

96Maggenti and Gardnershaped neuroglia cell. 2. Any star-shaped cell, especially instroma tissues.astrorhizae n.pl. [Gr. aster, star; rhiza, root] (PORIF) Starlikedepressions on the surface of the calcareous skeleton.astrosphere n. [Gr. aster, star; sphaira, ball] The central massof an aster lacking rays.astrotaxis n. [Gr. aster, star; taxis, arrangement] The orientationof certain organisms sensitive to polarized skylight,i.e., bees, ants and spiders.asymmetrical a. [Gr. asymmetros, without symmetry] Notsymmetrical; not alike on both sides of an axis; bilaterallyunequal.asymmetry n. [Gr. asymmetros, without symmetry] Lack ofsymmetry; unlikeness in form or development.asymptomatic a. [Gr. a, without; symptoma, a sign of disease]Lacking subjective evidence of a disease.asynaptic a. [Gr. a, without; synapsis, union] Pertaining to thecomplete failure or incomplete pairing of chromosomesduring the first meiotic division. asynapsis n.asynchronous a. [Gr. a, without; syn, together; chronos,time] Not simultaneous; not occurring at the same time.atactotrichy n. [Gr. ataktos, not arranged; trichos, hair]Chaetotaxy in which all setae are not describable in distinctpatterns and arrangements. see primordiotrichy.atavism n. [L. atavus, ancestor] Recurrence of an ancestralcharacter, after an interval of generations. atavistic a.ataxia n. [Gr. a, without; taxis, arrangement] Lacking musclecoordination.atelia n. [Gr. ateles, incompletedness] Incomplete or imperfectdevelopment.athecal a. [Gr. a, without; theke, case] (ANN) Without spermathecae.athecate a. [Gr. a, without; theke, case] 1. Lacking a theca. 2.(CNID: Hydrozoa) In Hydroids, lacking an investing cup orsheath.athericerous see aristate

Online Dictionary of Invertebrate Zoology 97athermobiosis n. [Gr. a, without; thermos, hot; biosis, mannerof life] 1. Dormancy induced by low temperatures inrelation to an organism. 2. The process of waste eliminationduring a resting stage at low temperature.athrocyte n. [Gr. athroos, collected; kytos, container] A sessiletype of coelomocyte, phagocytic in function.athrocytosis n. [Gr. athroos, collected; kytos, container] Theability of cells to absorb and retain particles in suspension.atmosphere n. [Gr. atmos, vapor; sphaira, ball] 1. The outercircle of an ocellate spot. 2. The envelope of air aroundearth that supports life.atoke n. [Gr. a, without; tokos, birth] (ANN: Polychaeta) Theanterior sexless portion of certain marine worms. atokousa. see epitoke.atoll n. [Mal. atoll] A circular coral reef surrounding a centrallagoon.atom n. [L. atomus, a small particle] 1. Any extremely smallparticle, dot or point. 2. An elementary particle which entersinto a chemical reaction.ATP adenosine triphosphateatracheate a. [Gr. a, without; trachia, windpipe] Without tracheae,or visible constriction between head and prothorax.atractoid a. [Gr. atraktos, spindle; eidos, form] Pertaining tospindle-shaped; fusiform.atrial a. [L. atrium, vestibule] 1. Of or pertaining to an atrium.2. (ANN) Referring to glandular tissue associated with acleft or coelomic invagination containing the male pore.atrial bag (BRYO) That part of a polypidian vesicle attached tothe frontal wall of a developing zooid, from which the tentaclesheath is formed.atrial cavity In procordates, a cavity located between thepharynx and the body wall.atrial cornua (ANN: Hirudinoidea) Horns or hornlike prolongationsof the atrium.atrial gland (ANN) Prostates without stalks.atrial orifice (ARTHRO: Insecta) The exterior opening of the

98Maggenti and Gardnerspiracular atrium.atrial sac (ANN: Oligochaeta) In primitive moniligastrid earthworms,the spermathecal diverticulum.atrichosy n. [Gr. a, without; trichos, hair] The absence of setaedue to evolutionary regession.atrichous a. [Gr. a, without; trichos, hair] 1. Lacking flagellaor cilia. 2. (CNID) Lacking spines or barbs, i.e., isorhizas,etc.atrichous isorhiza (CNID: Hydrozoa) A small nematocyst witha smooth tubule. see holotrichous isorhiza, basitrichousisorhiza.atriobursal orifice (ARTHRO: Chelicerata) The opening of theseminal receptacle of female spiders.atrium n.; pl. atria [L. atrium, vestibule] 1. A cavity, division,entrance or passageway of various invertebrates. 2. (ANN)a. A diverticulum of the spermatheca; a tubular or capsularprostate. b. Male reproductive organ in leeches, consistingof a thin-walled bursa, a thick-walled glandular and muscularchamber and a pair of atrial cornua opening into themuscular median chamber. 3. (ARTHRO: Insecta) A specializedarea of the trachea; a. A spiracular atrium. b. The preoralcavity in certain larvae. 4. (PORIF) A cavity into whichmany exhalant systems empty and conduct the contents toone or more usually terminal ocules. atriate a.atrium oris (ARTHRO: Crustacea) The preoral cavity.atrocha n. [Gr. a, without; trochos, wheel] (ANN: Polychaeta)A uniformly ciliated larva, lacking the preoral band. atrochala.atrophy n. [Gr. a, without; trophein, to feed] Decrease in sizeof a tissue, organ, or part after full development has beenobtained; a condition induced from lack of use, pathologicalcondition or lack of nourishment. see hypertrophy.atrous a. [L. ater, black] Black in color.attachment disk (ARTHRO: Chelicerata) The series of tiny zigzaglines or spots of silk that serve to anchor the draglinesof spiders.attenuate a. [L. ad, toward; tenuis, thin] To become thin,

Online Dictionary of Invertebrate Zoology 99slender, fine, extended, growing narrower, tapering.attingent a. [L. attignus, touching] Touching, making contact.attitude n. [L. aptus, suited] The posture or expression assumedby an organism.attractant n. [L. ad, toward; tractus, draw] A chemical substancecausing positive behavorial responses. see pheromone.attractor epimeralis muscle (ARTHRO: Crustacea) In Decapoda,a prominent muscle inserting along the line of thebrachiocardiac groove.attraction sphere see centrosomeattrition n. [L. ad, toward; tritus, rub] A rubbing out or grindingdown by friction.atyphlosolate a. [Gr. a, without; typhlos, blind; solen, channel]Without longitudinal infolding of the intestinal wall;without a typhlosole.atypical adv. [Gr. a, without; typos, shape] Irregular; notconforming to type.auditory a. [L. audire, to hear] Pertaining to the organs orsense of hearing.auditory nerve see Muller's organauditory organ Any specialized structure capable of beingstimulated by sound vibrations, such as tympanal organsand auditory hairs.auditory peg see scolopaleaulaeum n. [Gr. aule, courtyard] (ARTHRO: Insecta) In Diptera,a fringed plate found in the labium of many larvae.aulostomatous a. [Gr. aulos, pipe; stoma, mouth] Bearing atubular-shaped mouth.aurate a. [L. auris, ear] Having ears or ear-like expansions.aureate a. [L. aurum, gold] Golden yellow in color.aurelia n. [L. aurum, gold] (ARTHRO: Insecta) A chrysalis orpupa of butterflies.aurelian n. [L. aurum, gold] (ARTHRO: Insecta) A collector andbreeder of butterflies; a lepidopterist.

100Maggenti and Gardneraureole n. [L. aurum, gold] A circlet of color that dissipatesoutwardly.auricle n. [L. auricula, little ear] 1. Any ear-shaped structureor small lobe-like appendage. 2. An atrium or chamber ofthe heart. 3. (ARTHRO: Insecta) a. In Hymenoptera, a flatplate forming a part of the pollen basket or corbicula ofhoneybees. b. In Anisoptera, ventrolateral outgrowths oftergum two; oreillets. 4. (CTENO) In Lobata, the four ciliated,delicate lobes projecting from the equatorial level. 5.(MOLL) a. Paired chambers that receive blood from eachside of the body. b. In Bivalvia, an earlike protuberance onthe dorsal part of the shell. 6. (PLATY: Turbellaria) A bluntlateral chemical receptor. 7. (ROTIF) Paired ciliated lateralcoronal projections that aid in swimming. auricular a.auricular crura (MOLL: Bivalvia) Internal, blunt ridges swellingdistally to form low tubercles.auricularia larva (ECHINOD: Holothuroidea) A free-swimmingbilaterally symmetrical larva characterized by the main ciliatedband being increased in length due to sinuosity. seedipleurula.auricular sulcus (MOLL: Bivalvia) A furrow demarcating theauricle from the shell.auricular valve 1. A mechanism that controls the flow of bloodin various invertebrates. 2. (ARTHRO: Insecta) Pouches withincurrent ostioles in the heart that prevent the backflow orescape of hemolymph from this vessel.auriculate a. [L. auricula, little ear] Bearing an auricle or auricles.auriculate antennae (ARTHRO: Insecta) An antenna with basaljoints expanded into an ear-like cover.auriculo-openings see ostiumauriculo-ventricular a. [L. auricula, little ear; dim. venter,belly] (ARTHRO: Insecta) The outer valves of the heart betweenthe auricle and the chamber.auriform a. [L. auris, ear; forma, shape] Ear-shaped.aurophore n. [L. auris, ear; phoreus, bearer] (CNID: Hydrozoa)In siphonophores, a portion of the float or pneumato-

Online Dictionary of Invertebrate Zoology 101phore.austral a. [L. australis, south] Pertaining to a southern biogeographicalregion extending across North America betweenthe transition and tropical zones, including theUnited States and Mexico, except the boreal mountains andtropical lowlands.Australian Realm A zoogeographical region comprising Australia,New Zealand and Pacific islands.Austro-Columbian see Neotropicalautecology n. [Gr. autos, self; oikos, house; logos, discourse]The ecology of an individual organism or species stressingthe physical factors of the environment, as opposed tocommunity studies. see synecology.authority citation The practice of citing the name of the authorof a scientific name or name combination, i.e., X-usBrown, X-us albus Brown, Y-us albus (Brown).autoagglutination n. [Gr. autos, self; L. agglutinare, to cementto] The agglutination of an individual's cells by itsown serum.autochthonous a. [Gr. autochthon, from the land itself] Pertainingto aboriginal; indigenous; native; endemic; inherited.see allochthonous.autocopulation see hermaphroditismautodeme n. [Gr. autos, self; demos, people] Members of ataxonomic group that perform self-fertilization.autoevisceration n. [Gr. autos, self; L. ex, out; viscera, entrails](ECHINOD: Holothuroidea) Ejection of intestines andassociated organs caused by adverse environmental conditions,severe disturbance, or seasonally; regeneration occurswithin weeks.autofecundity n. [Gr. autos, self; L. fecundus, fruitful] Selffertilization,as in a few hermaphroditic animals.autogamy n. [Gr. autos, self; gamos, marriage] Self-fertilization;the fusion of two nuclei originating from a single cell.see allogamy.autogenesis n. [Gr. autos, self; genesis, beginning] Spontaneousgeneration; abiogenesis. autogenetic a.

102Maggenti and Gardnerautogeny n. [Gr. autos, self; genesis, birth] 1. Self-generation.2. Endogeny. 3. (ARTHRO: Insecta) The ability of Culicidaefemales to develop mature eggs without a prior bloodmeal. autogenous a.autogony see autogenesisautohemorrhage n. [Gr. autos, self; haimorrhagia, a bleeding](ARTHRO: Insecta) Voluntary exudation or ejection ofnauseous or poisonous blood through a rupture of the skinas a deterrent against predators.autoheteroploid n. [Gr. autos, self; heteros, different; aploos,onefold] A heteroploid derived from a single genome orfrom multiplication of its own chromosomes. see alloheteroploid.autoinfection n. [Gr. autos, self; L. inficere, to taint] Infectionof a host by microorganisms or parasites produced withinor upon the body of the same individual host.autointoxication n. [Gr. autos, self; L. intoxicare, to poison]Poisoning of an organism from a toxic substance producedwithin its own body.autokinesis n. [Gr. autos, self; kinesis, motion] Voluntarymovement. see allokinesis.autologous a. [Gr. autos, self; logos, discourse] Referring tobeing obtained or derived from an individual organism. seehomology, heterology.autolysis n. [Gr. autos, self; lysis, loosen] The degradation oftissues after death of a cell by the contained autogenousenzymes. autolytic a. see heterolysis.automatism n. [Gr. automatos, self-moving] The automaticactivity of tissues, organs, or organisms.automictic meiotic parthenogenesis A normal reduction divisionoccurs, followed by the fusion of the two nuclei sothat the diploid number of chromosomes is restored; oftenthe female pronucleus fuses with the second polar bodynucleus, or two cleavage nuclei may fuse; only females areproduced. see facultative meiotic parthenogenesis.automixis n. [Gr. autos, self; mixis, mingling] Obligatory selffertilization;egg and sperm being derived from the same

Online Dictionary of Invertebrate Zoology 103individual, as opposed to amphimixis; automictic parthenogenesis.automorphic see idiomorphicautomutagen n. [Gr. autos, self; L. mutare, to change; Gr.gennaein, to produce] Any mutagen produced in an organismas a normal or abnormal metabolite that may inducegene and chromosome mutations.autonomic a. [Gr. autos, self; nomos, usage] Functioning dueto internal causes; self-regulation; spontaneous. autonomousa. see choronomic.autoparasite n. [Gr. autos, self; parasitos, parasite] A parasiteexisting at the expense of another parasite.autopelagic a. [Gr. autos, self; pelagios, of the sea] Referringto organisms found only in the surface waters of the sea.autophagocytosis n. [Gr. autos, self; phagein, to eat; kytos,container] The consumption of contractile muscular tissueby its own cells, as opposed to leucocytes.autophagy n. [Gr. autos, self; phagein, to eat] The eating ofan appendage shed from the body by autotomy or otherwise.autoploid see autopolyploidautopolyploid n. [Gr. autos, self; polys, many; aploos, onefold;eidos, form] A polyploid originating from the doublingof a diploid chromosome set. see allopolyploid.autoskeleton n. [Gr. autos, self; skeleton, dried body] (PORIF)The endoskeleton, comprised of spicules or spongin fiberssecreted by the cells.autosomal linkage The linkage of alleles on the same autosome.autosome n. [Gr. autos, self; soma, body] Any chromosomeother than a sex-chromosome; euchromosome. see allosome.autospasy n. [Gr. autos, self; spaein, to pluck off] (ARTHRO:Chelicerata) The loss of appendages by breaking them at apredetermined locus of weakness when pulled by an outsideforce; frequent in spiders and other arachnids.

104Maggenti and Gardnerautosynapsis see autosyndesisautosyndesis n. [Gr. autos, self; syndesis, a binding together]The pairing of completely or partially homologous chromosomescontained in the same gametes at fertilization;autosynapsis. see allosyndesis.autotetraploid n. [Gr. autos, self; tetraple, fourfold] Atetraploid containing 4 sets of chromosomes per cell.autothysis see sting autotomyautotilly n. [Gr. autos, self; tillesthai, to pluck] Loss of appendagesby self-amputation. see autospasy.autotoky n. [Gr. autos, self; tokos, birth] The production ofprogeny by a single organism, including hermaphroditismand parthenogenesis.autotomize v.t. [Gr. autos, self; temnein, to cut] To shed apart intentionally; to effect autotomy.autotomy n. [Gr. autos, self; tome, a cutting] The act of reflexself-mutilation of a part or appendage of various invertebrates,i.e., annelids, cnidarians, crustaceans and insects.autotriploid n. [Gr. autos, self; triploos, threefold] A triploid inwhich the three diploid sets are identical. see allotriploid.autotrophic a. [Gr. autos, self; trophein, to nourish] Capableof synthesizing all substances needed for nutrition from inorganicfood substances. see heterotroph.autotype see heautotypeautozooecium n. [Gr. autos, self; zoon, animal; oikos, house](BRYO) A tube that encloses an autozooid.autozooid n. [Gr. autos, self; zoon, animal; eidos, form] 1.(BRYO) a. A zooid having at some stages of ontogeny aprotrusible lophophore, with or without the ability to feed.b. A common bryozoan containing feeding organs in thecolony; capable of all life functions in a monomorphic colony.2. (CNID: Anthozoa) In Alcyonaria, a feeding individualmember of a polymorphic colony.autozooidal polymorph (BRYO) An autozooid with a protrusiblelophophore, with or without feeding ability, differingfrom ordinary feeding zooids in size, shape, tentacle number,or other features.

Online Dictionary of Invertebrate Zoology 105auxiliaries n.pl. [L. auxilium, aid] (ARTHRO: Insecta) In Hymenoptera,potential queen bees (gynes) that, in associationwith a queen, become workers. see gyne.auxilia n.; pl. -lae [L. auxilium, aid] (ARTHRO: Insecta) Smallplates between the unguitractor and the claws; thebasipulvilli.auxiliary a. [L. auxilium, aid] Referring to that which supplements,aids or supports.auxiliary vein (ARTHRO: Insecta) In Diptera, the subcostal veinanterior to the radius.auxoautotroph n. [Gr. auxein, to increase; autos, self; trophe,nourishment] Any organism capable of synthesizingthe growth substances required in its development. seeauxoheterotroph.auxocyte n. [Gr. auxein, to increase; kytos, container] Anygerm cell in the growth period, during which snyapsis andtetrad formation occur.auxoheterotroph n. [Gr. auxein, to increase; heteros, other;trophe, nourishment] Any organism that is incapable ofsynthesizing the growth substances required in its development.auxotroph n. [Gr. auxein, to increase; trophe, nourishment]Nutritionally dependent cells, individuals or strains whosegrowth depends on a specific nutrient in addition to theirbasic food medium.avesiculate a. [Gr. a, without; L. vesicula, small bladder](ANN) a. Referring to a genital system without seminalvesicles. b. Refers to a nephridium without a bladder.avicular a. [L. dim. avis, bird] Beak-like.avicularium n.; pl. -ria [L. dim. avis, bird] (BRYO) An enlargedpedunculate operculum of polymorphs, resembling a bird'sbeak and more intricately reinforced than those of ordinaryfeeding autozooids.aviculoid a. [L. dim. avis, bird; Gr. eidos, form] Having winglikeprojections.axenic a. [Gr. a, without; xenos, guest] Without, or free fromassociated organisms; aseptic. see xenic, dixenic, mon-

106Maggenti and Gardneroxenic, polyxenic, trixenic.axial a. [L. axis, axle] Of or pertaining to an axis; relative tothe central axis of a cylindrical body or organ.axial cells (MESO: Rhombozoa) Central cells, comprised of anucleus and germinal cells (axoblasts).axial construction (PORIF) A type of skeletal organization withcertain components condensed to form a dense central regionor axis.axial filament 1. (ARTHRO: Insecta) see axoneme. 2. (PORIF) Aprotein core around which siliceous spicules are organized.axial gland (ECHINOD) A dark elongated mass of spongy tissueextending along the length of the stone canal, forming partof the hemal system; sometimes called axial organ orgenital stolon.axial gradient Gradation in metabolic rate along the threemain body axes, anterior-posterior, dorsoventral and median-lateral.axial organ see axial glandaxial stylet, axial spear see stomatostyle, odontostyleaxil n. [L. axilla, armpit] (ECHINOD: Asteroidea) The angleformed by junction of rays or straight-sided arms with nointerbrachial arcs.axil-arm (ECHINOD: Crinoidea) A main-axil arm and itsbranches, exclusive of terminal branchlets (omega-ramule).axilla n.; pl. axillae [L. axilla, armpit] (ARTHRO: Insecta) InHymenoptera, a triangular or rounded sclerite on each sideof the scutellum.axillaries see pteraliaaxillaris n. [L. axillaris, of an axil] (ARTHRO: Insecta) The secondand third anal wing veins.axillary a.; pl. -ies [L. axilla, armpit] 1. (ARTHRO: Insecta)Pertaining to the axilla. 2. (ECHINOD: Asteroidea) In an axil,applied to a single ossicle. 3. (ECHINOD: Crinoidea) A brachialsupporting 2 arm branches.axillary cell (ARTHRO: Insecta) A cell in the anal area of a

Online Dictionary of Invertebrate Zoology 107wing.axillary cord (ARTHRO: Insecta) The posterior edge of the articularmembrane of a wing base.axillary excision (ARTHRO: Insecta) In Hymenoptera, a notchin the hind wing that is at the distal end of the second analfurrow between the 2nd and 3rd anal veins.axillary furrow see plica jugalisaxillary incision (ARTHRO: Insecta) In Diptera, an incision onthe inner margin of a wing, distinguishing the alula fromthe main part.axillary lobe (ARTHRO: Insecta) One of the sclerites coveringthe base of a wing.axillary membrane (ARTHRO: Insecta) The membrane of thewing base extending from the tegula at the base of thecostal margin to the axillary cord at the base of the analarea.axillary plate (ARTHRO: Insecta) In Odonata, a large platehinged to the tergum, supported by an arm from the pleuralwing process.axillary region (ARTHRO: Insecta) That area of a wing basethat contains the axillary sclerites.axillary sclerites (ARTHRO: Insecta) Small plates between thenotum and base of the wing, functioning in wing-flexing;sometimes called ossicles or pteralia.axillary vein (ARTHRO: Insecta) A vein in the anal area of thehind wing.axis n.; pl. axes [L. axis, axle] A line of reference around,along or across where symmetry is established or gradientsmeasured.axis cylinder An axon.axoblast n. [Gr. axon, axle; blastos, bud] (MESO: Rhombozoa)Germinal cells of dicyemids that undergo cleavage and producenew individuals.axocoel n. [Gr. axon, axle; koilos, hollow] (ECHINOD) The firstpair of coelomic sacs in an embryo, that open to the surfaceby the hydropore.

108Maggenti and Gardneraxon, axone n. [Gr. axon, axle] A long-unbranched or sparselybranched, nerve fiber, which usually conveys impulsesaway from the cell-body of its neuron.axoneme n. [Gr. axon, axle; nema, thread] The core of a ciliumor flagellum, comprising microtubles; genoneme of achromosome.axoplasm n. [Gr. axon, axle; plasma, formed or molded] Thecytoplasm or neuroplasm of an axis cylinder.azoic era A geologic era embracing the first four or five billionyears of earth history, antedating any record of organizedlife forms.azonic a. [Gr. a, without; zone, belt] Not restricted to a zoneor locality.azurophil a. [F. azur, blue; Gr. philein, to love] Having an affinityfor staining with azure-eosin combinations. see eosinophil.azygobranchiate a. [Gr. a, without; zygon, yoke; branchia,gills] Pertaining to gills or ctenidia variously reduced on oneside.azygous n. [Gr. a, without; zygon, yoke] An unpaired appendage,structure or process. azygous, azygote a.

Bbaccate a. [L. bacca, berry] Berry-like in appearance; bacciform.bacillary a. [L. bacillum, little stick] Rod-shaped, or consistingof rod-shaped structures.bacillary band (NEMATA) A modification of the hypodermis,consisting of glandular and nonglandular cells.bacillary layer see brush borderbacilliform a. [L. bacillum, little stick; forma, shape] 1. Rodshaped.2. (ARTHRO: Insecta) In certain male Diptera, refersto a pair of sclerites in the postabdomen joining thehypandrium and epandrium.back n. [A.S. baec, the rear or dorsal part] The dorsal or uppersurface.back-cross A cross between a heterozygote and one of its parents.back-mutation The reversion by mutation of a mutant gene tothe form from which it was derived.bacteremia n. [Gr. bakterion, small rod; haima, blood] Thepresence of bacteria in the hemolymph or blood of invertebrates,without production of harmful toxins or other deleteriouseffects.bacteriophagous a. [Gr. bakterion, small rod; phagein, toeat] Feeding on bacteria.baculiform a. [L. baculum, stick or rod; forma, shape] Appearingrod- or staff-like.baculite n. [L. baculum, stick or rod] (MOLL: Cephalopoda) Astraight shelled ammonite, extinct at the end of the CretaceousPeriod.baenomere n. [Gr. bainein, to walk; meros, part] (ARTHRO:Insecta) The leg-bearing thoracic segment.baenopoda n. [Gr. bainein, to walk; pous, foot] (ARTHRO: Insecta)The thoracic legs.

110Maggenti and Gardnerbaenosome n. [Gr. bainein, to walk; soma, body] (ARTHRO:Insecta) The thorax.Baer's disc (PLATY: Trematoda) In Aspidogastrea, the large,ventral sucker. see opisthaptor.bailer n. [F. baille, a bucket] (ARTHRO: Crustacea) An exopodof the maxilla of crayfish and lobsters that functions inregulating the flow of water in the gill chamber; scaphognathite.balanced lethals Heterozygotes in which a gene mutation orchromosome structural change occurs that blocks normaldevelopment and is fatal before sexual maturity. see lethalfactor.balanced load A term describing a decrease in the overall fitnessof a population due to the component genes that aremaintained in the population because they add to fitness indifferent combinations, i.e., heterozygotes.balanced polymorphism A polymorphism maintained in thesame breeding population by a selective superiority of theheterozygotes over either type of homozygotes. see transientpolymorphism.balancers n.pl. [L. bis, two; lanx, plate, pan of a balance] (AR-THRO: Insecta) The halteres of Diptera.balanoid a. [Gr. balanos, acorn; eidos, like] Acorn shaped.balantin, balantine n. [Gr. balantidion, little bag] (ANN: Oligochaeta)Male and prostatic pores in segment xix.Balbiani's body/nucleus The yolk nucleus.Balbiani ring (ARTHRO: Insecta) In chironomid Diptera, a largeRNA puff on chromosome IV of the salivary glands duringlarval development.bald a. [ME. balled, equivalent to ball, white spot] Lacking specifichair or other surface covering.Baldwin effect The condition in which an organism can stay ina favorable environment, with modification of the phenotypeby mutation and selection, until genetic assimilationhas been achieved.ballonets n.pl. [OHG. balla, a spherical body] (NEMATA: Secernentea)Four inflated areas in the cephalic region, im-

Online Dictionary of Invertebrate Zoology 111mediately posterior to the lips, that form a collarette inGnathostomatidae; head bulb of some authors.ballooning n. [OHG. balla, a spherical body] (ARTHRO: Chelicerata)Flying through the air on silken lines spun by spiders.band n. [A.S. bindan, band] 1. A transverse marking broaderthan a line. 2. (ARTHRO: Insecta) a. In Diptera, the chromosomepairing of like chromomeres that produce the giantchromosomes. b. In male Lepidoptera, a descriptiveterm of a linear series of cornuti.barb n. [L. barba, beard] 1. Any spine or hair-like bristle with aprocess projecting obliquely or crosswise from the surface.2. A spine with teeth pointing backward.barbate, barbatus a. [L. barba, beard] Tufts or fascicles ofhair or short bristles; bearded; having tufts of hair.barbula n.; pl. -lae [L. dim. barba, beard] (ARTHRO: Insecta)In Coleoptera, a tuft of hairs or short bristles at the sides ofthe abdomen near the anal region of scarabaeoid larvae.bark n. [Sw. bark, rind] (PORIF) The outer casing of spongin ofthose having discontinuous fiber structure.baroceptor, baroreceptor n. [Gr. baros, weight; L. capere, totake] An organ perceiving changes in pressure.barotropism n. [Gr. baros, weight; tropein, to turn] A responseto pressure stimuli.barrier n. [OF. barre, bar] An obstacle or obstruction that limitsthe spread or distribution of animals.barrier reef see coral reefbasad adv. [L. basis, base; ad, to] Toward the base.basal a. [L. basis, base] Pertaining to the base; near the pointof attachment of a structure or appendage.basalar a. [L. basis, base; ala, wing] (ARTHRO: Insecta) Pertainingto the sclerites below the wing base.basal bud (BRYO: Gymnolaemata) The bud arising from thebasal wall of the parent zooid. see distal bud.basal canal (BRYO) The circumoral lacuna of the lophophoreinto which the internal lacunae of all the tentacles open.

112Maggenti and Gardnerbasal diaphragm (BRYO: Stenolaemata) The diaphragm actingas the floor of the living chamber.basal disc (BRYO: Stenolaemata) The encrusting proximalmostpart of an ancestrula.basalia a. [L. basis, base] (PORIF) Pertaining to spicules protrudingfrom the lower surface of a sponge.basalis n. [L. basis, base] (ARTHRO: Insecta) The main mandibularsclerite to which all other parts are joined.basal knobs (NEMATA) The posterior knobs of the oral stylet.see stylet knobs.basal lamina (PORIF) The attachment surface.basal margin (ARTHRO: Crustacea) In Cirripedia, the loweredge of the scutum, tergum or other plates.basal plates 1. (ECHINOD: Crinoidea) A cycle of 5 aboral calyxplates in primitive stalked crinoids. see radial plates. 2.(NEMATA) The circular base of the cephalic framework,composed of an annular structure with posteriorly directedrim, the basal ring, and six radial elements.basal platform (BRYO: Gymnolaemata) In Cheilostomata, themultizooidal skeletal layers of the basal zooidal walls; basalplate.basal ring (NEMATA) The annular structure that extends posteriorlyfrom the outer margin of the basal plate of the cephalicframework.basal sclerites (ARTHRO: Insecta) In Diptera, two lateral, verticallamellae uniting ventrally to form a trough that lodgesthe pharynx.basal suture (ARTHRO: Insecta) In Isoptera, the line alongwhich the wing separates from the body and sheddingtakes place.basal window (BRYO: Gymnolaemata) In Cheilostomata, thesubcentral, uncalcified section of an encrusting colony'sexterior basal zooidal wall.basal zooidal wall (BRYO) In Stenolaemata and Gymnolaemata,the interior or exterior zooidal supporting wall, normallyparallel to the orificial wall.

Online Dictionary of Invertebrate Zoology 113base n.; pl. bases [L. basis, base] 1. The bottom of anything.2. The main ingredient in anything that is a fundamentalelement or constituent. 3. The portion of a body to whichan appendage or structure is attached. 4. (MOLL) The extremityopposite the apex of a shell spire.basement membrane 1. The noncellular membrane underlyingthe epidermal cells of the body wall that separates itfrom the body cavity. 2. (ARTHRO: Insecta) Applied also tothe inner surface of the eye; the basilemma.basicarnal angle (ARTHRO: Crustacea) In Cirripedia, the intersectionof the basal and median dorsal margins of the dorsalplate (tergum).basicerite n. [Gr. basis, base; keras, horn] (ARTHRO: Crustacea)In Decapoda, the second segment of the antennalstalk of shrimp (Caridea) that bear flattened exopods.basiconic peg (ARTHRO: Insecta) Sensory organs in the formof short hairs or pegs projecting above the general surface.basicosta n. [L. basis, base; costa, rib] (ARTHRO: Insecta) Thebasal part of the coxa, as indicated by the basicostal suture.basicostal a.basicostal suture (ARTHRO: Insecta) A strengthening ridgethat indicates the external basal part of the coxa, the basicosta.basicoxite n. [L. basis, base; coxa, hip] (ARTHRO: Insecta) Thenarrow basal rim of the coxa.basifemoral ring (ARTHRO: Chelicerata) In Acari, the suture inthe basal segment of the femur, that separates the basiandtelofemur of the leg.basifemur n. [L. basis, base; femur, thigh] (ARTHRO: Chelicerata)In Acari, a segmental division of the femur, separatedfrom the telofemur by the basifemoral ring.basilaire see jugumbasilar a. [L. basis, base] Related to or situated at the base.basilateral angle see basitergal anglebasilemma see basement membranebasimandibula n. [L. basis, base; mandibulum, lower jaw]

114Maggenti and Gardner(ARTHRO: Insecta) In Orthoptera, a narrow sclerite betweenthe mandible and gena; a trochantin.basimaxilla n. [L. basis, base; maxilla, upper jaw] (ARTHRO:Insecta) The basal maxillary sclerite.basimetrical n. [Gr. basis, base; metrikos, of measuring] Thevertical or horizontal distribution of organisms at the seabottom.basinym n. [Gr. basis, base; onyma, name] The name uponwhich new names of species or higher classifications hasbeen based. see isonym.basioccludent angle (ARTHRO: Crustacea) In Cirripedia, theintersection of basal and occludent margins of the scutum.basiophthalmite n. [Gr. basis, base; ophthalmos, eye] (AR-THRO: Crustacea) The proximal segment of the eyestalk,that articulates with the distal segment (podophthalmite)bearing the corneal surface of the eye.basiperiphallus n.; pl. -li [Gr. basis, base; peri, around;phallos, penis] (ARTHRO: Insecta) In Protura, the basal ringof the periphallus, into which the acroperiphallus is sometimesretracted.basipharynx n. [Gr. basis, base; pharynx, gullet] (ARTHRO:Insecta) The epipharynx and hypopharynx combined.basipod(ite) n. [Gr. basis, base; pous, foot] 1. (ARTHRO: Insecta)The second segment of a telopodite; the first trochanter.2. (ARTHRO: Crustacea) see basis.basiproboscis n. [Gr. basis, base; proboskis, trunk] (ARTHRO:Insecta) In Diptera, the basal portion of the proboscis; therostrum.basipulvilli n.pl. [L. basis, base; pulvillus, small cushion] (AR-THRO: Insecta) In Diptera, the small lateral sclerite at thebase of the pulvillus.basirostral a. [L. basis, base; rostrum, bill] At the rostrumbase.basis n; pl. bases [L. basis, base] 1. A general term for thebase of any appendage. 2. (ARTHRO: Crustacea) a. A protopodsegment adjoining the coxa and carrying the exopodand endopod distally. b. The basipodite. c. A basal calcare-

Online Dictionary of Invertebrate Zoology 115ous or membranous plate functioning in anchorage of sessilebarnacles to the substrate.basiscopic a. [Gr. basis, base; skopein, to view] Looking towardthe base. see acroscopic.basiscutal angle (ARTHRO: Crustacea) Intersection of basaland scutal margins of the tergum in thoracic barnacles.basisternum n. [L. basis, base; sternum, breastbone] (AR-THRO: Insecta) That part of a thoracic sternum anterior tothe sternacostal suture and/or the sternal apophyses; sternannum;antesternite. see furcasternum.basistylus n. [Gr. basis, base; stylos, pillar] (ARTHRO: Insecta)1. In Diptera, the basal segment of the gonopods. 2. InProtura, the basal part of the stylus. see dististylus.basitarsal ring (ARTHRO: Chelicerata) A suture separating thebasitarsus and telotarsus of the legs; mesotarsal ring.basitarsal scissure (ARTHRO: Chelicerata) A scissure separatingthe basitarsus and telotarsus of the leg.basitarsus n.; pl. -si [Gr. basis, base; tarsos, flat of the foot](ARTHRO) 1. The proximal division of a tarsus; the metatarsus.2. In Chelicerata, separated from the telotarsus by thebasitarsal ring or scissure. basitarsal a.basitergal angle (ARTHRO: Crustacea) Intersection of thebasal and tergal margins of the scutum of thoracic barnacles.basitibial plate (ARTHRO: Insecta) In Apoidea, a small plate orscalelike projection at the base of the hind tibia.basitrichous isorhiza, basitrich (CNID) Isorhizal nematocystwith spines at the base of the tube only.basivalvula n.; pl. -lae [L. basis, base; dim. valva, fold] (AR-THRO: Insecta) A small sclerite at the base of the first valvulaeof the genitalia.basopinacocytes n.pl. [Gr. basis, base; pinax, tablet; kytos,container] (PORIF) Cells that form the basal epithelium; inCorvomeyenia , a fresh-water sponge, they actively ingestand digest bacteria.batatiform a. [L. batata, sweet potato; forma, shape] Resemblingthe shape of a sweet potato.

116Maggenti and GardnerBatesian mimicry A form of deceptive mimicry in which a palatablespecies assumes the appearance of a species distastefulor poisonous to a predator; false warning color;allosematic color; pseudaposematic color. see Mullerianmimicry.bathmis see pterostigmabathyal a. [Gr. bathys, deep] That zone over the continentalslope to a depth of perhaps 2000 meters.bathylimnetic a. [Gr. bathys, deep; limne, marsh] Pertainingto or inhabiting the depths of fresh water lakes or marshes.bathymetric a. [Gr. bathys, deep; metron, measure] 1. Pertainingto the science of measuring depths of oceans, seasor other large bodies of water. 2. Pertaining to the verticalor altitudinal distribution of organisms.bathymetric zone One of the horizontal divisions of an ocean;one of the contour zones of the ocean or sea.bathypelagic a. [Gr. bathys, deep; pelagos, sea] Living on ornear the bottom in the depths of the ocean. seeepipelagic, mesopelagic.battery n.; pl. -ies [F. battre, to beat] (CNID: Hydrozoa) Agroup of nematocysts on the tentacles of hydras and someother hydroid polyps.batumen n. [uncertain origin] (ARTHRO: Insecta) A layer ofpropolis, or hard cerumen plus various other materials thatenclose the nest cavity of a colony of stingless bees.batumen plates (ARTHRO: Insecta) Batumen walls partitioningportions of a larger cavity from that utilized as a nest cavityby stingless bees.bave n. [F. bave, drivel] (ARTHRO: Insecta) The double threadof fluid silk spun by caterpillars.B-chromosome, supernumerary, accessory or extrachromosomes Any chromosome of a heterogeneous categoryof chromosomes that differ in their behavior fromnormal or A-chromosomes.bdelloid a. [Gr. bdella, leech; eidos, form] Being leech-like inappearance.bead n. [A.S. gebed, prayer] (MOLL: Bivalvia) A rounded rib

Online Dictionary of Invertebrate Zoology 117protuberance.beaded see moniliformbeak n. [OF. bec, beak] 1. Anything projecting and ending in apoint. 2. (ARTHRO) a. In Chelicerata, the gnathosome ofacarines. b. In Crustacea, the anteroventral projection ofthe free margin of the carapace; not equivalent to rostrum.c. In Insecta, the snout, proboscis, or rostrum; in Homoptera,usually 3-segmented, arising from the ventroposteriorof the head and directed backward under the body. 3.(BRACHIO) The pedicel valve. 4. (BRYO) The avicularia. 5.(MOLL) a. An angular projection of the apex of an intermediatevalve; a mucronate valve; a similar projection of theupper surface of the valve anteriorly and between the suturallaminae is termed a false beak. b. In Bivalvia, noselikeangle, along or above the hinge margin, marking thearea of shell growth. c. In Cephalopoda, paired horny mandibles.beaked apex (ARTHRO: Crustacea) In Balanomorpha, the upperangle of the tergum formed into a long narrow point.bean shaped see reniformbeard n. [L. barba, beard] 1. Any tuft of filaments on any partof an organism. 2. (ARTHRO: Insecta) For Diptera, seemystax. 3. (MOLL) see byssus. bearded a.bedeguar, bedegar n. [F. bedeguar, Per. bad-awar, windbrought](ARTHRO: Insecta) A cynipid gall of Rhoditesrosae; a pin-cushion gall.beebread n. (ARTHRO: Insecta) A bitter pollen stored by beesin the honeycomb that when mixed with honey is used forfood by larvae and newly-emerged workers; cerago. seeambrosia, fungus garden.bee dance (ARTHRO: Insecta) A series of movements performedby honeybees upon returning to the hive, that informsother bees of the location of the food source.bee lice (ARTHRO: Insecta) Small, flattened, apterous dipteranflies that are commensal with honeybees, often epizoic onthe workers or queens.bee milk see worker jelly

118Maggenti and Gardnerbees n.pl. [A.S. beo, bee] (ARTHRO: Insecta) The flower-visiting,social or solitary, aculeate hymenopterous insects belongingto the superfamily Apoidea.beeswax n. [A.S. beo, bee; weax, wax] (ARTHRO: Insecta) Awax secreted by glands on the ventral surface of the abdomenof worker bees that is used in the construction ofhoneycombs.belemnoid a. [Gr. belemnon, javelin; eidos, form] Dartlike inshape.bell n. [A.S. belle, bell] 1. Any bell-shaped structure. 2. (CNID)a. In Hydrozoa, the umbrella of jellyfish. b. In Scyphozoa,the nectophores of siphonophores. 3. (NEMATA) The bursa.Bellonci organ see organ of Belloncibell shaped see campanulatebelonoid a. [Gr. belone, needle; eidos, form] Needle-like inshape.benthic a. [Gr. benthos, depths of sea] Pertaining to the seabottom;maybe extended to include some of the benthicanimals: crabs, snails, starfish, certain worms, clams,sponges, sea anemones, corals, bryozoans, crinoids, barnaclesand tunicates.benthopotamous a. [Gr. benthos, depths; potamos, river]Pertaining to organisms or plants living on the bottom of ariver or stream.Bergmann's rule The principal that the average body size isgeographically variable in that the animals are larger in thecooler climates of the range of a species.Berlese's organ see Ribaga's organberry n. [A.S. berie, berry] (ARTHRO: Crustacea) An egg ofcertain Decapoda.besomiform a. [A.S. besma, broom; L. forma, shape] Broomshaped.beta n. [Gr. beta] The second letter of the Greek alphabet ( )used to designate the second in a series, as -chlorophylland -chlorophyll.beta-chlorophyll (ARTHRO: Insecta) The chlorophyll that pro-

Online Dictionary of Invertebrate Zoology 119duces color.beta-female see teratogynebeta taxonomy A level of taxonomy involving the arrangmentof species into a natural system of lower and higher taxa.see alpha taxonomy, gamma taxonomy.bialate a. [L. bis, two; alatus, winged] Two-winged.biangular a. [L. bis, two; angulus, corner, bend] Having twoangles or double keeled.biarcuate a. [L. bis, two; arcuatus, bent like a bow] Twicecurved.biareolate a. [L. bis, two; areolatus, small places] Two celled,or having two areolae. see bilocular.biarticulate a. [L. bis, two; dim. artus, joint] Having twojoints; diarticular.biaxial a. [L. bis, two; axis, axle] Having two axes.bicanaliculate a. [L. bis, two; canalis, a channel] Having twochannels or grooves.bicarinate a. [L. bis, two; carina, keel] Having two carinae orkeel-like projections.bicaudal, bicaudate a. [L. bis, two; cauda, tail] Possessingtwo tails or anal processes.bicellular a. [L. bis, two; cellula, little cell] Composed of twocells.biciliate a. [L. bis, two; cilium, eyelash] Furnished with twocilia, flagella, or elaters.biconcave a. [L. bis, two; concavus, hollow or arched inward]Being concave on both sides; amphicoelous. see amphicyrtic.bicondylic see dicondylicbiconic a. [L. bis, two; Gr. konos, cone] Being formed as twocones placed base to base.biconvex a. [L. bis, two; convexus, arched outward] Beingconvex on opposite sides; lens-shaped. see amphicyrtic,amphicoelous.bicorn a. [L. bis, two; cornu, horn] Bearing two horns; cres-

120Maggenti and Gardnercentlike.bicornuate a. [L. bis, two; cornutus, horned] Having twohorns or cephalic processes.bicornuate uterus A uterus in which both uteri are fused, buthave short lateral extensions.bicron see nanometerbicuspidate a. [L. bis, two; cuspidatus, pointed] Being doublepointed; having two cusps or points.bidactyl n. [L. bis, two; Gr. daktylos, finger] (ARTHRO) An appendage,ambulacrum, apotele, or claw with two lateralungues. see monodactyl, tridactyl.bideficiency n. [L. bis, two; deficare, to be wanting] A form ofphanerotaxy, exhibited by the absence of two of the elementstypically present in a particular organism. seeholotaxy.bidentate a. [L. bis, two; dens, tooth] Having two teeth.bidenticulate a. [L. bis, two; dim. dens, tooth] Having twosmall teeth or tooth-like processes.bidesmatic a. [L. bis, two; Gr. desmos, bond] Pertaining totwo tendons attached at the base of the distal segment ofan appendage; a eudesmatic articulation.bidiscoidal a. [L. bis, two; Gr. diskos, circular plate; eidos,form] Having two disc-shaped parts.bidiverticulate a. [L. bis, two; devertere, to turn away] Havingtwo diverticula.biemarginate a. [L. bis, two; emarginatus, notched at theapex] Having two notches on the border or edge.biennial a. [L. bis, two; annus, year] Occurring once every twoyears.bifacial a. [L. bis, two; facies, face] Having opposite surfacesalike.bifarious a. [L. bis, two; fariam, in rows] Being arranged in 2rows, on either side of an axis; being oriented or pointed inopposite directions.

Online Dictionary of Invertebrate Zoology 121bifasciate a. [L. bis, two; fascia, band] With two broad welldefined bands or fascia.bifenestrate a. [L. bis, two; fenestra, window] (NEMATA: Secernentea)A term used to describe heteroderid fenestradivided by a broad vulval bridge so that it appears to betwo distinct semi-fenestra. see ambifenestrate.bifid a. [L. bis, two; findere, to split] Divided into twobranches, arms, or prongs, or into two equal parts by acleft; separated down the middle by a slit; divided by agroove into two parts.bifilar a. [L. bis, two; filum, thread] Having two filaments,threads, or fibers.biflabellate a. [L. bis, two; flabellum, fan] (ARTHRO) Twice fabellate;a form of antenna with each side of the jointshaving long flattened processes.biflagellate a. [L. bis, two; flagellum, whip] Having two flagella;dikont.biflex a. [L. bis, two; flectere, to bend] Bending in two directions.bifoliate colony (BRYO: Stenolaemata) An erect colony formedby two layers of zooids budding back to back from the interiormultizooidal median wall.bifollicular a. [L. bis, two; folliculus, small sac] Having twofollicles.biforate a. [L. bis, two; forare, to bore] Having two perforations.biform a. [L. bis, two; forma, form] Having two forms, or combiningcharacteristics of two forms.biformes n. [L. bis, two; forma, form] (ARTHRO: Crustacea) Acarapace that reflects sexual dimorphism in differing valveproportions for each sex of the same species.biforous spiracle (ARTHRO: Insecta) An immature's spiraclehaving two entrances (air tubes); annular-biforous spiracles.bifurcate a. [L. bis, two; furca, fork] Divided into twobranches, stems or knobs; two pronged.

122Maggenti and Gardnerbigeminal a. [L. bis, two; geminus, twin] Doubled; paired.bigener n. [L. bis, two; genus, kind] A bigeneric hybrid.bigeneric a. [L. bis, two; genus, kind] Pertaining to hybridsbetween species of different genera.bigiceriate, bigigeriate a. [L. bis, two; gigerium, entrail]Having two gizzards.biguttate a. [L. bis, two; gutta, drop, spot] Having two droplikespots.bijugate a. [L. bis, two; jugum, yolk] Being yoked two together;two-paired.bilabiate spiracle (ARTHRO: Insecta) An elongate or annularspiracle of certain larvae with a pair of projecting lips interiorto the peritreme; one having two lips at the slit-likeentrance.bilamellar a. [L. bis, two; lamella, plate] Having two lamellaeor plates; two-lipped.bilaminar a. [L. bis, two; lamina, thin plate] Consisting of twolamina or thin plates; diploblastic.bilaminate colony (BRYO: Gymnolaemata) A cheilostomatecolony with erect branches comprised of two layers of zooids,each with separate, but common exterior basal walls.bilateral a. [L. bis, two; latus, side] Having two equal or symmetricalsides.bilateral cleavage That in which the blastomeres exhibitmarked bilateral symmetry.Bilateralia, Bilatera A former division of the animal kingdomcontaining all those forms that show bilateral symmetry.bilateral symmetry Symmetry such that a body or part canbe divided through the longitudinal axis by one mediosagittalplane into equivalent right and left halves, each for allpractical purposes a mirror image of the other. see radialsymmetry.biliary vessels see Malpighian tubulesbilineate a. [L. bis, two; lineatus, of a line] Of or pertaining totwo lines; marked with two lines.bilobate, bilobed a. [L. bis, two; lobus, rounded projection]

Online Dictionary of Invertebrate Zoology 123Having two lobes.bilocular a. [L. bis, two; loculus, compartment] Divided intotwo cells, chambers, compartments or loculi.bimaculate a. [L. bis, two; macula, spot] Marked with twospots or stains.bimarginate a. [L. bis, two; margo, border] Having two margins.bimineralic skeleton (BRYO: Gymnolaemata) Zoarium orzooecium composed of layers of calcite and others of aragonite.bimuscular a. [L. bis, two; musculus, muscle] Having twomuscles.binary a. [L. binarius, from bini, pair] 1. Composed of twounits, elements or parts. 2. Refers to designations of twokinds of names. see binominal nomenclature.binary fission A form of asexual reproduction in which a cell,or organism divides into approximately equal parts. seetransverse fission.binary nomenclature see binominal nomenclaturebinate a. [L. bini, pair] Doubled; growing in pairs.binervate a. [L. bis, two; nervus, nerve] Having two nerves orveins.binocular a. [L. bini, pair; oculus, eye] Having two eyes.binodulose a. [L. bis, two; nodulus, little knot] Having twonodes, knobs, or swellings of small size.binomen n. [L. bis, two; nomen, name] The scientific designationof a species, consisting of a generic and a specificname. see binominal nomenclature, trinominal nomenclature.binomial nomenclature A system of nomenclature using twonames, first established for animals by Linnaeus in 1758and now generally referred to as binominal nomenclature.binominal a. [L. bis, two; nomen, name] Consisting of twowords or names.binominal nomenclature The system of nomenclatureadopted by the International Congress of Zoology, by

124Maggenti and Gardnerwhich the scientific name of an animal is designated byboth a generic and specific name.binotate a. [L. bis, two; nota, mark] Having two roundedspots.binovular a. [L. bini, pair; ovum, egg] Pertaining to two ova.binucleate a. [L. bis, two; nucleus, kernel] Having two nuclei.bioassay see biological assaybiocellate a. [L. bis, two; dim. oculus, eye] Having two ocelli.biocenose n. [Gr. bios, life; koinos, common] A community ofplants and animals that occupy a particular habitat; a bioticcommunity. see biocoenosis.biochemistry n. [Gr. bios, life; chemeia, chemistry] Biologicalor physiological chemistry; the chemistry of living organisms.biochore n. [Gr. bios, life; choros, place] A subdivision of biocycle,comprising a group of similar biotopes large enoughto form a recognizable habitat. see chore.biochrome n. [Gr. bios, life; chroma, color] Any natural pigmentfound in a living organism. see indigoid biochrome,quinone biochrome, schemochrome.biocoen n. [Gr. bios, life; koinos, common] All of the livingcomponents of an environment.biocoenosis n.; pl. -noses [Gr. bios, life; koinos, common] 1.A community of organisms occupying a biotope. 2. An aggregationof fossils comprised of the remains of organismsliving together. see thanatcoenosis.biocommunication n. [Gr. bios, life; L. communicare, tocommunicate] The process of conveyance or transfer ofinformation between non-human organisms.biocontrol see biological controlbiocycle n. [Gr. bios, life; kyklos, circle] Subdivisions of thebiosphere: land, sea and freshwater.biodegradable a. [Gr. bios, life; L. de, down; gradatus, step bystep; abilis, tending to be] Substances that can be brokendown by micro-organisms (mainly aerobic bacteria).biodemography n. [Gr. bios, life; demos, people; graphein, to

Online Dictionary of Invertebrate Zoology 125write] A science concerned with the statistical study of theecology and genetics of a given population.bioecology n. [Gr. bios, life; oikos, house; logos, discourse]The study of the interrelationships of plants and animalsand their environment.bioelectricity n. [Gr. bios, life; elektron, amber] The electricphenomena within living tissues.bioenergetics n. [Gr. bios, life; energos, active] The science ofconditions and laws governing the manifestation of energyin living organisms.biogen n. [Gr. bios, life; genos, beginning] The hypotheticalprotoplasmic unit of which cells are composed; precursor ofbios.biogenesis n. [Gr. bios, life; genesis, beginning] The doctrinethat living organisms originate from antecedent life. seeabiogenesis, neobiogenesis.biogenetic law The recapitulation theory of Haeckel that "ontogenyrecapitulates phylogeny". see palingenesis.biogenous a. [Gr. bios, life; gennaein, to produce] Being producedfrom living in or on other living organisms; providinglife.biogeny n. [Gr. bios, life; genesis, beginning] The evolution oforganisms, comprising ontogeny (individual) and phylogeny(tribal).biogeochemistry n. [Gr. bios, life; ge, earth; chemeia, chemistry]The study of the distribution and movement ofchemical elements within living organisms and their interactionwith the geographical environment.biogeography n. [Gr. bios, life; ge, earth; graphein, to write]That biological science dealing with the geographical distributionof plants and animals. see zoogeography.bioherm n. [Gr. bios, life; herma, mound] A body of rock composedlargely of sedentary organisms such as corals andmollusks.biological a. [Gr. bios, life; logos, discourse] Pertaining to biology,the science of living things.biological assay, bioassay The determination of the effect of

126Maggenti and Gardnerany stimulus, physical, chemical, biological, physiological,or psychological, by means of the response which it producesin living organisms or matter.biological classification The arrangement of organisms intotaxa on the basis of inferences concerning their genetic relationship.biological clock An endogenous physiological rhythm, such asmetabolic or behavioural rhythmical changes. see circadian.biological control The reduction in population of undesirableanimals and plants by the intentional introduction of apredator, parasite or disease; biocontrol.biological productivity The increase in biomass, normallymeasured in protein-time units.biological races Noninterbreeding sympatric populations thatare morphologically alike, but physiologically different dueto preference for food or other hosts. see sibling species.biological species concept A concept at the species levelstressing reproductive isolation, and the possession of agenetic program effecting such isolation; biospecies. seespecies.biology n. [Gr. bios, life; logos, discourse] The scientific studyof living things.bioluminescence n. [Gr. bios, life; L. luminescere, to growlight] The production of light by living organisms, as occursin the insect orders of Collembola, Homoptera, Diptera andColeoptera, all ctenophores, some cephalopods, a largenumber of polychaetes, and certain diplopods; biophotogenesis.biolysis n. [Gr. bios, life; lysis, to loosen] The disintegration oflife or organic matter; the decomposition of organic matteras a result of the activity of living organisms; death. biolytica.biomass n. [Gr. bios, life; L. massa, quantity, bulk] The totalweight of a population or other specified group of individualsper unit of area or volume.biome n. [Gr. bios, life] A major biological community of living

Online Dictionary of Invertebrate Zoology 127organisms characterized by distinctive dominant vegetationand associated animals.biometeorology n. [Gr. bios, life; meteoros, high in the air;logos, discourse] The science of the relationship of plantsand animals to weather.biometer n. [Gr. bios, life; metron, measure] An indicator organismthat determines climate and condition acceptability.biometry n. [Gr. bios, life; metron, measure] The statisticalstudy of biological phenomena; the application of mathematicsto the study of living organisms. see biostatistics.biomorphotic a. [Gr. bios, life; morphe, form] Concerning thedevelopment or change of form of a living organism by theformation of tissues.bion n. [Gr. bios, life; on, being] 1. A living, independent organism;a living cell or unit; synonymous with "individual".2. Sometimes used as a variant spelling of biome; a biont.bionomy, bionomics see ecologybiont n. [Gr. bion, life; on, being] A living thing; a member ofa biome.biophagous a. [Gr. bios, life; phagein, to eat] Pertaining to anorganism that feeds upon other living organisms or tissues.biophore, biophor n. [Gr. bios, life; phorein, to carry] A hypotheticalultimate supramolecular unit capable of life.biophotogenesis see bioluminescencebiophysics n. [Gr. bios, life; physis, nature] The application ofthe laws of physics to the study of living organisms.bioplasm n. [Gr. bios, life; plassein, to mold] Protoplasm.bioplast n. [Gr. bios, life; plassein, to mold] 1. A minute massof living protoplasm. 2. An amoeboid cell.biopoiesis n. [Gr. bios, life; poiesis, making] The origination ofthe first living thing, as well as the preceding chemicalhistory.biopotentiality n.; pl. -ties [Gr. bios, life; L. potens, powerful]The potential of a tissue developing into different structures.biopsy n. [Gr. bios, life; opsis, sight] The study of tissues of

128Maggenti and Gardnerliving organisms.biordinal crochets (ARTHRO: Insecta) Crochets of larvae arrangedin a single series or row, but having two alternatinglengths. see ordinal.bios n. [Gr. bios, life] Plant and animal life; organic nature.biosis n. [Gr. biosis, manner of life] 1. The condition of beingalive. 2. The condition of a specific mode of life.biospecies see biological species conceptbiospeleology n. [Gr. bios, life; spelaion, cave; logos, discourse]The scientific study of cave-dwelling organisms.biosphere n. [Gr. bios, life; sphaira, ball] That portion of theearth that contains living organisms, encompassing thesoil, air and water.biostasis n. [Gr. bios, life; stasis, a standing] The ability of organismsto tolerate environmental alterations without beingchanged themselves.biostatics n.pl. [Gr. bios, life; statos, stationary] The scienceof the structure of organisms in relation to their function.biostatistics n. [Gr. bios, life; statos, stationary] The branchof biometry that deals with vital statistics.biostrome n. [Gr. bios, life; stroma, bed] (MOLL: Bivalvia) Biocoenosisof hard shelled, sedentary organisms or sedimentfrom them.biosynthesis n. [Gr. bios, life; synthesis, composition] Theformation of an organic compound by an organism.biosystem see ecosystembiosystematics n. [Gr. bios, life; systema, an ordered arrangementof things] The study of the biology of populationsin respect to evolution and variation of a taxon; experimentaltaxonomy.biota n. [Gr. bios, life] The fauna and flora of an area or region.biotic a. [Gr. biotikos, of life] Of or pertaining to life.biotic insecticide An organism used to suppress a local pestpopulation.

Online Dictionary of Invertebrate Zoology 129biotic potential 1. The reproductive potential of a species. 2.An estimate of the rate of increase of a species in the absenceof predators, parasites or other inhibiting factors.biotonus n. [Gr. bios, life; tonos, tension] The ratio betweenassimilation and dissimilation of a hypothetic unit, cell, organor organelle (biogen).biotope n. [Gr. bios, life; topos, place] 1. An area that is uniformin its main climatic, soil and biotic conditions. 2. Anecological niche with suitable conditions for certain faunaand flora. see biochore, core.biotular spicules (PORIF) Amphidiscs; having scalloped disksthat may occur at both ends of the rhabdome.biotype n. [Gr. bios, life; typos, type] A group of genotypicallyidentical individuals; frequently used interchangeably withthe term race.biovular see binovularbiovulate a. [L. bis, two; ovum, egg] Having two ovules.biparasitic a. [L. bis, two; parasitus, one who eats at the tableof another] Being a parasite upon or in a parasite.biparental a. [L. bis, two; parentalis, parent] Pertaining to orderived from two parents.biparietal a. [L. bis, two; paries, wall] Provided with two paries.biparous a. [L. bis, two; parere, to beget] Producing twoyoung at a time.bipartite a. [L. bis, two; partitus, divided] Having two distinctparts; bifid.bipartite uterus A uterus with paired, tubular uteri that fuseat the point of junction with the vagina.bipectinate a. [L. bis, two; pecten, comb] Having branches ontwo sides like the teeth of a comb.bipectunculate a. [L. bis, two; pectunculus, small scallop] Minutelypectinate.bipennate a. [L. bis, two; penna, feather] Twice pinnate. bipenniforma.bipinnaria larva (ECHINOD: Asteroidea) The free-swimming,

130Maggenti and Gardnerbilaterally symmetrical larva; characterized by ciliated preoraland postoral bands and extending onto lobes projectingfrom the body; dipleurula larva. see brachiolaria.biplicate a. [L. bis, two; plicatus, fold] Twice plaited or folded.bipocillus n. [L. bis, two; poculum, cup] (PORIF) A spicule (microsclere)with a curved shaft and cup-shaped expansion ateither end; in Iophon , one discoid end and one pointed orforked end.bipod a. [L. bis, two; Gr. pous, foot] Having one pair of legs.bipody n. see tetrapod.bipolar a. [L. bis, two; polus, pole] 1. Having two poles orprocesses. 2. Pertaining to the polar regions.bipolarity n. [L. bis, two; polus, pole] 1. Being bipolar. 2.Pertaining to the polar regions, as comparing the flora andfauna between the northern regions and the southern regions,and with that in between. 3. Nerves having processesat both ends.biprostatic a. [L. bis, two; pro, before; stare, to stand] Havingtwo prostates.bipupillate a. [L. bis, two; pupilla, pupil of the eye] 1. Havingtwo pupils. 2. Having two ocelli or spots that resemble twopupils.biradial cleavage Cleavage in which the tiers of blastomeresare symmetrical with regard to the first cleavage plane.biradial symmetry A type of symmetry in which an organismconsists of radially arranged parts, equally arranged oneach side of a median longitudinal plane.biradiate a. [L. bis, two; radiatus, rayed] Having two rays orspokes. see diactinal, diaxon.biramous a. [L. bis, two; ramus, branch] Consisting of twobranches.biramous appendage (ARTHRO: Crustacea) An appendagewith two rami; also antennule or antenna with two flagellarelements; not all appendages of a crustacean are biramous.biramous parapodium (ANN) A parapodium having bundles ofsetae on both noto- and neuropodium.

Online Dictionary of Invertebrate Zoology 131birefringent a. [L. bis, two; refringens, refractive] Havingdouble refraction, high or low according to the differencebetween the refractive indices.birostrate a. [L. bis, two; rostrum, beak] Having two beak-likeprocesses.birotulate spicules (PORIF) A spicule having a disc or series ofradial, umbrella-like spokes at both ends; amphidiscs.birth pore Uterine pore; birth opening.bisegment n. [L. bis, two; segmentum, piece] One of twoequal segments of a line.biseptate a. [L. bis, two; septum, partition] Having two partitions.biserial a. [L. bis, two; series, row] Arranged in two rows, orsubdivided into two series.biserial crochets (ARTHRO: Insecta) Crochets of larvae withproximal ends arranged in two, usually concentric rows.see serial crochets.biserrate a. [L. bis, two; serra, saw] Having two notched orsaw-teeth.bisetose a. [L. bis, two; seta, bristle] Having two bristle-likeappendages.bisexual a. [L. bis, two; sexus, sex] 1. Of or pertaining to bothsexes. 2. A population composed of functional males andfemales. 3. An individual possessing functional male andfemale reproductive organs; hermaphrodite.bisinuate a. [L. bis, two; sinuare, to bend] Twice winding orbending; having two sinuations or notches.bistrate a. [L. bis, two; stratum, layer] Having two layers oftissues.bisulcate a. [L. bis, two; sulcus, groove] Of or pertaining totwice scored or grooved.bithecal a. [L. bis, two; theke, case] 1. Having two thecae. 2.(ANN) Having two spermathecae.bituberculate a. [L. bis, two; tuberculum, swelling] Havingtwo tubercles or swellings.biuncinate a. [L. bis, two; uncus, hook] Having two hooks.

132Maggenti and Gardnerbivalent a. [L. bis, two; valens, strong] 1. Having two completelyor partially homologous chromosomes pairing duringthe first meiotic division. see univalent. 2. Double orjoined in pairs; pertaining to an articulation permitting levatorand depressor movements.bivalve a. [L. bis, two; valvae, a folding door] Having twovalves or parts; clamlike.Bivalvia, bivalves n., n.pl. [L. bis, two; valvae, a folding door]A class of marine, estuarine or freshwater bivalve mollusks,in which the body is enclosed within two calcareous valves,or shells; other names for this class are Acephala, Conchifera,Pelecypoda, Conchophora, Dithra, Lamellibranchia,Lamellibranchiata, Elatobranchiata, Cormopoda, Tropipoda,Aglossa, Elatocephala, Anodontoda and Lipocephala.bivittate a. [L. bis, two; vitta, band] Having two broad longitudinalstripes or vittae.bivium n. [L. bivius, two-way] (ECHINOD: Asteroidea) Collectively,the two rays of a sea star, between which lies themadreporite. see trivium.bivoltine a. [L. bis, two; It. volta, time] Having two sets of offspringa year. see polyvoltine.bivulvar a. [L. bis, two; vulva, vulva] Having two vulvae in asingle female.bladder n. [A.S. blaeddre, bag] Any membranous sac or vesiclefilled with air or fluid.blade n. [A.S. blaed, leaf] 1. Any elongate, flattened, usuallystiff structure shaped like a leaf, sword or knife. 2. (AR-THRO: Insecta) The lacinia or galea. 3. (NEMATA) see lamina.blastaea n. [Gr. blastos, bud] Hypothetical animal ancestral toall metazoans; inferred from the blastula as a commonstage in the development of higher invertebrate animals.blastema n.; pl. -temata [Gr. blastema, bud] 1. Undifferentiatedcells that later develop into an organ or structure. a.The part of an organism that gives rise to a new organism,as in asexual reproduction. b. That which often gives rise toregeneration of a lost part or appendage. see anlage.

Online Dictionary of Invertebrate Zoology 133blastocephalon n. [Gr. blastos, bud; kephale, head] (ARTHRO:Insecta) The head of an embryo.blastocheme n. [Gr. blastos, bud; ochema, vehicle] (CNID) Areproductive bud in certain medusae.blastochyle n. [Gr. blastos, bud; chylos, juice] Fluid containedin a blastocoel.blastocoel(e) n. [Gr. blastos, bud; koilos, hollow] The primarycavity formed during the embryological development ofanimals; segmentation cavity; the subgerminal cavity.blastocyst n. [Gr. blastos, bud; kystis, bladder] (PLATY:Cestoda) In Trypanorhynca, a posterior bladder of themetacestode into which the body is withdrawn.blastocyte n. [Gr. blastos, bud; kytos, container] An embryoniccell before differentiation.blastoderm n. [Gr. blastos, bud; derma, skin] The primaryepithelium formed in early embryonic development of manyinvertebrates; germinal membrane.blastogenesis n. [Gr. blastos, bud; genesis, beginning] 1. Developmentby asexual reproduction, or of an organ or partfrom a blastema. 2. The transmission of inherited charactersby germ plasm. see embryogenesis.blastogenic a. [Gr. blastos, bud; genos, birth] Originating ingerm cells.Blastoidea, blastoids n., n.pl. [Gr. blastos, bud; eidos, form]A class of extinct echinoderms of the former SubphylumPelmatoza; Ordovician to Permian.blastokinesis n. [Gr. blastos, bud; kinesis, movement] Displacements,rotations and revolutions of an embryo withinan egg.blastomere n. [Gr. blastos, bud; meros, part] Cells formedduring primary cleavage of an egg, before the formation ofa distinct gastrula stage.blastophore n. [Gr. blastos, bud; phorein, to bear] 1. The externalopening of the enteron of a gastrula. 2. (ANN) Theendodermal cells brought into an internal position in theembryo during the mitotic division.blastopore n. [Gr. blastos, bud; poros, passage] The mouth-

134Maggenti and Gardnerlike opening from the archenteron to the exterior duringthe gastrula stage of development.blastostyle n. [Gr. blastos, bud; stylos, pillar] (CNID: Hydrozoa)The living axial portion of a modified gonangium, fromwhich numerous medusae are budded.blastozooid n. [Gr. blastos, bud; zoion, animal; eidos, form] Azooid or individual produced by asexual reproduction. seeoozooid.blastula n., pl. -lae [Gr. dim. blastos, bud] A stage near theend of cleavage, in the form of a hollow sphere bounded bya single layer of cells.blister n. [A.S. blastr, a swelling] Any vesicle or raised spot onthe surface of an organism.Blochmann's body (ARTHRO) Any intracellular organisms inthe egg; mainly bacteria; thought to be symbiotic.blood n. [A.S. blod, blood] The variously colored or colorlessfluid circulating in the vascular system or body cavity ofanimals, usually containing respiratory pigments, and carryingoxygen, food-materials, excretions, etc.blood cells Cellular elements of the blood; hemocytes; plasmatocytes.blood channel (ARTHRO: Insecta) In predacious larvae, achannel, either internal (duct or tube) or external (excavationor groove), usually extending the full length of the innermargin of the mandible.blood gills (ARTHRO: Insecta) Thin walled respiratory or osmoregulatoryevaginations continuous with the hemocoeland filled with blood, occurring in, but not confined toaquatic larvae.blood rooms (ARTHRO: Crustacea) In Conchostraca, a networkof anastomosing cavities in the body that function in bloodcirculation.blood sinus (MOLL: Bivalvia) A blood vessel which is irregularin shape without specialized walls.blood tube see blood channelblood vessel Any vessel or canal facilitating blood circulation.

Online Dictionary of Invertebrate Zoology 135blotch n. [OF. block, a clod of earth] A large irregular spot ormarking.blunt v. [uncertain origin] To dull; to neutralize or dilute.boat-shaped see navicular, scaphoidbody n. [A.S. bodig, body] 1. The physical structure of an organism.2. The main part of an organism as compared toits limbs or appendages. 3. The trunk. 4. The corpus.body cavity The principal cavity between the body wall andinternal organs of an organism: coelom, pseudocoelom orhemocoelom.body of Giardini see chromatin bodybody ring (ARTHRO: Crustacea) In Notostraca, the combinedtergite and sternite of a single somite, with or without legs.body somite (ARTHRO: Crustacea) A unit division comprisingthorax and abdomen. see cephalic somite.body valve see intermediate valvebody wall 1. The integument, the outer layer of many invertebrates,comprising the epidermis (hypodermis) and the cuticle.2. (BRYO) The wall enclosing the body cavity of a colonyand its parts. 3. (ECHI) The dermal, glandular, muscularand epithelial tissues that make up the wall of thetrunk.body whorl see last whorlbolsters n.pl. [A.S. bolster, support] (MOLL) A pair of supportsand muscle attachments for the radula.bolus n. [Gr. bolos, lump] Any rounded mass, such as collectedor chewed food.bombifrons n.pl. [F. bombe, convex; L. frons, forehead] (AR-THRO: Insecta) A rounded, blister-like protuberance on theforward part of the head.bombous a. [F. bombe, convex] A curved or rounded surface;blister-like.bombycic acid (ARTHRO: Insecta) An acid utilized by certainmoths to dissolve the gum binding the silk threads of thecocoon at imago emergence.bombycinous a. [Gr. bombycinus, silken] Of silk, or pale yel-

136Maggenti and Gardnerlow resembling fresh spun silk.book gill (ARTHRO: Chelicerata) In Merostomata, a gill composedof thin plates or lamella.book lung (ARTHRO: Chelicerata) A series of leaf-like respiratorypouches of arachnids, located on the internal ventralsurface of the abdomen, and believed to be modified insunkengills.bopyridum n. [NL. Bopyrus, type genus] (ARTHRO: Crustacea)In Malacostraca, a postlarva of an epicaridean isopod thatattaches to a permanent host.Bordas' gland (ARTHRO: Insecta) A paired, or fused into one,accessory gland of the sting apparatus of certain Hymenoptera,composed of multiple, densely packed cells whosecanaliculi end with a gathering duct; function unknown.boreal a. [L. boreas, north wind] Of or belonging to the northernbiogeographical region.borer n. [A.S. borian, bore] 1. An invertebrate that bores. 2.(ARTHRO: Insecta) An adult or larva that makes channels inwoody or vegetable tissue. 3. (MOLL: Bivalvia) A pelecypodthat burrows in stone or wood. 4. (MOLL: Gastropoda) Onethat bores through the shell of an oyster or other mollusk.boss n.; pl. bosses [F. bosse, hump] 1. Any protruberant part,prominence or swelling. 2. (ARTHRO: Chelicerata) In Arachnida,a smooth lateral prominence at the base of a cheliceraof spiders. 3. (ARTHRO: Crustacea) An umbo. 4. (AR-THRO: Insecta) In Diptera, a sclerotized, elevated area atthe base of the ventral brush in certain Culicidae larvae. 5.(ECHINOD: Echinoidea) The base of a spine on a sea urchintest. 6. (MOLL: Gastropoda) A rounded elevation of a shell,larger than a tubercle.bosselated a. [F. bosse, hump] Being covered with smallknob-like projections, composed of or covered with smallprotuberances.bothridial seta (ARTHRO: Chelicerata) Variously shaped setainserted into a bothridium.bothridium n.; pl. -ria [Gr. dim. bothros, trench] 1. (ARTHRO:Chelicerata) A chitinous cavity or projecting cup in which abothridial seta is inserted; (bothridial seta + bothridium =

Online Dictionary of Invertebrate Zoology 137trichobothrium). 2. (PLATY: Cestoda) One of 4 muscularlappets on the scolex of a tapeworm, often highly specializedwith many types of adaptations for adhesion.bothriotrichia n.pl. [Gr. bothros, trench; trichos, hair] (AR-THRO: Insecta) Slender seta arising from indentions in thetegument. bothronic a.bothrium n.; pl. -ria [Gr. bothros, trench] (PLATY: Cestoda)Dorsal or ventral grooves on the scolex that may be variouslymodified in the form of ruffles, or fused so as to forma tubular structure.botrucnids n.pl. [Gr. botrys, bunch of grapes; knide, nettle](CNID: Anthozoa) The septal filaments of certain mesentariesof tube anemones.botryoidal a. [Gr. botrys, bunch of grapes; eidos, form] In theform of a bunch or cluster of grapes.botryoidal tissue (ANN: Hirudinoidea) Connective tissue presentin the enteric canals.botryology n. [Gr. botrys, bunch of grapes; logos, discourse]The science of organizing objects or concepts into groupsand clusters.bottle-shaped see lagena, ampulla, ampulliformbouquet stage A meiotic prophase stage, including leptotene,zygotene and pachytene, in certain species where thechromosomes are oriented by one or both ends towardsone point of the nuclear envelope.bourrelet n. [F. bourrelet, circular pad] 1. A ridgelike prominenceor rounded edge. 1. (ARTHRO: Insecta) see parameres.2. (ECHINOD) A raised prominence on the interambulacralplates at the edge of the mouth. 3. (MOLL: Bivalvia)A ligamental area anterior and posterior to the resilifer.bourses copulatrices see copulatory chamberbouton n. [F. bouton, bud] (ARTHRO: Insecta) A lappet-liketerminal process of the glossa of bees; spoon; flabellum.bowlike see arc, arcuatebox n.; pl. boxes [A.S., fr. 1. buxus, boxwood] (MOLL: Bivalvia)A pair of empty, attached hinged (valves) shells of oysters.

138Maggenti and Gardnerbrachelytra n.pl. [Gr. brachys, short; elytron, sheath] (AR-THRO: Insecta) Having shortened wing covers or elytra.brachelytrous a.brachia n.pl. [L. brachium, arm] 1. Processes like arms. 2.(ARTHRO: Insecta) a. Paired, unfused processes resemblingarms surrounding the aedeagus; clasper; paramere. b. Atracheal or blood gill. 3. (BRACHIO) see brachidium.brachial a. [L. brachium, arm] 1. Pertaining to an arm-likeprocess or appendage. 2. (ARTHRO: Insecta) Pertaining tothe fore wing.brachial canal (CNID: Scyphozoa) A canal in the oral arm ofmedusae.brachial basket (ARTHRO: Insecta) In Odonata, a barrel-likechamber in the anterior two-thirds of the rectum that functionsby the intake and expulsion of water; rectal gills.brachial valve (BRACHIO) A valve containing any skeletal supportfor the lophophore, generally smaller than the pediclevalve; dorsal valve.brachidium n.; pl. brachidia [L. dim. brachium, arm](BRACHIO) The internal skeleton or brachial support for thelophophore, consisting of a calcareous loop or spire.brachiolaria n.; pl. -lariae [L. dim. brachium, arm] (ECHINOD:Asteroidea) The free-swimming, ciliated larva that developsfrom the bipinnaria and is characterized by three additionalarms extending from the anterior part of the ventral surface,anterior to the preoral loop.brachiole n. [L. dim. brachium, arm] (ECHINOD: Crinoidea) Theslender arm or arms extending from the ambulacralgroove.brachiophores n. [L. brachium, arm; Gr. phorein, to bear](BRACHIO) Blades of the secondary shell projecting fromthe side of the notothyrium and forming anteromedianboundaries of sockets in some brachial valves.Brachiopoda, brachiopods n.; n.pl. [Gr. brachys, short;pous, foot] A phylum of relatively small, solitary coelomatesenclosed within a bivalved shell and usually attachedto the substrate by a pedicle; common called lamp shells;brachiopods have one of the longest and best recorded fos-

Online Dictionary of Invertebrate Zoology 139sil histories in the animal kingdom.brachitaxis n.; pl. -taxes [Gr. brachium, arm; taxis, arrangement](ECHINOD: Crinoidea) A series of brachials extendingfrom radial or biradial to the distal extremity of thearm.brachium see brachiabrachycerous a. [Gr. brachys, short; keras, horn] Bearingshort antennae.brachydactyly n. [Gr. brachys, short; daktylos, digit] Abnormallyshort digits.brachymeiosis n. [Gr. brachys, short; meiosis, to makesmaller] Meiosis with the second meiotic division omitted.brachypleural a. [Gr. brachys, short; pleuron, side] (ARTHRO:Insecta) Pertaining to shortened pleura or side plates.brachypodous a. [Gr. brachys, short; pous, foot] Bearing ashort stalk or legs.brachypterous a. [Gr. brachys, short; pteron, wing] (ARTHRO:Insecta) Having short or abnormally short wings that donot cover the abdomen. see macropterous.brachypterous neoteinic see nymphoid reproductivebrachyptery see brachypterousbrachystomatous a. [Gr. brachys, short; stoma, mouth] (AR-THRO: Insecta) Having a short proboscis, as certain Diptera.brachytrachea n.; pl. -eae [Gr. brachys, short; tracheia,windpipe] (ARTHRO: Chelicerata) In Acari, an elongate, saclikestructure, sometimes branched, that functions in respiration.brachyurous a. [Gr. brachys, short; oura, tail] Having a reducedabdomen; having a short tail.braconid venom gland (ARTHRO: Insecta) A type of venomgland where numerous gland tubes end basically in thereservoir that has muscles but no glandular elements. seeapid venom gland.bract n. [L. bractea, small leaf] (CNID: Hydrozoa) A protectivemedusoid (hydrophyllium or phyllozooid) siphonophoran

140Maggenti and Gardnerwith a simple or branched gastrovascular canal.bracteiform a. [L. bractea, small leaf; forma, shape] Bractlike.bracteose a. [L. bractea, small leaf] With numerous bracts.bradyauxesis n. [Gr. bradys, slow; auxesis, growth] A form ofheterauxesis in which the growth process of a part is lessthan that of the whole. see isauxesisbradygenesis n. [Gr. bradys, slow; genesis, beginning] Retardeddevelopment in ontogeny. see tachygenesis.bradytelic a. [Gr. bradys, slow; telos, completion] Pertainingto evolution, evolving slowly; slower than the standardrate. see horotelic.brain n. [A.S. braegen, brain] 1. The nervous center of invertebrates.2. (ARTHRO) The cephalic nerve mass; the encephalon,the supraesophageal ganglion; the archicerebrum.3. (NEMATA) The nerve ring and associated ganglia.brain hormone (ARTHRO: Insecta) A secretion of the brain activatingthe prothoracic glands.branch n.; pl. branches [OF. branche, branch] 1. That whichputs forth branches. 2. A primary division of a taxonomicgroup. 3. A gill.branched see ramifybranchia n.; pl. -chiae [Gr. branchia, gills] Respiratory organs;a gill; a ctenidium.branchial a. [Gr. branchia, gills] Pertaining to gills or branchiae.branchial aperture The exterior opening of a gill chamber.branchial basket (ARTHRO: Insecta) In Odonata, a chamber ofthe rectum that contains the rectal gills.branchial carina (ARTHRO: Crustacea) In Decapoda, that partof the carapace extending posteriorly from the opening(orbit) in the anterior face over the branchial region.branchial chamber (ARTHRO: Crustacea) That area betweenthe body and carapace enclosing the branchiae; the gillchamber.branchial cleft A gill slit.

Online Dictionary of Invertebrate Zoology 141branchial crown (ANN: Polychaeta) A structure surroundingthe terminal mouth composed of ciliated, bipinnate filamentsfunctioning in suspension filter feeding and respiration;tentacular crown.branchial glands 1. (ARTHRO: Crustacea) Masses of connective-tissuecells, lacking ducts, that surround the venouschannels in branchiae. 2. (MOLL: Cephalopoda) Glandsalong the gill where they connect with the mantle; site ofhemocyanin production.branchial heart (MOLL: Cephalopoda) One of two hearts thatpumps blood to the gills of squid.branchial passage (MOLL: Bivalvia) A passage in gills thatcarries parts of the exhalant water system.branchial plume (ANN: Polychaeta) In certain Sabellidae andSerpulidae, a structure around the terminal mouth comprisedof semicircular lobes bearing a few to a series ofgrooved, ciliated filaments or radioles, each with a series ofpaired ciliated side branches or pinnules functioning in filterfeeding and respiration.branchial ray A gill ray.branchial region (ARTHRO: Crustacea) In Decapoda, the lateralpart posterior to the pterygostomial region, overlyingthe branchiae.branchial siphon (MOLL) The incurrent siphon.branchiate a. [Gr. branchia, gills] Having gills or branchiae.branchicolous a. [Gr. branchia, gills; colere, to inhabit] Parasitizinggills.branchiform a. [Gr. branchia, gills; forma, shape] Shaped likegills.branchiocardiac a. [Gr. branchia, gills; kardia, heart] Pertainingto gills and heart.branchiocardiac carina (ARTHRO: Crustacea) That part of acarapace dividing the branchial and cardiac region.branchiocardiac groove (ARTHRO: Crustacea) In Decapoda,an oblique groove on each side of the carapace separatingthe branchial and cardiac regions.

142Maggenti and Gardnerbranchiocardiac sinus (ARTHRO: Crustacea) One of severalsinus channels that facilitates blood flow from the gills tothe pericardial sinus and then to the heart.branchiopallial a. [Gr. branchia, gills; L. pallium, mantle](MOLL) Pertaining to the gill and mantle.branchiopneustic a. [Gr. branchia, gills; pneustikos, ofbreathing] (ARTHRO: Insecta) Pertaining to a form of respirationin larvae where the spiracles are functionally replacedby gills.branchiostegal area (ARTHRO: Crustacea) That part of a carapaceextending laterally and ventrally over the branchiae.branchiostegal spine (ARTHRO: Crustacea) In Decapoda, aspine on the carapace between the antennal and pterygostomialspines.branchiostegite n. [Gr. branchia, gills; stegos, roof] (ARTHRO:Crustacea) Expanded dorsal and lateral branchial region ofthe carapace that covers the gills.branchireme n. [Gr. branchia, gills; remus, oar] (BRACHIO)Any limb.branchitellum n.; pl. branchitella [Gr. dim. branchia, gills;telos, end] (MOLL: Bivalvia) A point on the posterioventralshell margin of oysters at the aboral end of the gills nearthe palliobranchial fusion.breakage plane or joint The site of autotomy in invertebrates.breastbone n. [A.S. breost, front of the chest; ban, bony] 1.The sternum. 2. (ARTHRO: Insecta) In certain dipterous larvae,a horny ventral process behind the oral opening, representingthe labium; anchor process; sternal spatula.breathing pore see spiraclebrephic a. [Gr. brephos, embryo] 1. Pertaining to an earlystage of development. 2. (BRACHIO) The juvenile stage inshell development after protegulum, shown by presence ofgrowth lines; from neanic shells, distinguished by absenceof radial ornamentation.brevaceratuba n.; pl. -tubae [L. brevis, short; cera, wax;tuba, trumpet] (ARTHRO: Insecta) A wax gland of scale in-

Online Dictionary of Invertebrate Zoology 143sects with an outlet short of the margin of the pygidium.breviate a. [L. brevis, short] 1. Shortened; smaller than normal.2. (ARTHRO: Insecta) Used to describe antennae thatare about the length of the head.brevicaudate a. [L. brevis, short; cauda, tail] Having a shorttail.brevilingual a. [L. brevis, short; lingua, tongue] Having ashort tongue.breviorate antennae (ARTHRO: Insecta) A term to describeantennae extending passed the head, but short of the bodylength. see brevissimate antenna.breviped a. [L. brevis, short; pes, foot] Having short legs.brevipennate a. [L. brevis, short; penna, wing] Having shortwings.brevirostrate a. [L. brevis, short; rostrum, beak] Having ashort beak or rostrum.brevissimate antennae (ARTHRO: Insecta) Antennae lengthshorter than head length.bridge n. [A.S. brycg, bridgework] 1. Chromosome arrangementat anaphase of meiosis produced from a dicentricstrand. 2. (ARTHRO: Insecta) In Odonata, a connecting wingvein.bridge cross vein (ARTHRO: Insecta) A cross vein anterior tothe bridge vein.bridging host An intermediate host that allows a parasite togo to a previously unsuitable host.bridle see frenulumbrin n. (ARTHRO: Insecta) A filament of silk of silkworms; whencoated with sericin, two adhere together, forming the bave.Brindley's gland (ARTHRO: Insecta) In certain adult Heteroptera,simple sac-like structures of the scent gland system,occurring in the hemocoele below the first visible abdominaltergite, towards the lateral margin.bristle n. [A.S. byrst, hair] Any of various stiff, coarse hairs orhairlike structures.bristle setae (NEMATA: Adenophorea) Ambulatory setae func-

144Maggenti and Gardnertioning in traction.brit n. sing. & pl. [Corn. bryth, speckeled] The minute marineanimals, mainly crustaceans, that form an important link inthe food chain of the aquatic environment.brochosomes n.pl. [Gr. brochos, cord; soma, body] (ARTHRO:Insecta) In leafhoppers, ultramicroscopic reticulated bodies,products of the Malpighian glands.bromatium n.; pl. bromatia [Gr. broma, food] A hyphal swellingon the fungus cultured by fungus ants on organic debrisin underground galleries.bronchia see tracheabrood n. [A.S. brod] The individuals hatched at the same timefrom eggs by a single parent and normally mature at aboutthe same time.brood canal (ARTHRO: Insecta) In Stylopidea, the passagebetween the female parasite and its puparium; a broodchamber.brood capsule (PLATY: Cestoda) A small hydatid cyst containing10 to 30 protoscolices; parasites of carnivores.brood chamber 1. (ARTHRO: Crustacea) a. In Cladocera, adorsal space between the trunk and enveloping carapacecontaining developing eggs and newly hatched young. b. InPeracarida, a space arising from the coxae of the thoraciclimbs, forming a marsupium in which eggs develop directly,without external metamorphosis. 2. (ARTHRO: Insecta) seebrood canal. 3. (BRYO) a. In Gymnolaemata, water-filledspace partly enclosed by the body wall of one or morepolymorphs, in which embryos grow during development.see ovicell. b. In Stenolaemata, a zooidal or extrazooidalinternal coelomic chamber that encloses eggs developinginto larvae. 4. (ECHINOD) see marsupium. 5. (MOLL: Gastropoda)In female Argonauta , a beautiful, calcareous, bivalvecase secreted by the two dorsal arms into which theeggs are deposited; females retain and usually remain withthe posterior of her body in the case; when disturbed, shewithdraws completely into the retreat.brood pouch Any space or sac-like cavity utilized as a uterus,in which eggs or embryos are developed; a brood chamber,

Online Dictionary of Invertebrate Zoology 145ovisac or marsupium.broom shaped see besomiformbrown bodies 1. (ANN: Oligochaeta) Spheroidal, ellipsoidal ordiscoidal masses, free in the coelomic cavities, containingcorpuscles or brown debris, setae, cysts of parasites,nematodes and various other foreign bodies. 2. (BRYO) InStenolaemata and Gymnolaemata, an encapsulated massof degenerating cells from the lophophore, gut, musclesand other nonskeletal parts of a zooid, retained in the bodycavity or expelled after regeneration of feeding and digestiveorgans. see brown deposit. 3. (ECHINOD: Holothuroidea)Small clumps of amoebocytes, parasites and otherejecta found in the coelom.brown deposit (BRYO: Stenolaemata) Granular deposits of ironoxide or pyrite believed to be fossilized organic material oforgans or brown bodies of degenerated organs.brownian movement The continual vibratory movement ofsmall particles dispersed in a fluid medium, as a result ofbombardment by the molecules of the medium.Brunner's organ (ARTHRO: Insecta) A soft tubercle at the baseof the hind femur of grasshoppers, against which the caudaltibiae press when at rest.brush border Projections of microvilli free on the surface ofepithelial cells that produce a brush-like appearance.brushes n.pl. [OF. broisse, brushwood] 1. A cluster of bristles,stout hairs or scales. 2. (ARTHRO: Insecta) a. In Diptera,anterior "mouth bristles" of some mosquitoe larvae, thatmay or may not be prehensile; posterior or respiratory siphonarea bristles. b. In Lepidoptera, anterior pheromonehair-like scales of noctuid moths, or posterior abdominalbrush of smooth hairs, function unknown.brush-organs (ARTHRO: Insecta) In male Lepidoptera, anteriorphermone-producing paired glands, storage organs anddistributive brushes functioning to elaborate and dispersesex attractants.brustia (ARTHRO: Insecta) Small spines or setae on the mandibles.Bryozoa, bryozoans n.; n.pl. [Gr. bryon, moss; zoon, animal]

146Maggenti and GardnerA phylum of sessile aquatic coelomates, formerly subdividedinto Ectoprocta and Entoprocta, and commonly calledmoss animals.bucca n.; pl. buccae [L. bucca, cheek] 1. The cheek. 2. (AR-THRO: Insecta) That area on both sides of the head belowthe compound eye and just above the mouth opening.buccal a. [L. bucca, cheek] Pertaining to the mouth or cheek.bucally adv.buccal appendage (ARTHRO) Any articulating mouth part.buccal cavity 1. The mouth or oral cavity. 2. (NEMATA) Thestoma.buccal cone (ARTHRO: Chelicerata) In Acarina, that portion ofthe mouthparts composed of hypostome and labrum.buccal field (ROTIF) A division of the corona; pertaining to thearea surrounding the mouth.buccal fissure The mouth opening.buccal frame (ARTHRO: Crustacea) In Brachyura, the structuralregion of the cephalon that encloses the mouthparts.buccal funnel (ARTHRO: Insecta) In Siphunculata, that portionof the fore-intestine that extends into the pharynx.buccal groove (ARTHRO: Crustacea) In Nephropidae, a transversegroove that connects the gastroorbital and antennalgrooves crossing the mandibular elevation behind the antennalspine.buccal mass (MOLL) A bulging mass comprising the radula andassociated structures.buccal tentacles/cirri (ANN) Elongate or digitiform food gatheringappendages in or around the mouth.buccal tube 1. (ARTHRO: Insecta) see food meatus. 2. (ROTIF)The tubular, ciliated area between the mouth and mastax.buccate a. [L. bucca, cheek] Having distended or protuberantcheeks.bucciniform a. [L. buccinum, a horn-shaped mollusk; forma,shape] (MOLL: Gastropoda) Resembling a trumpet shape;resembling the shape of a Buccinum mollusk.buccopharyngeal a. [L. bucca, cheek; Gr. pharynx, throat] 1.

Online Dictionary of Invertebrate Zoology 147Pertaining to the cheeks and pharynx. 2. Pertaining to themouth and pharynx.buccopharyngeal armature see cephalopharyngealskeletonbuccopharyngeal/salvary gland (MOLL: Gastropoda) In predaciousProsobranchia, a gland producing a sulfuric acidcontainingsecretion that is injected into its victim.bucculla n.; pl. buccullae [L. dim. bucca, cheek] (ARTHRO:Insecta) One of two ridges on the underside of the head oneither side of the beak or rostrum.Bucephalus cercaria (PLATY: Trematoda) Larva of the furcocercousgroup with the oral sucker on the midventral surfaceas in adults, with the tail arising from a large bulbousstructure instead of a stem.Buchner funnel A funnel with an interior perforated plate onwhich filter paper is placed that functions in vacuum filtration.bud n. [ME. budde, bud] A young individual produced by budding,prior to detachment from the parent.budding n. [ME. budde, bud] 1. The asexual reproduction of anew individual as the result of an outgrowth or bud fromthe parent organism. 2. (ARTHRO: Insecta) see colony fission.buffered populations Populations of organisms affecting oneanother in such a way as to maintain a population densitymean.buffer species An alternative food for a predator, thereby,buffering the effect of the predator on its normal prey.Bugel organ (ARTHRO: Insecta) A sense organ attached to theback of the tympanum, containing two scolopidia supportedby an apodemal ligament and an invagination of the tympanalframe.bulb n. [L. bulbus, a swelling] Any hollow globose organ.bulbose, bulbous, bulbar a. [L. bulbus, a swelling] Pertainingto or resembling a bulb.bulbus ejaculatorius (ARTHRO: Insecta) Ductus ejaculatorius.a. In some Hymenoptera, the swollen almost spherical

148Maggenti and Gardnerstructure. b. In Lepidoptera, the distal part. c. In Diptera, amuscled, syringe-like structure.bulla n.; pl. bullae [L. bulla, bubble] 1. A rounded prominance,blister- or knob-like. 2. (ARTHRO: Crustacea) Astructure secreted by the head and maxillary glands ofcertain parasitic female copepods that serves as an anchorfor attachment to gill filaments of fish. 3. (ARTHRO: Insecta)a. Weakened spots on concave wings that allows them tobend. see stigma. b. In diaspid Hemiptera, located in theterminal outlet of wax glands (ceratuba) at the inner end.c. In scarabaeoid Coleoptera, a sclerite that closes the trachea.4. (NEMATA: Secernentea) In Heteroderidae, knoblikestructures within the vulval cone of cysts near the underbridgeor fenestra.bullate a. [L. bulla, bubble] Having a blister-like appearance,inflated, swollen.bulliform a. [L. bulla, bubble; forma, shape] Bubble-shaped.bundle n. [A.S. byndele, a binding] 1. A band or group fastenedtogether. 2. A group of nerves, muscles or other fibers;a fasicle.burden n. [A.S. byrthen, load] The total number of infectiousparasites of an individual. see intensity.burrow n. [uncert. origin] A hole or excavation used as ashelter and habitation, or place of retreat. see fossorial.bursa n.; pl. bursae [L. bursa, purse] 1. Any pouch or sac, asac-like cavity. 2. A lateral cuticular extension adanal, orsurrounding the tail of male nematodes and acanthocephalansthat functions as claspers or guides duringcopulation; has also been applied by various workers to allcaudal alae. 3. (ECHINOD: Crinoidea) In Ophiurida, formedby infoldings of the body wall of the oral disc to either sideof the base of each arm, functioning in gas exchange or asbursal slits. see bursa copulatrix.bursa copulatrix 1. A genital pouch of numerous invertebrates.2. In certain male nematodes and acanthocephalans,a modified caudal ala or alae, circular or oval, may bedivided into two lateral symmetrical or asymmetrical lobes,separated by a dorsal lobe, and supported by rays or pa-

Online Dictionary of Invertebrate Zoology 149pillae; bursa. 3. (ARTHRO: Insecta) A female copulatorypouch developed from the tubular vagina in the genitalchamber for reception of the male aedeagus. see genitalchamber. 4. (MOLL) A copulatory pouch or sac for receivingsperm that will be stored for only a brief period; copulatorybursa. see seminal receptacle. 5. (PLATY: Turbellaria)In planarians, a blind pouch that holds the secretionsfrom the penis and adenodactyl gland (muscular organ),which then activates the sperm.bursal slits (ECHINOD: Crinoidea) Genital openings of thebursa of Ophiurida, through which water circulates for respiration,and ripe sex cells pass for fertilization or are retainedas brood until rupture of the aboral disk. see ophiopluteus.bursa seminalis see seminal bursabursicon n. [L. dim. bursa, purse] (ARTHRO: Insecta) A hormoneassociated with hardening and darkening of the cuticlefollowing ecdysis.bursiform a. [L. bursa, purse; forma, shape] Formed like apurse.buschelformigen Korper see racemose glandsbutt see hampebuttress n. [OF. bouterez, to thrust] 1. (ARTHRO: Insecta) InCulicidae pupae, a sclerotized, thickened basolateral part ofthe paddle; external buttress; external thickening; nervure.2. (MOLL: Bivalvia) A radiating ridge on the interior thatreinforces the hinge process.byssaceous a. [Gr. byssos, fine flax] Composed of fine filaments.byssal foramen (MOLL: Bivalvia) An opening in the right valvefor passage of byssus in Anomiidae oysters.byssal gape (MOLL: Bivalvia) An opening between the valvemargins for the passage of the byssus.byssal gland (MOLL: Bivalvia) A viscid secreting gland producingthe byssal threads that anchors the organism to rocksand solid objects; also called byssal pit. see byssus.byssal notch (MOLL: Bivalvia) A small opening or notch located

150Maggenti and Gardneron the ventral margin for the passage of the byssus fromthe byssal gland.byssal sinus (MOLL: Bivalvia) Corresponds to the byssal notchof the right valve, but shallower and on the left valve in thePectinacea.byssus n.; pl. byssi, byssuses [L. byssos, fine flax] 1. (MOLL:Bivalvia) Fibers or small bundles of silky threads by whichthey anchor themselves to the substratum; beard. 2.(NEMATA: Adenophorea) A series of elaborately branchedprojections at the poles of mermithid eggs, by which theyattach to plants.

Ccadavericole n. [L. cadaver, dead body; colere, to dwell] Anorganism feeding on the dead tissues of another organism.caddis n. [Gr. kadiskos, urn or box] (ARTHRO: Insecta) InTrichoptera, a case bearing larva.cadre n. [L. quadrus, square] (ARTHRO: Pentastomida) Thesclerotized mouth lining.caducous a. [L. caducus, falling] Naturally detached or shed;having the tendency to fall off early or before maturity.caducous muscle (ARTHRO: Insecta) In exo- and endopterygotes,larval muscles that may persist for a short time inthe adult and may play an important role until destroyed.caecum, cecum n.; pl. caeca [L. caecus, blind] 1. A pouch orsaclike cavity extending from the alimentary canal with anopening at only one end. 2. (BRACHIO) Evagination of theouter epithelium projecting into the endopuncta of theshell; pallial caecum; mantle papilla. 3. (ECHI) When present,a blind pouch arising from the posterior (precloacal)region of the intestine; function unknown. 4. (SIPUN) seerectal caecum. cecal, caecal a.Caenogaea, Cainogea n. [Gr. kainos, recent; gaia, earth] Azoogeographical region including the Nearctic, Palearctic,and Oriental regions, as opposed to Eogaea. caenogaeana.caenogenesis see cenogenesiscaisson n. [L. capsa, box] (ANN: Oligochaeta) A box-like arrangementof longitudinal muscle fibers in certain earthworms.calabar swelling Transient subcutaneous nodule or swellingresulting from the traversing filarial nematode Loa loa.calamistrum setae (ARTHRO: Chelicerata) In many cribellateAraneae, a row of curved bristle-like setae on the dorsalpart of the fourth metatarsus; functioning in combing silkfrom a special spinning organ.

152Maggenti and Gardnercalamus n. [L. calamus, reed] (NEMATA) The shaft of the spicule.calathiform a. [L. calathus, basket shaped, bowl-like; forma,shape] Shaped like a cup or bowl.calcanea see unguitractorcalcar n.; pl. -caria [L. calcar, spur] 1. A spur-like projection.2. (ARTHRO: Insecta) A spur- or horn-like hypertrophiedseta or spine, with roots that may be incorporated in thetegument. calcarate a.Calcarea n. [L. calcarius, of lime] A class of sponges of thePhylum Porifera, with skeleton formed of spicules of calciumcarbonate laid down as calcite; tissues unlike othersponge classes due to three grades of construction: asconoid,synconoid and leuconoid.calcareous a. [L. calcarius, of lime] Composed of, containing,or of the nature of limestone or calcium carbonate.calcariform a. [L. calcar, spur; forma, shape] Spur-like.calceolate a. [L. calceus, shoe] Slipper-shaped; oblong with acoarctate middle; calceiform; calceoliform.calceolus n.; pl. calceoli [L. dim. calceus, shoe] (ARTHRO:Crustacea) In Malacostraca, complex sensory organelles onthe antennules and accessory flagellum of amphipods.calciferous glands (ANN: Oligochaeta) Esophageal glands ofearthworms, excretory in function; controls the level ofcertain ions in the blood, particularly calcium and carbonateions; glands of Morren.calcific a. [L. calx, lime; facere, to make] Producing lime salts.calcipala n. [L. calcis, heel; pala, shovel] (ARTHRO: Insecta) Incertain Diptera, a flattened lobe at the apex of the basitarusof the hind leg.calcospherites n.pl. [L. calx, lime; sphaera, ball] (ARTHRO:Insecta) Calcium accumulated in the adipose-bodies of larvaeof phytophagous Diptera.calice n. [L. calyx, cup] (CNID) The open end of a coral skeleton.see corallite.calicle see calycle

Online Dictionary of Invertebrate Zoology 153calicoblastic epithelium (CNID: Anthozoa) A specialized portionof the ectoderm of corals that produces the aragoniteskeleton in the true or stony corals.caliology n. [Gr. kalia, hut; logos, discourse] The study ofdwellings or natural shelters utilized by animals.callosity n.; pl. -ties [L. callus, hard skin] 1. A state or qualityof being callous. 2. (MOLL: Gastropoda) The local thickenedpart of the callus or inductura of the shell.callous a. [L. callus, hard skin] Hardened; having a callus orcallosities.callow worker (ARTHRO: Insecta) A newly emerged adultworker ant whose exoskeleton is still relatively soft andlightly pigmented. see teneral.callum n. [L. callus, hard skin] (MOLL: Bivalvia) A sheet ofshelly material filling in the anterior gape in the shell ofcertain adult mollusks.callus n.; pl. calluses, calli [L. callus, hard skin] 1. An unusuallyhardened or thickened area; a rounded swelling. 2.(ARTHRO: Insecta) In brachycerous Diptera, a knoblikeswelling on the cuticle. 3. (MOLL: Gastropoda) A shelly substance(inductura) on the parietal region or extending fromthe inner lip over base or into the umbilicus of the shell.calobiosis n. [Gr. kalos, beautiful; biosis, manner of life] Aform of symbiosis in which a species lives in the nest of,and at the expense of another either temporarily or permanently.calomus n. [Gr. kalamos, stalk, reed] (NEMATA) The shaft ofthe spicule between the manubrium and the lamina; sometimescalled the spicule shaft.caloric a. [L. calor, heat] Of or pertaining to heat.calorigenic a. [L. calor, heat; genere, to produce] Generatingheat.calorimetry n. [L. calor, heat; metricus, of measuring] Themeasurement of heat exchange in an organism or in asystem.calotte n. [F. calotte, skull cap] 1. (MESO: Rhombozoa) Theheadlike region of dicyemids. 2. (NEMATOM) Anterior ex-

154Maggenti and Gardnertremity of a nematomorph, often marked by a white areafollowed by a darkened band.calthrop n. [ML. calcitrapa, a four-pointed weapon used to obstructenemy movements] (PORIF) A tetraxon spicule withfour rays more or less equal.caltrop spines (ARTHRO: Insecta) In Lepidoptera, specializedtibial spurs of limacodid larvae.calva n. [L. calvaria, skull] A skull-cap; an epicranium.calvarium n. [L. calvaria, skull] (NEMATA) Subcuticular cephalicframework.calvous a. [L. calvus, bald] Lacking hair; bald.calx n.; pl. calces [L. calx, heel] 1. A heel, or the portion of alimb corresponding to the heel. 2. (ARTHRO: Insecta) Thedistal end of the tibia.calyciform a. [Gr. kalyx, cup; L. forma, shape] Calyx-like orgoblet-shaped.calycine a. [Gr. kalyx, cup] Cuplike; calyx-like.calycle n. [Gr. kalyx, cup] 1. (ARTHRO: Crustacea) A small capon the umbones. 2. (CNID: Hydrozoa) The theca of hydroids.calyculate a. [Gr. dim. kalyx, cup] (ARTHRO) Pertaining to antennaefurnished with cup-shaped joints for insertion ofnext annulus.calyculus n.; pl. -li [Gr. dim. kalyx, cup] 1. Any cup-shapedstructure; calycle. 2. (CNID: Hydrozoa) A cavity of a coralcontaining the polyps.calyoptis larva see calyptopis stagecalypteres n.pl. [Gr. kalypto, cover] (ARTHRO: Insecta) InDiptera, small membranous lobes or disk-like structures atthe base of the wing, just above the halter. see alula;squama.calyptoblastic a. [Gr. kalyptos, covered; blastos, bud] (CNID:Hydrozoa) Pertains to hydranths in which the gonophoresare commonly borne singly or multiply on stalked blastostylesthat are encased in peridermal gonothecae.calyptobranchiate a. [Gr. kalyptos, covered; branchia, gills]

Online Dictionary of Invertebrate Zoology 155Bearing gills imperceptible from the exterior.calyptodomous a. [Gr. kalyptos, covered; L. domus, house](ARTHRO: Insecta) Pertains to nests, especially of socialwasps, in which brood combs are surrounded by an envelope.see gymnodomous.calyptopis stage (ARTHRO: Crustacea) In Euphausiacea, thethird larval stage characterized by differentiation of abdomenand appearance of compound eyes. see zoea.calyptostase n. [Gr. kalyptos, covered; stasis, standing] (AR-THRO: Chelicerata) A stase in which acarine instars aresubject to regressive characters from losing the use of appendagesand mouthparts, to remaining enclosed in thetegument of the preceding stase or in the egg-shell; nymphochrysalis.calyptostasic a. see protelattosis, elattostase.calyptra n. [Gr. kalypto, cover] A hood or cap. see alula.Calyptratae n. [Gr. kalyptos, covered] The Calyptrate Muscoidaeof former classifications, including Tachinidae, Metopiidae,Muscidae, Oestridae and Cuterebridae. see Muscoidea(=Calyptratae).calyptron see calypterescalyx n.; pl. -yxes, -ycis, -yces [Gr. kalyx, cup] 1. Any cuplikearea into which structures are set. 2. (ARTHRO: Insecta)a. A flattened cap of neuropile in an insect brain, acomponent of the corpus pedunculatum. b. In certain femaleinsects, an expansion of the oviduct into which theovarioles open. c. In male Lepidoptera, a funnel-shapedexpansion of the basal part of the vas deferens. 3. (CNID:Anthozoa) The spicules containing the basal portion of theanthocodium of some soft corals; calice. 4. (ECHINOD: Crinoidea)The body disk that is covered with a leatherytegumen containing calcareous plates.camarodont lantern (ECHINOD) When the large epiphyses arefused across the top of each pyramid of Aristotle's lantern.camera n. [L. camera, chamber] (ARTHRO: Insecta) a. Curvednarrow sclerite that supports the paired lobes of thearolium. b. A curved band of cuticle supporting the proximalend of a pulvillus.

156Maggenti and Gardnercameral liquid (MOLL: Cephalopoda) A fluid found in the mostrecently formed nautiloid shell chambers.cameration n. [L. camera, chamber] Divided into chambers.camerostome n. [L. camera, chamber; stoma, mouth] (AR-THRO: Chelicerata) A ventral groove in the propodosome ofAcarina, wherein lies the capitulum (gnathosoma).campaniform a. [L. campana, bell; forma, shape] Bell ordome-shaped.campanulate a. [L. dim. campana, bell] Formed like a bell;bell-shaped.campestral a. [L. campester, of fields] Inhabiting open countryand grassland.campodeiform larva (ARTHRO: Insecta) A larva having theform of the thysanuran genus Campodea , elongate andflattened, with well developed legs and antennae, and usuallyactive; said of certain active carnivorous larvae; thysanuriformlarva; oligopod larva.campus n.; pl. campi [L. campus, field] (ARTHRO: Insecta) Thebare or almost bare ventral region of the tenth, or fusedninth and tenth, abdominal segments of scarabaeoid larvae,in front of an entire or anteriorly split teges, or in frontof the paired tegilla.Canadian Zone A biogeographical zone comprising the southernpart of the great transcontinental coniferous forests ofCanada, the northern parts of Maine, New Hampshire andMichigan, and a strip along the Pacific Coast extendingsouth to Cape Mendocino and the greater part of the highmountains of the United States and Mexico. Easterly it coversthe Green, Adirondack and Catskill Mountains and thehigher mountains of Pennsylvania, West Virginia, Virginia,western North Carolina and eastern Tennessee; in theRockies, extending continuously from British Columbia towestern Wyoming and in the Cascades from British Columbiato southern Oregon with a narrow interruption alongthe Columbia River.canal n. [L. canalis, channel] 1. A groove, tube, or duct. 2.(ARTHRO: Insecta) The groove or sulcus on the mandible ormouth structures of insect larvae. 3. (CNID) Part of the

Online Dictionary of Invertebrate Zoology 157gastrovascular system; in medusae may be radial or circularwith interconnections. 4. (MOLL: Gastropoda) A narrow,semitubular extension of the aperture.canalaria a. [L. canalis, channel] (PORIF) Referring to spiculesin the lining of canals.canaliculate a. [L. dim. canalis, channel] Having longitudinalgrooves, channels or sutures.canaliculus n.; pl. -uli [L. dim. canalis, channel] 1. A minutecanal. 2. (ARTHRO: Insecta) In Lepidoptera, an elongatesclerotized structure that functions as a support or guidefor the aedeagus. 3. (BRYO: Stenolaemata) The large styleinflecting septumlike projections into the zooecial chamberparallel to the length.canaliferous a. [L. canalis, channel; ferre, to carry] (MOLL)Having a canal-like extension of the aperture in the form ofsmall grooves or furrows.canalization n. [L. canalis, channel; Gr. izein, to make] Thecharacteristic developmental pathways that achieve a standardphenotype in spite of genetic or environmental disturbance.canalizing selection The selection of genes to stabilize thedevelopmental pathways so as to make the phenotype lesssusceptible to the effect of environmental or genetic disturbances.canal of fecundation (ARTHRO: Insecta) The seminal canal offemale Coleoptera.canal system (PORIF) Passageways through which waterpasses from the surface pores to the osculum or excurrentopenings.cancellate, cancellated a. [L. cancellatus, latticed] Beingmarked with numerous ridges or lines; pertaining to a networkformed by small interlacing bars; reticulated.cancrisocial a. [L. cancer, crab; socius, companion] Livingwith or on the shell of a crab; commensalism with crabs.cancroid a. [L. cancer, crab; Gr. eidos, like] Resembling acrab.cane n. [L. candeo, shine, glow] (NEMATA) A refringent thick-

158Maggenti and Gardnerening of the posterior cuticle void of ornamentation. seecalvarium.canella n.; pl. canellas, -ae [Gr. dim. kanna, reed] (ARTHRO:Insecta) A furrow that extends from a spiracle to the lateralmargin of the body of coccoid insects.canines n.pl. [L. canis, dog] (ARTHRO: Insecta) A pair of heavilychitinized spines originating from the mandibles of mayflies,adapted for holding food.canities n. [L. canus, hoary] Grayness or whiteness of hair.cannibalism n. [Sp. canibal, caribal, through Arawakan, fr.Carib calina, galibi, Caribs lit.; strong men] Eating the fleshof other individuals of the same species.cannula n.; pl. cannulae [Gr. dim. kanna, reed] A small tube.canthariasis n. [Gr. kantharis, blister-beetle; -iasis, a diseasedcondition] (ARTHRO: Insecta) The invasion of humansand other animals by coleopterous larvae.cantharidin n. [Gr. kantharis, blister-beetle] A chemical producedby adults of the family Meloidae that causes skinblisters; the drug is obtained for medical use from thesouthern European Lytta vesicatoria, commonly known asSpanish fly.cantharophilous a. [Gr. kantharis, blister-beetle; philein, tolove] (ARTHRO: Insecta) Pollination by beetles.canthus n. [Gr. kanthos, edge, corner] (ARTHRO: Insecta) Acuticular bridge across compound eyes that partially orcompletely divides the eyes into an upper and lower half.capacious a. [L. capax, roomy] Able to contain a great deal;roomy; large; ample; spacious.capacitation n. [L. capax, roomy] 1. Cause to become capable;qualify. 2. In spermatogenesis, the physiologicalchanges between insemination and fertilization.capillary a. [L. capillus, hair] Hair-like.capillate a. [L. capillus, hair] Having a covering of long slenderhair.capilliform chaeta (ANN) A long, undivided dorsal hair.capillitium see cucullus

Online Dictionary of Invertebrate Zoology 159capitate a. [L. caput, head] An apical knoblike enlargement ora headlike structure; capitate antenna or hairs.capitellum see capitulumcapitular apodeme (ARTHRO: Chelicerata) In Acari, an apodemeseparating the cheliceral frame and the infracapitulum.capitular saddle (ARTHRO: Chelicerata) In Acari, that area ofthe cervix separating the two cheliceral grooves.capituliform a. [L. caput, head; forma, shape] Having anenlarged terminal part, like a capitulum.capituliform tooth (MOLL) The broad, flat-topped, outermostadmedian on either side of the radula.capitulum n.; pl. -la [L. caput, head] 1. A small knoblike protuberance.2. (ARTHRO: Chelicerata) The anterior body regionof a mite or tick which bears the mouth parts; thegnathosoma. 3. (ARTHRO: Crustacea) a. In Cirripedia, aportion of the carapace that encloses the body, commonlyprotected by calcareous plates. b. In Ostracoda, an anteriorprominence in the complex tooth and socket hingement. 4.(ARTHRO: Insecta) a. The enlarged tip of an insect antennaor proboscis. b. In Diptera, the small tubercle at the tip ofhalteres. 5. (CNID: Anthozoa) In Actinaria, an upper, thinwalledregion of the column. 6. (NEMATA) a. The head ormanubrium of a spicule. b. A flange of the gubernaculumcuneus.caprification n. [L. caprificus, wild fig tree] The method orprocess of pollination by Blastophaga psenes, a chalcid figwasp, that breeds in wild capri figs and serves to pollinateSmyrna figs.caprificator n. [L. caprificus, wild fig tree] (ARTHRO: Insecta)The chalcid fig wasp, Blastophaga psenes that performs theprocess of caprification.capsula n.; pl. -lae [L. dim. capsa, box] A capsule.capsular, capsulate a. [L. dim. capsa, box] In the form of, orenclosed within a capsule.capsular flame cells Flame cells that open directly into abladder at the end of a canal.

160Maggenti and Gardnercapsule n. [L. dim. capsa, box] A sac-like membrane resultingfrom macroscopic alien objects enclosing an organ, egg,foreign body, etc. see giant cell.captaculum n.; pl. -ula [L. captare, to snatch at, catch](MOLL: Scaphopoda) One of numerous slender retractiletentacles with sucker-like tips, arising from the dorsal surfaceof the head; used in gathering foraminifera and verysmall mollusks.capuliform a. [L. capulus, holder; forma, shape] (MOLL: Gastropoda)Having the shape of a depressed cone with eccentricapex and near-apical part of the shell slightly coiled,as in Capulus .caput n.; pl. capita [L. caput, head] 1. The head or knob-likeprotuberance. 2. The head with all its appendages.capylus n. [LL. cappa, hood] (ARTHRO: Insecta) A hump on thedorsal aspect of the segments of many insect larvae.caraboid, carabidoid a. [Gr. karabos, a kind of beetle] (AR-THRO: Insecta) Resembling Carabidae; a carabid beetle;the second instar larvae of Meloidae, the blister beetles.carapace n. [Sp. carapacho, covering] 1. Any fused series ofsclerites covering a portion of the body. 2. (ARTHRO: Chelicerata)a. In Acari, the more or less fused dorsal scleritesof the cephalothorax covering the idiosoma of mites andticks. b. In Arachnida, the upper covering of the cephalothorax.3. (ARTHRO: Crustacea) a. A cuticular, usually calcified,structure formed by the posterior and lateral extensionof the dorsal sclerites of the head of many decapodsand other crustaceans, often covering head and thorax. b.In bivalves, a fold of integument extending from the maxillarysegment forming the shell. c. In some Cirripedia, themantle usually with calcified plates. 4. (ROTIF) The rigidcuticle of many rotifers.carapace angles (ARTHRO: Crustacea) In Conchostraca, theintersection of the straight dorsal margin by the anteriorand posterior ribs.carapace carina (ARTHRO: Crustacea) The narrow ridge on thesurface of a carapace.carapace costae (ARTHRO: Crustacea) Fine to coarse closely

Online Dictionary of Invertebrate Zoology 161spaced radial ridges, that do not cross the umbo; radiallirae.carapace costellae (ARTHRO: Crustacea) Fine radial ridges,extending from the ventral margin to and across the umbo,generally numerous on any given valve, especially in Conchostraca.carapace groove (ARTHRO: Crustacea) Various types of furrowson the surface of a carapace.carapace growth line (ARTHRO: Crustacea) The peripheralmargin of successive membranes added to the shell duringeach molt.carapace horn (ARTHRO: Crustacea) The anterodorsal terminationof carapace valves in some archaeostracans; in others,may be indurated or produced into long processes.carapace lirae (ARTHRO: Insecta) Linear concentric ridges parallelto and interspaced between the growth lines.carapace region (ARTHRO: Crustacea) Differentiated portion ofthe surface of a carapace.carapace spines (ARTHRO: Crustacea) Variously placed, sharpprojections from the carapace.carapace tooth (ARTHRO: Insecta) Various blunt or smallsharp spinous projections on a carapace, often broaderthan a spine.carbohydrates n.pl. [L. carbo comb. form, carbon; Gr. hydor,water] Compounds containing carbon, hydrogen and oxygenin the ratio of 1:2:1. see monosaccharide, disaccharide,polysaccharide.carcinoid a. [Gr. karkinos, crab; eidos, like] Pertaining to orresembling crabs.carcinology n. [Gr. karkinos, crab; logos, discourse] Thatbranch of zoology that studies Crustacea.cardate mastax (ROTIF) In the genus Lindia, a sucking type ofmastax characterized by forked manubria with the suckingaction produced by the unci.cardia n. [Gr. kardia, heart] 1. (ARTHRO: Insecta) An anteriorcardiac chamber of the midgut of Diptera; the proventriculusof some authors. 2. (BRYO) Part of the digestive tract

162Maggenti and Gardnerinto which the esophagus opens, sometimes differentiatedinto gizzard and stomach. 3. (NEMATA) The esophago-intestinalvalve.cardiac a. [Gr. kardia, heart] Pertaining to or near the heart.cardiac notch or incision (ARTHRO: Crustacea) Indentation onthe posterior margin of a carapace.cardiac pyloric valve (ARTHRO: Crustacea) In Decapoda, acalcified triangular plate that may be flat or curved, generallycovered with elongate setae pointing backwards, orcovered by a thick corrugated layer of pigmented chitin;functioning as a guard to the pyloric opening.cardiac region (ARTHRO: Crustacea) In Decapoda, the medianpart posterior to the cervical groove, between the urogastricand intestinal regions.cardiac sinus (ARTHRO) The dorsal part of the embryonichemocoel of certain arthropods, that corresponds to a circulatorysystem, a part of which becomes the lumen of thedorsal blood vessel.cardiac sphincter (ARTHRO: Insecta) Circular muscles at theentrance to the midgut of certain insects; cardiac valve;stomodeal valve.cardiac stomach 1. (ARTHRO: Crustacea) In Decapoda, theanterior portion of the stomach. 2. (BRYO: Phylactolaemata)That part of the stomach between the cardiac valve andcaecum. 3. (ECHINOD: Asteroidea) The large, loosely foldedadoral stomach of a sea star, that is capable of beingeverted when feeding.cardiac tooth (ARTHRO: Insecta) In Decapoda, a tooth on themid-line of a carapace just posterior to the cervical groove.cardiac valve 1. A valve at the junction of the foregut andmidgut of many invertebrates. 2. (NEMATA) see cardia.cardiform a. [Gr. kardia, heart; L. forma, shape] Resemblingthe shape of a heart.cardinal a. [L. cardo, hinge] 1. (ARTHRO: Insecta) Referring tothe cardo. 2. (MOLL: Bivalvia) Applied to the central or principalteeth in the hinge of a shell.cardinal area 1. (BRACHIO) The posterior sector of the articu-

Online Dictionary of Invertebrate Zoology 163late valve. 2. (MOLL: Bivalvia) A flat or curved surface betweenthe beak and the hinge line.cardinal axis (MOLL: Bivalvia) An imaginary line on which theshell valves are hinged.cardinal cell see trianglecardinal costa (MOLL: Bivalvia) A ridge marking the cardinalarea from the outer face of the shell.cardinal crura (MOLL: Bivalvia) Narrow teeth radiating fromthe apex of the ligament pit.cardinales The cardines. see cardo.cardinalia a. [L. cardinalis, pert. to a hinge] (BRACHIO) Outgrowthsof the secondary shell in the posteromedian regionof the brachial valve, functioning in articulation, support ofthe lophophore, and muscle attachment.cardinal margin (BRACHIO) The curved posterior margin of theshell.cardinal plate (BRACHIO) A plate extending across the posteriorend of the brachial valve, consisting of outer hingeplates and inner hinge plates or plate.cardinal platform (MOLL: Bivalvia) An internal plate containingteeth below the beak and adjoining parts of the dorsalmargin; hinge plate.cardinal process (BRACHIO) A blade or boss of the secondaryshell placed medially in the posterior end of the brachialvalve for the separation or attachment of the diductor muscles.cardinal tooth (MOLL: Bivalvia) The hinge tooth positionednear the beak.cardines pl. of cardocardinosternal a. [L. cardo, hinge; Gr. sternon, chest] (AR-THRO: Insecta) Of or pertaining to the cardo and the sternumof a labial segment.cardinostipital a. [L. cardo, hinge; a stipes, a stem] (ARTHRO:Insecta) Pertaining to the cardo and stipes taken together.cardioblasts n.pl [Gr. kardia, heart; blastos, bud] (ARTHRO:Insecta) Special cells during embryology that originate

164Maggenti and Gardnerfrom the upper angle of the coelomic sac to form the heartand dorsal blood vessel.cardiocoelom n. [Gr. kardia, heart; koilos, hollow] The coelomthat forms the pericardium.cardiocoelomic a. [Gr. kardia, heart; koilos, hollow] Pertainingto the venous openings from the heart to the body cavity.cardo n., pl. cardines [L. cardo, hinge] 1. A hinge or turningpoint. 2. (ARTHRO) a. A basal segment or division of themaxillary appendage. b. In Diplopoda, seen externally asthe basal cheek lobe. 3. (MOLL: Bivalvia) The hinge.cardosubmental a. [L. cardo, hinge; sub, under; mentum,chin] (ARTHRO: Insecta) Pertaining to the cardo and thesubmentum.caridean lobe (ARTHRO: Crustacea) In caridean shrimps, anexternal rounded projection on the basal part of the exopodof the first maxilliped.caridoid facies (ARTHRO: Crustacea) A group of charactersthat distinguish primitive eumalacostracan crustaceans:enclosure of the thorax by the carapace, movable stalkedeyes, biramous antennules, antennae with scaphocerites,thoracopods with natatory exopods, ventrally flexed abdomen,and caudal fan.carina n., pl. -nae [L. carina, keel] 1. Any keel-like structureor elevated ridge. 2. (ARTHRO: Crustacea) a. A well definedprojecting ridge on the outer surface of the carapace of podocopanostracods. b. The unpaired posteriodorsal plate ofthoracic barnacles; in lepadomorphs, l of up to 4 unpairedplates of the capitulum; in verrucomorphs, the compartmentalplate between the rostrum and fixed tergum; inbalanomorphs, compartmental plate, with alae on eachside, opposite the rostrum. 3. (ARTHRO: Insecta) a. A formof sharp distal cornuti of the genitalia of certain male Lepidoptera.b. For Othroptera see frontal costa. c. The fusedventral outer wall of the aedeagus of male fleas. 4. (BRYO)The median ridge on the zoarium surface. carinal a.carinal latus (ARTHRO: Crustacea) The plate on each side ofthe carina of a lepadomorph barnacle.

Online Dictionary of Invertebrate Zoology 165carinal margin (ARTHRO: Crustacea) In thoracic barnacles, theedge of any plate adjacent to the carina, and occludingwith the carinal margin of the opposed tergum.carinate a. [L. carina, keel] 1. Ridged or keeled; furnished withraised lines or ridges. 2. Possessing a carina. 3. (ARTHRO:Crustacea) In Conchostraca, a valve bearing rib(s). seeratite.cariniform a. [L. carina, keel; forma, shape] Keel-shaped;tropeic.carinolateral n. [L. carina, keel; lateralis, of the side] (AR-THRO: Crustacea) One of a pair of compartmental plates ofbalanomorph barnacles, usually overlapping the carina oneach side, with the radius on the carinal side and the ala onthe lateral side; the carinal latus of lepadomorphs.carious a. [L. caries, decay] Decayed; having surface depressions;corroded.carminate, carminated a. [Ar. qirmiz, deep red] Mixed orstained with carmine.carmine n. [Ar. qirmiz, deep red] A crimson dye derived fromthe cocineal insect Coccus cacti that is used as a histologicalstain.carneous a. [L. carnosus, fleshy] Resembling flesh in color orsubstance.carnivore n. [L. carnis, flesh; vorare, to devour] A flesh eater,i.e., an animal preying on other animals or feeding on theirflesh.carnivorous a. [L. carnis, flesh; vorare, to devour] Eating orliving on flesh or other animals.carnosan n. [L. carnis, flesh] (BRYO) Those autozooids buddeddirectly from other autozooids, or alternate with othergroups of kenozooids.carnose a. [L. carnosus, fleshy] Pertaining to a soft, fleshysubstance.Carolinian Faunal Area The humid division of the Upper Australzone, including much of the eastern United States fromsouthern New England to Georgia, and extending west tothe 100th meridian.

166Maggenti and Gardnercarotene, carotin n. [L. carota, carrot] An important hydrocarbonpigment in plants and animals; -carotene, C 40 H 56 ,also known as provitamin A. carotenoid a.carotenophore n. [L. carota, carrot; Gr. phorein, to bear] Apigmented stigma or eye-spot.carotin see carotenecarotinalbumen see astaxanthin, insectoverdin, pterinepigmentscarpocerite n. [L. carpus, wrist; Gr. keras, horn] (ARTHRO:Crustacea) The distal segment (5th) of the antennal peduncle.carpophagous a. [Gr. karpos, fruit; phagein, to eat] Feedingon fruit.carpopod(ite) n. [L. carpus, wrist; Gr. pous, foot] 1. (ARTHRO)The fifth segment of a generalized arthropod appendage. 2.(ARTHRO: Chelicerata) The patella. 3. (ARTHRO: Crustacea)The carpus. 4. (ARTHRO: Insecta) The tibia.carpus n.; pl. carpi [L. carpus, Gr. wrist] 1. The wrist. 2. (AR-THRO: Crustacea) The antepenultimate segment of thethoracopod or pereopod; the carpopod(ite). 3. (ARTHRO:Insecta) The area of the wing at which they transverselyfold; the pterostigma of Odonata; the radius and cubitusextremity of the fore wing. 4. (MOLL: Cephalopoda) Thetentacle.carrefour area (MOLL: Gastropoda) In certain pulmonates,that area into which the hermaphroditic duct discharges, alarge albumen gland and small fertilization pouch open, andthe sperm duct and oviduct begin.carrier cell (PORIF) A migratory choanocyte that transportssperm to the oocyte.carrier state A type of attenuated infection characterized bythe presence of a pathogenic microorganism within or uponhost tissues.carrion n. [L. caries, decay] The dead or putrefying flesh of ananimal.cartilage n. [L. cartilago, gristle] 1. A translucent, elastic substance.2. (MOLL) a. In Bivalvia, a supplement to the liga-

Online Dictionary of Invertebrate Zoology 167ment that controls the opening of the valves. b. In Cephalopoda,supporting the brain.cartilage pit (MOLL: Bivalvia) A depression for the inner part ofthe ligament.cartilaginous a. [L. cartilaginosus, gristle] Pertaining to cartilagein structure or appearance.carton n. [L. carta; leaf of paper] (ARTHRO: Insecta) Any paper-likematerial made and used by insects in the constructionof shelters.caruncle n. [L. dim. caro, flesh] 1. A fleshy excrescence orprotuberance. 2. (ANN) A sensory lobe extending behindthe prostomium. 3. (ARTHRO: Chelicerata) In Acari, a basalexpansion on the tarsus that forms a sucker.cary see also karycaryolytes, carolites n.pl. [Gr. karyon, nut; lytikos, loosing]Numerous small nucleated masses of protoplasm, probablyderived from muscles, minute grains and other fragmentsof disintegrating tissues.cast n. [ON. kasta, throw] 1. Anything that is shed in a formresembling the original. 2. (ANN: Oligochaeta) The excrementof an earthworm. 3. (ARTHRO: Insecta) The moltedexoskeletons of arthropod instars. 4. (MOLL) An extraneoussubstance molded in the interior of a fossil shell, the shellitself having disappeared.castaneous a. [L. castanea, chestnut] Pertaining to or of thecolor of a chestnut; brown; sepia.caste n. [L. castus, pure] (ARTHRO: Insecta) 1. A group of individualsof a particular morphological type, age group, orother, that performs special functions in a colony. 2. Agroup of individuals in a colony that are morphologicallydistinct and specialized in behavior.caste polyethism (ARTHRO: Insecta) In social insects, morphologicalcastes that are specialized for the functionswhich they perform. see polyethism, age polyethism.casting n. [ON. kasta, throw] 1. Material discarded or cast offby an animal. 2. (ANN: Oligochaeta) The excrement of anearthworm.

168Maggenti and Gardnercastration n. [L. castratus, geld] Any process that inhibits orinterferes with the production of mature ova or spermatozoain the gonads of an organism.cat- see also katcatabolismn. [Gr. kata, down; bolein, to throw] The destructivephase of metabolism, including the processes involvedwith converting complex compounds into simpler ones, especiallythose involved in the release of energy. seeanabolism.catachoma n. pl. -ata [Gr. kata, down; choma, mound](MOLL: Bivalvia) One of many small pits in the peripheral,inner surface of the left valve for reception of an anachoma.catakinesis a. [Gr. kata, down; kinesis, movement] Pertainingto molecules, atoms or protoplasm low in energy content.see anakinesis.catalase n. [Gr. kata, down; allassein, to change] An enzymefound in essentially all living cells except anaerobic bacteriathat catalyzes the decomposition of hydrogen peroxide towater and oxygen. catalatic a.catalepsy n. [Gr. katalepsis, seizure] A state of immobilizationin which the body and limbs are often plastic with musclerigidity in the limbs retaining any unusual position intowhich they are placed. cataleptic a., n.catalog, catalogue n. [Gr. kata, down; legein, to pick out] Anindex to taxonomic literature arranged by taxa includingthe most important taxonomic and nomenclatural referencesto the taxon involved.catalysis n.; pl. -ses [Gr. kata, down; lyein, to dissolve] Analteration in velocity of a reaction due to the presence of acatalyst.catalyst n. [Gr. kata, down; lyein, to dissolve] A substancethat causes an acceleration of a chemical reaction and remainsitself unchanged in the process, or is reconstituted atthe end of the reaction.cataphract, cataphractus n. [Gr. kata, down; phrassein, toenclose] Armored with a hard callous skin, or with closelyunited scales.

Online Dictionary of Invertebrate Zoology 169cataplasia n. [Gr. kata, down; plastos, to spread over] Regressivechange or decline; reversion to a more primitivecharacter.cataplasmic a. [Gr. kataplassein, to spread over] Irregulargalls caused by parasites or other factors.catapleurite see coxopleuritecataplexy n. [Gr. kata, down; plessein, to strike] Feigningdeath. see catalepsy.catastrophism n. [Gr. katastrophe, overturning] Cuvier's explanationof geological catastrophies resulting in the existenceof fossil faunas.catatrepsis see katatrepsiscatena n.; pl. -nabe [L. catena, chain] (ARTHRO: Insecta) Inmale Lepidoptera, a series of longitudinal scale-like dentationson a membranous plate, covering the proximal part ofthe aedeagus of Anophia. see cornuti.catenation n. [L. catena, chain] An arrangement, connectionor succession in a regular series; a chain.cateniform see catenulatecatenulate a. [L. dim. catena; chain] In chainlike form; colormarkings or indentation on butterfly wings, or shells.catenuliform a.caterpillar n. [LL. cattus, cat; pilosus, hairy] (ARTHRO: Insecta)An eruciform larva; the wormlike larva of a butterfly,moth, sawfly or scorpionfly.cation n. [Gr. kata, down; ienai, to go] Any ion bearing a positivecharge. cationic a. see anion.catoprocess n. [Gr. kata, down; L. processus, go forward](ARTHRO: Insecta) The lowest process of each half of theanal segment; subanal lobe; subanal appendage.cauda n. [L. cauda, tail] A tail or tail-like appendage; extensionof the anal segment, or appendage terminating the abdomen.caudad adv. [L. cauda, tail; ad, toward] Toward the tail regionor posterior end of the body. see cephalad.caudal a. [L. cauda, tail] Pertaining to a tail or tail-like ap-

170Maggenti and Gardnerpendage or extremity; located at or on the tail.caudalabiae n.pl. [L. cauda, tail; labia, lip] (ARTHRO: Insecta)In Coccidae, the labiae of the abdomen.caudal alae (NEMATA) Lateral cuticular extensions on the posteriorend of male nematodes; the bursa.caudal appendage 1. (ARTHRO: Crustacea) One of the terminal,multiarticulate or simple, uniramous paired appendagesof barnacles, homologous with caudal furca of othercrustaceans. 2. (NEMATA) The terminal portion of the tailused for food storage in certain larval mermithids and discardedduring larval penetration.caudalaria n. [L. cauda, tail; -aria, a thing like] (ARTHRO: Insecta)The notal wing process on the posterior part of eachlateral margin of the scutum.caudal bursa (NEMATA) A peloderan bursa that completely enclosesthe male tail.caudal fan 1. (ARTHRO: Crustacea) A structure formed of laterallyexpanded uropods and telson that functions in swimmingor steering and balancing; tailfan. 2. (ARTHRO: Insecta)For mosquito larvae see ventral brush.caudal filaments (ARTHRO) 1. Thread-like processes at theposterior end of the abdomen. see cercus. 2. For Crustaceasee caudal ramus.caudal furca (ARTHRO: Crustacea) Paired caudal rami of theterminal abdominal segment or telson; small lobes orspines situated near the terminus of the telson.caudal gills (ARTHRO: Insecta) In Odonata, the three externalgills extending from the end of the body of zygopteran larvae.caudal glands Glands of the tail region of many invertebrates,i.e., spinneret, cement gland, adhesive gland.caudalid n. [L. cauda, tail] (NEMATA) A cephalid (subcuticularnerve commissure) located slightly anteriad of the anus.caudal ocelli (ANN: Hirudinoidea) In piscicolid leeches, eyespotson the caudal sucker.caudal papillae (NEMATA) Papillae located on the tail.

Online Dictionary of Invertebrate Zoology 171caudal pore (NEMATA) The spinneret.caudal process (ARTHRO: Crustacea) In Ostracoda, the posterior,upward projection of the valve border.caudal ramus pl. rami (ARTHRO: Crustacea) One of paired appendages,usually rodlike or bladelike, sometimes filamentousand multiarticular just anterior to the anal segment ortelson; caudal filaments; caudal style; cercus; cercopod;furcal ramus; stylet.caudal setae see cercuscaudal shield (SIPUN) A flat and circular or sub-conical, furrowedor grooved, horny cap at the posterior extremity ofthe trunk.caudal siphon (ARTHRO: Crustacea) In Ostracoda, the posteroventralopening in the valve border, sometimes a tubularstructure.caudal style see caudal ramuscaudal supplements (NEMATA) Papillate glandular structureson the ventral surface in the caudal region of the male.caudal sympathetic system see stomogastric nervoussystemcaudal vesicle (ARTHRO: Insecta) In braconid larvae, the hindguteverted through the anus forming a vesicle responsiblefor about one third of the total gaseous exchange.caudal wing (NEMATA) The bursa.caudate a. [L. cauda, tail] 1. Bearing a tail or tail-like appendage.2. (MOLL) Having the columella of a univalve shellelongated at the base.caudocephalad adv. [L. cauda, tail; Gr. kephale, head] Directedtoward the head from the caudal region.caudula n.; pl. -lae [L. dim. cauda, tail] A little tail.caul n. [L. caulis, stalk] (ARTHRO: Insecta) The fat bodies oflarvae, thought to produce the organs of the future adults;epiploon.caulescent a. [L. caulis, stalk] Being intermediate betweensessile and stalked.cauliculus n.; pl. -li [L. dim. caulis, stalk] (ARTHRO: Insecta)

172Maggenti and GardnerThe larger of the two stalks supporting the calyx of themushroom body of the protocerebral lobes.cauliform a. [L. caulis, stalk; forma, shape] Stemlike.cauligastric a. [L. caulis, stalk; Gr. gaster, stomach] (ARTHRO:Chelicerata) Pertaining to those of the subphylum that arenarrowly joined between prosoma and opisthosoma. seelatigastric.cauline a. [L. caulis, stalk] (CNID: Hydrozoa) A term used todescribe nematotheca attached to the main stem of a hydroidcolony.caulis n.; pl. caules [L. caulis, stalk] (ARTHRO: Insecta) Thefunicle of the antenna; the corneous basal part of the jaws.caulome n. [Gr. kaulos, stem] (CNID: Hydrozoa) An erect stemor stalk of a solitary polyp.causal agent or organism Any organism or chemical that inducesa given disease; a causative agent.cavate a. [L. cavus, hollow] Hollowed out; cave-like.cavernicolous a. [L. caverna, cave; colare, to inhabit] Inhabitingcaves.cavernous a. [L. cavernosus, full of hollows] Full of cavities orhollow spaces; divided into small spaces.cavity n.; pl. -ties [L. cavus, hollow] A hollow space or opening.ceca see caecumcecidium n. [Gr. dim. kekis, gall] A gall.cecidogenous a. [Gr. kekis, gall; gennaein, to produce] Producinggalls on plants, as by insects and nematodes.cecum see caecumceiling n. [L. caelum, sky] The maximum population densityfor a given set of circumstances.cell n. [L. cella, chamber] 1. A unit consisting of a nucleus andcytoplasm surrounded by a cell membrane that collectivelymake up the structural and functional unit in plants andanimal bodies. 2. (ARTHRO: Insecta) a. One of the manysmall chambers in a bee or wasp colony, utilized for rearingyoung or storing food. b. A space in the wing membrane of

Online Dictionary of Invertebrate Zoology 173an insect, partly (an open cell) or completely (a closed cell)surrounded by veins. c. A cavity under the ground containingan insect pupa.cell body see neuroncell constancy A situation in many microscopic invertebrateswhere the multiplication of cells ceases at hatching, exceptfor the reproductive system, and growth is by enlargementof existing cells. see eutely.cell culture The growing of cells in vitro.cell division The reproduction of cells by karyokinesis and cytokinesis.cell doctrine see cell theorycellifugal a. [L. cella, chamber; fugare, to flee] Passing from acell. see cellipetal.cellipetal a. [L. cella, chamber; petere, to seek] Passing towardsa cell.cell lineage Following individual blastomeres to their ultimatefate in the formation of definite parts of the organism.cell membrane see plasma membranecell organ A differentiated part of a cell that has a specialfunction, such as a centrosome, organoid, or organelle.cells of Semper (ARTHRO: Insecta) The cells of the crystallineeye cone, whose intercellular membranes form a cruciformpattern when the cone is seen in transverse section.cell theory All organisms are composed of cell(s); a cell is thesmallest unit of matter that is alive (functional unit) proposedby Schwann for animals in 1838-40; cells are the reproductiveunits of all organisms; cellular.cellulae n.pl. [L. dim. cella, chamber] (ARTHRO: Insecta)Round or oval-like areas on the exocuticle of certain Coccidae(Lecaniidae); dermal pores; dermal cells.cellular affinity (PORIF) Pertaining to the selective adhesivenessfound among the cells.cellulase n. [L. dim. cella, chamber] A digestive enzyme thathydrolyzes cellulose in food.cellule n. [L. dim. cella, chamber] 1. A small cell. 2. (ARTHRO:

174Maggenti and GardnerInsecta) A small area between the veins of an insect wing,usually a completely enclosed area.'cellules en crois' (PORIF) Non-flagellated cells arranged in atetraradial fashion in the amphiblastula of Calcaronea.cell wall A thin, nonliving sheath or pellicle that lies outsidethe plasma membrane of certain animal cells; more generallyapplicable to plant cells.celsius n. [Anders Celsius] The name of the temperature scalehaving 100 divisions or degrees between freezing (0 ) andboiling (100 ); abbrev. C.; formerly called centigrade.cement n. [L. caementum, chips (now applied to a substanceused as a "binder")] A substance produced by various invertebratesand utilized as an adhesive protective layer.cement gland 1. Any of certain glands of invertebrates thatsecrete an adhesive substance. 2. (ACANTHO) A gland orglands near the male testes that secretes a binding mediumthat facilitates copulation with the female. 3. (AR-THRO: Crustacea) Specialized dermal cells of barnacles thatsecrete the calcareous substance of the valves. 4.(NEMATA) see caudal gland. 5. (ROTIF) see pedal glands.cement layer 1. (ARTHRO: Chelicerata) In Acari, the outerlayer of cerotegument. 2. (ARTHRO: Insecta) The thin layeroutside the wax of certain insect bodies, that may consistof tanned protein or a shellac-like substance and mayfunction in protecting the wax or take the form of meshworkreservoirs of lipids.cement sac That portion of an invertebrate oviduct that functionsin covering eggs.cenchrus n.; pl. cenchri [Gr. kenchros, millet] (ARTHRO: Insecta)In Hymenoptera, specialized lobes on the metanotumof certain sawflies that contact with rough areas on theunderside of the fore wing to hold them in place; sometimesfunctioning as a stridulatory apparatus.cenenchyma see coenenchymacenogenesis, caenogenesis n. [Gr. kainos, recent; genesis,beginning] The repetition of phylogeny by ontogeny,caused by heterochrony (temporal displacement), heterotropy(spacial displacement) or larval adaptation. cenoge-

Online Dictionary of Invertebrate Zoology 175netic a. see palingenesis.cenogenous a. [Gr. koinos, common; gennaein, to produce]Oviparous at one season of the year and at other times viviparous.cenosis, coenosis n. [Gr. koinos, common] 1. A community;biocoenosis. 2. Association. 3. A community dominated bytwo distinct species, that may or may not be mutually antagonistic.cenospecies n.pl. [Gr. kainos, recent; L. species, kind] Speciesthat can interbreed.Cenozoic a. [Gr. kainos, recent; zoe, life] A geological historyfrom the beginning of the Tertiary to the present, that sawa rapid evolution of mammals, birds, grasses, shrubs, andhigher flowering plants, but with little change in invertebrates.centigrade see celsiuscentimeter n. [L. centum, hundred; metron, measure] Onehundredth (.0l) part of a meter or two fifths (0.3937) of aninch. Abbrev. cm. see meter.centrad adv. [Gr. kentron, center; L. ad, toward] Toward thecenter or interior.centradenia n. [Gr. kentron, center; aden, gland] (CNID: Hydrozoa)A type of siphonophore hydroid colony.central area 1. (MOLL: Polyplacophora) The upper surface ofan intermediate valve, lying centrally, and sometimes differingin sculpture from the lateral areas. 2. (NEMATA: Secernentea)The nonstriated region around the vulva in theMeloidogyne perineal pattern.central cell (PORIF) A cell located in the cavity of a choanocytechamber.central nervous system In invertebrates, a system to whichthe sensory impulses are transmitted and from which motorimpulses pass out. a. In radially symmetric animals,structured in the form of one or two rings. b. In elongateanimals, usually consists of an anterior bilobed cerebralganglion (brain), and paired longitudinal ventral cords thatare usually connected by the circumesophageal nerve ring.

176Maggenti and Gardnercentral region (ARTHRO: Insecta) The costal region of a wing.central symmetry system (ARTHRO: Insecta) The medianfield of the moth wing pattern delimited basally and distallyby the light central line of the transverse, anterior andposterior lines.central tube (NEMATA) The sclerotized cylindrical axis of thehead skeleton of nematodes, through which the stylet extendsduring feeding.centric fusion The fusion of two acrocentric chromosomes toform a single metacentric chromosome through translocationand as a rule, the loss of a centromere.centrifugal a. [Gr. kentron, center; L. fugare, to flee] 1.Turning from or being thrown away from the center. 2.Moving toward the periphery, as nerve impluses.centriole n. [Gr. kentron, center] Either of the two minutespherical bodies in a cell center that migrates to oppositepoles during cell division and serves to organize the alignmentof the spindles.centripetal a. [Gr. kentron, center; L. petere, to move toward]Turning inwardly from the outside or periphery; toward thecenter. see centrifugal.centripetal canal (CNID) One of numerous blind canals runningfrom the circular canal toward the apex of the bell incertain jellyfish.centris n. [L. centrum, sting] (ARTHRO: Insecta) In Hymenoptera,the sting.centrodorsal a. [Gr. kentron, center; L. dorsum, back] 1. Referringto central and dorsal. 2. (ECHINOD: Crinoidea) Pertainingto a cirriferous ossicle, fused or semifused, attachedto the theca.centrogenous a. [Gr. kentron, center; gennaein, to produce]1. Growing from the center. 2. (PORIF) A spicule growingfrom a common center.centrolecithal egg (ARTHRO) A type of arthropod egg in whichthe nucleus is located centrally in a small amount of nonyolkycytoplasm surrounded by a large mass of yolk untilfertilized; when nuclear divisions begin the nuclei migrate

Online Dictionary of Invertebrate Zoology 177to the periphery to proceed with superficial cleavage, withthe yolk remaining central. see isolecithal egg,mesolecithal egg, telolecithal egg.centromere n. [Gr. kentron, center; meros, part] The part onthe chromosome where it becomes attached to the spindle.centrophormium n. [Gr. kentron, center; phormis, basket]Round basket-like Golgi bodies.centroplasm see centrosomecentrosome n. [Gr. kentron, center; soma, body] A specializedarea of condensed cytoplasm that contains the centrioles atthe beginning of mitosis; also called centrosphere, cytocentrum,microcentrum, attraction sphere, and paranuclearbody.centrosphere see centrosomecentrotylote a. [Gr. kentron, center; tylos, knob] (PORIF) Indiactinal monoaxons, having the knob near the middle ofthe shaft of a spicule.centrum n.; pl. -trums [Gr. kentron, center] A center or centralmass.cephalad adv. [Gr. kephale, head; L. ad, toward] Toward thehead or anterior end; rostrad. see caudad.cephalaria n. [Gr. kephale, head; -aria, a thing like] (ARTHRO:Insecta) In a generalized insect, the alaria present on eachlateral margin of the prescutum anterior to the prephragma.cephalate a. [Gr. kephale, head] Having a head or head-likestructure.cephaletron n. [Gr. kephale, head; etron, belly] (ARTHRO:Chelicerata) The anterior body region of Limulidae, thehorseshoe crabs.cephalic a. [Gr. kephale, head] Pertaining to the head or anteriorend.cephalic bristles (ARTHRO: Insecta) In Diptera, specializedbristles occurring on the head.cephalic cage (ANN: Polychaeta) Long forwardly directed setaeencircling the mouth.

178Maggenti and Gardnercephalic capsule (NEMATA) An internal modification of the cephaliccuticle forming an endoskeletal helmet, often posteriorlydelimited by a distinct groove on the exterior cuticle.cephalic constriction (ARTHRO: Crustacea) In Myastacocarida,a constriction delimiting anterior antennulary part of thehead from the posterior part.cephalic flexure (ARTHRO: Crustacea) In Decapoda, forward,or occasionally upward, deflection of the anterior sterna.cephalic foramen (ARTHRO: Insecta) The posterior or occipitalforamen of the head through which the alimentary canaland other organs pass.cephalic framework (NEMATA: Secernentea) A subcuticularframework that supports the lip region, and to which areattached the stylet protractor muscles.cephalic gland (ARTHRO: Insecta) A gland opening on to thelabium and connecting with the ventral tube by a groove inthe cuticle in the ventral midline of the thorax, that secretsmoisture to aid walking on dry surfaces.cephalic grooves/slits (NEMER) Deep or shallow furrows,lined with a ciliated epithelium, that occur laterally on thesides of the head; thought to be chemosensory.cephalic heart (ARTHRO: Insecta) In Odonata, a specializedpulsating organ that exerts pressure against the egg-shellin hatching and forces out a cap-like operculum; a pulsatingorgan.cephalic hood (MOLL: Bivalvia) A chitinous covering protectingthe anterior adductor muscle at a young burrowing stage.cephalic incision (NEMATA) Anterior extensions of the cephalicsuture dividing the posterior part of the capsule into lobes.cephalic lobes 1. (ARTHRO: Insecta) In embryology, the regionof the prostomium, and usually that of the tritocerebralsomite. 2. (NEMER) Brain lobes on the expanded anteriorregion.cephalic pole (ARTHRO: Insecta) An elongated egg in theovariole aligned with the head of the parent.cephalic region Pertaining to, on, in, or near the head.cephalic rim (ANN: Polychaeta) A flange encircling the head.

Online Dictionary of Invertebrate Zoology 179cephalic salivary glands (ARTHRO: Insecta) A pair of glandslying against the posterior wall of the head of bees, thatunite with the thoracic salivary gland to form a commonduct. see postocellar glands.cephalic setae (NEMATA) Setae-like sensilla of the outer ofthree circlets around the anterior neck region or mouth.cephalic shield 1. (ARTHRO: Crustacea) A chitinous, somewhatcalcified covering of the head region formed of fused tergitesof cephalic somites, commonly having pleura. 2.(MOLL: Gastropoda) In Opisthobranchia, an expandedthickening of the dorsal surface of the head that may attimes extend dorsally over the back.cephalic somite (ARTHRO: Crustacea) A unit division of the cephalicregion usually recognized as one of five somites thatbear distinctive paired appendages; a cephalomere.cephalic stomodeum (ARTHRO: Insecta) That part of a stomodeumcontained in the head.cephalic suture (NEMATA: Adenophorea) The posterior delimitationof the cephalic capsule in marine nematodes.cephalic tentacles see frontal tentaclescephalic veil (ANN: Polychaeta) A delicate hood-like membraneseparating the opercular paleae from the buccal tentaclesin Pectinariidae.cephalic ventricle (NEMATA) The fluid-filled area anterior tothe end of the esophagus.cephalic vesicle (ARTHRO: Insecta) A single sac formed by theunion of the larval pharynx and its diverticula, throughwhich it is presumed that fluid passes to circulate into andaround the embryo.cephalid n. [Gr. kephale, head] (NEMATA) A nerve commissureof a highly refractive nature that extends from lateral cordto lateral cord ventrally or dorsally, anteriorly they extendfrom dorsal to ventral. see caudalid, hemizonid, hemizonion.cephaliger n. [Gr. kephale, head; L. gerere, to bear] (ARTHRO:Insecta) The anterior process of the cervical sclerite thatarticulates with the condyle of the cranium; the head-

180Maggenti and Gardnerbearing process.cephalization n. [Gr. kephale, head] The process by which thehighest degree of specialization became localized in theanterior end, or in the head, in animal development.cephaloboid a. [Gr. kephale, head; eidos, form] (NEMATA)Having the appearance of a Cephalobus nematode: anesophagus with a long, narrow anterior portion and a pearshapedvalvate basal bulb.cephalocaudal suture (ARTHRO: Insecta) In certainVespoidea, the median suture dividing the mesepisternum.cephaloconi n.pl. [Gr. kephale, head; konos, cone] (MOLL:Gastropoda) In Clionidae, a circlet of adhesive oral papillae;two or three pairs of conical buccal appendages.cephalogaster n. [Gr. kephale, head; gaster, stomach] (AR-THRO: Crustacea) A contractile organ in adult epicarideanisopods functioning in sucking blood and possibly respiration.cephalomere n. [Gr. kephale, head; meros, part] 1. Thosesegments of a metamerically segmented animal that areconsidered to be part of the head. 2. (ARTHRO: Crustacea)see cephalic somite.cephalon n.; pl. -la [Gr. kephale, head] The anterior body region;the head.cephalopharyngeal skeleton (ARTHRO: Insecta) In Diptera,articulated sclerites of the mature larva; a secondary development:mandibular sclerites, intermediate sclerite,pharyngeal sclerite, chitinized, anterior, invaginated portionof the mouth parts.cephalophorous a. [Gr. kephale, head; phoreus, bearer](MOLL) Pertaining to having a head.cephalophragma n. [Gr. kephale, head; phragma, partition](ARTHRO: Insecta) In certain Orthoptera, a v-shaped partitiondividing the head into an anterior and posterior chamber.Cephalopoda, cephalopods n.; n.pl. [Gr. kephale, head;pous, foot] A Class of Mollusca containing the squid, cuttlefish,octopus, argonaut, and spirula, with head-foot bearing

Online Dictionary of Invertebrate Zoology 181a ring of appendages, (many, 10 or 8), generally equippedwith adhesive structures, suckers or hooks.cephalopodium n. [Gr. kephale, head; pous, foot] (MOLL:Cephalopoda) The head region, consisting of head andarms.cephalopsin n. [Gr. kephale, head; ops, eye] A purple-likephotopigment found in the eyes of cephalopods and certainother invertebrates.cephalosome n. [Gr. kephale, head; soma, body] (ARTHRO)The head region of an arthropod; in crustaceans, this includesonly somites bearing maxillipeds or gnathopods, orboth.cephalostegite n. [Gr. kephale, head; stege, roof] (ARTHRO:Crustacea) The anterior part of the cephalothoracic shield.cephalotheca n. [Gr. kephale, head; theke, case] (ARTHRO:Insecta) The head covering in a pupa.cephalothorax n. [Gr. kephale, head; thorax, chest] (ARTHRO)A descriptive term used for many arthropods indicating theanterior region of the body combining head and thorax;sometimes used to denote fusion with one or more of thethoracic segments, as in crustaceans and coccids; forarachnids, see prosoma.cephalotrocha larva (PLATY: Turbellaria) A polyclad turbellarianresembling a trochophore-like stage, but distinguishedfrom the trochophore by the possession of onepreoral and one postoral ciliated band; a young Muller'slarva.cephalous a. [Gr. kephale, head] Pertaining to the head.cephalula n. [Gr. dim. kephale, head] (BRACHIO) A freeswimmingembryonic stage.ceraceous a. [L. cera, wax] Waxy.cerago n. [L. cera, wax] Beebread.ceral a. [L. cera, wax] Of or pertaining to wax.cerambycoid larva (ARTHRO: Insecta) Flattened or cylindrical,naked, smooth and distinctly segmented larva, resemblingthose of Cerambycidae and some Buprestidae and Elateridae.

182Maggenti and Gardnerceraran setae (ARTHRO: Insecta) The conical setae of the cerariiof soft scale insects.cerarius n.; pl. cerarii [L. cera, wax] (ARTHRO: Insecta) InHemiptera, a structure on the dorsum of the body of mealybugs, consisting of pores and setae; sometimes sclerotized.ceras n.; pl. cerata [Gr. keras, horn] 1. A horn or horn-likeappendage. 2. (MOLL: Gastropoda) In some Nudibranchia,numerous projections that act as gills on the dorsal bodysurface, may be club shaped or grapelike and usually brilliantlycolored in red, yellow, orange, blue, green, or acombination of colors; functioning in respiration, containingblood from the hemocoel and tubular branches of the digestivegland.ceratheca, ceratotheca n. [Gr. keras, horn; theke, case] (AR-THRO: Insecta) That portion of a pupal shell surroundingthe antenna.ceratite n. [Gr. keras, horn] (MOLL: Cephalopoda) An ammonoidcephalopod found in the Permian Period and typical ofTriassic deposits.ceratoid a. [Gr. keras, horn; eidos, form] Horny; horn-like orhorn-shaped.ceratophore a. [Gr. keras, horn; phoreus, bearer] (ANN: Polychaeta)Pertaining to the basal joint of an antenna.ceratuba n.; pl. -tubae [L. cera, wax; tuba, trumpet] (AR-THRO: Insecta) In Hemiptera, the terminal outlet of certainwax glands of scale insects, variable in shape and size.cercal a. [Gr. kerkos, tail] Pertaining to the tail or cercus.cercaria n.; pl. -rae [Gr. kerkos, tail] (PLATY: Trematoda) Thefree-swimming larval form of a digenetic trematode; producedby asexual reproduction within a sporocyst or redia.cercariaeum n. [Gr. kerkos, tail] (PLATY: Trematoda) A cercariawithout a tail.cercaria ornata (PLATY: Trematoda) A cercaria with a fin onthe tail.cerci pl. of cercuscercid n. [Gr. kerkis, shuttle] (PORIF) A minute migrating cellproduced by division of the archaeocytes.

Online Dictionary of Invertebrate Zoology 183cercobranchiate n. [Gr. kerkos, tail; branchia, gills] (ARTHRO:Insecta) The respiratory apparatus of odonatan insectnymphs, consisting of three terminal lamellate caudal gills.cercocystis n. [Gr. kerkos, tail; kystis, bladder] (PLATY:Cestoda) A cysticercoid with a tail.cercoide n. [Gr. kerkos, tail; eidos, shape] (ARTHRO: Insecta)One of a pair of genital appendages on abdominal segments9 and 10 of certain insects.cercomer n. [Gr. kerkos, tail; meros, part] (PLATY: Cestoda) Aposterior, knob-like attachment on a procercoid or cysticercoid,usually bearing the hooks of the oncosphere.cercopod n. [Gr. kerkos, tail; pous, foot] 1. (ARTHRO: Crustacea)A segmented terminal process located on the telson.see caudal ramus. 2. (ARTHRO: Insecta) Jointed foot-likeappendages of the last abdominal segment. see cercus.cercus n.; pl. cerci [Gr. kerkos, tail] (ARTHRO) One of a pair ofappendages that arise at the posterior of the abdomen ofarthropods that function as sense organs; abdominal filaments;acrocercus; anal forceps; anal styles; anal stylets;caudal filaments; caudal setae; caudal ramus; spinnerets ofSymphyla; tergal valves; for Coleoptera see urogomphi.cere v.t. [L. cera, wax] To wax or cover with wax.cerebellum n. [L. dim. cerebrum, brain] The subesophagealganglion.cerebral eyes Paired eyespots embedded in or near the substanceof the brain area.cerebral ganglion In invertebrates, one of a pair of ganglia(or fused median ganglion) situated in the head or anteriorportion of the body; the dorsal ganglion; cerebroganglion.see brain.cerebral organs 1. (NEMER) One of paired ciliated tubes associatedwith the dorsal ganglion and opening to the exterior,that function as chemical sense organs. 2. (SIPUN) The anteriormargin of the cerebral ganglion made up of high columnarepithelium, probably not sensory in function.cerebroganglion see cerebral ganglioncerebroidae n.pl. [L. cerebrum, brain] (ARTHRO: Insecta) The

184Maggenti and Gardnerganglionic center of the brain.cerebropedal a. [L. cerebrum, brain; pes, foot] (MOLL) Pertainingto nerve strands connecting the dorsal cerebral andventral pedal ganglia.cerebropleural ganglion (MOLL: Bivalvia) A ganglion justabove the mouth.cerebrosides n.pl. [L. cerebrum, brain; F. -ide, from oxide]Phospholipids probably common to all living cells.cerebrovisceral a. [L. cerebrum, brain; viscera, viscera](MOLL) Pertaining to, or connecting the cerebral and visceralganglia.cerebrum n. [L. cerebrum, brain] 1. The primary cephalic oranterior ganglion or ganglia. 2. (ARTHRO: Insecta) The supraesophagealganglion, or brain. cerebral a.cereous a. [L. cereus, waxen] Wax-like.ceriferous a. [L. cera, wax; ferre, to carry] Bearing or producingwax.cerinula larva (CNID: Anthozoa) In Ceriantharia, pelagic larvaeresembling medusae with flagella and a circlet of marginaltentacles; many genera have been named from the pelagiclarvae but the adults and life cycle are unknown.cernuous a. [L. cernuus, facing earthward] Drooping; nodding;pendulous; having the apex more or less bent downward orinclining.cerodecyte n. [L. cera, wax; Gr. kytos, container] Oenocytes;applied to such cells because they were presumed to aid informing and conserving wax.cerotegument n. [L. cera, wax; tegumentum, covering] (AR-THRO: Chelicerata) In Acari, tegumental layers generallydistinguishable by an outer cement layer covering the lipidlayer; part of the epiostracum; part of the epicuticle; superficialepicuticular layers; tectostracum.cerulean n. [L. caeruleus, sky-blue] Azure or sky-blue.cerumen n. [L. cera, wax] (ARTHRO: Insecta) A mixture ofresin and wax used for nest construction by stingless bees,and to a minor extent by Apis.

Online Dictionary of Invertebrate Zoology 185cervacoria n. [L. cervix, neck; corium, leather] (ARTHRO: Insecta)The cephalic membranous end of the cervix, attachedto the walls of the head near the foramen.cervical a. [L. cervix, neck] Of or pertaining to the neck, or tothe cervix of an organ.cervical alae (NEMATA: Secernentea) In some animal parasiticnematodes, wide lateral anterior alae, single, bifid or trifid,often with internal supporting struts.cervical ampulla (ARTHRO: Insecta) In Orthoptera, cervicalmembrane capable of becoming a swollen dorsal vesiculeprotruding immediately behind the head; functioning in ecdysis.cervical condyles see occipital condylescervical duct (NEMATA) The excretory duct.cervical foramen (ARTHRO: Insecta) The occipital foramen ofcoleopterous larvae.cervical furrow (ARTHRO: Crustacea) In Decapoda, a transversegroove in the median part of a carapace, betweenthe gastric and cardiac regions, curving toward the antennalspine; cervical suture.cervical gland 1. (ARTHRO: Insecta) The dorso-lateral glandsof the larvae of primitive sawflies located between the headand thorax. 2. (NEMATA) The excretory gland.cervical groove 1. (ARTHRO: Crustacea) In Decapoda, a transversegroove on the carapace marking the general separationof the head and thoracic areas. 2. (NEMATA) Transversegroove on the ventral surface, or completely encirclingthe cervical (=cephalic) region marking the line ofseparation of the lip region from the rest of the body.cervicalia n. [L. cervix, neck] (ARTHRO: Insecta) The scleritesof the cervix or neck.cervical notch or incision (ARTHRO: Crustacea) Strong indentationof a carapace at the level of the cervical groove.cervical papillae (NEMATA) Paired lateral papillae in some Secernenteaand Chromadoria; lateral sensory sensilla locatedanteriorly, usually on the so-called neck region;deirids.

186Maggenti and Gardnercervical pore (NEMATA) The ventromedian excretory pore.cervical sclerite (ARTHRO: Insecta) Lateral sclerite or scleritesin the neck or cervix membrane, between the head andprothorax; jugular sclerites.cervical shield (ARTHRO: Insecta) A chitinous plate on theprothorax of caterpillars immediately behind the head; asclerotized pronotum; a prothoracic shield.cervical sinus (ARTHRO: Crustacea) In Cladocera, a rounded toangular indentation anteriorly along the edge of the carapace,exposing the rear part of the head.cervical suture see cervical groovecervical vesicle (NEMATA) Distended cuticle anterior to thecervical groove.cerviculate a. [L. cervix, neck] Having a long neck or neck-likeportion.cervicum n. [L. cervix, neck] (ARTHRO) The neck region.cervinus a. [L. cervinus, deer] Reddish, deer-gray.cervix n.; pl. cervices [L. cervix, neck] 1. The neck or necklikepart. 2. A constriction of the mouth of an organ. 3.(ARTHRO: Chelicerata) In Acariformes, the dorsal part of theinfracapitulum, between the line of attachment of the cheliceralframe and the base of the labrum, and laterally bythe lateral ridges, and encompasses the capitular saddleand cheliceral grooves. 4. (ARTHRO: Insecta) A membranousregion that extends from the occipital foramen at theback of the head to the prothorax.cesious a. [L. caesius] Bluish-gray.cespiticolous a. [L. caespes, turf; colere, to inhabit] Inhabitinggrassy places.cespitose, caespitose a. [L. caespes, turf] Growing in denseclumps or tufts; matted.cestiform a. [L. cestus, girdle; forma, shape] Girdle-shaped.Cestoda, cestodes n.; n.pl. [L. cestus, girdle] A class of elongate,dorsoventrally flattened obligate parasitic worms thatdevelop in an intermediate vertebrate or invertebrate hostand spend their adult life mainly in vertebrates; commonly

Online Dictionary of Invertebrate Zoology 187called tapeworms.chaeta n.; pl. chaetae [Gr. chaite, hair] (ANN) Seta.chaetiferous see setiferouschaetiger n. [Gr. chaite, hair; L. gerere, to bear] (ANN) Anysegment bearing setae.Chaetognatha, chaetognaths n.; n.pl. [Gr. chaite, hair;gnathos, jaw] A phylum of free-living planktonic or benthicanimals, commonly called arrowworms, having an elongatedmore or less translucent body with large graspingspines at the head and a posterior horizontal tail fin.chaetoparia n.; pl. -pariae [Gr. chaite, hair; pareion, cheek](ARTHRO: Insecta) In scarabaeoid larvae, the inner part ofthe paria covered with bristles.chaetophorous a. [Gr. chaite, hair; pherein, to bear] Bearingbristles.Chaetopoda n. [Gr. chaite, hair; pous, foot] Annelids thathave setae, the Polychaeta and Oligochaeta.chaetosemata n.pl.; sing. chaetosema [Gr. chaite, hair;sema, sign] (ARTHRO: Insecta) In some families of Lepidoptera,one pair, rarely two pairs, of sensory organs locatedon the head in the form of setose tubercles.chaetotaxy n. [Gr. chaite, hair; taxis, arrangement] Pattern,arrangement and nomenclature of bristles on any part ofthe exoskeleton. chaetotactic, chaetotaxal a.chainette n. [F. chainette, a catenary curve] (PLATY: Cestoda)A longitudinal band of single or double rows of very smallhooks located on the tentacles.chaintransport (ARTHRO: Insecta) The passing of food fromone worker ant to another during transport to the nest.chalastogastrous a. [Gr. chalastos, loose; gastros, stomach](ARTHRO: Insecta) Having the abdomen attached to thethorax by a broad base, as in certain Hymenoptera.chalaza n.; pl. -zas, -zae [Gr. chalaza, pimple] (ARTHRO: Insecta)A pimple-like swelling on the body-wall that bears aseta.chalceous, chalceus a. [Gr. chalkos, copper] Brassy in color

188Maggenti and Gardneror appearance.chalimus stage (ARTHRO: Crustacea) In Monstrilloida, a larvalinfective stage that fixes to the host with a frontal filament;parasites of various marine invertebrates.challenge n. [OF. chalangier, contest] The testing of inducedimmunity of a potential host by exposure to parasites afterimmunization.chalone n. [Gr. chalinos, to curb] Any internal secretion withinhibitory actions. see hormone.chalybeate, chalybeatus, chalybeous, chalybeus a. [Gr.chalybos, steel] Metallic steel-blue in color.chambered a. [Gr. kamara, chamber or vault with archedroof] Having divisions or provided with a chamber.chambered organ (ECHINOD: Crinoidea) A five chamberedstructure, encased in the cup-like cavity of the aboral nervoussystem; connecting canals form the nerves of the stalkand cirri.chank n. [Hind. cankh, conch shell] (MOLL: Gastropoda) Apear- or top-shaped shell utilized as ornaments and banglesand held sacred by the Hindus (the Xancus pyrum andthe pear Turbinella ).channeled, channelled a. [L. canalis, groove] Having furrows,grooves or channels; directed into or along a channel.chaperon see clypeuschaplet n. [OF. chapel, hat] 1. A small crown. 2. A terminalprocess in the form of a circle of hooks or similar structures.character n. [Gr. charassein, to make clear] A distinguishingfeature, trait or property of an organism that distinguishesa member from a different group or taxon; taxonomiccharacter.character displacement A divergence of equivalent charactersin a sympatric species due to the selective effects ofcompetition. see character divergence.character divergence A name given by Darwin to the differencesdeveloping in two or more related species in theirarea of sympatry resulting from selective effects of compe-

Online Dictionary of Invertebrate Zoology 189tition. see character displacement.character gradient see clinecharacter index A numerical value, compounded from theratings of several characters, indicating a degree of differenceof related taxa; also a rating of an individual, particularlya hybrid, in comparison with its most nearly relatedspecies.checkered see tessellatecheek groove see genal groovecheeks n.pl. [A.S. ceace, cheek] 1. In most invertebrates, thelateral portions of the head. 2. (ARTHRO: Insecta) Below theeyes and lateral to the mouth; parafacials. see gena. 3.(NEMATA) The ampulla of an amphid.cheilorhabdions n.pl. [Gr. cheilos, lip; dim. rhabdos, rod](NEMATA) The cuticularized walls of the cheilostome. seerhabdions.cheilostome n. [Gr. cheilos, lip; stoma, mouth] (NEMATA) Theanteriad region of the stoma, that is lined by external cuticleformation.cheironym see chironymchela n.; pl. chelae [Gr. chele, claw] 1. (ARTHRO) A lateralmovable claw on a limb: pincerlike, with opposed movableand immovable fingers; occasionally both fingers move. 2.(ARTHRO: Insecta) Has been applied to feet of some Anoplurain which the opposable claw performs a holdfastfunction. see claw. 3. (PORIF) A type of microsclere with ashort, straight or curved axis and recurved teeth at bothends.chelate a. [Gr. chele, claw] Pincerlike, or possessing or resemblingchelae.chelenchium see cheilostomechelicera n.; pl. -erae [Gr. chele, claw; keras, horn] (ARTHRO:Chelicerata) Anterior most pair of appendages, functioningin grasping, holding, tearing, crushing or piercing; pincherlikein scorpions, but modified as poison fangs in spidersand as biting mouth parts of ticks.cheliceral frame (ARTHRO: Chelicerata) That part of the tegu-

190Maggenti and Gardnerment to which the chelicerae are attached.cheliceral boss (ARTHRO: Chelicerata) In Araneae when present,a tear-shaped or wedge-shaped process on the distalpart of the chelicera where it comes into contact with theclypeus.cheliceral gland (ARTHRO: Chelicerata) One of paired glands inthe dorsal part of the prosoma; the orifice is in the chelicerae.cheliceral groove (ARTHRO: Chelicerata) One of paired longitudinalgrooves in the dorsal surface of the infracapitulum,receiving and guiding the chelicera.cheliceral sheath (ARTHRO: Chelicerata) A paired membranoussheath that attaches the chelicera to the cheliceralframe so as to allow extension and retraction.cheliceral teeth (ARTHRO: Chelicerata) Serrations along theborders of the cheliceral groove.Chelicerata, chelicerates n.; n.pl. A subphylum of arthropodswithout antennae, divided into three classes: theMerostomata, or horseshoe crabs; the Arachnida, spiders,scorpions, mites and relatives; and the Pycnogonida, or seaspiders.cheliferous a. [Gr. chele, claw; L. ferein, to bear] Bearing orterminating in claws or chelae.cheliform a. [Gr. chele, claw; L. forma, shape] Pincherlike.cheliped n. [Gr. chele, claw; L. pes, foot] A claw-bearing appendage;forceps that bear at its tip a chela.cheloniform a. [Gr. chelon, tortoise; L. forma, shape] Turtleor tortoise-shaped; limpet-like.chelophores n.pl. [Gr. chele, claw; pherein, to bear] (ARTHRO:Chelicerata) Chelicerate first appendages of the arthropodclass Pycnogonida.chemiluminescence n. [Gr. chemeia, pert. chemistry; L. luminescere,to grow light] Enzymatic light production withoutincrease in temperature in the course of a chemical reaction;bioluminescence.chemoceptor see chemoreceptor

Online Dictionary of Invertebrate Zoology 191chemodifferentiation n. [Gr. chemeia, pert. chemistry; L.differens, dissimilar] The chemical change in cells precedingtheir visible characteristic difference in embryonic development.chemoheterotroph n. [Gr. chemeia, pert. chemistry; heteros,different; trophe, nourishment] An organism that uses organiccompounds as both energy and a carbon source.chemokinesis n. [Gr. chemeia, pert. chemistry; kinesis,movement] Increased movement of an organism due tothe presence of a chemical substance. chemokinetic a.chemoreceptor n. [Gr. chemeia, pert. chemistry; L. receptor]A sense organ stimulated by chemical substances that maybe perceived as smell (olfaction) or direct contact.chemoreflex n. [Gr. chemeia, pert. chemistry; L. reflexus,bent or turned back] A reflex as a result of chemicalstimulus.chemosensory a. [Gr. chemeia, pert. chemistry; L. sensus,sense] Being sensitive to chemical stimuli. see chemoreceptor.chemosynthesis n. [Gr. chemeia, pert. chemistry; synthesis,composition] 1. Synthesis of organic chemical compoundsin organisms. 2. A type of autotrophic nutrition throughwhich organisms obtain their energy by oxidation of variousinorganic compounds instead of from light. see photosynthesis.chemotaxis n.; pl. -taxes [Gr. chemeia, pert. chemistry;taxis, arrangement] Movement of a motile organism or cellin response to chemical stimulus. a. Positive chemotaxis:movement toward the stimulus; chemotropism. b. Negativechemotaxis: movement from the stimulus. see taxis, tropism.chemotropism n. [Gr. chemo, pert. chemistry; trope, turn]Reaction induced by a chemical stimulus. see tropism.chevron n. [Gr. chevron, rafter] (ANN: Polychaeta) A V-shapedblack, chitinous jaw piece at the base of the eversiblepharynx of some Glyceridae.chevron groove (MOLL: Bivalvia) A V-shaped furrow on thecardinal area for ligament insertion.

192Maggenti and Gardnerchiasma n.; pl. -mata [Gr. chiasma, cross] 1. (ARTHRO: Insecta)A crossing of nerves in the nerve center. a. External(outer): a crossover between the lamina ganglionaris andthe medulla externa. b. Internal (inner): a crossover betweenmedula externa and medula internal. 2. An X-shapedchromosome formation seen in meiotic cell division, due tobreakage, exchange, and reciprocal fusion of equivalentsegments of homologous chromatids. chiasmic a.chiasmatype theory A Genetic theory postulating chiasmataare the result of crossing-over; being formed at the rightpoints at which the exchange between (non-sister) chromatidstook place.chiaster n. [Gr. χ; aster, star] (PORIF) A type of microsclereaster with very blunt rays.chiastoneury n. [Gr. chiasma, cross; neuron, nerve] (MOLL) Inprosobranchs and a few other taxa, a condition in whichthe visceral loop is distinctively twisted; crossing of the visceralconnectives; streptoneury. chiastoneural a. seeorthneury, euthyneury.chilaria n.pl.; sing. chilarium [Gr. cheilos, lip] (ARTHRO: Chelicerata)In Merostomata, small rudimentary appendageson the reduced 7th (pregenital) metamere of king crabs.chilidium n. [Gr. dim. cheilos, lip] (BRACHIO) A plate coveringthe notothyrium, when present, in the dorsal valve; chilidialplates if more than one. see homeochilidium.chilognath n. [Gr. cheilos, lip; gnathos, jaw] (ARTHRO: Diplopoda)Fusion of the first maxillae into a lower lip or gnathochilarium.Chilopoda, chilopods n.; n.pl. [Gr. cheilos, lip; pous, foot] Agroup of terrestrial arthropods, commonly called centipedes,characterized by having numerous trunk segments,each with a single pair of walking legs, except the firstsegment that bears a pair of forcipulate poison fangs.chiloscleres n. [Gr. cheilos, lip; skleros, tough] (ARTHRO: Insecta)Dark brown spots, on either side of the labrum incertain ant larvae.chimera, chimaera n.; pl. -ras [Gr. chimaira, she-goat] Anindividual with a mixture of tissues, genetically different in

Online Dictionary of Invertebrate Zoology 193constitution. see gynandromorph.chimney n. [Gr. kaminos, fireplace] (MOLL: Bivalvia) A tubeformed of agglutinized particles derived from boring, extendingover the posterior end of the shell and sometimesextends anteriorly nearly to the mesoplax. see siphonaltube.chimopelagic a. [Gr. cheimon, winter; pelagos, sea] Certaindeep-sea organisms that appear at the surface only inwinter.chink n. [A.S. cinu, chink or crack] 1. A long and narrow cleft,crack or slit. 2. (MOLL: Gastropoda) The margin of thecolumella in Lacuna; umbilical chink.chironym, cheironym n. [Gr. cheir, hand; onyma, name] Amanuscript name for a species; an invalid name until published.chirotype n. [Gr. cheir, hand; typos, type] The type specimendesignated in a manuscript as the "chironym" that becomesvalid upon publication.chisels see laciniachitin n. [Gr. chiton, tunic] A linear polysaccharide that consistspredominately, or perhaps entirely, of -linked -acetyl-D-glucosamine residues found in the exoskeleton of arthropods,nematode eggshells, annelid cuticle, thecate hydroids,and also in some plants, especially fungi.chitinase n. [Gr. chiton, tunic; -asis, denoting enzymes] Anenzyme, or family of enzymes capable of decomposing chitin;found in molting fluid and as a secretion from chitinovores.chitinization n. [Gr. chiton, tunic; izein, cause to be] Theprocess of depositing chitin, or being chitinized. chitinizeda.chitinogenous a. [Gr. chiton, tunic; gennaein, to produce](ARTHRO) Pertaining to epidermal cells that secrete the chitin.chitinophilus a. [Gr. chiton, tunic; philos, loving] Pertaining tomicro-organisms found in association with chitin andthought to derive nourishment from it. see chitinovore.

194Maggenti and Gardnerchitinous a. [Gr. chiton, tunic] (ARTHRO) Composed of or resemblingchitin, a colorless, hard amorphous compound;seen as the principal constituent of the hard covering of insectsand crustaceans, the horny material as in the ligamentof bivalve mollusks, the internal shell remnant of thesquids and the horny operculum of many gastropods.chitinous cradle (ARTHRO: Insecta) Chitinized arms or barsthat form the endoskeleton of the head of scale insects.chitinous plate of Hayes see nesiumchitinovore n. [Gr. chiton, tunic; L. vorare, to devour] A micro-organismwith the ability to digest chitin. see chitinophilus.chitonostracum n. [Gr. chiton, tunic; ostrakon, shell] (AR-THRO: Chelicerata) In Acari, the thickest layer of the cuticlebetween epiostracum and hypodermis. see ectostracum.chitosan n. [Gr. chiton, tunic] A deacetylated derivative of chitin(polymeric glucosamine) that gives a characteristic violetcolor with iodine; the most commonly used qualitativetest for the presence of chitin.chitose n. [Gr. chiton, tunic] A decomposition product of chitin;an acetyglucosamine and glucosamine salt.chlamydate, chlamydeous a. [Gr. chlamys, mantle] Bearinga cloak or mantle-like structure.chloragen cells (SIPUN) Yellow-brown cells on the peritonealsurfaces, especially the intestine. see chloragogen cells.chloragocyte n. [Gr. chloros, yellow-green; -agogue, thatwhich stimulates; kytos, container] A chloragogen cell.chloragogen cells (ANN) Yellowish-brown or greenish cellsthat surround the intestine of annelids that function in intermediarymetabolism, similar to the role of the liver invertebrates; also spelled chloragen, chloragogue,chlorogog.chloragosomes n.pl. [Gr. chloros, yellow-green; -agogue, thatwhich stimulates; soma, body] Yellowish-brown or greenishglobules formed in chloragogen cells.chlorocruorin n. [Gr. chloros, yellow-green; L. cruor, blood](ANN: Polychaeta) A green respiratory pigment found in the

Online Dictionary of Invertebrate Zoology 195blood; an iron porphyrin, differing from hemoglobin in oneof the side chains, hence green pigment.chlorogog see chloragogen cellschlorogogue see chloragogen cellschlorophyll n. [Gr. chloros, yellow-green; phyllon, leaf] Thegreen pigment of plants and certain protozoa and bacteria,involved in photosynthesis.choana n.; pl. -ae [Gr. choane, funnel] Funnel-shaped.choanocyte n. [Gr. choane, funnel; kytos, container] (PORIF) Aflagellate cell crowned by a collar of cytoplasmic tentaclesthat generates currents of water; a collar cell.choanocyte chamber (PORIF) A cavity enclosed by a group ofchoanocytes.choanoderm n. [Gr. choane, funnel; derma, skin] (PORIF) Anysurface that is lined by choanocytes.choanosome n. [Gr. choane, funnel; soma, body] (PORIF) Thatarea of the body that houses choanocyte chambers.chondrioconts n.pl. [Gr. chondros, grain; kontos, puntingpole] Tubular and vesicular interior structures of mitochondria.chondriodieresis n. [Gr. chondros, grain; dieres, double] Alterationsin mitochondria during cell division.chondriokinesis n. [Gr. chondros, grain; kinesis, movement]Reproduction of mitochondria and their distribution in mitosisand meiosis.chondriolysis n. [Gr. chondros, grain; lysein, to loosen] Thedisintegration of mitochondria.chondriome, chondrioma n. [Gr. chondros, grain; -ome,group] The total mitochondrion content of a cell.chondriosome n. [Gr. chondros, grain; soma, body] The mitochondria.chondrocyst n. [Gr. chondros, grain; kystis, bladder] (PLATY:Turbellaria) Rhabdite of somewhat granular texture in landplanarians.chondroid a. [Gr. chondros, cartilage; eidos, shape] Resemblingcartilage.

196Maggenti and Gardnerchondrophore n. [Gr. chondros, cartilage; pherein, to bear] 1.(CNID: Hydrozoa) A disc-like colony of floating hydroids ofthe order Chondrophora; a chrondrophoran. 2. (MOLL: Bivalvia)A pit or large spoon-shaped form projecting fromthe hinge plate; support for the inner hinge cartilage.chone n. [Gr. choane, funnel] (PORIF) A canal that penetratesthe cortex into which the dermal pores generally open.chord, chorda n. [L. chorda, string] A cord, nerve or filament.chordal a.chord of the wing (ARTHRO: Insecta) The straight line joiningthe leading and trailing edges of a wing.chordotonal organ Subcuticular sense organs of insects andperhaps nematodes that consist of one to several hundredchordotonal sensilla (scolopidia); attached to the cuticlethat function as mechanoreceptors; abundant in tympanalorgans; a scolopophorus organ. see tympanal organ,myochordotonal organ.chore n. [Gr. choros, place] An area in which geographical orenvironmental conditions are in harmony. see biochore,biotype.chorion n. [Gr. chorion, membrane enclosing the fetus] Theoutermost shell or membranous covering of the egg ofvarious invertebrates.choriothete n. [Gr. chorion, membrane enclosing the fetus;thete, servant] (ARTHRO: Insecta) A muscular structure ofcyclical development that adheres to the chorion of the eggof Glossina and the Pupipara , and by the actions of themuscles aids in the removal of the chorion.chorology n. [Gr. choros, place; logos, discourse] The sciencedealing with the geographical distribution of organisms; zoogeography.choronomic a. [Gr. choros, place; nomos, place or conditionfor living] The external influences effecting animals, suchas geographical or regional environment. see autonomic.chorotype n. [Gr. choros, place; typos, type] A local type.chroma n. [Gr. chroma, color] The hue and saturation of acolor, i.e., red, green, brown, etc., as opposed to black,

Online Dictionary of Invertebrate Zoology 197white and gray.chromaffin a. [Gr. chroma, color; L. affinis, related to] Stainingstrongly with chromium salts; also called chromophil;chromophile.chromaphil see chromaffin-chromasia, -chromasie suff. [Gr. chroma, color] Condition ofpigmentation or of staining, as in achromasia, polychromasia.chromatic a. [Gr. chroma, color] Capable of being stained bycoloring agents.chromatic body see chromatoid bodychromatid n. [Gr. chroma, color] One of two spiral filamentsthat make up a chromosome, and separate in cell division,each going to a different pole of the dividing cell and eachbecoming a daughter chromosome at anaphase in mitosis.chromatin n. [Gr. chroma, color] The more readily stainablesubstance in the cell nucleus; karyotin. see euchromatin,heterochromatin.chromatin body (ARTHRO: Insecta) A special rDNA containingbody in the oocyte nucleus during early oogenesis ofdytiscid water beetles; body of Giardini.chromatocyte see chromocyteschromatogen organ see axial glandchromatography n. [Gr. chroma, color; graphien, to draw] Ananalytical method of chemical analysis based on the selectiveabsorption of inorganic or organic compounds througha porous medium.chromatoid body A body containing ribonucleoprotein materialfound near the nucleus during certain stages of spermatogenesis.chromatoid grains In cell protoplasm, granules that stainsimilarly to chromatin.chromatolysis n. [Gr. chroma, color; lysein, to loosen] Thesolution and breaking up of chromatin. chromatolytic a.chromatophore n. [Gr. chroma, color; phoreus, bearer] A singlehighly branched cell or synctia containing pigment

198Maggenti and Gardnergranules that may disperse in the branches or concentratein the center and effect color changes in various invertebrates.chromatotropism n. [Gr. chroma, color; trope, turn] A taxisin response to stimulation by a particular color.chromidium n.; pl. -midia [Gr. dim. chroma, color] Any of thebasophilic fibrils in the cytoplasm that are composed ofRNA-containing parts and RNA-free parts.chromioles n.pl. [Gr. dim. chroma, color] The minute granulesof which a chromomere is composed.chromoblast n. [Gr. chroma, color; blastos, bud] An embryoniccell that develops into a pigment cell.chromocenter n. [Gr. chroma, color; kentron, center] A granuleof heterochromatin, whose numbers vary in the interphasenuclei.chromocytes n. [Gr. chroma, color; kytos, container] 1. Pigmentedcells. 2. (PORIF) Pigmented amoebocytes containedin the mesogloea.chromogen n. [Gr. chroma, color; genos, birth] A colorlesssubstance that is the precursor of a pigment.chromogenesis n. [Gr. chroma, color; genesis, beginning]Color production.chromolipids n.pl. [Gr. chroma, color; lipos, fat] The carotenoidsand related pigments.chromomere n. [Gr. chroma, color; meros, part] One of thebead-like concentrations of chromatin found along thelength of a chromosome.chromonema n.; pl. -nemata [Gr. chroma, color; nema,thread] The smallest light microscopic strand in chromosomesand chromatids.chromophile n. [Gr. chroma, color; philos, loving] 1. Chromaffin.2. (ARTHRO: Insecta) A blood cell, intermediate ortransitional between prohemocytes, plasmatocytes andpossibly other types of blood cells.chromophilic, chromaphilic a. [Gr. chroma, color; philos,loving] Staining readily, as certain cells. see chromophobecells.

Online Dictionary of Invertebrate Zoology 199chromophobe cells Cells that do not absorb stains readily.see chromophilic.chromophore n. [Gr. chroma, color; phorein, to bear] A groupof atoms to whose presence definite color in a compoundare attributed, and when combined with certain salt-forminggroups (auxochromes) produce dyes.chromoprotein n. [Gr. chroma, color; proteios, primary] Acompound protein that contains a pigment, as in hemoglobinof higher animals and hemocyanin of lower animals.chromosomal aberration see chromosome aberrationchromosomal inversion Reversal of the linear order of thegenes in a segment of a chromosome.chromosomal vesicle see karyomerechromosome n. [Gr. chroma, color; soma, body] One of thedeeply staining DNA-containing bodies in the nucleus of thecell that carries genetic information arranged in a linear sequence.see diploid, haploid, polyploid.chromosome aberration In a broad sense, all types ofchanges in chromosome structure and chromosome number.chromosome complement The group of chromosomes derivedfrom a particular gametic or zygotic nucleus, composedof one, two or more chromosome sets; karyotype.chromosome diminution In embryogenesis, the eliminationof certain chromosomes from cells that form somatic tissue.chromosome map The graphic representation showing theposition of genes belonging to a particular linkage group.chromosome mutation A structural change in chromosomesegments involving gain, loss or relocation.chromosomin n. [Gr. chroma, color; soma, body] A nonhistonechromosomal protein.chromotropic a. [Gr. chroma, color; trope, turn] Controllingpigmentation.chronic a. [Gr. chronos, time] Of long duration; not acute.chronocline n. [Gr. chronos, time; klinein, to slant] A mor-

200Maggenti and Gardnerphological character gradient in the time dimension.chronotropic a. [Gr. chronos, time; trope, turn] Affecting therate of action, as accelerating or inhibiting.chrysalis, chrysalid n.; pl. chrysalises, chrysalides [Gr.chrysos, gold] (ARTHRO: Insecta) The pupa, especially of abutterfly with complete metamorphosis; an obtect pupa.chrysalloid a. [Gr. chrysos, gold; eidos, like] Like a chrysalis;golden.chrysosymphily n. [Gr. chrysos, gold; syn, together; philios,loving] (ARTHRO: Insecta) Friendly relations between antsand lepidopterous larvae.chyle n. [Gr. chylos, juice] Partially digested nutrients in thealimentary canal.chyle stomach (ARTHRO: Insecta) The ventriculus.chylific ventricle (ARTHRO: Insecta) The midgut.cibarial armature (ARTHRO: Insecta) In certain female Culicidae,a series of specialized spicules (cibarial teeth and spicularridges on the cibarial ridge).cibarial bar see cibarial crestcibarial crest (ARTHRO: Insecta) In certain female Culicidae, atransverse ridge at the ventral posterior margin of the cibariumsupporting the cibarial teeth; cibarial bar.cibarial dome (ARTHRO: Insecta) In certain Diptera, a domeshaped spiculate structure protruding at the posterior marginof the cibarium. see clypeopalatum.cibarial pump (ARTHRO: Insecta) The sucking pump; in Lepidopteraand Hymenoptera, combined with a pharyngealpump.cibarial ridge (ARTHRO: Insecta) In certain female Culicidae,one of a series of short spiculate ridges posterior to the cibarialcrest; part of the cibarial armature.cibarial seta (ARTHRO: Insecta) One of several types of setaeborne within the cibarium of some female Culicidae; dorsal,palatal and ventral setae; cibarial sensillum.cibarial teeth (ARTHRO: Insecta) In some female Culicidae, aseries of spicules, cones, and or rods borne on the cibarial

Online Dictionary of Invertebrate Zoology 201crest on the ventral posterior margin of the cibarium.cibarium n. [L. cibarius, pert. food] (ARTHRO: Insecta) Thatpart of the pre-oral cavity enclosed by the hypopharynxand the clypeus; the sucking pump in Hemiptera. see precibarium.cibivia n. [L. cibarius, pert. food; via, road] (ARTHRO: Insecta)The sucking tube, food channel or food canal of sucking insects.cicatrix n.; pl. cicatrices [L. cicatrix, scar] 1. A scar or scarlikemarking. 2. (ARTHRO: Insecta) Large, pore-like structuresof giant scale insects, often appearing on the bodysurrounded by a chitinized rim.cilia n. pl.; sing. cilium [L. cilium, eyelid] Vibratile hair-likeprocesses on the surface of a cell or organ, shorter andmore numerous than flagella. ciliary a.ciliary feeding Feeding accomplished by ciliary action in conjunctionwith a flow of water.ciliary loop (CHAETO) A delicate epidermal structure of twoconcentric rings of cells on the dorsal surface of the headand neck, sometimes extending onto the trunk, and possiblyfunctioning in movement of sperm.ciliate a. [L. cilium, eyelid] Provided with cilia; edged with parallelhairs; fringed; having minute hairs.ciliated funnels (ECHI) Small, ciliated cup- or funnel-shapedstructures attached to the outer surface of the anal vesicles.ciliated groove 1. (ECHI) A ciliated channel along the ventralsurface of the mid-intestine to the precloacal caecum; occasionallyforming a ridge and closely associated with thesiphon. 2. (SIPUN) A ciliated channel along the ventral surfaceof the intestine from anterior region of the pharynx(esophagus) to the rectum.ciliograde a. [L. dim. cilium, eyelid; gradus, step] Movementby means of cilia.ciliolate a. [L. dim. cilium, eyelid] Minutely ciliated.ciliolum n.; pl. ciliola [L. dim. cilium, eyelid] A minute or secondarycilium.

202Maggenti and Gardnercilium sing. of ciliacimier n. [Sp. cim(a), peak] (ARTHRO: Insecta) The head crestof the pierid butterfly chrysalis.cincinnulus see retinaculumcinclides n.pl.; sing. cinclis [Gr. kinklis, latticed gate] (CNID:Anthozoa) In Actinaria, permanent or temporary perforationsof the columnar body wall that permit the extrusion ofwater or acontia.cinct a. [L. cinctum, girdle] Belted, girdled or encircled.cinereous a. [L. cinereus, ash colored] Ash-gray, ashen, orhaving the color of wood ashes.cingulum n. [L. cingulum, girdle] 1. Any band or girdle-likestructure. 2. (ANN) The clitellum. 3. (MOLL) The coloredbands or spiral ornamentation on certain univalve shells. 4.(ROTIF) The outer ciliary band of the coronal disc. cingulatea.circadian a. [L. circum, about; dies, day] Pertaining to ametabolic or behavorial phenomena in living organisms atabout twenty-four hour intervals; circadian rhythm; diurnalrhythm.circa-equatorial About the equator; around or near the middle.circinate a. [Gr. kerkos, circle] Ring-shaped; spirally rolled.circlet n. [Gr. kerkos, circle] A small circle; a ring.circomyarian n. [Gr. kerkos, circle; mys, muscle] A musclecell in which contractile fibrils completely surround the sarcoplasm.see platymyarian, coelomyarian.circular muscle layer 1. The outermost muscular layer. 2.(BRYO: Phylactolaemata) In the body, the outer of the twothin muscle layers, between the peritoneum and the epithelium.3. (ECHI) In all, except for genus Ikeda . 4.(SIPUN) May be grouped into defined bands or fasicles orformed in sheets.circular overlap The phenomena in which a chain of contiguousand intergrading populations of one species curvesback until the terminal links overlap geographically and arethen found to be reproductively isolated from each other,

Online Dictionary of Invertebrate Zoology 203and as such, behave as if they belong to separate species;a rassenkreis.circular plate (ARTHRO: Insecta) In Syrphidae larvae, a weaklysclerotized refractive area on the dorsal inner sector of theposterior spiracular plate; however, in saprophytic forms asunken area at or just above the center of the posteriorspiracular plate.circulation n. [L. circulare, to make round] In higher invertebrateforms, movement of blood within definite channels inthe body; in other forms, movement of blood in the bodycavity fluid.circulatory system The cardiovascular system; the heart andblood vessels. a. Closed system: the blood is confined totubes throughout its entire course. b. Open system: theblood leaves the arteries and circulates through bodyspaces before reentering the heart.circulus n.; pl. circuli [L. circulus, ring] 1. Any ring-like arrangement,i.e., the branching of small blood vessels. 2.(ARTHRO: Insecta) In scale insects, a glandular structurethat discharges its contents internally.circumanal a. [L. circum, around; anus, anus] About or surroundingthe anus.circumapical band (ROTIF) The second division of the coronathat encircles the margin of the head. see buccal field.circumboreal a. [L. circum, around; Gr. boreas, north wind]Pertaining to the north, i.e., distribution around the borealregion.circumcapitular furrow (ARTHRO: Chelicerata) In Acari, thefurrow around the base of the gnathosoma.circumcolumellar a. [L. circum, around; columella, pillar]Surrounding a columella.circumenteric ring (NEMATA) A commissural nerve ring thatencircles the esophagus (pharynx).circumesophageal, circumoesophageal a. [L. circum,around; Gr. oisophagos, gullet] Structures or organs encirclingthe esophagus.circumesophageal commissure The major commissure of

204Maggenti and Gardnerthe nervous system of many invertebrates to which andfrom which ramify anteriorly and posteriorly directednerves and nerve cords; sometimes called the nerve ring.circumesophageal connectives The nerve strand connectiveson each side of the esophagus connecting the superesophagealganglia and subesophageal ganglia of arthropods,annelids and brachiopods; circumoesophagealconnectives.circumfenestrate a. [L. circum, around; fenestra, window](NEMATA) In Heterodera spp., in which a vulval bridgeacross the vulval cone is not present, producing only a singleopening. see ambifenestrate.circumferential a. [L. circum, around; ferre, to bear] Of orpertaining to the circumference; encompassing; encircling.circumferential canal see ring canalcircumfilum n.; pl. circumfila [L. circum, around; filum,thread] (ARTHRO: Insecta) In dipteran Cecidomyid, antennaljoints bearing elaborately looped or wreathed, thinwalledchemoreceptors with pores lying among fine surfaceridges.circumflex a. [L. circum, around; flexibilis, bendable] Bent orwinding, esp. blood vessels or nerves.circumgenital a. [L. circum, around; gignere, to beget] 1.Surrounding the genital pore. 2. (ARTHRO: Insecta) In scaleinsects, groups of small circular glands with an excretoryorifice at the tip, surrounding the genital pore.circumocular a. [L. circum, around; oculus, eye] Around orsurrounding the eye.circumocular sulcus (ARTHRO: Insecta) A commonly occurringgroove that strengthens the rim of the eye; may developinto a deep flange protecting the inner side of the eye.circumoesophageal see circumesophagealcircumoral a. [L. circum, around; os, mouth] Encircling themouth.circumpedal a. [L. circum, around; pes, foot] Surrounding thebase of a leg.circumpharyngeal commissures (connectives) (ANN: Oli-

Online Dictionary of Invertebrate Zoology 205gochaeta) The two parts of the nerve collar surrounding theesophagus and linking the ventral nerve cord with thecerebral ganglia.circumscissile a. [L. circum, around; scindere, to cut] Splittingalong a circular line, as in hatching.circumsepted a. [L. circum, around; septum, partition] (AR-THRO: Insecta) Pertaining to a wing being encircled by avein.circumversion n. [L. circum, around; vertere, to turn] (AR-THRO: Insecta) In Diptera, the rotation of the postabdomenduring imaginal development.circumvolution n. [L. circum, around; volvere, to turn around]Around an axis or center; a whorl; rotation; revolution.cirral ossicles (ECHINOD: Crinoidea) Pertaining to the smallossicles of a cirrus of sea lilies.cirrate a. [L. cirrus, curl] Having curls or cirri.cirrate antenna (ARTHRO: Insecta) An antenna with very longcurved lateral branches, with or without fringes of hair; apectinate antenna. see plumose.cirri pl. of cirruscirriferous a. [L. cirrus, curl; ferre, to bear] Bearing a curl ortendril.cirrophore n. [L. cirrus, curl; Gr. phorein, to bear] (ANN: Polychaeta)The basal section of a cirrus.cirrose, cirrous a. [L. cirrus, curl] Bearing tendrils or cirri.cirrostyle n. [L. cirrus, curl; Gr. stylos, pillar] (ANN: Polychaeta)The distal section of a cirrus.cirrus n.; pl. cirri [L. cirrus, curl] 1. Any slender, usually flexiblestructure or appendage. 2. Has been used for hair onappendages of insects and male copulatory organs in variousinvertebrates. 3. (ANN: Polychaeta) Small, tentacle-likeprotuberances on the parapodia, peristomium and pygidium.4. (ARTHRO: Crustacea) In barnacles, a thoracicmultiarticulate appendage, usually flattened laterally andcurled anteriorly, with food gathering function. 5. (ECHI-NOD: Crinoidea) The aboral ring of unbranched jointed appendages,curved and tapered at the end that aid in fas-

206Maggenti and Gardnertening to rocks, coral or soft substrata. 6. (MOLL: Bivalvia)A bundle of fused cilia that filters particles from the waterentering the gill. 7. (NEMATA) Elaborate cephalic appendagessuch as those found in Chambersiella. 8. (PLATY) Thepenis or copulatory organ of trematodes and cestodes.cirrus acuum (ARTHRO: Insecta) A rounded sclerotized form ofcornuti of male Lepidoptera, often bearing dense spinehairs.cirrus pouch or sac Pouch or sac containing the copulatoryorgan (cirrus) of various invertebrates.cisternae n.pl. [L. cisterna, underground reservoir for water]Any of various flattened, membranous, fluid-filled vesicles.cistron n. [Gr. kiste, box] The functional gene; the section of aDNA molecule that specifies the formation of a particularpolypeptide chain.citrine a. [L. citrus, citron-tree] Lemon-yellow in color.citron shaped Having the form of a large lemon.cladi, clads n.pl. [Gr. klados, branch] (PORIF) The threeshorter rays of a tetraxon spicule, that may be forked orbranched at their free ends.cladism n. [Gr. klados, branch] A method by which organismsare ordered and ranked entirely on the basis of the mostrecent branching point of the inferred phylogeny. cladistica.cladocerous a. [Gr. klados, branch; keras, horn] Havingbranched horns or antennae.cladogenesis n. [Gr. klados, branch; genesis, beginning]Branching evolution; the splitting of species, i.e., speciation.see anagenesis.cladogram n. [Gr. klados, branch; gramma, picture] A dendrogrambased on the principles of cladism; a strictly genealogicaldendrogram, ignoring rates of evolutionary divergence.cladome n. [Gr. klados, branch] (PORIF) The three short raysor cladi of a tetraxon spicule.cladotylote a. [Gr. klados, branch; tylos, knob] (PORIF) In diactinalmonaxons, a tylote having somewhat recurved clads

Online Dictionary of Invertebrate Zoology 207at each end.cladus n.; pl. cladi [Gr. klados, branch] (PORIF) Smallerbranch of a tetraxon spicule. cladose a.clamp n. [D. klamp] (PLATY: Trematoda) A complex set ofsclerotized bars, forming a pinching organ on the opisthaptorof a monogenetic trematode.clandestine evolution Evolutionary change introduced anddeveloped in juvenile stages and incorporated into descendantadult stages by paedomorphosis.Claparede organs see urstigmataclasper n. [ME. claspen, to embrace] 1. (ARTHRO: Crustacea)An appendage, including antenna, modified for holding offemale during copulation; or an organ for fixation in parasites.2. (ARTHRO: Insecta) a. A modified male appendageof certain insects that enables the male to hold to the femaleduring copulation. b. The harpe of male Lepidoptera.3. (MOLL: Bivalvia) An extension of the shell which tends toattach to objects.claspette see harpagonesclasp filament see dististylusclasping apparatus (ARTHRO: Crustacea) A movable, heavilysclerotized sclerite of male ostracods, that articulates withthe midportion of the peniferum in a socket near the ventralcardo and the loop of the spermatic tube; probably atactile organ.class n. [L. classis, division] A taxonomic group used in classificationof organisms into which a phylum or division is divided,and which in turn is subdivided into orders.classical taxonomy A taxonomic method incorporating theuses of morphological, serological, and biochemical data inclassifying, describing and naming of organisms. see taxonomy.classification n. [L. classis, division; -fic, make] The processof delimitation, ordering, and ranking taxa (populations andgroups of populations) at all levels by inductive procedures.clathrate, clathrose a. [L. clathratus, latticed] 1. Divided likelatticework. 2. (MOLL: Gastropoda) Shells having orna-

208Maggenti and Gardnermentation of spiral and transverse components that intersectto form a broad lattice.clausilium, claucilium n. [L. claudere, to close] (MOLL: Gastropoda)In Clausiliidae, a calcareous closing device thateffectively seals the apertural lamellation; collectivelycalled lunellarium.claustrum n. [L. claustrum, bar] 1. A bolt or bar. 2. (ARTHRO:Insecta) Any structure uniting wings in flight, i.e., hooks,thickened margins, or a jugum. 3. (CNID: Scyphozoa) Thetransverse circumferential membrane dividing the stomachpouches in some medusae.clava n.; pl. clavae [L. clava, club] 1. Any club-shaped structure.2. (ARTHRO: Chelicerata) The ventral mouth part ofticks. 3. (ARTHRO: Insecta) The terminal enlarged joints ofthe antenna; clavola.claval furrow (ARTHRO: Insecta) A flexion line of the wingsfound just behind the posterior cubital vein; cubito-analfold.claval suture (ARTHRO: Insecta) In Hemiptera, the suture ofthe front wing separating the clavus from the corium.claval vein (ARTHRO: Insecta) A vein in the clavus.clavate a. [L. clava, club] Enlarged at the tip; club shaped.clavicle n. [L. dim. clavis, key] (MOLL: Bivalvia) A buttress forsupport of the chondrophore.clavicula n. [L. dim. clavis, key] (ARTHRO: Insecta) Coxa of ananterior leg.clavicular lobe (ARTHRO: Insecta) In Homoptera, that portionof the hind wing behind the anal veins.claviform a. [L. clava, club; forma, shape] Club-shaped;clavate.clavola n. [L. dim. clava, club] (ARTHRO: Insecta) The antennabeyond the second segment; flagellum.clavule n. [L. dim. clava, club] 1. (ECHINOD: Echinoidea) InSpatangoida, a minute ciliated spine on the test. 2. (PORIF)A modified triaxonal spicule with a disk or bulb at one end.clavulus see frenulum

Online Dictionary of Invertebrate Zoology 209clavus n. [L. clavis, key] (ARTHRO: Insecta) 1. The oblong ortriangular anal portion of the fore wing of certain hemipteranand homopteran insects. 2. Rounded, peaked orbrush-like process of the dorsal margin of the sacculus ofcertain Lepidoptera. 3. The area between the claval furrowand the jugal fold on wings without a vannus.claw n. [A.S. clawu, claw] Any sharp structure terminating ananimal limb that is adapted for clawing or clutching; unguis;apotele. see chela.claw teeth (ARTHRO: Chelicerata) The teeth, varying in numbers,lining the curve of the true claws.claw tufts (ARTHRO: Chelicerata) The pair of dense tufts of adhesivehairs present below the paired claws at the tip of thetarsi of many spiders.clear-zone eye see superposition eyecleavage n. [A.S. cleophian, split] The process by which thedivision of the egg cell gives rise to all the cells of the organism.cleavage cells The cells formed during cleavage; a blastomere.cleavage nucleus 1. The nucleus of a fertilized egg cell or zygote.2. The nucleus of egg cells that develop parthenogenetically.cleft a. [A.S. cleofian, split] Split or forked.cleidoic a. [Gr. kleis, bar; oion, egg] Pertaining to an egg enclosedwithin a shell or membrane that is permeable onlyto gasses.cleme n. [Gr. klema, shoot, twig] (PORIF) In megascleres, anuncinate spicule.cleptobiosis n. [Gr. kleptein, to steal; biosis, manner of life](ARTHRO: Insecta) A form of symbiosis in which one speciesrobs the food stores, feeds on refuse piles, or in other wayssteals food from another species, but does not nest in closeassociation. see lestobiosis.cleptoparasitism n. [Gr. kleptein, to steal; parasitos, one whoeats at the table of another] (ARTHRO: Insecta) In Hymenoptera,a parasitic relationship in which a female seeks out

210Maggenti and Gardnerprey or stored food of another, usually of a different species,and appropriates it for the rearing of her own offspring.climatic isolation Prevention of interbreeding between two ormore populations because of differential preferences in climaticconditions. see geographical isolation/barriers.climax n. [Gr. klimax, ladder] 1. A stage in the community oforganisms that have reached equilibrium with existing environmentalconditions; arrives at the final stage in thenatural succession. 2. A mature and stabilized stage of abiotic community extending over a vast geographic area.climograph n. [Gr. klima, slope; graphein, to write] A diagramon which localities are represented by the annual cycle oftemperature and rainfall.clinal a. [Gr. klinein, to slope] The gradual varying of characteristics.cline n. [Gr. klinein, to slope] A change in population characteristicsover a geographical area, usually related to a correspondingenvironmental change; geocline.clinology n. [Gr. klinein, to slope; logos, discourse] The studyof the retrogression or decline of organisms after maturity,or after their phylogenetic apex as a group.clistogastrous a. [Gr. kleistos, enclosed; gaster, belly] (AR-THRO: Insecta) In Hymenoptera, having a petiolated abdomen.clitellate a. [L. clitellae, pack saddle] (ANN: Oligochaeta) Havinga clitellum; the age or stage during which the earthwormhas a clitellum.clitellum n. [L. clitellae, pack saddle] (ANN: Oligochaeta) Aglandular annular swelling of the epidermis; the gland cellsthat secrete material to form a cocoon; cingulum.clithrum n.; pl. clithra [Gr. clithros, bar] (ARTHRO: Insecta)One of a pair of sclerotic rings of the epipharynx, thatseparates the corypha and the paria of certain scarabaeoidlarvae.cloaca n.; pl. -cae [L. cloaca, canal] The terminal portion ofthe digestive tract in various invertebrates that functions as

Online Dictionary of Invertebrate Zoology 211a digestive, excretory and reproductive duct. cloacal a.cloacal aperture The external opening of the cloaca; the vent.cloacal cavity see spongocoelcloacal passage (MOLL: Bivalvia) A passage in exhalant mantlechamber that serves as a cloaca.cloacal tubus see tubusclone n. [Gr. klon, twig] 1. All the descendants derived byasexual reproduction from a single sexually produced individual.2. (PORIF) A ray-like arm; a desma.clonotype n. [Gr. klon, twig; typos, type] 1. An asexuallypropagated specimen from a part of a type specimen orholotype. 2. The phenotype or homogenous product ofcloning.clonus n. [Gr. klonos, violent confused motion] Muscle contractionsinterspersed with relaxation in rapid succession;incomplete tetanus.closed a. [L. claudere, to close] (MOLL: Bivalvia) Pertaining topelecypods, the shells of which do not gape.closed cell (ARTHRO: Insecta) A wing cell completely surroundedby veins, and not reaching the wing margin.closing apparatus of a spiracle (ARTHRO: Insecta) One ortwo movable valves in the spiracular opening or internalconstriction closing off the atrium from the trachea.closing band (ARTHRO: Insecta) A soft, convex valvular fold ofthe inner closing mechanism of a spiracle.closing bow (ARTHRO: Insecta) A crescentric or semicircularelastic bar functioning as the inner closing mechanism of aspiracle.clubbed a. [ON. klubba, club] Having the distal part or segmentenlarged.club shaped see clavatecluster n. [A.S. clyster, cluster] Collecting together for suchpurposes as prior to mating or hibernation, low temperatures,etc.; agminate.clypeal a. [L. clypeus, shield] Of or pertaining to the clypeus.

212Maggenti and Gardnerclypeal fovea (ARTHRO: Insecta) In Ichneumonid Hymenoptera,one of two anterior tentorial pits, appearing as ashallow impression in the groove between the clypeus andface.clypeal phragma (ARTHRO: Insecta) In Diptera, a flat apodemeextending from the exposed part of the clypeus tothe lateral margin of the cibarium.clypeate a. [L. clypeus, shield] Shaped like a shield; having aclypeus; scutate; peltate; escutcheon.clypeate/clypeatus head (ARTHRO: Insecta) Pertaining to aflattish head, with broad flat margins in the clypeus andfront.clypeiform a. [L. clypeus, shield] Clypeate.clypeolabral suture (ARTHRO: Insecta) The suture betweenthe clypeus and the labrum. clypeolabral a.clypeolus see anteclypeusclypeopalatum n. [L. clypeus, shield; palatum, roof of themouth] (ARTHRO: Insecta) A division of the palatum of Culicidae,formed by the ventral surface of the clypeus; theroof of the cibarium. see labropalatum.clypeus n. [L. clypeus, shield] 1. (ARTHRO: Chelicerata) Theanterior tagma between eyes and cheliceral bases inarachnids. 2. (ARTHRO: Crustacea) That part of the headbearing the labrum. 3. (ARTHRO: Insecta) The sclerite onthe lower part of the face, usually separated from the fronsby an epistomal sulcus or suture, and maybe divided intoan anteclypeus and a postclypeus. 4. (BRACHIO) That partof the cephalon bearing the labrum; a plate situated anteromediallyon the head formed by fusion of basal segmentsof the antennae.clypofrons n. [L. clypeus, shield; frons, front] (ARTHRO: Insecta)The transverse groove delimiting the clypeus fromthe frons.cnida cnidae pl. see nematocystCnidaria, cnidarian n. [Gr. knide, nettle] 1. A phylum ofprimitive eumetazoans, including the hydras, jellyfish, seaanemones and corals, each bearing nematocysts. 2. In

Online Dictionary of Invertebrate Zoology 213some classifications considered a subphylum of Coelenterata.3. Sometimes considered synonymous with Coelenterata.cnidoblast, nematoblast, nematocyte n. [Gr. knide, nettle;blastos, bud] (CNID) A round or ovoid interstitial cell thatforms a nematocyst.cnidocil n. [Gr. knide, nettle; L. cilium, eyelid] (CNID) A smallpointed projection on a nematocyst that acts as a triggerduring discharge.cnidocyst n. [Gr. knide, nettle; kystis, bladder] (CNID) A rigidoval capsule containing the eversible thread in the cnidoblast.cnidophore n. [Gr. knide, nettle; phorein, to bear] (CNID) Acontractile stalk with an enlarged hollow tip bearingnematocysts; present on the tentacles of some medusae.cnidopod n. [Gr. knide, nettle; pous, foot] (CNID) The basalportion of a nematocyst.cnidorhagi n. [Gr. knide, nettle; rhax, grape] (CNID) Clustersof rounded projections of tube anemones that are filledwith nematocysts.cnidosac, cnidus sac n. [Gr. knide, nettle; sakkos, bag](MOLL: Gastropoda) Cells in the distal tip of the cerata inwhich undischarged nematocysts ingested from cnidariansare stored and later used for defense.coacervate a. [L. coacervare, to heap up] Piled up; collectedinto a crowd; densely clustered.coactus a. [L. coactus, compress] Pertaining to a short stoutform; condensed.coadaptation n. [L. cum, with; ad, to; aptus, to fit] The selectionprocess that tends to accumulate harmonious interactionsof genes brought together by natural selection.coadunate a. [L. coadunare, to unite with] 1. Combined orjoined together. 2. (ARTHRO: Insecta) Elytra when permanentlyunited at the suture.coagulation n. [L. coagulare, to curdle] The formation of aclot; to change from a liquid to a viscous or solid state.coagulin n. [L. coagulare, to curdle] A constituent of blood

214Maggenti and Gardnerthat aids in coagulation.coagulocyte n. [L. coagulare, to curdle; Gr. kytos, container](ARTHRO) Specialized granular hemocytes. see cystocytes.coagulum n. [L. coagulare, to curdle] A semisolid mass; a clot;curd.coalesce v.i. [L. coalitus, united] To come together into one;to fuse or blend.coalescent a. [L. coalitus, united] A growing together, uniting.coalite v.i. [L. coalitus, united] To unite or associate.coalite stilt prolegs (ARTHRO: Insecta) Having a portion of theprolegs united into one organ for a part of their length,with a bifid apex.coarctate a. [L. coarctatus, compressed] 1. Crowded together;compressed; contracted. 2. (ARTHRO: Insecta) Having theabdomen separated from the thorax by a constriction.coarctate larva (ARTHRO: Insecta) 1. A larva similar to thedipteran puparium in which the skin of the preceding instaris not completely shed, being attached to the caudal end ofthe body. 2. The sixth instar of a meloid larva with the fifthexuvium present; a pseudopupa; a semipupa.coarctate pupa (ARTHRO: Insecta) A type of pupa in certainDiptera, with the last larval skin being retained as a protectivepuparium, with tracheal connection maintainingcontact between the pupa within the larval skin with theoutside.cocardes n.pl. [F. cocarde, insignia] (ARTHRO: Insecta) Lateralprotrusible vesicles at the sides of the thorax and abdomenof Malachiidae beetles.coccinellin n. [Gr. kokkinos, scarlet] (ARTHRO: Insecta) A defensivesecretion (C 13 H 23 NO), of the ladybug beetle Coccinellaseptempunctate, that has a bitter taste and smellthat repels the ant Myrmica rubra.coccineous a. [Gr. kokkinos, scarlet] Cochineal red; scarlet.cocephalic a. [L. cum, together; Gr. kephale, head] (ARTHRO:Insecta) Having a prognathous head in which only the foramenexists.

Online Dictionary of Invertebrate Zoology 215cochineal n. [Gr. kokkinos, scarlet] (ARTHRO: Insecta) A crimsondye commercially extracted from the dried bodies ofthe homopterous insect Dactylopius coccus (cochinealscale) cultivated in South America, Mexico and the CanaryIslands. see quinone biochrome.cochleate a. [Gr. kochlias, snail with a spiral shell] Spirallytwisted like a snail shell; screw-like.cockle n. [Gr. konkylion, shell] (MOLL: Bivalvia) The heartshapedshells or valves of the family Cariidae .cocoon n. [F. cocon, shell] A protective case or covering of anegg mass, larva, pupa, or adult of various invertebrates.cocoon-breaker or cutter (ARTHRO: Insecta) Structures or anelevated ridge of the pupa of certain Lepidoptera, often onthe meson of the head; functioning in exiting the cocoon.code n. [L. codex, tablet] The International Code of ZoologicalNomenclature.codominant a. [L. cum, with; dominus, master] Pertaining togenes when both alleles of a pair are fully expressed in theheterozygote.codon n. [L. codex, tablet] The genetic unit of three adjacentnucleotides that specify a single amino acid in a polypeptidechain.codonocephalus larva (PLATY: Trematoda) A metacercariasimilar to a neascus larva.coe- For words not found here see ce- or cae-.coecum, coeca see caecumCoelenterata, coelenterate n. [Gr. koilos, hollow; enteron,intestine] 1. A group of diploblastic, mostly marine animalswith a single internal cavity with an oral opening. 2. Cnidaria(=Coelenterata). 3. A phylum containing two subphyla,Cnidaria and Ctenophora in some classifications.coelenteron n. [Gr. koilos, hollow; enteron, intestine] The singlecavity, or sole body space of a coelenterate, serving asa stomach and excretory organ, and by outgrowths, as aprimitive vascular system.coeloblast see hypoblast

216Maggenti and Gardnercoeloblastula n.; pl. -lae [Gr. koilos, hollow; blastos, bud] 1.A hollow blastula; a blastula without qualification. 2. (PO-RIF: Calcarea) The simple type of blastula larva found inCalcinia .coeloconoid a. [Gr. koilos, hollow; konos, cone; eidos, form]Approaching conical but with concave sides; extraconic. seeconoid, cyrtoconoid.coelogastrula n. [Gr. koilos, hollow; gaster, stomach] A gastruladerived from a coeloblastula.coelom n. [Gr. koilos, hollow] The body cavity or space betweenthe body wall and internal organs lined with mesodermin many metazoan animals.Coelomata n. [Gr. koilos, hollow] In some classifications, ataxonomic group comprising those metazoans that have acoelom or body cavity formed in and surrounded by mesodermat some stage in their life cycle.coelomate a. [Gr. koilos, hollow] Having a coelom or bodycavity.coelomesoblast n. [Gr. koilos, hollow; mesos, middle; blastos,bud] In segmentation, the mesoblastic bands that willform the wall of the coelom and outgrowths.coelomic canals and sacs (SIPUN) Dermal canals, spaces ordiverticula containing coelomic fluid connected with thebody cavity through small pores; possibly aiding respiration.coelomic cavity That area between the viscera and the bodywall.coelomic funnel The nephrostome.coelomic papillae (SIPUN) Small, flat, leaf-like processes onthe coelomic surface of the body wall, usually anterior ofthe nephridial attachment.coelomic sacs Cavities representing the coelom that appear inthe mesoderm in embryology.coelomocytes n.pl. [Gr. koilos, hollow; kytos, container] 1.Corpuscles (usually amoebocytes) in the coelomic or pseudocoelomicfluids of invertebrates. 2. (ANN) amoebocytesand elaeocytes. 3. (ECHINOD) The spindle-shaped cells,

Online Dictionary of Invertebrate Zoology 217phagocytes, and crystal cells. 4. (NEMATA) The mesenchymatouscells in the body cavity. see pseudocoel cells,pseudocoelomocytes.coelomoduct n. [Gr. koilos, hollow; L. ducere, to lead] Anyduct that connects the coelom to the external surface ofthe body, usually applied to the terminal tubule ofnephridia; in onchophorans and mollusks, excretory and/orreproductive functions.coelomopores n.pl. [Gr. koilos, hollow; poros, passage] 1.(BRYO) A body wall pore connecting the coelom with theexterior; the pore at the base of the tentacles throughwhich the ova are extruded; supraneural pore. 2. (MOLL:Cephalopoda) Nautiloid ducts between the pericardial cavityand the exterior.coelomostome n. [Gr. koilos, hollow; stoma, mouth] The externalopening of a coelomoduct.coelomyarian n. [Gr. koilos, hollow; mys, muscle] (NEMATA)Muscle structure in which the contractile fibrils are not onlynext to the subcuticula, but also extend varying distancesup the side of the muscle cell and partially enclose the sarcoplasm.see platymyarian, circomyarian.coelozoic a. [Gr. koilos, hollow; zoon, animal] Living in thelumen of a hollow organ, i.e., the intestine.coenenchyma, coenenchyme n.; pl. coenenchymata [Gr.koinos, common; enchyma, infusion] (CNID: Anthozoa)Thick cellular mesoglea connecting adjacent polyps of alcyonariancorals. coenenchymal a.coenobiosis n. [Gr. koinos, common; biosis, manner of life] Aconsociation of plants and animals of different species.coenoblast n. [Gr. koinos, common; blastos, bud] Embryonicgerm layer originating both in the endoderm and mesoderm.coenocyte n. [Gr. koinos, common; kytos, container] A multinucleatecondition of discrete cells resulting from repeatednuclear division unaccompanied by cell fission; giant cell.coenoecium n. [Gr. koinos, common; oikos, house] (BRYO)The common secreted investment of a colony, gelatinous,chitinous, or calcareous.

218Maggenti and Gardnercoenogenetic see cenogeneticcoenogenous see cenogenouscoenogony n. [Gr. koinos, common; gone, generation] Reproductioninvolving coenocytes.coenosarc n. [Gr. koinos, common; sarx, flesh] (CNID: Hydrozoa)The hollow living tubes of the upright branching individualsof a colony. see stolon, perisarc.coenosite n. [Gr. koinos, common; sitos, food] A free orseparable commensal organism.coenospecies n. [Gr. koinos, common; L. species, kind] Collectively,those related species or ecospecies that can intercrossto form hybrids that are sometimes fertile.coenosteum n.; pl. -tea [Gr. koinos, common; osteon, bone]1. (CNID: Hydrozoa) The calcareous mass forming theskeleton of a compound coral. 2. (PORIF: Sclerospongiae)The basal skeleton of a stromatoporoid sponge.coenotrope n. [Gr. koinos, common; trope, turn] A form ofbehavior common to a group or species.coenure see coenuruscoenurus n. [Gr. koinos, common; oura, tail] (PLATY: Cestoda)A metacestode in the family Taeniidae, in which scolicesbud from an internal germinative membrane inside a bladderlikesac. see cysticercus.coenzyme n. [L. cum, with; Gr. en, in; zyme, yeast] An organicsubstance associated with an enzyme in order tofunction; an organic cofactor.coevolution n. [L. cum, with; evolvere, to unroll] Developmentof genetically determined traits in two species to facilitatesome interaction, usually mutually beneficial. see counterevolution.coexistence n. [L. cum, with; existere, to exist] Existing at thesame time and place with another.cofactor n. [L. cum, together; facere, to act] Any accessorysubstance (inorganic or organic) attached to an enzymeand necessary for its function; such as a metallic ion or acoenzyme.

Online Dictionary of Invertebrate Zoology 219cohabitants n.pl. [L. cum, together; habitare, to dwell] Organismsthat dwell with others.cohesion n. [L. cum, together; haerere, to stick] Attractionbetween molecules of the same substance.cohort n. [L. cohors, enclosure] In older classifications, indefinitetaxonomic groups ranked above a superorder, betweenclass and order, or related families.coila n.; pl. -ae [Gr. koilos, hollow] (ARTHRO: Insecta) Thepoint upon the body on which the articulation of an appendageis made.coincident a. [L. cum, with; incadere, to fall on] Occupying thesame position.coinductura n. [L. cum, with; indutus, clothed] (MOLL: Gastropoda)In some bellerophonts, a rather thick, obliquely layeredshelly coating, extending over the inner lip from withinthe aperture, covering part of the inductura proper.coition, coitus n. [L. coire, to go together] Mating; copulation.colacobiosis see calobiosiscold-blooded see poikilothermalcold-light Light emitted by bioluminescent organisms; envolvingrelatively little heat.coleopteroid a. [Gr. koleos, sheath; pteron, wing] (ARTHRO:Insecta) Pertaining to the Coleoptera; beetlelike.coleoptery n. (ARTHRO: Insecta) In some Hemiptera, the coriumand membrane of the hemeletron are not well differentiated,with the hemeletron appearing like a beetle'selytron.coliform a. [L. colum, sieve; forma, shape] Sieve-like, cribriform.collabral a. [L. collare, band for the neck; labrum, lip] (MOLL:Gastropoda) Shells with the growth lines conforming to theshape of the outer lip.collagen n. [Gr. kolla, glue; L. genos, to produce] Fibrousprotein material in connective tissues binding togethermany cells and tissues; relatively inelastic.collagenase n. [Gr. kolla, glue; genos, to produce; -asis, de-

220Maggenti and Gardnernoting enzymes] A proteolytic digestive enzyme.collar n. [L. collare, band for the neck] 1. Any of variousstructures comparable with a collar. 2. (ANN: Polychaeta)Specially developed outgrowths carried on the first thoracicsegment of certain worms that function in tube-building inassociation with calcium-secreting glands. 3. (ARTHRO:Chelicerata) In Acari, a circular line or ridge at the place ofepiostracal attachment of setae, ungues, and rutellum. 4.(ARTHRO: Insecta) Between the head and thorax. a. Theneck in Hymenoptera. b. In Diptera, the neck; the prothorax;sclerites attached to the prothorax or its processes. c.In Coleoptera, the prothorax. d. In Lepidoptera, thesclerites attached to the prothorax, shielding the neck. e.In Heteroptera, the anterior constricted part of the pronotum,usually set off by a groove. 5. (BRYO: Gymnolaemata)In Ctenostomata zooids, a pleated membranous structureattached to the diaphragm. 6. (CNID: Anthozoa) The scapusof sea anemones, standing up as a prominent fold, beforejoining the capitulum; the parapet. 7. (PORIF) Monaxonsthat project obliquely upwards from the pinacoderm.collar cell A choanocyte.collare n. [L. collare, band for the neck] The more or less elevatedposterior part of the collum.collarette n. [L. dim. collare, band for the neck] 1. (CHAETO)Thickened distended cells in the neck region that in somespecies extend posteriorly along the trunk for some distance;in one instance as far as the lateral fins. 2. (NEMATA)Either anterior or posterior cuticular extensions forming anannular ring in the neck region.collateral a. [L. cum, with; latera, sides] A subsidiary; indirect;a lateral branch of an axon.collateral intestine (ECHI) A tube associated with the midgut.collaterial see colleterial glandscollatoria n. [Gr. kolla, glue; -toria, derived Latin for appropriateplace] The duct of the colleterial gland.collecting basket (ARTHRO: Insecta) Hairs, bristles or spineson the forelegs that function in collecting or holding food

Online Dictionary of Invertebrate Zoology 221while consuming it.collenchyma, collenchyme n. [Gr. kolla, glue; NL. enchyma,type of cell tissue] Mesenchyme when there is a great dealor large amounts of gelatinous intercellular material andcells are relatively few in number.collencyte n. [Gr. kolla, glue; en, in; kytos, container] (PORIF)A mobile cell responsible for collagen secretions.colleterial glands, colletric glands, sebific glands 1. (AR-THRO: Crustacea) Single or paired glands of certain femalesor hermaphrodites that produce a sticky substance forbinding eggs together. 2. (ARTHRO: Insecta) Paired glandsof females that secrete a substance to cement eggs togetheror to the substratum, or to provide a material forthe egg capsule or ootheca.colleterium see colleterial glandscolletocystophore see rhopaliumcolliculum n.; pl. colliculi [L. dim. collis, hill] A small elevation.colliculate, colliculose a.colligate v.t. [L. cum, with; ligare, to bind] To tie or bind together.colligation n. [L. cum, with; ligare, to bind] The combining togetherof isolated facts.colloblast n. [Gr. kolla, glue; blastos, bud] (CTENO) Adhesivecells; sticky cells covering much of the surface of the tentaclesthat are used to capture and ingest prey.collophore n. [Gr. kolla, glue; phoreus, bearer] (ARTHRO: Insecta)In Collembola, a respiratory osmoregulatory organ,or ventral tube, on the venter of the 1st abdominal segment.collum n.; pl. colla [L. collum, neck] 1. The neck or collarlikestructure. 2. (ARTHRO) The armoured tergite on the firstsegment behind the head in millipeds and pauropods thatfunctions in locomotion. 3. (ARTHRO: Insecta) a. The slenderconnection between the head and thorax in Hymenoptera,Diptera and Hemiptera. b. The constriction of the medianplate of the aedeagal apodeme prior to the fulcrum inmale fleas.

222Maggenti and Gardnercolon n. [Gr. kolon, large intestine] (ARTHRO: Insecta) Thelarge intestine; that part of the hindgut between the ileumand the rectum.colonial organism An aggregate of cells all alike in structureand function.colonici (ARTHRO: Insecta) In Phylloxera, see radicola; inaphids, see alienicola.colony n. [L. colonia, farm] 1. A group of individuals of thesame species living in close association with each other. 2.(BRYO) A morphological and functional unit comprised ofone or more kinds of physically connected zooids, multizooidalparts and in certain colonies extrazooidal parts. 3.(ARTHRO: Insecta) In social insects, those groups of individualsthat construct nests or rear offspring in a cooperativemanner. see aggregation.colony control (BRYO) A process that influences changes ofthe functional and morphological aspects of zooids belongingto a colony from those of a solitary animal.colony fission (ARTHRO: Insecta) In social Hymenoptera, theestablishement of new colonies by the departure of one ormore reproductive forms plus groups of workers from theparental nest, in which comparable units remain to perpetuatethe parental colony; sometimes called hesmosis inants; sociotomy in termites. see swarming.colony odor (ARTHRO: Insecta) In social insects, the odorfound on the bodies of individuals belonging to a colony,that serves as an indicator to other members of the samespecies whether or not they are nestmates. see nest odor.color change in insects 1. Short term reversible physiologicalchanges that do not involve the production of new pigments.2. Morphological change is a long-term change resultingfrom formation of new pigments and not usually reversible.color (colour) of insects Color resulting from a variety ofstructures and pigments; when in combinations of pigments,results from abundance and position.colubrine a. [L. colubrinus, snakelike] Snakelike.colulus n.; pl. coluli [L. dim. colus, spindle] (ARTHRO: Cheli-

Online Dictionary of Invertebrate Zoology 223cerata) The slender or pointed appendage immediately infront of the spinnerets in some spiders; in others, greatlyreduced or seemingly missing; homologue of the anteriormedian spinnerets or cribellum.columella n. [L. dim. of columna, column] 1. A rod, pillar orcolumn. 2. (CNID: Anthozoa) The central skeletal mass ofmany corals. 3. (MOLL: Gastropoda) The solid or hollowpillar of a univalve shell around which the whorls are arranged.4. (NEMATA) A structural unit of the female uteruscomposed of columns of cells believed to form the eggshell; prouterus; quadricolumella; tricolumella; oogenotop;crustaformeria.columellar fold (MOLL: Gastropoda) A spiral wound ridge onthe columella that projects into the interior of the shell.columellar lip (MOLL: Gastropoda) The internal lip of the apertureof a shell.columellar muscle (MOLL: Gastropoda) In snails, a large muscleattached in the upper portion of the shell spire; used todraw the soft parts into the shell.column n. [L. columna, column] 1. Any column-shaped structure.2. (CNID) The body. 3. (ECHINOD: Crinoidea) Segmentsthat makeup the stem.columnals n.pl. [L. columna, column] (ECHINOD: Crinoidea)The single row of superimposed, round or pentagonalskeletal stems.columnar a. [L. columna, column] Formed like a column.comarginal a. [L. cum, with; margo, edge] (MOLL: Bivalvia)Coinciding with the growth lines of the shell; concentric.comate a. [L. comatus, with long hair] 1. Having hair; hairy. 2.(ARTHRO: Insecta) Having hair on the upper surface.comb n. [A.S. camb, comb] 1. Any of various comb-like structures.2. (ARTHRO: Chelicerata) The pecten of scorpions. 3.(ARTHRO: Insecta) a. The strigil. b. The many brood cells orcocoons regularly arranged in the nests of many species ofsocial wasps and bees. c. The pecten or pollen rake of honeybees.see combs. 4. (CTENO) see comb rows. 5. (ECHI-NOD: Crinoidea) In Comasteridae, the modified segments ofthe distal part of the lower pinnules. 6. (MOLL) The

224Maggenti and Gardnerctenidium.comb collar (ARTHRO: Crustacea) In certain Cirripedia, the retractablemembrane supporting a row of uniform setae, atthe superior angle of the aperture.combination colors Colors arising from a combination of pigmentaryand structural features. see color change in insects.comb plate see swimming platecomb-rib see comb rowscomb rows (CTENO) Eight radially arranged bands of cilia thatare partly fused in transverse rows; swimming plates;costa; comb-ribs; ctenes; paddle plate.combs n.pl. [A.S. camb, comb] 1. Any of various comb-likeprocesses. 2. (ARTHRO: Insecta) a. A row of specializedspines or scales of Culicidae larvae centered on each sideof abdominal segment eight; certain hairs on the uppersurface of the maxillae used to clean the mouth brushes.see lateral combs. b. Ridges of cuticle that frequentlybear spines. see comb.comb shaped see pectinatecomet stage (ECHINOD: Asteroidea) A regenerating asteroidwith a group of little arms at one end of a big arm.comitalia n.pl. [L. comitare, to accompany] (PORIF) The smalldi- or tri-actine spicules. see principalia.commensal n. [L. cum, with; mensa, table] One of the partnerspecies involved in commensalism; a coenosite.commensalism n. [L. cum, with; mensa, table] A symbioticrelationship in which one of the two partner species benefits,without apparent effects on the other species. seesymbiosis, parasitism.comminute v.t. [L. cum, with; minuere, to lessen] To reduceto minute particles or powder; pulverize; triturate.commiscuum n. [L. cum, with; miscere, to mix] A group ofindividuals all of which can potentially exchange genes.commissural induration (ARTHRO: Chelicerata) In mites,sclerotized thickening along the inner part of a commissural

Online Dictionary of Invertebrate Zoology 225line to support the lip walls.commissural line (ARTHRO: Chelicerata) 1. In arachnids, unionbetween two lips. 2. In Acari there are three or four, twosuperiors and one or two inferiors.commissural plane (MOLL: Bivalvia) The plane of the valvecommissure.commissural shelf (MOLL: Bivalvia) The shelflike part of theshell abutting the commissure peripherally.commissural vessels/lateral commissures (ANN) Pairedsegmental lateral blood vessels from the dorsal vessel toanteriorly join the ventral vessel and more posteriorly, thesub-neural vessel; when contractile, they are called lateralhearts or pseudohearts.commissure n. [L. commissura, joint] 1. Connection betweentwo bodies, structures, organs or nerve fibers; a junction,seam or closure. 2. (ARTHRO: Chelicerata) In Acari, the oralcommissures. 3. (MOLL: Bivalvia) The line of joining of thevalves of the shell. commissural a.common a. [L. communis, general] Of frequent or ordinary occurrence;occurring on two adjacent parts or appendages.common bud see confluent budding zonecommon name A colloquial or vernacular name.common oviduct (ARTHRO: Insecta) In female genitalia, theectodermal part of the oviduct, from fusion of paired oviductsto gonopore; oviductus communis; medium oviduct.common salivary duct (ARTHRO: Insecta) In Diptera, thecommon median part of the salivary duct opening into thesalivary pump.common vitelline duct (PLATY: Turbellaria) Connects thevitelline ducts to the ootype.communal a. [L. communis, common] Living as a colony.communication n. [L. communis, common] 1. Action on thepart of one organism that alters the probability pattern ofbehavior in another organism. 2. Sending of signals thatinfluence the behavior or development of others.community n.; pl. -ties [L. communis, common] A group of

226Maggenti and Gardnerplants and/or animals of one or more species in a givenarea or region that are related by environmental requirements.comose a. [L. comosus, hairy] Having hair; hairy; ending in atuft; comate.compass n. [OF. compasser, go around] (ECHINOD: Echinoidea)A slender radial piece of the lantern of Aristotle thatpasses outward from the vicinity of the esophagus.compact v.t. [L. compaginatus, joined] To be close together;to join firmly; to consolidate.compartmental plate (ARTHRO: Crustacea) One of severalrigidly articulated plates forming part of the shell wall ofsessile barnacles.compensatory sac see contractile vesselcompetence n. [L. competere, to compete for] The ability ofan embryonic primordium to differentiate in a specific direction,under appropriate stimuli.competition n. [L. competere, to compete for] The simultaneousendeavor of two or more organisms to survive whenthe essential resource of the environment is not sufficientfor both.competitive exclusion The principle that no two species cancoexist at the same time in the same locality when theirecological requirements are identical; Gause's rule; exclusionprinciple.complanate a. [L. complanatus, flattened] Flattened; level.complement see chromosome complementcomplemental male In certain annelids and barnacles, a smallmale that inhabits the same area occupied by a hermaphroditicform.complemental reproductive see supplementary reproductivecomplementation n. [L. complementum, something thatcompletes] The appearance of wild-type phenotype in anorganism or cell containing two different mutations combinedin a hybrid diploid.

Online Dictionary of Invertebrate Zoology 227complete coverage see valve coveragecomplete metamorphosis (ARTHRO: Insecta) The transformationperiod encompassing larva, pupa and adult;holometabolous metamorphosis. see incomplete metamorphosis.complex n. [L. complexus, entwine] Pertaining to a number ofrelated taxonomic units, often units in which the taxonomyis difficult or confusing. see group.complexus n. [L. complexus, entwine] An aggregate.complicant a. [L. cum, with; plicare, to fold] 1. Folding or extendingover another. 2. (ARTHRO: Insecta) The elytron.complicate a. [L. cum, with; plicare, to fold] Folded longitudinally;folded together or in an irregular manner.composite a. [L. cum, with; ponere, to put] 1. A componentpart; compound. 2. (ANN: Oligochaeta) Pertaining to certainstalked glands of pheretimas annelids that contain severalsimilar units.composite nest (ARTHRO: Insecta) A nest inhabited by acommunal colony. see compound nest.compound a. [L. cum, with; ponere, to put] Composed of severalelements of similar or dissimilar parts united into asingle structure.compound antenna A capitate antenna comprised of severaljoints.compound eye (ARTHRO) A composite optic organ, the externalsurface consisting of circular facets that are very closetogether, or of facets in contact and more or less hexagonalin shape. see mosaic theory.compound nest (ARTHRO: Insecta) A nest inhabited by two ormore species of social insects, where broods of each speciesare kept separate. see mixed nest.compound ocellus Any ocellate spot containing three or morecircles of color.compound phanere In phanerotaxy, composed of two differentelements, one basal and one distal.compound rostrum (ARTHRO: Crustacea) In balanomorph

228Maggenti and Gardnerbarnacles, a compartmental plate formed by fusion of rostrolateralswith rostrum or of fused rostrolaterals. see rostrum.compound skeletal wall (BRYO: Stenolaemata) An interiorskeletal wall, calcified on the edges and both sides; thevertical wall.compressed a. [L. compressus, pressed together] Flattenedfrom side to side or top to bottom; nearly flat, with reducedthickness.compression n. [L. compressus, pressed together] A fossilizedorganism's carbonized remains produced by compressiveforces.compressor n. [L. compressus, pressed together] A musclethat serves to compress.compressor of the labrum (ARTHRO: Insecta) The single orpaired median muscle attached on the anterior and posteriorwalls within the labrum.Comstock-Kellogg glands (ARTHRO: Insecta) In some acrididOrthoptera, a pair of glands thought to produce a sex-attractantsubstance.Comstock System or Comstock-Needham (ARTHRO: Insecta)The principal wing veins and their branches namedand numbered.conarium n.; pl. -aria [L. conus, cone] (CNID: Hydrozoa) Theearliest larva known that becomes a primary gastrozooid,and later develops an enlarged pneumatophore.concameration n. [L. cum, with; camera, chamber] 1. Dividedinto chambers or cavities. 2. An arched hollow near thehinge area of a shell.concatenate a. [L. cum, together; catena, chain] To join orlink together; connect in a series or chain; having a seriesof points placed in regular order.concave a. [L. cum, with; cavus, hollow] Rounded and hollow,as the interior of a sphere. see convex.concavoconvex a. [L. concavus, hollowed or arched inward;convexus, arched outward] Pertains to being concave onone surface and convex on the other.

Online Dictionary of Invertebrate Zoology 229concentric a. [L. cum, with; centrum, midpoint of a circle]Something having a common center, i.e., lines or ridgescurving around a center; arcs having the same center. seecomarginal.conceptacula seminis (ARTHRO: Insecta) A mesodermal organof certain females for the storage of sperm after depositioninto a mesospermalege.conceptive a. [L. concipere, to receive] Capable of conceiving.conch n. [L. concha, shell] (MOLL: Gastropoda) A trumpetshell; a large marine univalve shell.concha n.; pl. -chae [L. concha, shell] Any structure shapedlike a shell.conchate a. [L. concha, shell; -atus, provided with] 1. Conchiform.2. (ARTHRO: Insecta) In Orthoptera, having ashell-like inflation of the auricle in the tibia.Conchifera see Bivalviaconchiferous a. [L. concha, shell; fere, to bear] Producing orhaving a shell; testaceous.conchiform a. [L. concha, shell; forma, shape] Shell-shaped;conch-like in form; conchoid.conchin see conchiolinconchiolin n. [L. concha, shell] (MOLL) The organic componentforming the thin outer layer of the shell; conchin. see nacre.conchitic a. [L. concha, shell] Composed of shells, as limestonesand marbles in which shell fragments are noticeable.conchology n. [L. concha, shell; Gr. logos, discourse] Thebranch of zoology dealing with the arrangement and descriptionof mollusks based upon a study of their hardparts. conchological a.conchophora see Bivalviaconchostracan carapace interspace (ARTHRO: Crustacea)Any area between two growth lines of the conchostracancarapace; intervales; growth zone; growth band.conchostracan carapace interval (ARTHRO: Crustacea) Any

230Maggenti and Gardnerspace between two ribs, costae, or costellae of the conchostracancarapace.conchostracan carapace ribs (ARTHRO: Crustacea) Strongradial ridges with intervals of variable width radiating fromand across the umbo, usually nodose at intersections ofgrowth lines.conchula n. [L. concha, shell] (CNID: Anthozoa) A modified siphonoglyphof certain sea anemones that is provided at theoral end with a spout-like lip.conchyliomorphite n. [L. concha, shell; Gr. morphe, form] Afossil imprint of a shell.concinate a. [L. concinnus, well-arranged] Neat; elegant.concolor a. [L. concolor, colored uniformly] 1. Of uniformcolor. 2. (ARTHRO: Insecta) Having the upper and lowersurfaces of Lepidoptera with the same coloring.concrescence n. [L. cum, together; crescere, to grow] Thegrowing together of parts; joining; coalescing; the union ofparts originally separated.concretion n. [L. cum, together; crescere, to grow] A massingtogether of parts or particles.concurrent a. [L. cum, together; currere, run] Meeting orcoming together; acting in conjunction, as a joint or vein.condensation n. [L. cum, together; densare, to thicken] 1.The act or process of condensing. 2. Descendents passingthrough the ancestral part of ontogeny faster than their ancestorsdid during phylogeny; it may occur by deletion ofsteps or accelerated development.conditioned reflex The habitual response in the nervous systemarising from a particular outside stimulus.conditioning n. [L. conditio, agreement, state] The process ofacquisition by an animal of the capacity to respond to anew stimulus by associating the new stimulus with an oldone.conduction n. [L. conducere, to lead together] The movementof heat, sound waves, or nerve impulses through an organism'scells or tissues.conductivity n. [L. conducere, to lead together] The ability to

Online Dictionary of Invertebrate Zoology 231transmit an impulse.conductor n. [L. conducere, to lead together] A structure specializedfor the transmission of excitation.conduplicate a. [L. cum, together; duplicare, to double] Doubledor folded together; folded together lengthwise.condyle n. [Gr. kondylos, knuckle] 1. A knoblike process thatforms the fulcrum for joint movement. 2. (ARTHRO) Thesurfaces between arthropod joints, that provide the fulcraon which the joints move. 3. (BRYO: Gymnolaemata) Insome cheilostomates, one of a pair of bilateral skeletalprotruberances on which the operculum of an autozooid ormandible of an avicularium is hinged; in asymmetrical aviculariacan be single. 4. (MOLL: Bivalvia) An enlargedprominent end of a shell. condylar, condylic, condyloida.cone n. [L. conus, cone] 1. Any cone-shaped structure. 2. Theconical crystalline body of a compound eye, not alwayssolid crystalline and occasionally not conical. see crystalline.3. (ARTHRO: Insecta) The head shape of a thrip. 4.(NEMATA: Secernentea) The vulval cone of heteroderidcysts.cone cell (ARTHRO: Insecta) One of the four cells that producethe crystalline cone.cone-shaped see cyrtoconicconferted a. [L. confertus, pressed together] Densely assembledor packed; crowded.confluent a. [L. confluere, flowing together] Flowing together;merging; running together as confluent spots withoutmarked lines of distinction.confluent budding zone (BRYO: Stenolaemata) Coelomicbudding space and surrounding exterior walls connectingbody cavities of buds or combinations of buds and zooids.confluent multizooidal budding zone (BRYO: Stenolaemata)Confluent budding zone that originates outside of the zooidalboundaries opposite the endozone.confluent zooidal budding zone (BRYO: Stenolaemata) Aconfluent budding zone originating within the outer

232Maggenti and Gardnercoelomic space of zooids opposite exozone; in some taxa,opposite distal endozone.congeneric a. [L. congener, of same race] 1. A term applied tospecies of the same genus. 2. Belonging to the same kind,class, or stock.congenetic a. [L. cum, together; Gr. genesis, beginning] Havingthe same origin.congenital a. [L. cum, together; gignere, to beget] Of or pertainingto a condition present at birth.congenital disease A disease present in an animal at birth;not necessarily inherited.congested a. [L. congestus, heap together] Overcrowded;distended.congestin n. [L. congestus, heap together] (CNID: Anthozoa)The toxin of sea anemone tentacles.conglobate a. [L. cum, together; globatus, make into a ball]Gathered together into a ball or rounded structure; spherical.conglobate gland see phallic glandconglomerate a. [L. cum, together; agglomeratus, gatheredinto a mass] Irregularly grouped in spots; massed together;bunched or crowded.congression n. [L. congressus, meeting] The movement ofchromosomes to the spindle equator during mitosis.conical a. [L. conus, cone] Cone-shaped; conic; tapering to apoint.conico-acuminate Shaped like a long, pointed cone.coniculus n. [L. dim. conus, cone] (ARTHRO: Chelicerata) Inmites, the malapophyses and lips enclosing the preoralcavity; the rostrum.coniferous a. [L. conus, cone; ferre, to bear] Bearing a conelikeprocess.coniform larvae (ARTHRO: Insecta) Cone-shaped larva,pointed at the head end, and enlarged, obtuse or truncateat the caudal end.conispiral a. [L. conus, cone; spira, coil] With a spire project-

Online Dictionary of Invertebrate Zoology 233ing as a cone; conoid.conjoined a. [L. cum, together; jungere, to join] United orjoined together; adnate.conjugation n. [L. conjugare, to join together] Denotes coupling,connecting or uniting chromosomes, nuclei, cells, orindividuals. conjugate a.conjunctiva n.; pl. -tivas [L. cum, together; jungere, to join](ARTHRO: Insecta) The membranous infolded portion of thesegments of the body-wall. see intersegmental membrane.conjunctive a. [L. cum, together; jungere, to join] Cojoining,connecting or connective.connate a. [L. connatus, born together] Originating together;fused together or immovably united.connective n. [L. connexus, join] A longitudinal cord of nervefibers connecting successive ganglia.connective tissues Tissues with cells that are irregularly distributedthrough a relatively large amount of intercellularmaterial.connector neurone see association neuronconnexiva n. pl.; sing. -vum [L. connexus, join] (ARTHRO: Insecta)The lateral flanges (laterotergites or paratergites) ofthe abdomen, where the ventral plates are attached to themain tergal plates. see pulmonarium.connivent a. [L. connivere, to close the eyes] Converging orcoming close together; arching inward so the points meet.conoid a. [Gr. konos, cone; eidos, form] Having the form of acone; conoidal. see cyrtoconoid, coeloconoid.conotheca n. [Gr. konos, cone; theke, case] (MOLL: Cephalopoda)The thin integument of a phragmocone.conscutum n. [L. cum, together; scutum, shield] (ARTHRO:Chelicerata) The dorsal shield at the level of the anteriortwo pairs of legs, formed by the scutum and alloscutumunited in certain ticks.consensual a. [L. consensus, agreement] Pertaining to an involuntaryaction or movement correlated with a voluntary

234Maggenti and Gardneraction or movement.conservative characters Characters that change slowly duringevolution.consociation see myrmecobiosisconsocies n.pl. [L. cum, with; socius, companion] 1. A portionof an association characterized by one or more of thedominants of the association. 2. A portion of an associationlacking one or more of its dominant species. see associes,isocies, subsocies.consortism n. [L. consortium, fellowship] Symbiosis in whichthe relationship between organisms is a fellowship. seehelotism.conspecific a. [L. cum, together; species, particular kind; facare,to make] Pertaining to individuals or populations belongingto the same species.consperse a. [L. conpersus, besprinkled] Thickly and irregularlyscattered with minute markings.constant n. [L. constare, to stand firm] An invariable or fixedquantity.constricted a. [L. constrictus, drawn together] Narrowed;compressed or drawn together at some point.constriction n. [L. constrictus, drawn together] 1. Any constrictedpart or place. 2. An unspiralized region of a chromosomeat metaphase.constrictor n. [L. constrictus, drawn together] A muscle thatcompresses or constricts a cavity, orifice, or organ.constrictor vulvae (NEMATA) Muscles that function to closethe vulva; possibly the large sphincter of the vagina. seedilator vulvae.consute a. [L. consuere, to sew together] Having minutestitch-like markings, differing in color from the generalsurface.conterminous a. [L. cum, together; terminus, boundry] 1.Touching at the boundry, contiguous. 2. Having like boundsor limits.contiguous a. [L. contiguus, bordering] Touching or adjoining

Online Dictionary of Invertebrate Zoology 235at the edge.continental drift The hypothetical movement of continentsacross the surface of the earth.continuous variation Individuals differing from each other bysmall steps, often just barely discernible. see discontinuousvariation.contorted a. [L. contortus, twisted together] Twisted orstraining out of shape or place.contour n. [L. cum, with; tornare, to turn] The outline; theperiphery.contract v. [L. cum, with; trahere, to draw] To draw together;to reduce in size; to shrink. contractile a.contractile tubules (SIPUN) Numerous, short and simple, orlonger and branching tubules originating from the contractilevessel and extending into the body cavity; polian tubules.contractile vessel(s) (SIPUN) A single or pair of tubes attachedto the surface of the esophagus, anteriorly communicatingwith the fine vessels in the tentacles and endingblindly posteriorly; compensatory sac.contractility n. [L. cum, together; trahere, to draw] The capabilityof muscle fibers to contract.contractin n. [L. cum, together; trahere, to draw] Thought tobe neurohumor that induces contraction of the chromatophores.contracture n. [L. cum, together; trahere, to draw] Contractionof muscles enduring after stimulus has ceased.contralateral a. [L. contra, against; latus, side] Pertaining to,or associated with similar parts on the opposite side. seeipsilateral.contranatant a. [L. contra, against; natare, to swim] Swimmingor migrating against the current. see denatant.conule n.; pl. conuli [L. dim. conus, cone] (PORIF) The tentlikeelevation of the surface membrane. conulose a.conus n.; pl. coni [L. conus, cone] Any cone-shaped structure.convergence n. [L. convergere, to incline] Morphological

236Maggenti and Gardnersimilarity in distantly related forms; homoplasy.convergent a. [L. convergere, to incline] 1. Tending to approach.2. Organisms having similar characters.convergent evolution Having similar adaptive structuresamong unrelated organisms due to environmental surroundings.converse eyes Eyes in which the distal ends of retinal cellsface the exterior of the cup or vesicle. see inverse eyes.convex a. [L. convexus, arched outward] Having a curved,rounded surface, as that of an external segment of a globe.see concave.convexity n. [L. convexus, arched outward] (MOLL: Bivalvia)The degree to which the shell is convex.convex vein (ARTHRO: Insecta) One that tends to fold upwardor follows the ridges of the wing.convolute a. [L. convolutus, rolled up] 1. Rolled or woundupon themselves. 1. (ARTHRO: Insecta) A wing rolledaround its body. 2. (MOLL) The last whorl of a shell embracingearlier ones and concealing them. see involute.convoluted gland (ARTHRO: Insecta) In some aculeates, a partof the venom producing structures invaginated into thevenom sac; in formacine ants it is external to this sac; notfound in bees.convolution n. [L. convolutus, rolled up] A coiling or twisting,as of something rolled or folded on itself.co-ordinate a. [L. cum, together; ordo, rank] In nomenclature,of the same value.co-ordination n. [L. cum, together; ordo, rank] The productionof harmonious interaction of the various parts andprocesses of an organism.copal n. [Ab.Am. copalli, a resin from tropical leguminoustrees] A complex mixture of amber-like resins from varioustropical trees.coparasitism n. [L. cum, together; parasitus, one who eats atthe table of another] The parasitism of a host by more thanone parasite.

Online Dictionary of Invertebrate Zoology 237copepodid n. [Gr. kope, oar; pous, foot] (ARTHRO: Crustacea)Postnaupliar developmental stage of copepods, often quitesimilar in body form to the adult.Cope's rule The generalization in which there is a steady increasein size in phyletic series.coprobiont n. [Gr. kopros, dung; bios, life] A coprozoic organism;a dung living organism.coprophagous a. [Gr. kopros, dung; phagein, to eat] Feedingupon feces; scatophagous; merdivorous. coprophagy n.coprophilic a. [Gr. kopros, dung; philos, loving] Growing in oron dung; coprozoic.coprozoite n. [Gr. kopros, dung; zoon, animal] A dung-inhabitingor coprozoic animal. coprozoic a.copularium n. [L. copulare, to couple; -arium, place for] (AR-THRO: Insecta) An initial nest cell founded by the primaryreproductives in the establishment of a termite colony.copulate v.i. [L. copulare, to couple] To unite in sexual intercourse.copulation n. [L. copulare, to couple] Pairing, coupling orjoined; sexual union of male and female; to copulate.copulation chamber (ARTHRO: Insecta) A nuptial chamber excavatedby certain Scolytinae beetles in the tunnel, whereincopulation takes place.copulatory bursa see bursa copulatrix, bursacopulatory cap (ACANTHO) The mucilaginous, proteinaceousmaterial thought to aid the union of partners during copulationand insemination that soon hardens to form a coveringaround the extremity of the female genitalia.copulatory chamber (ANN: Oligochaeta) An invagination containingthe male pore that reaches through the body wallinto the coelom; bursa copulatrix; copulatory pouch.copulatory organ Organs for the transfer or reception ofsperm during copulation.copulatory pouches (ANN: Oligochaeta) The spermathecae ofearthworms in older publications.copulatory sac Bursa copulatrix, copulatory pouch, seminal

238Maggenti and Gardnerreceptacle, seminal bursa.copulatory setae/chaetae (ANN: Oligochaeta) Those that appearnear or in the same segment as the spermathecae inearthworms; sometimes referring to similar setae in anadjacent, but athecal segment.copulatory warts (NEMATA) In males, enlarged genital papillae.copulo [L. copulare, to couple] "In copulo" correct form for describingcopulation.coquina n. [Sp. shellfish, cockle] A whitish limestone made upof marine shell fragments and corals, used for roadbedsand building materials.coracidium n. [Gr. korax, crow] (PLATY: Cestoda) 1. An onchosphereor hexacanth embryophore. 2. The ciliated, freeswimmingonchosphere of a fish tapeworm hatching fromthe egg.coral n. [Gr. korallion, coral] (CNID) The calcium carbonateexterior skeleton formed by corals inhabiting warm shallowwaters, masses of which form reefs and islands.coralliferous a. [Gr. korallion, coral; ferre, to bear] Pertainingto coral.coralline n. or a. [Gr. korallion, coral] 1. Any corallike animal,as certain Hydrozoa and Bryozoa. 2. Resembling coral inthe pinkish-red color.corallite n. [Gr. korallion, coral] The skeleton of an individualcoral polyp.coralloid a. [Gr. korallion, coral] Having the form or appearinglike coral; coralliform.corallum n. [Gr. korallion, coral] The skeleton of a solitarypolyp or a colony of corals.coral reef A calacareous mass formed by colonies of coral organisms;types include: 1. Fringing reef, extending out to aquarter of a mile from shore. 2. Barrier reef, separated bya lagoon from a shore. 3. Atoll, a circular reef encircling alagoon of water.corbel n. [L. corbis, basket] (ARTHRO: Insecta) An ovate areaof fringed bristles at the distal end of the tibia in certain

Online Dictionary of Invertebrate Zoology 239coleopterans.corbicula n.; pl. -lae [L. dim. corbis, basket] (ARTHRO: Insecta)A smooth area on the outer surface of the hind tibiaof Apidae, surrounded on each side by a fringe of longcurved hairs, that serves for carrying pollen and other materialsto the nest; a pollen basket.corbiculate a. [L. dim. corbis, basket] Having the shape of asmall basket; pertaining to corbiculae.corbiculoid teeth (MOLL: Bivalvia) Having 3 cardinal teeth ineach valve and a median tooth below the beak in the rightvalve. see arcticoid teeth.corbula n. [L. corbula, little basket] (CNID: Hydrozoa) A phylactocarpwith leaflike protective branches arching over theenclosed gonangia.corcula n. [L. dim. cordis, heart] (ARTHRO: Insecta) A chamberof the dorsal vessel, through which the blood flows.cord n. [L. chorda, cord] 1. Any long, rounded cordlike structure.2. (MOLL: Gastropoda) A round-topped, moderatelycoarse spiral or transverse linear sculpture on a shell surface.cordate a. [L. cordis, heart] Having the shape of a heart;cordiform.cordlike see restiformcordon n. [L. chorda, cord] (NEMATA) Longitudinal, cuticularcordlike thickening extending posteriorly from near the oralopening; may be straight, recurved or form loops; presentmainly in the spiruroid nematode family Acuariidae. seeepaulet.cordotonal organ see proprioceptorcordylus n.; pl. cordyli [Gr. kordyle, swelling] (CNID: Hydrozoa)Small clubs composed of large gastrodermal cells coveredby a thin epidermis, mounted on sensory cushionsbetween the tentacle bases of certain hydromedusae;sense clubs.core n. [L. cordis, heart] 1. The central part of anything. 2.(BRYO: Stenolaemata) Either laminated or nonlaminatedskeletal material, or a combination of both, that form the

240Maggenti and Gardnerstylets.corema, corematis n.; pl. -ata [Gr. korema, broom] (ARTHRO:Insecta) Paired eversible sacs of the ventro-lateral regionsof certain male Lepidoptera, containing hairpencils orbrushes, functioning in phermone dispersal; Julien's organ.coreum see coriumcor frontale (ARTHRO: Crustacea) Special pulsating structureor accessory heart formed from enlargement of the anteriormedian artery in front of the triturating stomach in Malacostraca.coriaceous a. [L. corium, leather] Tough and leathery; ofleathery texture.coring a. [L. cor, heart] (PORIF) A term used to describe thecontents of a fiber, either spicules or sand and spicule debristaken up by the sponge.corium n.; pl. -ria [L. corium, leather] (ARTHRO) 1. The membranesof the flecture areas (articular and intersegmentalmembranes) in segmented appendages. 2. The middle divisionof an elytron. corial a.cormidial orifice (BRYO: Gymnolaemata) Skeletal support forthe zooidal orifice produced by more than one zooid.cormidium n.; pl. cormidia [Gr. dim. kormos, trunk of a tree](CNID: Hydrozoa) A siphonophore gastrozooid with a tentacleand one or more gonophores of one sex; sensu stricto,cormidia are colonies within colonies. see eudoxome.Cormopoda see Bivalviacormopod(ite) see thoracopodcormus n. [Gr. kormos, trunk of a tree] 1. The body, colony,or polypary of a compound animal. 2. (ARTHRO: Crustacea)see thorax.cornea n.; pl. -neas [L. corneus, of horn] The transparent cuticlecovering the ommatidia of a compound eye. corneala.corneagen cells The epidermal cells that produce the cornea,and later produce the corneal pigment cells.corneagen layer That part of the epidermis extending beneath

Online Dictionary of Invertebrate Zoology 241the cornea, normally consisting of two cells in each ommatidium;when absent, the cornea is secreted by thecrystalline cone cells. see cornea.corneal facet One of the lenses of modified cuticle covering anommatidium or the array of lenses that gives a compoundeye its faceted appearance.corneal lens (ARTHRO: Insecta) The modified cuticle coveringthe ocellus.corneal pigment cells (ARTHRO) The two corneal cells thatenvelop each crystalline cone of a compound eye; in thedeveloping eye, distal to the cone they secrete the corneallense; also called primary pigment cells, corneagenouspigment cells and primary iris cells. see retinular pigmentcell, accessory pigment cell.cornein n. [L. corneus, of horn] (CNID) The organic basis ofcorals.corneous a. [L. corneus, of horn] Resembling horn; of hornliketexture; corniform.cornicle n. [L. dim. cornu, horn] (ARTHRO: Insecta) In aphids,one of a pair of movable, flap covered, pre-caudal tubesprojecting from the dorsum of segment 6, that expellslipid-filled cells; thought to be a defense mechanism.corniculate a. [L. dim. cornu, horn] Having horns or smallhorn-like structures.corniculum n.; pl. -ula [L. dim. cornu, horn] (ARTHRO: Insecta)A small horn-like process of the cuticula of larvae,often present on the suranal plate.corniculus n.; pl. -uli [L. dim. cornu, horn] 1. (ARTHRO: Chelicerata)In some mites, a horn-shaped infracapitular seta onthe malapophysis. 2. (ARTHRO: Insecta) In Orthoptera, refersto the hardened tips of the dorsal and ventral valves ofthe ovipositer, used to dig holes in the ground for thedeposition of eggs. see urogomphi.cornification n. [L. dim. cornu, horn; facere, to make] Formationof horn or horn-like material; keratinization.corniform a. [L. cornu, horn; forma, shape] A long mucronateor pointed process similar to the horn of an ox.

242Maggenti and Gardnercornu n.; pl. cornua [L. cornu, horn] 1. A horn or horn-shapedstructure. 2. (ARTHRO: Insecta) The horn-like processes inthe cephalo-pharyngeal skeleton of dipterous larvae. cornuala.cornuti n.pl.; sing. cornutus [L. cornutus, horned] (ARTHRO:Insecta) Sclerotized armature of the aedeagus of male Lepodoptera,in the form of slender single spines, scale-likedentations, dense spine-hairs or rasplike teeth; sometimesbreaking off during copulation and remaining in the bursacopulatrix of the female.corona n. [L. corona, crown] 1. A crownlike structure or organof various invertebrates. 2. (ARTHRO: Insecta) In Lepidopteramale genitalia, a specialized row of armament setae,teeth or spines on the cucullus. 3. (ECHINOD) a. In Crinoidea,a central mass and arms: a crown. b. In Echinoidea,a test, minus the apical system. 4. (ROTIF) A mainciliary wreath surrounding the mouth of a rotifer. coronala.corona ciliata see ciliary loopcoronal a. [L. corona, crown] (PORIF) Referring to being locatedon the rim of an oscule.coronal disc (ROTIF) The ciliary wreath on the anterior part ofthe head region.coronal suture (or branch) (ARTHRO: Insecta) A longitudinalsuture occurring along the midline of the vertex, betweenthe compound eyes; the stem of the Y-shaped epicranialsuture; the metopic suture.coronal systebm (ECHINOD: Echinoidea) In sea urchins, platesforming the wall of the test.corona radiata (NEMATA: Secernentea) In Strongylida, a seriesof leaf-like or fringe-like structures encircling/bordering thelabial region; the internal and external or outer leaf crownof some authors.coronary a. [L. corona, crown] Crown-shaped or crownlike;encircling.coronate a. [L. corona, crown] Having a crown, corona orsimilar structure.

Online Dictionary of Invertebrate Zoology 243coronate egg (ARTHRO: Insecta) An egg with the upper endsurrounded by a circlet of spines or comparable structures.coronet n. [L. dim. corona, crown] A small or inferior corona orcrown.corpora pl. of corpuscorpora allata pl.; sing. corpus allatum (ARTHRO: Insecta)Specialized endocrine glands, usually a pair of glandularbodies (may be fused to a single median organ) behind andlinked to the brain by small nerve fibers, that produce juvenilehormones regulating metamorphosis and yolk depositionin the egg; ganglia alata.corpora cardiaca pl.; sing. corpus cardiacum (ARTHRO: Insecta)Paired specialized endocrine glands, closely associatedwith the aorta and forming part of its wall and behindthe brain, that store and release hormones concerned withthe regulation of the brain and other physiological effects.corpora incerta see corpora allatacorpora optica pl.; sing. corpus opticum (ARTHRO: Insecta)A pair of small bodies lying above the pons cerebralis in thedorsal part of the brain, connected with the glomeruli ofthe ocellar nerves and the medullae externae of the opticlobes; thought to be association centers for both the ocelliand compound eyes.corpora pedunculata pl; sing. corpora pedunculatum (AR-THRO: Insecta) The pedunculate or mushroom bodies of theprotocerebrum, said to have an important role in visual integrationin Hymenoptera, but in other insects plays a partin the selection and sequential organization of behavioralpatterns.corpora ventralia pl.; sing. corporus ventralium (ARTHRO:Insecta) Ventral or lateral bodies that lie ventrolaterally inthe protocerebrum just above the antennal glomeruli of thedeutocerebrum, and connected to a transverse commissuretract; they are association centers connected to manyother parts of the brain.corpotentorium n. [L. corpus, body; tentorium, tent] (AR-THRO: Insecta) Fusion of the anterior and posterior tentorialarms; the body of the tentorium.

244Maggenti and Gardnercorpus n.; pl. corpora [L. corpus, body] 1. A body or structure.2. (ARTHRO: Insecta) a. The body. b. In many Collembola,the basal part of the minute pair of appendages onthe 3rd abdominal segment; the appendages themselvesknown as the retinaculum or hamula. 3. (NEMATA) Themost anterior part of the esophagus, usually cylindrical inshape, but may be subdivided into a slender anterior portion(procorpus) followed by a swollen, often valved, bulb(metacorpus).corpus adiposum The fat-body.corpus centrale (ARTHRO: Insecta) The central "body" of abrain, anterior or ventral to the pons cerebralis.corpuscle n. [L. dim. corpus, body] A small cell floating freelyin a fluid such as blood or lymph or embedded in an intercellularmatrix.corpuscular a. [L. dim. corpus, body] Pertaining to the natureof or composed of corpuscles or particles.corpus esophagi see corpuscorpus luteum (ARTHRO: Insecta) The mass of degeneratingfollicle epithelium left in an egg chamber after discharge ofthe egg, that sometimes persists and becomes compressedto form a new plug at the entrance to the pedicel.corpus mandibulae (ARTHRO: Insecta) The mandibular body.corpus scolopale see scolopalecorrelated characters Features or qualities associated eitheras manifestations of a well-integrated ancestral gene complex,or because they are functionally correlated.correlated response A change in one character (phenotype)occurring as an incidental consequence of selection for aseemingly independent character, such as reduced fertilityresulting from selection for high bristle number in pomaceor vinegar flies ( Drosophila ).correlation n. [LL. correlatio, relationship] 1. The act or processof correlating. 2. The degree to which statistical variablesmeasure the association of two or more variables. a.Correlation coefficient (r) has a value from zero to -1 or+1.

Online Dictionary of Invertebrate Zoology 245corridor n. [L. currere, to run] A gallery or passageway madeby an animal.corrode v. [L. corrodere, to gnaw to pieces] To consume orwear away.corrugate a. [L. corrugare, to wrinkle] Wrinkled; contractedinto alternate ridges and furrows.corselet see prothoraxcortex n.; pl. cortices [L. cortex, bark] 1. The outermost coveringlayer of a structure. cortical a. 2. (PORIF) The ectosomewhen thick and gelatinous or fibrous, or packed withspicules of a special type.cortical layer 1. (ARTHRO: Insecta) A region at the surface ofthe egg devoid of yolk. 2. (NEMATA) see epicuticle,exocuticle, mesocuticle, endocuticle.corticate a. [L. cortex, bark] Having a special cortex, or externallayer.corticiform a. [L. cortex, bark; forma, shape] Sculptured ortextured like bark.corticolous a. [L. cortex, bark; colere, to dwell] Living in or onthe bark of plants.coruscant a. [L. coruscare, to flash] Rapid intermittent flashingor gleaming, as of fireflies.corvinus a. [L. corvus, crow] Deep, shining black.coryogamy see koriogamycorypha n.; pl. coryphae [Gr. koryphe, top] (ARTHRO: Insecta)That region of certain scarabaeoid larvae, betweenthe epipharynx and the clithra, sometimes bearing setae;often merged with the acropariae into a common apical regionwhen the clithra are absent.corysterium n. [Gr. korys, helmet] (ARTHRO: Insecta) In certainfemales, an abdominal glandular structure that functionsin secreting the glutinous egg covering.cosmiotaxy n. [Gr. kosmios, well ordered; taxis, arrangement]Secondary formation of recognizable and simple organs.cosmiotrichy n. [Gr. kosmios, well ordered; thrix, hair] Setalcosmiotaxy.

246Maggenti and Gardnercosmopolitan a. [Gr. kosmos, world; polites, citizen] Worldwidein distribution; ecumenical; pandemic.cosmopolite n. [Gr. kosmos, world; polites, citizen] A plant oranimal occurring in most parts of the world.cosmotropical a. [Gr. kosmos, world; tropikos, of turning] Occurringthroughout most of the tropics.costa n.; pl. costae [L. costa, rib] 1. Any rib-like structure. 2.(ARTHRO: Crustacea) Any thickened portion of thepeniferum of ostracods. 3. (ARTHRO: Insecta) a. The longitudinalwing vein of certain insects, forming the anteriormargin of the wing. b. A dorsal, marginal part of the valvaof male Lepidoptera, bearing a variety of structures andprocesses. 4. (BRACHIO) a. Radial ridge on the exteriorsurface of the shell, originating at the margin of the protegulalnode. b. Any coarse rib. 5. (BRYO: Gymnolaemata)One of commonly two spines fused medially and intermittentlylaterally, that form the costal shield of cribrimorphcheilostomate zooids. 6. (CNID) Prolongations of the septaof certain corals, that connect to the surface layer. 7.(CTENO) The row of swimming plates (ctenes) that occupyadradial positions. 8. (MOLL) The rounded ridge on thesurface of a mollusk shell, greater than a chord. costal a.costaeform a. [L. costa, rib; forma, shape] Rib-like.costal area (ARTHRO: Insecta) That portion of a wing immediatelybehind the leading edge (anterior or front margin).costal brace (ARTHRO: Insecta) The thick veinlet at the base ofthe wing of mayflies, that runs from the costa to the radius.costal break (ARTHRO: Insecta) A point on the costa of a wingwhere the sclerotization is weak or lacking, or the vein appearsto be broken.costal cell (ARTHRO: Insecta) The space of the wing betweenthe costa and the subcostal vein.costal cross veins (ARTHRO: Insecta) In wings with numerousveins, those that extend between the costa and the subcosta.costal field (ARTHRO: Insecta) That area of the fore wing ofOrthoptera adjacent to the anterior margin or costa; the

Online Dictionary of Invertebrate Zoology 247anterior field.costal fold (ARTHRO: Insecta) An eversible fold in the fore wingnear the costa of certain hesperioid butterflies that containsbrushes of modified scales that function to disperse pheromones.costal hinge (ARTHRO: Insecta) The nodal furrow.costalia see costacostal margin (ARTHRO: Insecta) The leading edge of a wing.see anal margin, apical margin.costal membrane (ARTHRO: Insecta) In Hymenoptera, thesurface of the wing in front of the costal vein.costal nervure (ARTHRO: Insecta) The costa.costal region (ARTHRO: Insecta) The upper area of a wingnear the costa.costal sclerite (ARTHRO: Insecta) In wings, a sclerite at thebase of the costa.costal shield (BRYO: Gymnolaemata) The discontinuous frontalshield or part of the frontal shield of cheilostomate zooids,produced by intermittently fused or unfused spines overspreadingthe uncalcified part of the frontal wall.costal spines (ARTHRO: Insecta) In generalized Lepidoptera, atuft of slightly curved spine-like setae on the costa of thehind wing near the base, that functions in holding thewings together.costal vein (ARTHRO: Insecta) The subcosta of Lepidoptera.costate a. [L. costa, rib] Having a longitudinal rib or ribs;having costae.costella n.; pl. costellae [L. dim. costa, rib] 1. A small costaor rudimentary rib. 2. (MOLL: Bivalvia) A narrow, linear elevationof the shell surface.costellate a. [L. dim. costa, rib] Bearing costellae.costiform a. [L. costa, rib; forma, shape] Shaped like a costaor raised rib.costoradial a. [L. costa, rib; radius, ray] (ARTHRO: Insecta) Ofor pertaining to the radius and the costa of the wing.

248Maggenti and Gardnercostula n.; pl. costulae [L. dim. costa, rib] 1. (ARTHRO: Insecta)In Hymenoptera, a small ridge that separates theexterno-median metathoracic area into two parts. 2.(MOLL) One of the small ridges on the shell.costulate a. [L. dim. costa, rib] Being less prominently ribbedthan costate.coterminous see conterminouscotyla, cotyle n. [Gr. kotyle, a cup] A cuplike cavity or organ;an acetabulum.cotyliform, cotyloid a. [Gr. kotyle, a cup; L. forma, shape]Cup-shaped.cotylocercous cercariae (PLATY: Trematoda) Larval marinetrematodes with tails that are broad, short, with cupshapedsuckers, functioning as adhesive organs.cotylocidium n. [Gr. kotyle, cup; L. caedere, to cut] (PLATY:Trematoda) Larvae of Aspidogastridea with tufts of cilia forswimming and a posterior ventral sucker without alveoli orhooks.cotyloid cavity (ARTHRO: Insecta) The acetabulum or coxalcavity.cotype Formerly used for syntype or paratype.counterevolution n. [L. contra, against; evolutus, unrolled]Development of traits in a population in response to exploitation,competition, or other detrimental interactionwith another population. see coevolution.countershading n. [L. contra, against; A.S. sceadu, shade] Incamouflaging, an animal being dark dorsally and pale ventrallyand therefore appearing evenly colored and inconspicuous.coupling n. [L. copulare, to join] Bringing or coming together;linking; specifically sexual union.court n. [L. cohors, enclosed space] (ARTHRO: Insecta) In bees,an assemblage of workers that form a circle around aqueen, antennating, licking and sometimes feeding her.courtship n. The behaviour pattern in animals prior to copulationbetween members of the same species, differentsexes, that facilitates a receptive condition.

Online Dictionary of Invertebrate Zoology 249covariation n. [L. con, with; varius, diverse] Coincident variation;correlation.cowled a. [L. cucullus, hood] Shaped like a hood; hooded.coxa n.; pl. -ae [L. coxa, hip] (ARTHRO) 1. The first or proximalsegment of a leg that articulates basally with the wall ofthe thorax. 2. In Crustacea, the segment of an appendageadjoining the body sternite, except in forms having a precoxa;coxopodite. coxal a.coxacava see coxal cavitycoxa genuina see coxa veracoxal bridge (ARTHRO: Insecta) The attachment structure betweenthe sternum and pleuron; the pre- and post-coxalbridges.coxal cavity (ARTHRO: Insecta) The cavity in which the coxaarticulates; an acetabulum; coxacava.coxal corium (ARTHRO: Insecta) The articular membrane encirclingthe base of a coxa.coxal endite (ARTHRO: Crustacea) A lobe issuing from the innermargin of the coxa.coxal epipodites (ARTHRO: Insecta) The small pairs of unjointedstyli on the coxae of the legs.coxal exite (ARTHRO: Crustacea) A lobe issuing from the outermargin of the coxa; coxepipod.coxal file (ARTHRO: Insecta) A series of ridges on the coxa ofthe middle legs that by rubbing with a scraper on the trochanterof the hind leg produce sounds; a stridulatory apparatus.coxal glands 1. (ARTHRO: Chelicerata) The excretory organs ofarachnids; in Araneae, located opposite the coxae of thefirst and third legs, that function in collecting wastes into asaccule and discharging them through tubes opening behindthe coxae. 2. (ARTHRO: Insecta) Variously modifiedeversible glandular structures at the base of the legs. 3.(ONYCHO) The nephridia of Peripatus .coxal lobe (ARTHRO: Insecta) In certain larvae, a triangularabdominal area extending from the hypopleurum towardthe meson of the sternum.

250Maggenti and Gardnercoxal plate Plate-like expansions or dilatations of the coxa.coxal process (ARTHRO: Insecta) A structure of the pleuron,with which the coxa articulates at the ventral extremity ofthe pleural suture.coxal sacs (ARTHRO: Diplopoda) Eversible thin-walled sacs inthe coxae of the legs.coxal stridulatory organ (ARTHRO: Insecta) In Hemiptera,longitudinal striations of the coxal base and the cephalicmargin of the lateral plate of the coxal cavity.coxal stylets (ARTHRO: Insecta) The coxal epipodites.coxal vesicle (ARTHRO: Insecta) In Collembola, the basal partof the ventral tube, believed to represent the fused coxaeof the segmental appendages and the vesicles.coxa rotatoria (ARTHRO: Insecta) A coxa with a monocondylicjoint; having a single condyle.coxa scrobiculata (ARTHRO) A coxa with a dicondylic joint;having two points of articulation.coxa vera (ARTHRO: Insecta) The anterior portion of the mesoandmetathoracic coxae; the coxa genuina.coxepipod(ite) see coxal exitecoxifer n. [L. coxa, hip; ferre, to bear] (ARTHRO: Insecta) Thepleural pivot of the coxa.coxite n. [L. dim. coxa, hip] 1. The basal segment of certainabdominal appendages. 2. (ARTHRO: Crustacea) see protopod(ite).3. (ARTHRO: Insecta) In male Thysanura bearing adistal stylus.coxocerite n. [L. coxa, hip; Gr. keras, horn] (ARTHRO: Insecta)The proximal or basal segment of an antenna.coxomarginale see basicoxitecoxomeres n.pl. [L. coxa, hip; meros, part] (ARTHRO: Diplopoda)The three segments of the mandible.coxopleure see episternumcoxopleurite n. [L. coxa, hip; Gr. pleura, side] (ARTHRO: Insecta)A sclerite of the thoracic pleuron, that articulateswith the dorsal margin of the coxa; in lower pteryotic ordersforms the trochantin and a ventral articulation with

Online Dictionary of Invertebrate Zoology 251the coxa.coxopod(ite) n. [L. coxa, hip; Gr. pous, foot] (ARTHRO) Thebasal or first segment of an appendage; a coxa.coxosternal a. [L. coxa, hip; Gr. sternon, chest] (ARTHRO: Insecta)Of or pertaining to the coxosternum.coxosternal plate (ARTHRO: Insecta) In Thysanura, the fusedcoxites and sternum of each segment.coxosternite a. [L. coxa, hip; Gr. sternon, chest] The coxite;pleurosternite.coxosternum n. [L. coxa, hip; Gr. sternon, chest] (ARTHRO:Insecta) The abdominal sternum; a plate of compound originthat includes the areas of the limb bases; pleurosternum.coxotrochanteral joint (ARTHRO) One of the two primarybendings of a typical arthropod leg; pertaining to the joiningof the coxa and the trochanter. see femorotibial joint.craniad adv. [Gr. kranion, skull; L. ad, toward] Toward thehead or anterior end.cranium n.; pl. -niums [Gr. kranion, skull] The sclerotic, skulllikepart of the head capsule. cranial a.craspedon n.; pl. craspeda [Gr. kraspedon, edge] 1. (CNID:Hydrozoa) Those possessing a velum. 2. (PLATY: Cestoda)Those with segments that overlap.craspedote a. [Gr. kraspedon, edge] 1. Having a velum. 2.(PLATY: Cestoda) Having the anterior proglottid overlappingthe next posterior one.crassa n.; pl. crassae [L. crassus, thick] (ARTHRO: Insecta)The mandibular apodemes.crassus a. [L. crassus, thick] Coarse, thick or tumid in structure.crateriform a. [L. crater, bowl; forma, shape] Having the formof a saucer or hollow, shallow bowl; pertaining to a crateror funnel.craw n. [ME. crawe] (ARTHRO: Insecta) The crop.crawler n. [ON. krafla, to paw] 1. One that crawls. 2. (ARTHRO:Insecta) The first instar nymph of coccids, bearing legs and

252Maggenti and Gardnerantennae. 3. (ANN) An annelid.cremaster n. [Gr. kremastos, hung] (ARTHRO: Insecta) 1. Theterminal abdominal segment of a pupa. 2. In a subterraneanpupa, a terminal spine. 3. The hooked caudal extremityof the pupa that suspends the chrysalids. cremastrala.crena n.; pl. crenae [L. crena, notch] A notch, cleft or indentation.crenate a. [L. crena, notch] Having a scalloped or toothedmargin; indented; notched.crenation n. [L. crena, notch] 1. One of a series of roundedprojections forming the edge of an object or structure. 2.(NEMATA) Used to describe the outer lines of the lateralfield.crenature n. [L. crena, notch] A rounded projection; the indentationas between crenations.crenulate a. [L. dim. crena, notch] Finely notched or scalloped;plicate; annulet.crepera n. [L. crepera, dark] A ray of paler color on a darkbackground.crepidal punctures (ARTHRO: Insecta) In Scarabaeoidea beetles,a group of microsensilla located anterior to the crepis.crepis n.; pl. crepides [Gr. krepis, base] 1. (ARTHRO: Insecta)In Scarabaeoidea larvae, a thinly sclerotized, anteriorlyconcave, median cross bar of the haptolachus, usuallyasymmetrical and indicated by a fine line when present; atransverse, strongly bowed bar. 2. (PORIF) An ordinaryminute monaxon, triradiate or tetraxon spicule on whichlayers of silica have been irregularly deposited.crepitaculum n.; pl. -la [L. crepitaculum, rattle] (ARTHRO: Insecta)A stridulating organ.crepitation n. [L. crepitans, rattling] (ARTHRO: Insecta) Thedischarge of fluid with an audible explosion, used by certainbeetles as a defense mechanism.crepuscular a. [L. crepusculum, dusk] Activity in dim illuminationof shade or twilight. see nocturnal.crescent n. [L. crescere, to grow] Crescent-shaped; sickle-

Online Dictionary of Invertebrate Zoology 253shaped. crescentic, crescentiform a.crest n. [L. crista, crest] A ridge or linear prominence on anypart of the head or body. see cristate, carinate.cribellate a. [L. dim. cribrum, sieve] (ARTHRO: Crustacea) Aterm used to describe the irregular woven silk webs ofcertain spiders due to the action of the colulus on theemerging silk.cribellum n. [L. cribrum, sieve] 1. (ARTHRO: Chelicerata) Inspiders, a sieve-like, transverse plate, usually divided by adelicate keel into two equal parts, located in front of thespinnerets; the modified anterior median spinnerets. 2.(ARTHRO: Insecta) A sieve-like chitinous plate near the uppersurface of the mandibles.cribrate colony (BRYO: Stenolaemata) A sheetlike or frondosecolony with flattened, anastomosing branches separated byfenestrules.cribriform a. [L. cribrum, sieve; forma, shape] Sieve-like; cribrose.cribriform organ (ECHINOD: Asteroidea) Rows of small,webbed, flattened fringing spines forming enclosed passagesfor water transport from the marginal plates acrossthe oral surface of certain starfishes.cribriform plates (ARTHRO: Insecta) Cuticular pitted or sievelikeplates of certain scale insects, located on the dorsalsurface of the abdomen.cribrimorph n. [L. cribrum, sieve; Gr. morphe, form] (BRYO:Gymnolaemata) Autozooids bearing costal shields composedcompletely, or in part, of spines fused medially, andmost commonly intermittently along lengths.cribripore n. [L. cribrum, sieve; porus, passage] (PORIF) 1. Aspecialized exhalant structure of sponges where severalexhalant systems combine to empty into a subsurface cavity.2. In Polymastia (Demospongiae) an inhalent pore.cribrose see cribriformcrinite a. [L. crinitus, hairy] Having hair or hair-like growths.Crinoidea see Crinozoacrinome n. [L. crinis, hair] A network formed in cytoplasm by

254Maggenti and Gardnerbasophil substances that react to vital staining.crinose a. [L. crinis, hair] Hairy.Crinozoa, crinoids n., n.pl. [Gr. krinon, lily; zoion, animal] Asubphylum of echinoderms that includes all the stalked andmost primitive living forms; formerly known as Pelmatozoa,which is still in use by some authors.crispate a. [L. crispus, curly] Having a wrinkled or fluted margin;ruffled; irregularly twisted.criss-cross Pertaining to passage of sex-linked traits from parentsto offsping of the opposite sex.crista n.; pl. -tae [L. crista, crest] 1. A ridge or crest. seecristae. 2. (MOLL: Cephalopoda) A long narrow strip withlong hairs divided into sections by cells lacking hairs in thestatocysts; functioning to register movement and acceleration.crista acoustica, crista acustica (ARTHRO: Insecta) A chordotonalorgan of the fore tibia of certain Orthoptera, thatcontain a series of scolopidia; organ of Siebold.crista dentata (ARTHRO: Crustacea) In Decapoda, a toothedcrest on the ischium of the third maxilliped.cristae n.pl., sing. crista [L. crista, crest] Shelflike inner foldsof membrane in a mitochondrion composed of a middledouble layer of phospholipid molecules with a layer of proteinmolecules on each side.crista metopica (ARTHRO: Chelicerata) The propodosomalplate of adult prostigmated mites.cristate a. [L. crista, crest] Having a prominent carina or crest;cristiform.cristiform see cristatecristulate a. [L. dim. crista, crest] Having a small crescent-likeridge or crest.critical group A taxonomic group of organisms that cannot besubdivided into smaller groups.croceous a. [Gr. krokotos, saffron-yellow] Of the saffron-yellowcolor.crochet, crotchet n. [F. crochet, small hook] 1. (ARTHRO: In-

Online Dictionary of Invertebrate Zoology 255secta) In Lepidoptera and on other insect larvae, one of aseries of sclerotized hooklike cuticular structures, in rowsor circles on the prolegs; also on cremaster of chrysalides;frequently called hooks. 2. (ANN) see crotchet.crook n. [ON. krokr, crook] A hook; recurved tip; bend orcurve.crop n. [A.S. crop, craw] An enlarged portion in the alimentarycanal in certain invertebrates functioning in storage ortransporting and passing on to the digestive tract; theingluvies; esophageal bulb.crop caeca (ANN: Hirudinoidea) Segmental pouches or diverticulaof the crop.cross n. [OF. crois, cross] An organism produced by two differingforms; hybrid.crossed-lamellar shell (MOLL: Bivalvia) A shell structure withsecondary lamellae inclined in alternate directions withinthe primary lamellae.cross-fertilization The union of gametes from different individuals;allogamy; allomixis; xenogamy. see self-fertilization.crossing over The exchange of corresponding portions of homologouschromosomes during synapsis.cross-reflex The reaction of an effector on one side of thebody to stimulation of a receptor on the opposite side.cross section A cut of an organism or structure at right anglesto the longitudinal axis; a transverse cut.cross-striation In striped and cardiac muscle fibers, darkbands running across a fiber perpendicular to the myofibrilsand representing lines of A-bands.cross veins Any vein connecting adjacent longitudinal veins.crotchet n. [F. crochet, small hook] 1. A hooked or forklikeprocess. 2. (ANN) A curved seta (chaeta), notched at thedistal ends. 3. (ARTHRO: Insecta) see crochet.crown n. [L. corona, crown] 1. A circular structure at or nearthe summit of an organ or part. 2. A corona. 3. (ECHINOD:Crinoidea) The whole crinoid without stem; corona. 4.(NEMATA) see corona radiata.

256Maggenti and Gardnercruciate a. [L. crux, cross] Crossing; shaped like a cross.cruciform a. [L. crux, cross; forma, shape] Resembling across; cross-shaped.cruciform muscles (MOLL: Bivalvia) Two bundles of musclefibers joining valves and intersecting to form a cross.crumena n. [L. crumena, purse] (ARTHRO: Insecta) An internalpouch in the head for retraction of mandibular and maxillarybristles.crura n.pl.; sing. crus [L. crus, leg] 1. Any leg-like part. 2.(BRACHIO) A pair of prongs (brachidium) extending fromthe cardinalia or septum to support the lophophore. 3.(MOLL) A stalk or peduncle. 4. (NEMATA) Lateral extensionsof the cuneus of the gubernaculum. 5. (PLATY: Turbellaria)Branches of the intestine of a flatworm. crural a.crura cerebri (ARTHRO: Insecta) The two large nerve cordsconnecting the supra- and subesophageal ganglia.cruralium n. [L. crus, leg] (BRACHIO) A U-shaped ridge of thebrachial valve that bears adductor muscles.crural plates (BRACHIO) Vertical plates that attach the crura tothe dorsal valve.crural process (BRACHIO) The pointed portion of the crus, directedobliquely inwardly and ventrally.crus sing. of cruraCrustacea, crustaceans n.; n.pl. [L. crusta, shell] One of thedivisions of arthropods, having chitin-encased bodies thatmay or may not be impregnated with calcium salts; containsthe shrimp, crabs, lobsters, barnacles, water fleas,sand hoppers, fish lice, wood lice, sow bugs, pill bugs,scuds and slaters. crustaceous a.crustaformeria see columellacryophilic a. [Gr. kryos, icy cold; philios, loving] Adapted forliving at a low temperature.crypsis n. [Gr. kryptos, hidden] An aspect of the appearance oforganisms whereby they avoid detection by others; camouflage.crypt n. [Gr. kryptos, hidden] A pitlike depression; follicle;

Online Dictionary of Invertebrate Zoology 257cavity; simple gland or tube.cryptic a. [Gr. kryptos, hidden] 1. Concealing; stillness; silence;death-feigning; protective coloration. 2. A form ofpolymorphism controlled by recessive genes. crypsis n.cryptic color Sematic or protective coloration, designed toblend an animal with its background. see anticrypticcolor.cryptic species A species in which the diagnostic charactersare not easily perceived and that do not hybridize undernormal conditions; a sibling species.cryptobiosis n. [Gr. kryptos, hidden; bios, life] 1. Living in aconcealed or secluded environment. 2. A term used to describean organism that shows no visible signs of life, withmetabolic activity brought to a reversible standstill.cryptocephalic pupa (ARTHRO: Insecta) In Diptera, a pupalstage after the larval-pupal apolysis in which markedchanges of form appear through evagination of the headwithout molting, then proceeds to a phanerocephalic pupa.cryptocyst n. [Gr. kryptos, hidden; kystis, bladder] (BRYO:Gymnolaemata) 1. One of the two basic wall morphologiesof bryozoans consisting of wholly interior walls, leaving asuperficial hypostegal coelom uniting contiguous zooids.see gymnocyst. 2. A calcareous plate that functions as ahydrostatic organ in Cheilostomata. cryptocystal a.cryptocystidean n. [Gr. kryptos, hidden; kystis, bladder](BRYO) Autozooids of anascan or ascophorancheilostomates bearing frontal shields (cryptocysts) formedby calcification of the internal body walls grown into bodycavities subparallel to and beneath the frontal walls.cryptodicyclic see pseudomonocycliccryptodont shell (MOLL: Bivalvia) In some groups of early origin,refers to lack of hinge teeth. see ctenodont shell.cryptogastra a. [Gr. kryptos, hidden; gaster, stomach] Havingthe venter or belly covered or concealed. see gymnogastra.cryptogene a. [Gr. kryptos, hidden; genos, beginning] Of unknowndescent.

258Maggenti and Gardnercryptogram n. [Gr. kryptos, hidden; gramma, written character]Method that expresses in a standard code form a collectionof data used in classification.cryptogyne n. [Gr. kryptos, hidden; gyne, female] (ARTHRO:Insecta) In ants, having queens that are indistinguishablefrom the workers.cryptomphalous a. [Gr. kryptos, hidden; omphalos, navel](MOLL: Gastropoda) Having the opening of the umbilicus ofa shell completely plugged.cryptonephridial tubes Malpighian tubules with distal endsclosely associated with the rectum and forming a convolutedlayer over its surface.cryptoneurous a. [Gr. kryptos, hidden; neuron, nerve] Havingno distinct nervous system.cryptoniscus n. [Gr. kryptos, hidden; oniskos, sowbug] (AR-THRO: Crustacea) An intermediate, planktonic larval stageof epicaridean isopods with pereopods modified as holdfasts,that is seeking a permanent host; stage afterepicaridium.cryptopentamera a. [Gr. kryptos, hidden; pente, five; meros,part] Pertaining to 5-jointed feet, with the 4th joint smalland inconspicuous. see cryptotetramera.cryptopleuron a. [Gr. kryptos, hidden; pleuron, rib] (ARTHRO:Insecta) A condition in which the pronotum covers a largepart of the propleuron.cryptorhesis n. [Gr. kryptos, hidden; rheos, flow] The processof internal secretion.cryptosolenial a. [Gr. kryptos, hidden; solen, channel] (AR-THRO: Insecta) In certain Coleoptera, the area of attachmentof the Malpighian tubules with the hind-gut.cryptotetramera a. [Gr. kryptos, hidden; tetra, four; meros,part] Pertaining to 4-jointed feet with one joint small andinconspicuous. see cryptopentamera.cryptothorax n. [Gr. kryptos, hidden; thorax, breastplate](ARTHRO: Insecta) An assumed thoracic ring between themeso- and metathorax.cryptotoxic a. [Gr. kryptos, hidden; toxikon, poison] (ARTHRO:

Online Dictionary of Invertebrate Zoology 259Insecta) Pertaining to caterpillars that use volatile secretionsthat are released through an emission tube. see erucism,paraerucism, phanerotoxic, lepidopterism.Cryptozoa n. [Gr. kryptos, hidden; zoon, animal] An ecologicalgroup of cryptozoic terrestrial animals living in leaf litter,under twigs and pieces of bark and stone.cryptozoic a. [Gr. kryptos, hidden; zoon, animal] Living inconcealment.cryptozoite n. [Gr. kryptos, hidden; zoon, animal] A stage ofthe malarial organism arising from the injected sporozoitethat is found living in tissues before entering the blood; apreerythrocytic schizont of Plasmodium spp.cryptozone n. [Gr. kryptos, hidden; zone, girdle] (ECHINOD:Asteroidea) The marginal plates of starfish that are notclearly distinct.Cryptozoology n. [Gr. kryptos, hidden; zoon, animal; logos,discourse] The study of the Cryptozoa.crystal cell 1. (ARTHRO: Insecta) In Drosophila larvae, a typeof hemocyte (possibly an oenocytoid) that contains tyrosinase.2. (ECHINOD) Coelomocytes containing rhomboidcrystals.crystalline a. [Gr. krystallos, rock crystal] Appearing transparentlike crystal.crystalline body see crystalline conecrystalline cone (ARTHRO: Insecta) The hard, clear intracellularstructure of the eucone eye, produced by Semper cellsbeneath the cornea and bordered laterally by the primarypigment cells; also known as vitreous body or crystallinebody. see acone eye, pseudocone eye, eucone eye,exocone eye.crystalline style (MOLL: Gastropoda/Bivalvia) A translucentcylindrical rod in the style sac of the stomach, whirled onits axis by ciliary movement, releasing carbohydrate digestingenzymes.crystalline tract (ARTHRO: Insecta) 1. In beetles with exoconeeyes, a strand formed by the Semper cells across the clearzone to the rhabdon. 2. In skipper butterflies and some

260Maggenti and Gardnerditrysian moths (Bombycoidea), a strand formed by theretinula cells.C-shaped Semi-circular or cresent shape; U-shaped.ctene n. [Gr. kteis, comb] (CTENO) The swimming plate; therow of ctenes is a costa; a comb-rib.ctenidium n.; pl. -nida [Gr. dim. kteis, comb] 1. (ARTHRO: Insecta)a. A series of stout, peg-like spines on the head(genal ctenidium) and first thoracic tergite (pronotalctenidium) of many fleas. b. A row of comblike bristles onthe hind tarsus of Psocoptera. 2. (CTENO/MOLL) A respiratorygill-comb. see gill.cteniform a. [Gr. kteis, comb; L. forma, shape] Comb-shaped.ctenocyst n. [Gr. kteis, comb; kystis, bladder] (CTENO) Anaboral sense organ; the apical organ; the balancing organ.ctenodont shell (MOLL: Bivalvia) In some groups of early originhaving hinges with many teeth transverse to the margin.see cryptodont shell.ctenoid a. [Gr. kteis, comb; eidos, form] Comblike; having amargin of small teeth.ctenolium n. [Gr. dim. kteis, comb] (MOLL: Bivalvia) In somePectinacea, a comblike row of small teeth on the lower sideof the byssal notch.Ctenophora, ctenophores n., n.pl. [Gr. kteis, comb; phoreus,bearer] A phylum of marine coelenterates commonly calledsea walnuts or comb jellies, that are free swimming andbiradially symmetrical with 8 rows of fused ciliary plates(combs or ctenes) at some stage of their life.ctenopod n. [Gr. kteis, comb; pous, foot] (ARTHRO: Crustacea)An appendage (cirrus) of barnacles with long paired setaeon segments of lesser curvature and a few setae distally oneach articulation of greater curvature; like a comb. seeacanthopod, lasiopod.ctenose a. [Gr. kteis, comb] Comblike.Ctetology n. [Gr. ktetos, that may be had; logos, discourse]That aspect of biology concerned with acquired characters.cubical a. [L. cubus, cube] Cube-shaped.

Online Dictionary of Invertebrate Zoology 261cubital a. [L. cubitum, elbow] (ARTHRO: Insecta) Pertaining tothe cubitus of a wing.cubital area (ARTHRO: Insecta) In a wing, the area betweenthe two branches of the cubitus and is associated proximallywith the distal median plate of the wing base.cubital cell see cubital areacubital forks (ARTHRO: Insecta) Branching of the cubitus; theprimary cubital fork and the secondary cubital fork.cubital nerve/vein see cubituscubital supplement (ARTHRO: Insecta) In a wing, the cubitoanalloop being divided longitudinally by a midrib-like vein.cubito-anal (ARTHRO: Insecta) In a wing, the cubitus and analvein.cubito-anal cross vein (ARTHRO: Insecta) A cross vein in awing between the cubitus and an anal vein.cubito-anal excision (ARTHRO: Insecta) A notch in the marginof a wing where the anal and preanal areas join.cubito-anal fold see claval furrowcubito-anal loop (ARTHRO: Insecta) In certain Odonata, a loopformed in the anal area between veins A 2 and Cu 2 ; footshapedloop.cubitus n. [L. cubitus, reclined] (ARTHRO: Insecta) The fifthvein of a typical wing; the longitudinal vein posterior to themedia vein.cuboid a. [L. cubus, cube; Gr. eidos, form] Nearly resemblinga cube in shape. cuboidal a.cucullate a. [L. cucullus, hood] Hooded; having a hood-likestructure or mark.cucullus n.; pl. -li [L. cucullus, hood] 1. (ARTHRO: Chelicerata)A transverse flap at the anterior edge of the carapace, thatcompletely covers and protects the mouth and chelicerae inRicinulei spiders and some other orders, where it bears themedian eye (first somite of the body). 2. (ARTHRO: Insecta)A hood-like process on the distal or dorsodistal part of thevalva of male Lepidoptera, usually hairy or setose.cucumbitate a. [L. cucumis, cucumber] Shaped like a cucum-

262Maggenti and Gardnerber.cucumiform a. [L. cucumis, cucumber; forma, shape] Havinga cucumber-like form.cuiller n. [F. cuiller, spoon] (ARTHRO: Insecta) In male Lepidoptera,a spoon-like ventro-distal process of the clasper.cuilleron see alulacuirass n.; pl. cuirasses [F. cuirasse, leather breastplate] Aprotective covering, such as cuticle, plates, scales or shells.culmen n. [L. culmen, summit] (ARTHRO: Insecta) The carinaof a caterpillar.culmicolous a. [L. culmus, stalk; colere, to dwell] Living ongrasses.cultellate a. [L. cultellus, knife] Knife-like in appearance.cultellus n.; pl. -li [L. cultellus, knife] 1. A sharp knife-like organ.2. (ARTHRO: Insecta) a. The blade-like lancets of certainblood-sucking flies. b. Has been used for mandibles.cultrate a. [L. cultratus, knife-shaped] Shaped like a pruningknife; cultriform.culture n. [L. cultus, cultivated] The cultivation of micro-organismsor tissues in a prepared nutrient media.culus n. [L. culus, fundament] The anus.cumulate v.; -lated [L. cumulatus, heap up] To accumulate ingroups or heaps.cumulus n.; pl. -li [L. cumulus, heap] An accumulation; agroup or heap.cuneate a. [L. cuneatus, wedge-shaped] Wedge-shaped; cuneiform.cuneus n. [L. cuneus, wedge] 1. (ARTHRO: Insecta) A terminal,more or less triangular segment of the corium of the forewing. 2. (NEMATA) The ventral arm of the gubernaculum.cup n. [A.S. cuppe, cup] Any structure resembling a cup.cupola organ see sensillum campaniformiumcupreous a. [L. cupreus, of copper] Copper colored, coppery.cup shaped Cupuliform; cyathiform.

Online Dictionary of Invertebrate Zoology 263cupula n.; pl. -ae [L. dim. cupula, tub] (MOLL: Cephalopoda)The functional unit of the sensory nerves of the cristae indibranchiates.cupulate a. [L. dim. cupula, tub] Cup-shaped; bearing a cupule.cupule n. [L. dim. cupula, tub] A small sucker or acetabulum ofvarious invertebrates.cupuliform a. [L. cupula, tub; forma, shape] Cup-shaped; cyathiform.curculionids n.pl. [L. curculio, weevil] (ARTHRO: Insecta) U- orC-shaped larvae with a distinct head, robust body andlacking legs; adults with chewing mouthparts at the end ofa snout.cursipeds n.pl. [L. cursor, runner; pes, foot] (ARTHRO: Chilopoda)In the order Lithobiida, ambulatory legs of the firstto 13 pairs used for locomotion.cursoria n. [L. cursorius, of running] (ARTHRO: Insecta) Anorthopteran group of insects with legs well formed for rapidmovement.cursorial a. [L. cursorius, of running] Fitted or adapted forrunning.curvate a. [L. curvatus, bend] Curved.curvinervate a. [L. curvus, bent; nervus, nerve] (ARTHRO: Insecta)Having wing veins distinctly curved.cusp n. [L. cuspis, point] A prominence or point, esp. on thecrown of a tooth; a denticle. cuspate, cuspidal a.cuspidate a. [L. cuspidatus, pointed] Terminating in a sharppoint, as bristles or mollusk shells.cuspidoblast cells (MOLL) Special cells that secrete teeth.cuspis n. [L. cuspis, point] (ARTHRO: Insecta) In Hymenoptera,an immovable process projecting from the free distal end ofthe volsellar plate. see digitus.custodite a. [L. custodis, guardian] Guarded, as an enclosedlarva.cutaneous a. [L. cutis, skin] Pertaining to or of the nature ofskin.

264Maggenti and Gardnercuticle, cuticula n. [L. dim. cutis, skin] The noncellular externallayer of the body wall of various invertebrates.cuticular a. [L. dim. cutis, skin] Of or pertaining to the cuticle.cuticular colors (ARTHRO: Insecta) Pertaining to the black andbrown colors usually resulting from the color of the cuticle,along with other pigments occurring in the epidermal cellsor internal tissues.cuticularization n. [L. dim. cutis, skin] To form into cuticle.cuticular layering Structural strata within the cuticle of invertebrates.cuticular ornamentation A mark or sculpture of any type onthe cuticle of an animal.cuticular pores Minute pores opening at the surface of the cuticle.cuticular sheath see scolopalecuticulin n. [L. cuticula, skin] (ARTHRO: Insecta) A compoundmaterial of uncertain chemical nature that forms the epicuticle.cuticulin layer 1. (ARTHRO: Chelicerata) In mites, the epiostracum.2. (ARTHRO: Insecta) Layer extending over thesurface of the body and over cuticular projections such asbristles and scales as well as epidermal invaginations.cuttle bone (MOLL: Cephalopoda) The internal calcified shellremnant of cuttlefish.Cuvierian organs (ECHINOD: Holothuroidea) A few, or a tuft oflong blind tubules extending from the base of the respiratorytrees to the anus; ejected as sticky filaments to entanglepossible predators; sometimes called 'cotton spinners'.cyaneous a. [Gr. kyaneos, dark-blue] Dark blue.cyanescent a. [Gr. kyaneos, dark-blue; L. escens, become]Having a deep bluish tinge or shading; cerulean.cyanoblast n. [Gr. kyaneos, dark-blue; blastos, bud] The immaturestage of a cyanocyte (hemocyte) that containspolyribosomes, cisternae often filled with dense granularmaterial, small Golgi apparatus and mitochondria; reported

Online Dictionary of Invertebrate Zoology 265to be typical of an active protein-synthesizing and storingcell.cyanocyte n. [Gr. kyaneos, dark-blue; kytos, container] Ahemocyte that breaks down and releases hemocyanin intothe hemolymph. see cyanoblast.cyanogenic a. [Gr. kyaneos, dark-blue; gennaein, to produce]1. Production of the blue color. 2. Used to describe pungentand irritating vapors emitted by certain arthropods.cyanophilous a. [Gr. kyaneos, dark-blue; philos, loving]Showing a special affinity for blue or green stains.cyathiform a. [L. cyathus, cup; forma, shape] Cup-shaped;cupuliform; a little widened at the top.cyathotheca n. [Gr. cyathus, cup; theke, case] (ARTHRO: Insecta)The cover of the thorax of a pupa.cybernetics n. [Gr. kybernetikos, good at steering] Science ofthe processes of communication and control in an animal.cycle n. [Gr. kyklos, circle] A circle; circular; arranged in a circle;to pass through a cycle of changes. cyclic a.cyclocoele n. [Gr. kyklos, circle; koilos, hollow] (PLATY: Trematoda)That area of the intestinal cecae that end blindlyor are fused posteriorly.cyclocoelic a. [Gr. kyklos, circle; koilos, hollow] Having theintestine spirally coiled.cyclodont n. [Gr. kyklos, circle; odons, tooth] (MOLL: Bivalvia)Dentition curving out from under the umbones and twistedinto line in the cardinal margin, as in Cardiinae.cyclogeny n. [Gr. kyklos, circle; genes, producing] The productionof a series of different morphological types in a lifecycle.cyclolabia n. [Gr. kyklos, circle; L. labium, lip] (ARTHRO: Insecta)The short forceps of certain earwigs that are of variablelengths in the same species.cyclomorphosis n. [Gr. kyklos, circle; morphe, form] A seasonalnongenetic change of phenotype in marine zooplankton,as certain cladocerans and rotifers.cyclopean, cyclopic a. [Gr. kyklos, circle; ops, eye] A single

266Maggenti and Gardnermedian eye developed under certain artificial conditions, ora mutation in place of the normal pair.cyclopoid larva (ARTHRO: Insecta) The larva of proctotrupoidHymenoptera with a hypermetamorphosis, characterized bya swollen cephalothorax, large sickle-like mandibles and apair of bifurcate processes of various forms.cyclops stage (ARTHRO: Crustacea) Post-metanaupliar stage ofa copepod.cyclosystem n. [Gr. kyklios, circular; systema, placed together](CNID: Hydrozoa) In milleporinan medusae, consistingof several dactylopores surrounding a central gastropore.cydariform a. [L. cydarum, kind of ship; forma, shape] Globoseor orbicular, but truncated at opposite ends.cydippid larva (CTENO) A larva with developmental stages resemblingadult cydippids, and thus may be larval stages ofother orders.cylindraceous a. [Gr. kylindros, cylinder] Pertaining to or likea cylinder.cylindrical a. [Gr. kylindros, cylinder] Round, cylinder-like withparallel sides.cylindroconic a. [Gr. kylindros, cylinder; konos, cone] Havingthe shape of a cylinder terminating in a cone.cymba n. [Gr. kymbe, small boat] (PORIF) A spicule shaped likea boat.cymbium n. [Gr. kymbe, small boat] (ARTHRO: Chelicerata)The boat-shaped tarsus of the copulatory pedipalpus incertain spiders. see paracymbium.cymbiform a. [Gr. kymbe, small boat; L. forma, shape] Boatshaped;navicular; scaphoid.cymose a. [L. cyma, young shoot] (CNID: Hydrozoa) Pertainingto the budding zone that continues to bud and formbranches.cynopodous a. [Gr. kyon, dog; pous, foot] Having non-retractileclaws.cyphonaute larva pl. -nautae (BRYO: Gymnolaemata) A free-

Online Dictionary of Invertebrate Zoology 267swimming larva with a triangular profile and strongly compressedlaterally; most of the body is enclosed by a bivalveshell.cyphopod n. [Gr. kyphos, bent; pous, foot] (ARTHRO: Diplopoda)In Julidae, large, sclerotized bases of aborted appendagesbehind the second pair of legs.cyphosomatic a. [Gr. kyphos, bent; soma, body] (ARTHRO:Insecta) Pertaining to larvae with the dorsal surface curvedand the ventral surface straight or flat.cypraeiform a. [L. Cypris, Venus; forma, shape] Oval, rolledinward from each side.cyprid n. [L. Cypris, Venus] (ARTHRO: Crustacea) In somerhizocephalan barnacles, larval stage after cypris and beforekentrogon.cypris n. [L. Cypris, Venus] (ARTHRO: Crustacea) In bivalvebarnacles, the nonfeeding larval stage prior to metamorphosisinto the cyprid, kentrogon and adult stage, sonamed because of its resemblance to the ostracod genusCypris.cyrenoid type see corbiculoid teethcyrtoconic a. [Gr. kyrtos, curved; konos, cone] Cone-shaped.cyrtoconoid a. [Gr. kyrtos, curved; konos, cone; eidos, like]Approaching a cone in shape, but with convex sides. seeconoid, coeloconoid.cyrtocyte n. [Gr. kyrtos, curved; kytos, container] Protonephridialsystem with a fenestrated area in the basalpart of the nephridial canal in many groups of invertebrates.cyrtopia n. [Gr. kyrtos, curved; ops, eye] (ARTHRO: Crustacea)In Euphausiacea, the fifth larval stage in which the antennabecomes modified and ceases to serve in locomotion andposterior legs and gills appear.cyst n. [Gr. kystis, bladder] 1. A small sac, capsule or bladderlikestructure. 2. A protective covering formed about an organismduring unfavorable conditions or reproduction. 3.(NEMATA: Secernentea) The tanned cuticle of certain maturefemale nematodes (Heterodera or Globodera) in which

268Maggenti and Gardnereggs are retained.cystacanth n. [Gr. kystis, bladder; akantha, thorn] (ACANTHO)A juvenile having all adult structures, except the reproductivesystem is immature; proceeds to a quiescent state inan arthropod intermediate host; adulthood is reached wheningested by the definitive vertebrate host.cystenchyma n. [Gr. kystis, bladder; en in; kyma, swollen] Aparenchyma with large vesicular cell structure.cystencyte n. [Gr. kystis, bladder; en, in; kytos, container](PORIF) A polysaccharide-secreting cell in fresh-watersponges with contents enclosed in a single vesicle.cystic a. [Gr. kystis, bladder] Contained in a gall or cyst.cysticercaria cercaria (PLATY: Trematoda) In Azygiidae, alarge cercaria of the cystophorous type, with a short flattail ending in a pair of flat clapper-like appendages (fercocystocercous).cysticerci pl. of cysticercuscysticercoid a. [Gr. kystis, bladder; kerkos, tail; eidos, form](PLATY: Cestoda) A tapeworm cyclophyllidean metacestodedeveloping from an oncosphere that has penetrated the gutof an intermediate host; it usually has a "tail" and a wellformedscolex that is not invaginated. see cysticercus.cysticercosis n. [Gr. kystis, bladder; -osis, suff. denoting disease]An infection with one or more cysticerci.cysticercus n.; pl. -cerci [Gr. kystis, bladder; kerkos, tail](PLATY: Cestoda) A tapeworm metacestode with an introverted,invaginated scolex that forms on a germinativemembrane enclosing a fluid-filled bladder; a bladder worm;proscolex. see coenurus, hydatid.cystid n. [Gr. kystis, bladder] (BRYO) The external wall of a zooid.cystidean larva (ECHINOD: Crinoidea) A larval stage in whichthe stalk appears, but the arms are not yet present.cystiphragm n. [Gr. kystis, bladder; phragma, fence] (BRYO)The lateral skeletal partition curving from the zooecial wallinto the chamber.cystocercous cercariae see cystophorous cercariae

Online Dictionary of Invertebrate Zoology 269cystocytes n.pl. [Gr. kystis, bladder; kytos, container] (AR-THRO: Insecta) 1. A type of specialized granular hemocytethat has a small, sharply defined nucleus and a pale, hyalinecytoplasm containing black granules; coagulocytes. seegranulocyte. 2. Has also been applied as cells that enclosegonadial germ cells, follicle cells of an ovary, and cyst cellof the testis.cystogenic cells (PLATY: Trematoda) Secretory cells in a cercariathat produce a metacercarial cyst.cystoidal diaphragm (BRYO: Stenolaemata) A transverseskeletal structure formed by two diaphragms in contactpart way across the zooecial chamber and enclosing thecompartment between them.cystoid body (NEMATA) In the genus Meloidoderita, the tanneduterus (light to dark brown in color), irregular to roundoval,filled with eggs and larvae.cyston n. [Gr. kystis, bladder] (CNID: Hydrozoa) A colony dactylozooidmodified for excretory function.cystophorous cercaria (PLATY: Trematoda) 1. A large cercariawith a bulbous chamber at the anterior end of the tail intowhich the body can be withdrawn; also called cystocercous,cysticercaria, macrocercous cercaria. 2. The cercaria of thefamily Halipegdae that have a short tail with 5 appendages,all differing from each other.cystopore n. [Gr. kystis, bladder; poros, pore] (BRYO) Extrazooidalskeletal structures composed of adjacent and superimposedvesicles.cystozooid n. [Gr. kystis, bladder; zoon, animal] (PLATY:Cestoda) The body portion of a metacestode; a juveniletapeworm.cytaster n. [Gr. kytos, container; aster, star] An aster-like figurein animal cells containing the centrioles, formed in cytoplasmoutside the nucleus before mitosis and meiosis.cytobiotaxis see cytoclesiscytocentrum see centrosomecytochemistry n. [Gr. kytos, container; chemeia, pert. chemistry]The science of cell chemistry.

270Maggenti and Gardnercytochimera n. [Gr. kytos, container; chimaera, monster] Thesame combination of tissues or parts of tissue having differentchromosome numbers.cytochrome n. [Gr. kytos, container; chroma, color] Any of aclass of hemoproteins that function in electron and/or hydrogentransport because of a reversible valency change oftheir heme irons.cytocidal a. [Gr. kytos, container; L. caedere, to kill] Thatwhich kills cells.cytocinesis see cytokinesiscytoclesis n. [Gr. kytos, container; klesis, summons] A cellgroup that influences the development or differentiation ofsurrounding cells; cytobiotaxis. see organizer.cytococcus n.; pl. -cocci [Gr. kytos, container; kokkos, seed]The nucleus of a cytula.cytogamy n. [Gr. kytos, container; gamos, marriage] Cell fusionor conjugation.cytogenetics n. [Gr. kytos, container; genesis, beginning] Thecomparative study of chromosomal mechanisms and behaviorin populations and taxa, and their effect on inheritanceand evolution.cytogony n. [Gr. kytos, container; gonos, progeny] Reproductionby single cells.cytokinesis n. [Gr. kytos, container; kinesis, movement] Thechanges occurring in the protoplasm of the cell outside ofthe nucleus during cell-division.cytolemma n. [Gr. kytos, container; lemma, skin] Plasmamembrane.cytology n. [Gr. kytos, container; logos, discourse] The studyof the structure and physiology of a cell.cytolysis n. [Gr. kytos, container; lysein, to dissolve] Cell dissolutionor degeneration.cytomembrane n. [Gr. kytos, container; L. membrana, skin]The basic unit of the membrane system of a cell; unitmembrane.cytomorphosis n. [Gr. kytos, container; morphe, form] All

Online Dictionary of Invertebrate Zoology 271changes in cells or generations of cells from undifferentiatedstage to death; cellular change.cytopempsis n. [Gr. kytos, container; pempsis, mission] Passageinto, through and from a cell or capillary by a particle.cytophagy n. [Gr. kytos, container; phagein, to eat] Cellsfeeding on cells.cytoplasm n. [Gr. kytos, container; plasma, formed ormolded] The protoplasm of a cell excluding the nucleus,usually a slightly viscous fluid with inclusions suspended init; the site of the chemical activities of the cell.cytoplasmic factor A genetic factor in the cytoplasm.cytoplasmic inheritance Inheritance of characters whosedeterminants are not located on the chromosomes.cytosis n. [Gr. kytos, container] Non-specific cellular ingestionor egestion processes by pinocytosis or phagocytosis.cytosol n. [Gr. kytos, container; solvere, to set free] Groundprotoplasm of the cell exclusive of organelles or other particles.cytosome n. [Gr. kytos, container; soma, body] A non-specificname for membrane bound polymorphous bodies in the cellcytosol.cytostatic a. [Gr. kytos, container; statikos, standing] Anyagent that inhibits cell growth and multiplication.cytotaxonomy n. [Gr. kytos, container; taxis, arrangement;nomos, law] A method of taxonomy based on size, shapeand number of chromosomes in somatic cells. see taxonomy.cytotoxin n. [Gr. kytos, container; toxikon, poison] Cell poison.cytula n. [Gr. dim. kytos, container] The fertilized egg cell orparent cell.

Ddacryoid a. [Gr. dakryon, tear; eidos, form] Tear-shaped.dactyl n.; pl. -tyles [Gr. daktylos, finger] 1. A finger or toe; adactylus; a pretarsus; a digit. 2. (ARTHRO: Crustacea) Theultimate segment of a thoracopod; a dactylopodite.dactylethra n. [Gr. daktylethra, finger sheath] (BRYO: Stenolaemata)A degenerate feeding zooid closed by a terminaldiaphragm, or an aborted, shortened polymorph.dactylognathite n. [Gr. daktylos, finger; gnathos, jaw] (AR-THRO) The distal segment of a maxilliped.dactyloid a. [Gr. daktylos, finger; eidos, form] Finger-like.dactylopod(ite) n. [Gr. daktylos, finger; pous, foot] (ARTHRO)1. The terminal segment of a generalized leg or appendageusually claw-like; the pretarsus. 2. For Crustacea see dactyl.dactylopore n. [Gr. daktylos, finger; poros, passage] (CNID:Hydrozoa) An opening in the coenosteum of a milleporinancoral for a dactylozooid.dactylozooid n. [Gr. daktylos, finger; zoon, animal] (CNID:Hydrozoa) In colonial hydrozoans, a hydroid modified forprotection and the capture of prey; protective polyp, zooidor machozooid; a hydrocyst; a palpon. see tentaculozooid,gastrozooid.dactylus n. [Gr. daktylos, finger] 1. (ARTHRO: Insecta) Astructure of the tarsus. 2. (MOLL: Cephalopoda) see tentacle.dance n. [OF. dancer, dance] (ARTHRO: Insecta) Communicativemovements of honeybees, usually performed on theircombs.daphnid a. [Gr. daphne, laurel] (ARTHRO: Crustacea) Any waterflea, esp. those in the genus Daphnia .dart n. [OF. dard, dagger] 1. Anything that pierces or wounds.2. (ECHINOD) The spiculum. 3. (MOLL: Gastropoda) A sting

Online Dictionary of Invertebrate Zoology 273or dart of certain snails.dart sac (MOLL: Gastropoda) A muscular caecum of the vaginathat produces a fine-pointed calcareous shaft that is 'shot'by partners before courtship, lodging in the integument andreleasing a stimulus for courtship behavior.Darwinism n. [C. Darwin, English naturalist] The theory ofspecies origin through natural selection working on smallinherited differences in individuals.dauer larvae (NEMATA) A quiescent stage entered by someparasitic larvae while enclosed in the cast cuticle of theprevious stage.dauermodification n. [Ger. dauer, duration; L. modificare, toregulate] Character change usually induced by extreme environmentalfactors that survives for several generations.daughter n. [A.S. dohter, daughter] The offspring of a division,not implying sex, such as in daughter cells or daughternucleus; a daughter chromosome applies to chromatidsafter metaphase.daughter cells The two cells resulting from division of a singlecell.daughter cyst (PLATY: Cestoda) Fluid filled bladder with protoscolescesformed by exogenous budding of the germinalepithelium of a unilocular hydatid cyst.day-eye (ARTHRO: Insecta) The apposition eyes adapted foruse in daytime when light is abundant.dealate, -ated a. [L. de, away from; alatus, winged] (ARTHRO:Insecta) Loosing wings, as ants and termites, by casting orbreaking off. dealation n.death n. [A.S. death, death] Irreversible cessation of the activitiesand breakdown of the structure of protoplasm.deaurate a. [L. de, away from; auratus, golden] Having a goldcolor that appears rubbed or worn.decacanth n. [Gr. deka, ten; akantha, thorn] (PLATY: Cestoda)A ten-hooked larva that hatches from the egg; a lycophore.decalcification n. [L. de, away from; calcarius, of lime; ficare,to make] Loss of calcium salts from living tissues; removingcalcium salts from tissues with acids.

274Maggenti and Gardnerdecamerous a. [Gr. deka, ten; meros, part] Having ten partsor divisions.decapodid larvae (ARTHRO: Crustacea) Larvae of Decapodathat swim with their pleopods; a megalopa stage larva.decathecal a. [Gr. deka, ten; theke, case] (ANN: Oligochaeta)Earthworms having ten spermathecae, usually in five pairs.decephalic a. [L. de, away from; Gr. kephale, head] (ARTHRO:Insecta) Having a prognathous head with structures dividingthe foramen.deciduous a. [L. deciduus, falling off] Having a part or partsthat may fall off or be shed.deck n. [D. dek, cover] (MOLL) A septum or small sheet ofshelly substance in the umbonal region connecting the anteriorand posterior ends of a valve.declinate a. [L. de, away from; clinatus, sloping] Bendingaside in a curve with the apex downward.declivitous, declivous a. [L. de, away from; clivis, hill] Slopingdownward; gradually descending.decollate a. [L. de, away from; collum, neck] (MOLL: Gastropoda)Pertaining to cut or broken off, as the apex on someland gastropods; wearing away at the apex; decapitation ordiscarding the apical whorls.deconjugation see desynapsisdecorticate v.t. [L. de, away from; cortex, bark] To divest ofthe exterior coating; deprived of the cortex or outer coat.decticous a. [Gr. dektikos, biting] (ARTHRO: Insecta) Havingfunctional mandibles in the puparium, cell, or cocoon. seeadecticous.decumbent a. [L. decumbere, to lie down] Bending downward;upright at the base and bending down at the tip.decurved a. [L. de, away from; curvus, bend] Bowed orcurved downward.decussated a. [L. decussatus, formed crosswise like the letterX] 1. Intersected; striations or bristles crossing at acuteangles forming a series of X's. 2. (ARTHRO: Insecta) Pertainingto bristles of some Diptera. 3. (MOLL: Gastropoda)

Online Dictionary of Invertebrate Zoology 275Pertaining to radial ribs.dedetermination n. [L. de, away from; determinare, to limit]Reversion of cells to their embryonic state.dedifferentiation n. [L. de, away from; differentia, difference]Loss of traits of specialized cells formed during the courseof differentiation.defaunate n. [L. de, away from; Fauna, deity of herds andfields] To remove from an organism its commensalistic ormutualistic microfauna, for which the organism ordinarilyserves as a host.defecate v.i. [L. defaecare, to void excrement] To void feces.deferent a. [L. de, away from; ferre, to carry] Carrying away;deferent duct.deficiency n., pl. -cies [L. deficiens, wanting] Structuralchange resulting in the loss of a terminal part of a chromosome.definition n. [L. definitus, limited] 1. Limitation; defining limits.2. In taxonomic work, the formal statement of charactersdelimiting the taxonomic category.definitive host One in which the terminal (frequently sexual)stage of the parasite occurs; primary host. see intermediatehost.definitive reservoir A host or location in which a natural supplyof the terminal stage (frequently sexual) of a parasiteoccurs.deflected a. [L. de, away from; flectere, to bend] 1. Bentbackward or to one side or downward. 2. (ARTHRO: Insecta)Wings having the inner margins lapping and the outer marginsdeclining toward the sides.deflected front (ARTHRO: Crustacea) In some Decapoda, thebroadly downturned front margin of the carapace.deflexed a. [L. de, away from; flectere, to bend] Bent abruptlydownward.defoliator n. [L. de, away from; folium, leaf] Any agent, animalor chemical that destroys the leaves of plants.deformed a. [L. deformis, misshapen] 1. Disarranging or set-

276Maggenti and Gardnerting in an unusual form. 2. (ARTHRO: Insecta) The knottedor twisted antennae in male Meloidae.degenerate v.i. [L. degenerare, to depart from its kind] Toretrogress to a lower type; to deteriorate.degenerate code The genetic code in which more than onenucleotide triplet codes for the same amino acid.degeneration n. [L. degenerare, to depart from its kind] Aprogressive deterioration to a less specialized or functionallyless active form; retrogressive development.dehiscence n. [L. dehiscere, to split open] The cracking, splittingor tearing of an opening in an organ or structure alonglines of weakness. dehiscent a.deirids see cervical papillaedelamination n. [L. de, away from; lamina, a thin plate] 1.Split or divided into layers, as cells forming a new layer. 2.Gastrulation in which the endoderm is split off as a layerfrom the internal surface of the blastoderm.delimitation n. [L. de, away from; limes, boundry] 1. Settingor marking a boundry. 2. In taxonomy, a formal statementof the characters of a taxon that establishes its limits. seedescription, diagnosis, differential diagnosis.delthyrium n.; pl. -ria [Gr. 4th letter, delta; thyrion, door](BRACHIO) The central triangular notch in the ventral valve,open to the hinge line; facilitating the passage of the pedicle;usually closed off from the hinge plate by thedeltidium. delthyrial a. see notothyrium.deltidial plates (BRACHIO) A plate or pair of plates growingmedially from the margin of the delthyrium, almost orcompletely closing it.deltidium n.; pl. -tidia, [Gr. 4th letter Δ, delta; -idion, dim.](BRACHIO) A plate that closes off the delthyrium, in someforms there are two plates; also called pseudodeltidium.deltoid a. [Gr. 4th letter Δ, delta; eidos, shape] Triangular inshape.demanian system (NEMATA) A complex system consisting ofpaired efferent tubes connecting the intestine and uteri

Online Dictionary of Invertebrate Zoology 277with one another and sometimes posteriorly with the exterior;thought to be seminal storage tubes.demarcation line (MOLL: Bivalvia) Imaginary line joiningpoints on the beak with points of maximum transversegrowth of the shell margin; forms dorsoventral profile.deme n. [Gr. demos, people] A population within a species; anassemblage of potentially interbreeding individuals at agiven locality.demersal a. [L. de, away from; mergere, to plunge] Living onor near the bottom of a lake or sea.demibranchs n.pl. [Gr. demi, half; branchia, gills] (MOLL: Bivalvia)A pair of ciliated gill filaments composed of two flatlamellae (inner demibranch and outer demibranch) in whichthere are blood vessels that facilitate respiration and mucociliaryfeeding.demiplate n. [Gr. demi, half; OF. plate, flat] (ECHINOD) A reducedambulacral plate in a compound plate in the test.demiprovinculum n. [Gr. demi, half; pro, before; vinculum,bond] (MOLL: Bivalvia) One half of the median part of thehinge margin of the prodissoconch. see prodissoconch.Demospongiae n. [Gr. demos, multitude; spongos, sponge] Aclass of sponges composed of spongin fibers alone or togetherwith siliceous spicules that are differentiated intomegascleres (larger size) or microscleres (smaller size) ofdiverse shapes.denatant a. [L. de, away from; natare, to swim] Swimming,drifting or migrating with the current. see contranatant.dendriform a. [Gr. dendron, tree; L. forma, shape] Branchedlike a tree; dendroid.dendrite n. [Gr. dendron, tree] Neural aborizations or branchingfibrils that conduct impulses toward the neurocyte.dendritic a.dendritic see dendroiddendritic flame cells (ACANTHO) Central canal from whichmany smaller canals separate and end in pouches containingcilia.dendritic thickening (BRYO) Extreme skeletal thickening along

278Maggenti and Gardneraxes of colony branches.dendrobranch(ia) n. [Gr. dendron, tree; branchia, gills] (AR-THRO: Crustacea) A type of gill with lamellae divided intoarborescent bundles.dendrogram n. [Gr. dendron, tree; gramma, written character]Any branching, tree-like diagram designed to indicatedegrees of relationship.dendroid a. [Gr. dendron, tree; eidos, form] 1. Shrub-shaped;shaped like a small tree; dendriform. 2. (BRYO) A solid ramosecolony. 3. (PORIF) A sponge skeleton branching repetitivelywith little or no anastomosis between successivebranches.dendron see dendritedendrophagous a. [Gr. dendron, tree; phagein, to eat] Feedingon woody tissues.dendrophilous a. [Gr. dendron, tree; philein, to love] Living inwoody tissue, or on trees.denematize a. [L. de, away from; Gr. nematos, of thread] Todivest of nematodes.denizen n. [OF. denzein, one living within] Any animal that hasbecome naturalized.dens n.; pl. dentes [L. dens, tooth] 1. A tooth or tooth-likeprocess. 2. (ARTHRO: Insecta) a. In Collembola, the proximalsegment of the furcula (springing fork). b. Dentes=teeth or other pointed structures on the inner side of themandible.densariae n.pl. [L. dens, tooth] (ARTHRO: Insecta) Distinctthickenings of the margins of the incisurae of scale insects.density-dependent factors Factors (direct or inverse) whoseeffects on a population are dependent upon the density ofthat particular population.density-independent factors Factors whose effects on apopulation are not dependent upon the density of that particularpopulation.dentacerores n.pl. [L. dens, tooth; cera, wax; os, mouth](ARTHRO: Insecta) In coccoids, irregularities in the membranesurrounding the anus; denticulate pores.

Online Dictionary of Invertebrate Zoology 279dental plates (BRACHIO) Plates of secondary shell supportingthe hinge teeth on the ventral valve.dental sclerite (ARTHRO: Insecta) The sclerite at each side ofthe base of the mandibular sclerite of muscid larvae.dental sockets (BRACHIO) Excavations in the posterior marginof the brachial valve for reception of hinge teeth.dentate a. [L. dens, tooth] Toothed, or with tooth-like processes.dentatelirate a. [L. dens, tooth; lira, furrow] Having teeth andfine raised lines or grooves.dentate-serrate Teeth with serrated dentations on the edges.dentate-sinuate Teeth with a wavy indented margin.denticles n.pl. [L. denticulus, little tooth] 1. Small, tooth-likeprojections. 2. (ARTHRO: Crustacea) In cirripeds, toothleton the sutural edge of the radius of the compartment plate,or opposed buttress of adjoining plate. 3. (ANN: Polychaeta)The paragnaths. denticulate a.dentigerous ridges Elevations bearing small teeth or toothlikeprojections.dentition n. [L. dens, tooth] 1. All teeth including differentforms, sizes, etc. 2. (MOLL: Bivalvia) A collective term includinghinge teeth and sockets.denuded a. [L. de, away from; nudus, bare] Divested of allcovering.depauperate a. [L. de, away from; pauper, poor] 1. Impoverishingor exhausting. 2. Falling short of the natural size ordevelopment from being impoverished or starved. 3. (AR-THRO: Insecta) An impoverished or dying ant colony.deportation n. [L. de, away from; portare, to carry] (ARTHRO:Insecta) In social insects, the transport of adults or youngto a new nest.depressed a. [L. de, away from; pressus, bear down] 1.Pressed or kept down; sunken below the general surface.2. (MOLL: Gastropoda) Refers to a shell low in proportion todiameter.depressor n. [L. de, away from; pressus, bear down] Any

280Maggenti and Gardnermuscle that lowers or depresses any appendage.depressor ani (NEMATA) An H-shaped muscle that dilates therectum and elevates the posterior lip of the anus.depressor muscle crests (ARTHRO: Crustacea) In balanomorphbarnacles, elevated denticles or ridges on the innersurface of the tergum near the basicarinal angle for attachmentof the depressor muscles.depuration n. [L. de, away from; puratus, cleanse] The act ofcleansing; free from impurities.derived character Any character that differs materially fromthe ancestral condition.derma, dermis n. [Gr. derma, skin] 1. The layer of the cuticle,laminated in structure, beneath the epidermis. 2. (PORIF)The extreme outer surface layer of membrane or reinforcementby spicules and/or sand. dermal a.dermal cells see cellulaedermal glands 1. (ARTHRO: Crustacea) A cell or cells in theepidermis traversed by canals communicating with thesurface through fine ducts. 2. (ARTHRO: Insecta) Hypodermalunicellular glands which secrete wax, cement, pheromones,etc.dermalia n.pl. [Gr. derma, skin] (PORIF: Hexactinellida) Spiculesat or beneath the dermal surface.dermal pores see cellulaedermatoblasts n.pl. [Gr. derma, skin; blastos, bud] (ARTHRO:Insecta) In an embryo, the outer thin layer of cells whichform the ventral body wall. see neuroblasts.dermatozoon n. [Gr. derma, skin; zoion, animal] Any animalparasitic on the skin.dermis n. [Gr. derma, skin] (PORIF) The skinlike external covering.dermoptic sense The response of an animal to light or shadowafter removal of eyes and other photosensors.dermosclerites n.pl. [Gr. derma, skin; skleros, hard] (CNID:Anthozoa) Calcareous spicules (sclerites) of alcyonariancoral polyps, produced by scleroblasts embedded in the

Online Dictionary of Invertebrate Zoology 281mesoglea or stolons (or both) or in the coenenchyma connectingthe polyps.dermoskeleton n. [Gr. derma, skin; sketeto, dried hard] Theexoskeleton.descending a. [L. de, away from; scandere, to climb] Directeddownwards or caudad; detrorse.desclerotization n. [L. de, away from; Gr. skleros, hard] Areduction of sclerotin in sclerotized parts or structures.description n. [L. describere, to delineate] In taxonomy, amore or less complete formal statement of the charactersof a taxon without delimiting it from coordinate taxa. seedelimitation, diagnosis, differential diagnosis.desegmentation n. [L. de, away from; segmentum, piece]The fusion of segments formerly separated.deserticolous a. [L. desertum, a waste place; colere, to inhabit]Desert-inhabiting.desiccate v. [L. desiccare, to dry up] To dry up; a process ofpreserving.desiccation n. [L. desiccare, to dry up] An inactive dry state ofvarious invertebrates, directly referable to extreme, dryconditions.desma n.; pl. -mata [Gr. desmos, bond] (PORIF:Demospongiae) In Lithistida, branched, irregular interlockingmegascleres consisting of layers of silica irregularly depositedon ordinary spicules.desmacyte n. [Gr. desmos, bond; kytos, container] (PORIF)Long slender cells in the cortex and around the internalchannels; fiber cells.desmen n.pl. [Gr. desmos, bond] (NEMATA: Adenophorea)Transverse rings around the bodies of Desmoscolecida;concretion rings.desmergate n. [Gr. desmos, bond; ergates, worker] (ARTHRO:Insecta) A form of ant intermediate between the typicalworker and the soldier; can also be used to designate theintermediate forms between the large and small workers incertain genera.desmoneme n. [Gr. desmos, bond; nema, thread] (CNID: Hy-

282Maggenti and Gardnerdrozoa) A small nematocyst of hydras with a short unarmedspirally coiled tubule, which functions in entanglingand wrapping around bristles of prey; volvent.desmosome n. [Gr. desmos, bond; soma, body] 1. That portionof a cell membrane specialized for adhesion to aneighboring cell. 2. (ARTHRO: Insecta) An attachment areabetween epidermal and muscle cells; the muscle fibrils ofthe muscles attach on one side and the epidermal microtubulesattach on the other side of the desmosome. seehemidesmosome, tonofibrillae.Desmospongiae n. [Gr. desmos, bond; spongos, sponge] Aclass of sponges encompassing 90% of all existing spongeswith ancestory tracing back to simple Cambrian sponges(500 million years).Desor's larva (NEMER) Oval ciliated postgastral stage (in theegg) of Lineus ; develops like the pilidium larva.desquamation n. [L. de, away from; squama, scale] Peelingor scaling off of cuticle or epidermis in flakes.desynapsis n. [L. de, away from; Gr. synaptos, joined together]Separation of paired chromosomes during the diplotenephase of the first meiotic division; desyndesis; deconjugation.see asynapsis.desyndesis see desynapsisdeterminant n. [L. de, away from; terminus, limit] A hypotheticalunit of inheritance.determinate a. [L. de, away from; terminus, limit] Havingwell-defined outlines or boundry limits.determination n. [L. de, away from; terminus, limit] A processthat initiates a specific pathway of development amongthose that are available to the cell or embryo.detorsion n. [L. de, away from; torquere, to twist] 1. Theprocess of twisting back or removing torsion; unwinding. 2.(MOLL: Gastropoda) A term used to describe the reversal oftorsion. see orthoneury, torsion.detoxification, detoxication n. [L. de, away from; toxicum,poison] Removal of toxic materials by metabolizing them.detriophagous a. [L. detritus, worn away; Gr. phagein, to eat]

Online Dictionary of Invertebrate Zoology 283Feeding on detritus.detritivore n. [L. detritus, worn away; vorare, to devour] Anyorganism that feeds on detritus. detritivorous a.detritus n. [L. detritus, worn away] An aggregate of fragmentarymaterial, such as decomposing parts of plants andanimals.detrorse a. [L. de, away from; versus, turn] Directed downward.see antrorse, retrorse.deuterocerebrum see deutocerebrum, mesocerebrumdeuterostome n. [Gr. deuteros, second; stoma, mouth] Truecoelomates with radial cleavage of the egg, the blastoporebecoming the anus, the coelom formed by enterocoely, includingEchinodermata, Chaetognatha, Hemicordata andChordata. see protostome.deuterotoky n. [Gr. deuteros, second; tokos, birth] Parthenogeneticreproduction in which progeny of both sexes areproduced from female gametes. see arrhenotoky, thelyotoky.deutocerebral commissure (ARTHRO) The connection betweenthe sensory neuropiles on both sides of the brain.deutocerebral region (ARTHRO) That portion of a brain dividedinto dorsal sensory and ventral motor areas.deutocerebrum n. [Gr. deuteros, second; L. cerebrum, brain](ARTHRO) The median region of a brain which receives theantennal nerves (first antennae in crustaceans, see mesocerebrum)and contains their association centers; lacking inchelicerates (scorpions, spiders and mites). deuterocerebrala.deutogyne n. [Gr. deuteros, second; gyne, woman] A femaleof a species which is morphologically different from theprimogyne and has no male counterpart. see protogyne.deutomalae n.pl. [Gr. deuterous, second; malon, cheek] 1.(ARTHRO: Symphyla) The second pair of mouth appendagesin certain myriapods. 2. (CHAETO) A broad plate formed bythe fusion of the second pair of mouth appendages.deutonymph n. [Gr. deuteros, second; nymphe, chrysalis](ARTHRO: Chelicerata) The second stage nymph of arach-

284Maggenti and Gardnernids.deutoplasm, deuteroplasm n. [Gr. deuteros, second;plasma, formed or molded] A substance other than the nucleusand cytoplasm in a cell, esp. yolk in an egg cell;metaplasm. see energid.deutoscolex see pseudoscolex proscolexdeutosternum see subcapitular gutterdeutovum n. [Gr. deuteros, second; L. ovum, egg] (ARTHRO:Chelicerata) a. The resting, incompletely developed stagefollowing the shedding of the chorion of the egg of mitesand spiders. b. A prelarva. c. The second egg.development n. [F. developper, to unfold] The progressiveproduction of the phenotypic characteristics of an organism.developmental cycle (ARTHRO: Insecta) The period betweenthe laying of an egg and eclosion of the adult from the pupalcase.developmental homeostasis The ability to produce a normalphenotype in spite of developmental or environmental disturbances.deviate n. [L. de, away from; via, way] Any animal which differsfrom corresponding developmental stages of others ofthe same species.devolution n. [L. de, away from; evolvere, to unroll] Retrogradedevelopment; degeneration.De Vriesianism Hypothesis that evolution in general, andspeciation in particular, are the results of drastic mutation.see saltation.dexiotorma n.; pl. -mae [Gr. dexios, on the right; torma,socket] (ARTHRO: Insecta) 1. A small sclerotic ring ofscarabaeoid larvae, extending inward from the epipharynx,occasionally bearing a heel-shaped pternotorma. 2. Theright torma.dexiotropic a. [Gr. dexios, on the right; trope, turn] A rightturning spiral, as in shells.dextral a. [L. dexter, right] Right-handed; to the right of themedian line.

Online Dictionary of Invertebrate Zoology 285dextral gastropods (MOLL) A gastropod with genitalia on theright side of the head-foot mass or pallial cavity; commonlythe shell, when viewed with the apex uppermost, has theaperture on the right. see sinistral gastropods.dextron a. [L. dexter, right] Pertaining to the right side of thebody.dextrorse a. [L. dexter, right; vertere, to twist] An organismspirally twisting to the right. see sinistrorse.diacresis see diaeresisdiactinal a. [Gr. dis, twice; aktis, ray] Being pointed at bothends.diactinal monaxon (PORIF) A monaxon that develops bygrowing in both directions, while originating from a centralpoint; diactine; rhabdus.diactine see diactinal monaxondiaene n. [Gr. dis, twice; triaina, trident] (PORIF) A form of triaeneproduced by loss of one ray from the cladome.diaeresis n. [Gr. diairein, to divide] (ARTHRO: Crustacea) Atransverse groove on the posterior part of an exopod(rarely endopod) of a uropod appendage; occasionally dividingthe exopod into two movable parts.diagenodont teeth (MOLL: Bivalvia) Having differentiated cardinalteeth (up to 3) and lateral teeth (up to 2) on thehinge plate.diagnosis n.; pl. -noses [Gr. diagignoskein, to distinguish] Aformal statement of the characters distinguishing one taxonfrom closely related taxa.diagnostic a. [Gr. diagignoskein, to distinguish] Uniquelycharacterizing a taxon.diagonal ridge (MOLL: Bivalvia) A ridge running diagonallyfrom the umbo toward the posteriolateral margin of thevalve.diakinesis n. [Gr. dia, through; kinesis, movement] The finalstage of prophase in the first meiotic division; paired, contractedchromosomes with the disappearance of nucleolusand nuclear envelope.

286Maggenti and Gardnerdialyneury n. [Gr. dialyein, to reconcile; neuron, nerve](MOLL: Gastropoda) Having zygoneural connections on bothleft and right sides.dialysis n.; pl. dialyses [Gr. dia, through; lyein, to loose]Separation of dissolved crystalloids and colloids through asuitable membrane.dialyzate, dialysate n. [Gr. dia, through; lyein, to loose] Usedfor both the material that will and will not diffuse through amembrane.diamorph n. [Gr. dia, through; morphe, form] (PORIF) A cellmass of spherical form and a continuous pinacodermformed as a result of aggregation of dissociated cells.diapause n. [Gr. dia, through; pausis, a stopping] A quiescentphase during the development of an organism in whichmost physiological processes are suspended; maybe optional,obligatory or internally controlled. see amphodynamous.diaphanous a. [Gr. dia, through; phanos, light] Showing lightthrough its substance; transparent; translucent; clear.diaphragm n. [Gr. diaphragma, partition, wall] 1. Any of thehorizontal dividing membranes of a body cavity. 2. Astructure controlling admission of light through an aperture.3. (ARTHRO: Insecta) a. In Heteroptera, separatingthe general body cavity from the genital chamber. b. InLepidoptera, that which closes the body cavity caudally,comprised of dorsally the fultura superior and ventrally thefultura inferior. 4. (BRYO) a. In Stenolaemata, the membranousor skeletal partition which extends transverslyacross the entire zooidal chamber. b. In Gymnolaemataautozooids, the muscular ring of the body wall. 5. (CNID:Hydrozoa) A delicate chitinous floor that supports the hydranth.6. (ECHI) A thin-walled, funnel-like septum incompletelyseparating an anterior or peripharyngeal coelomfrom the general body cavity.diapolar cells (MESO) Ciliated somatodermal cells located betweenthe parapolar and uropolar cells; trunk cells.diarhyses n.pl. [Gr. dis, twice; rhysus, delivering] (PORIF:Hexactinellida) Radial canals that run through the skeletal

Online Dictionary of Invertebrate Zoology 287wall and have a single flagellated chamber.diarthrosis n. [Gr. dis, twice; arthron, joint] An articulationthat permits free movement. diarthrodial a.diarticular a. [Gr. dis, twice; articulus, joint] Said of, or pertainingto two joints.diastase, diastatic see amylasediastole n. [Gr. diastole, difference] The regular expansion ofthe heart during which it fills with blood; the relaxatoryphase. diastolic a. see systole.diastomian a. [Gr. dia, through; stoma, mouth] (ARTHRO: Insecta)Pertaining to the orifice, (excluding ostiole), of themetathoracic scent gland of Heteroptera, consisting of apair of relatively widely spaced openings. see omphalian.diastomatic a. [Gr. dia, through; stoma, mouth] Through thestomata or pores.diathesis n. [Gr. dia, through; thesis, position] An inheritedconstitutional state whereby an individual is especially vulnerableto a certain type of reaction, disease or development.diatom rake (ARTHRO: Insecta) A structure of the galea ofmayfly nymphs composed of bristles and pectinated spines,or of hairs or spines on the maxillae, functioning in scrapingfood.diaulic a. [Gr. dis, twice; aulos, pipe] 1. With two separateducts open to the surface. 2. (MOLL: Gastropoda) Male andfemale portions with separate gonopores. see monaulic,triaulic.di-axial (ARTHRO: Chelicerata) Pertaining to chelicerae of spiderswith the paturon projecting either forward or downwith the fangs moving inward towards each other. see paraxial.diaxon n. [Gr. dis, twice; axon, axis] Having two axes or twoaxis-cylinder processes.diblastula n. [Gr. dis, twice; blastos, bud] (CNID) A coelenterateembryo consisting of 2 layers arranged around a centralcavity.dibranchiate a. [Gr. dis, twice; branchia, gills] Having two

288Maggenti and Gardnergills.dicentric a. [Gr. dis, twice; kentron, midpoint of a circle] Havingchromosomes or chromatids with two centromeres.dicerous, dicerus a. [Gr. dis, twice; keros, horn] Having twohorns, tentacles or antennae.dichogamy n. [Gr. dicha, in two; gamos, marriage] The productionof male and female gametes at different times inan hermaphroditic organism; protogynous and protandroushermaphrodites. dichogamous a. see homogamy.dichopatry n. [Gr. dicha, in two; L. patria, native country]Populations geographically separated to the extent that individualsof the involved species never meet. see parapatricspeciation.dichoptic a. [Gr. dicha, in two; ops, sight] Having eyes separateddorsally by integument. see holoptic.dichotomize v.t. & i. [Gr. dicha, in two; temnein, to cut] Tocut into two parts; to divide into pairs.dichotomous a. [Gr. dicha, in two; temnein, to cut] Divided ordividing into two parts; successive bifurcation; two-forked.dichotomy n.dichotriaene n. [Gr. dicha, in two; triaina, trident] (PORIF) Atetractinal megasclere with forked clads.dichroism n. [Gr. dis, twice; chros, color] The property ofshowing two very different colors, one by transmitted lightand the other by reflected light, or as some dyes stainingdifferent tissues different colors.dichromatic a. [Gr. dis, twice; chroma, color] 1. Having twocolor varieties. 2. Seeing only two colors.dichthadiform ergatogyne (ARTHRO: Insecta) In army ants,an individual of an aberrant reproductive caste, characterizedby a wingless alitrunk, large gaster, and expandedpostpetiole.dichthadiigyne n. [Gr. dichthadios, double; gyne, female](ARTHRO: Insecta) A permanently wingless ant with greatlyreduced eyes, massive pedicel, abdomen and ovaries, andstrong legs.dicondylic a. [Gr. dis, twice; kondylos, knuckle] Pertaining to

Online Dictionary of Invertebrate Zoology 289an articulation with two condyles; bicondylar.dicostalia see secundibractsdicranoclone n. [Gr. dikranon, pitchfork; klon, twig] (PORIF) Amegasclere spicule having a desma with swollen terminalcouplings.dictyonal framework (PORIF) Spicules fused together into arigid framework.dictyonine n.; pl. dictyonalia [Gr. diktyon, net] (PORIF: Hexactinellida)Rays of regular hexactines fused at their tips toform a more or less regular three dimensional network.dictyosome n. [Gr. diktyon, net; soma, body] The flattenedset of membranes resembling a stack of plates found in aGolgi body.dicyclic a. [Gr. dis, twice; kyklos, circle] (ECHINOD: Crinoidea)Calyx plates of primitive stalked crinoids that have an additionalfive infrabasal plates on the aboral side of the basalseries found in the monocyclic condition; further platesmay be present.didactyl a. [Gr. dis, twice; daktylos, finger] Having two tarsi ofequal length. didactyl n.; didactylism n.; didactylous a.didelphic a. [Gr. dis, twice; delphys, womb] Having two uteri.see amphidelphic.diductor muscles (BRACHIO) Two pairs of muscles that openvalves of articulates, commonly attached to brachial valveimmediately anterior to beak; principal pair usually insertedin pedicle valve on either side of adductor muscles withposterior accessory pair.didymous a. [Gr. didymos, double] Formed in pairs; twin;double.diecdysis n. [Gr. dia, through; ekdysis, escape from molt]Condition in which ecdysial processes are going on continuouslyand one ecdysis cycle passes rapidly into another.diecious see dioeciousdiel a. [L. dies, day] Occurring in a 24 hour period.dietella n.; pl. -ae (BRYO) Large laterobasal pore chamber thatfunctions in interzooidal communication. see pore cham-

290Maggenti and Gardnerbers.differentia n.; pl. -tiae [L. differentia, difference] The specificdifference of one species from other species of the samegenus.differential diagnosis A statement of characters distinguishinga given taxon from other specifically mentionedequivalent taxa. see delimitation.diffracted a. [L. dis, twice; frangere, to break] 1. Bent in differentdirections. 2. Separated into parts.diffusate n. [L. diffusus, spread out] Material that diffusesthrough a semi-permeable membrane; dialyzate.diffuse a. [L. diffusus, spread out] 1. Not sharply distinct atthe edge or margin. 2. Widely spread; extended. 3. (MOLL:Gastropoda) The aperture when spread out or widened.diffusion n. [L. diffusus, spread out] The spreading of a dissolvedsubstance through solvent by virtue of the randommovements of its molecules or ions.diffusion tracheae (ARTHRO: Insecta) Cylindrical tracheae notsubject to collapse. see ventilation tracheae.digametic see heterogameticdigenesis n. [Gr. dis, twice; genesis, beginning] Alternation ofgenerations.digenetic a. [Gr. dis, twice; genesis, beginning] With sexualreproduction in the mature forms and asexual reproductionin larval stages.digenoporous a. [Gr. dis, twice; genos, birth; poros, passages]Having two genital pores.digestion n. [L. digestus, render food assimilable] The processby which nutrient materials are rendered soluble and absorbablefor incorporation into the metabolism.digit n. [L. digitus, finger] A finger or finger-like structure; atoe.digital a. [L. digitus, finger] Digit-like.digitated a. [L. digitus, finger] Fingered or clawed; divided intofinger-like processes.digitate processes (SIPUN) Finger-like processes or leaf-like

Online Dictionary of Invertebrate Zoology 291projections originating at the dorsal surface of the brain.digitation n. [L. digitus, finger] (MOLL: Gastropoda) The fingerlike,outward projection from the outer lip of the shell.digitelli n.pl. [L. dim. digitus, finger] (CNID: Scyphozoa) Tentacle-likegastric filaments on the inner edge of each septum.digitiform a. [L. digitus, finger; forma, shape] Shaped like, orfunctioning like a finger.digitules n. [L. digitulus, little finger] (ARTHRO: Insecta) Appendagesin the form of dilated or knobbed hairs on thefeet of scale insects. see empodium.digitus n.; pl. -ti [L. digitus, finger] 1. A digit. 2. (ARTHRO: Insecta)a. The dactylus. b. In Hymenoptera genitalia, acurved or hooked, strongly muscled process projectingfrom the vosellar plate, movably opposed to the cuspis.diglyphic a. [Gr. dis, twice; glyphein, to engrave] (CNID: Anthozoa)In sea anemones, having two siphonoglyphs: onesiphonoglyph= sulcus; two siphonoglyphs= sulculus.dignathan a. [Gr. dis, twice; gnathion, jaw] (ARTHRO) Havingmandibles and one pair of maxillae, such as Pauropoda andDiplopoda. see trignathan.digoneutic a. [Gr. dis, twice; goneuein, to produce] Havingtwo broods in one year. digoneutism n.digonic a. [Gr. dis, twice; gone, seed] Sperm and ova are producedin separate gonads of the same individual. see syngonic,amphigonic.dikont a. [Gr. dis, twice; kontos, punting pole] Biflagellate.dilacerate v.t.; -ated [L. dis, apart; lacera, torn] To tear topieces; tear apart.dilatated a. [L. dilatus, spread] Having a wide margin; flattened;expanded; widened.dilate v.t. [L. dilatus, spread] To expand or distend.dilator n. [L. dilatus, spread] A muscle that functions to dilate.dilator valve (NEMATA) Ventrolateral hypodermal muscles thatfunction to open the vulva. see constrictor valve.dilute a. [L. dilutus, mixed] Being diluted; thin; weak.

292Maggenti and Gardnerdimeric a. [Gr. dis, twice; meros, part] 1. Having two parts. 2.Bilaterally symmetrical.dimerous a. [Gr. dis, twice; meros, part] 1. Composed of twoparts. 2. Having two tarsal segments.dimidiate a. [L. dimidius, half] 1. Divided into two equal parts.2. Only one-half the normal development. 3. (ARTHRO: Insecta)Having an elytra that covers only half the abdomen.dimorph n. [Gr. dis, twice; morphe, form] An individual displayingdimorphism.dimorphism n. [Gr. dis, twice; morphe, form] A morphologicaldifference in form, color, size or sex in a single population.dimorphic a. see sexual dimorphism, polymorphism.Dimyaria n.pl. [Gr. dis, twice; mys, muscle] (MOLL: Bivalvia)Taxon sometimes used to include those bivalve molluskswhose shells are closed by two adductor muscles;dimyarian, dimyaric a.; dimyarian a. & n.dinergate n. [Gr. deinos, terrible; ergates, worker] (ARTHRO:Insecta) A soldier ant, characterized by a huge head andmandibles (for defense) and a thoracic structure sometimesthe size of the female, or in the development of itssclerites.dinergatogyne n. [Gr. deinos, terrible; ergates, worker; gyne,woman] (ARTHRO: Insecta) A mosaic form in ants, combiningthe characteristics of a dinergate and a ergatogyne.dinergatogynomorph n. [Gr. deinos, terrible; gyne, woman;morphe, form] (ARTHRO: Insecta) In ants, any individual inwhich female characteristics alternate with worker and soldier.dinophthisergate n. [Gr. deinos, terrible; phthisis, decline;ergates, worker] (ARTHRO: Insecta) In ants, a soldierworkerpupal mosaic that fails to progress to the adultstage due to parasitism or other interference.dioecious a. [Gr. dis, twice; oikos, house] Separate sexes;males and females being different individuals; gonochoristic;unisexual; opposed to monoecious.dioptrate a. [Gr. dis, twice; ops, eye] Having eyes or ocelli dividedby a septum or line.

Online Dictionary of Invertebrate Zoology 293dioptric a. [Gr. dis, twice; ops, eye] Refractive; vision by refractionof light.diorchic a. [Gr. dis, twice; orchis, testicle] Having two testes.see monorchic.diphagous parasitoid (ARTHRO: Insecta) In Hymenoptera, aspecies in Adelinidae in which the male (parasitoid) andfemale inhabit the same host species, but both feed differently.see heterotrophic parasitoid, heteronomous hyperparasitoid.diphygenetic a. [Gr. diphyes, twofold; genesis, beginning]Producing two different types of embryos.diphyletic a. [Gr. dis, two; phyle, race) Pertaining to animalswhich are derived from two ancestral lines.dipleurula n. [Gr. dis, twice, dim. pleuron, side] (ECHINOD)Collective term applied to planktonic bilaterally symmetrical,ciliated larvae; echinopaedium. see auricularia, doliolaria,pluteus, bipinnaria larva.diplobiont n. [Gr. diploos, twofold; bionai, to live] An organismwith two morphologically distinct haploid and diploidgenerations. see haplobiont.diploblastic a. [Gr. diploos, twofold; blastos, bud] Having twoembryonic germ layers, ectoderm and endoderm.diplocotylea cercaria (PLATY: Trematoda) An amphistomecercaria with a pigmented anterior end. see pigmentacercaria.diplodal a. [Gr. diploos, twofold; hodos, way] (PORIF) Leuconoidsponges with narrow canals leading into and out of theflagellated chambers. see aphodus, prosodus.diploergate n. [Gr. diploos, twofold; ergates, worker] (AR-THRO: Insecta) A mosaic ant showing characteristics ofboth major and media workers.diplogangliate a. [Gr. diploos, twofold; ganglion, ganglion]With paired ganglia.diploid a. [Gr. diploos, twofold] Having dual (2n) chromosomes,the normal number of cells in all but the maturegerm cells in any individual derived from a fertilized egg.see duplex, haploid, polyploid, chromosome.

294Maggenti and Gardnerdiplokaryon n. [Gr. diploos, twofold; karyon, nut] The nucleusof the zygote containing two diploid genomes. see amphikaryon.diplonema a. [Gr. diploos, twofold; nema, thread] Whenchromosome tetrads begin separation, resulting in chiasmataat the points of cross over; sometimes used to denotediplotene stage.diploneural a. [Gr. diploos, twofold; neuron, nerve] Having adouble nerve supply.diplont n. [Gr. diploos, twofold; on, being] An organism withdiploid somatic cells and haploid gametes. see haplont.diplophase n. [Gr. diploos, twofold; phasis, state] Diploidphase in the life cycle of an animal (fertilization to meiosis);diplotene stage in the prophase of meiosis; zygophase.see haplophase.Diplopoda, diplopod n. [Gr. diploos, twofold; pous, foot] Aclass of arthropods, commonly called millipedes, having thebody somites fused into diplosegments, each with two pairsof legs.diplosegment n. [Gr. diploos, twofold; L. segmentum, piece](ARTHRO: Diplopoda) Fusion of two body segments resultingin a segment with two pairs of legs each; a diplosomite.diplosome n. [Gr. diploos, twofold; soma, body] A doublecentrosome; paired centrioles.diplosomite n. [Gr. diploos, twofold; soma, body] (ARTHRO:Diplopoda) A diplosegment. see prozonite, metazonite.diplostenoecious a. [Gr. diploos, twofold; stenos, narrow;oikos, house] Pertains to the phenomena of certain speciesoccurring in two contrasting habitats.diplostichous a. [Gr. diploos, twofold; stichos, line] 1. Arrangedin two rows or series. 2. (NEMATA: Adenophorea) InMermithida, the stichosome.diplostomulum n. [Gr. diploos, twofold; L. dim. stoma,mouth] (PLATY: Trematoda) Strigeoid metacercaria in thefamily Diplostomatidae.diplotene a. [Gr. diploos, twofold; tainia, ribbon] The fourthstage of meiotic prophase one when paired chromatids be-

Online Dictionary of Invertebrate Zoology 295gin to separate. see diplonema.diplozoic a. [Gr. diploos, twofold; zoon, animal] Bilaterallysymmetrical.dipneumonous a. [Gr. dis, twice; pneumon, lung] Having twolungs.diporpa n. [Gr. dis, twice; porpe, buckle] (PLATY: Trematoda)A larval stage in the life cycle of the monogean Diplozoonthat permanently unites with another.dipterocecidium n. [Gr. dis, twice; pteron, wing; dim. kekis,gall] (ARTHRO: Insecta) A gall formed by any dipterous insect.dipterous a. [Gr. dis, twice; pteron, wing] (ARTHRO: Insecta)Belonging to the insect order Diptera.direct eyes (ARTHRO: Chelicerata) The anterior median pair ofeyes in spiders.directive mesentaries (CNID: Anthozoa) In Zoantharia, thedorsal and ventral pairs of specialized mesentaries attachedto the siphonoglyph.directive rib (MOLL: Bivalvia) A rib on the shell surface lying ina single plane.directive spiral (MOLL: Bivalvia) A directive rib that is spiral ina single plane.direct metamorphosis see incomplete metamorphosisdirect wing muscles (ARTHRO: Insecta) The axillary and dorsalmuscles of a wing.disaccharides n.pl. [L. dis, twice; saccharum, sugar] A carbohydratewhich can be hydrolized into two monosaccharides.disc, disk n. [L. discus, circular plate] 1. Any flattened part inthe form of a disc. 2. Circumoral area of many animals. 3.(ARTHRO: Insecta) In Coleoptera, the general dorsal surfaceof the elytra, usually marked by longitudinal striae correspondingto a row of sclerotized pillars connecting the upperand lower faces of the elytra. 4. (ECHINOD: Asteroidea)The central part of the body. 5. (MOLL: Bivalvia) The wholevalve exclusive of the auricles in Pectinacea. discal a.discal area (ARTHRO: Insecta) In wings, the central area or

296Maggenti and Gardnerarea covered by the discal cell.discal bristle (ARTHRO: Insecta) In Diptera, one or more pairsof bristles in the mid-dorsal wall of the abdominal segment.discal cell (ARTHRO: Insecta) A cell in the basal or central partof the wings.discal cross vein (ARTHRO: Insecta) A cross vein behind thediscal cell in a wing.discal elevation (ARTHRO: Insecta) In Hemiptera, the centralarea of the anterior wing raised above the surroundinglevel.discal patch (ARTHRO: Insecta) In male hesperoid butterflies,conspicuous patches, tufts, or brushes of modified scales,sometimes contained in eversible folds of the anterior wing.discal scutellar bristles see dorsoscutellar bristlesdiscal seta (ARTHRO: Insecta) Large seta on the dorsal surfaceof the operculum.discal vein (ARTHRO: Insecta) In Lepidoptera, a crossveinclosing the discal or median cell of the wing.disciform a. [L. discus, circular plate; forma, shape] Havingthe shape of a plate or disc; discoid.discinid n. [L. discus, circular plate] (BRACHIO:Inarticulata) Aplanktonic bivalve larva with round valves, and five pairs ofmajor setae, the fourth of which is larger than the others.discleritous a. [L. dis, twice; Gr. skleros, hard] (ARTHRO) Pertainingto tergites and sternites being distinct and separate.see synscleritous.discocellular vein (ARTHRO: Insecta) The discal vein.discoctasters n.pl. [Gr. diskos, circular plate; okto, eight; aster,star] (PORIF) Spicules containing 8 rays terminating indisks; discooctasters.discodactylous a. [Gr. diskos, circular plate; daktylos, finger]Having a sucker at the end of a digit.discohexaster n. [Gr. diskos, circular plate; hex, six; aster,star] (PORIF) A spicule with 6 rays meeting at right anglesand terminating in discs; the individual rays may bebranched.

Online Dictionary of Invertebrate Zoology 297discoid a. [Gr. diskos, circular plate; eidos, form] 1. Flat andcircular; disc-like; disciform; discous. 2. (MOLL) Certainunivalve shells with whorls coiled in one plane.discoidal a. [Gr. diskos, circular plate: eidos, form] 1. Approachinga disc in form. 2. (MOLL: Gastropoda) Convoluteor involute and more or less flattend, as the spire of ashell.discoidal area 1. The middle area of an organ. 2. (ARTHRO: Insecta)The middle of a wing; discoidal field.discoidal areolets see discal cellsdiscoidal cell (ARTHRO: Insecta) 1. An outstanding cell of awing. 2. In Odonata, the quadrilateral. 3. In Diptera, themedian cell.discoidal crossvein see discal cross veindiscoidal field see discoidal areadiscoidal triangle see trianglediscoidal vein (ARTHRO: Insecta) 1. In Hymenoptera, the veinforming a continuation of the median vein beyond the endof the transverse median vein, and extending along theposterior margin of the first discoidal cell. 2. In Orthoptera,the first and largest branch of the humeral vein. 3. In Diptera,the media 2 . 4. The anterior intercalary vein.discolor, discolour n. [L. discolor, of different colors] Changeof color; more than one color.discontinued varices (MOLL: Gastropoda) Varices of shellformation when revolution is not in a straight line withthose of the next.discontinuous variation Phenotypic variation in an animalpopulation in which the characters do not grade into eachother; qualitative inheritance. see continuous variation.discooctasters see discoctastersdiscordent margins (MOLL: Bivalvia) Valve margins notmatching, but overlapping one another.discorhabd n. [Gr. diskos, circular plate; rhabdos, rod] (PORIF)A linear spicule with disc-like outgrowths arising from astraight axis.

298Maggenti and Gardnerdiscota n. [Gr. diskos, circular plate] (ARTHRO: Insecta) Adultdevelopment from imaginal discs in the embryo. see adiscota.discotriaene n. [Gr. diskos, circular plate; triaina, trident](PORIF) A tetractinal spicule with three rays flattened flushin one plane with a short pointed fourth axis.discrepant a. [L. discrepantia, discordancy] Discordant; disagreeing;different.discrete a. [L. discretus, separated] Well separated; applied todistinct parts.discrimen n. [L. discrimen, division] (ARTHRO: Insecta) A medianlongitudinal sulcus with an internal ridge running alongthe middle of the sternum.discus n. [L. discus, circular plate] A flat circular structure,part or area.disease n. [L. dis, without; F. aise, comfort] An alteration offunction or structure of a tissue or organ or of an organism;sickness; malady; impaired health.disjugal furrow (ARTHRO: Chelicerata) Pertaining to the furrowseparating the prosoma and opisthosoma of mites.disjunct a. [L. disjunctus, disunited] 1. Pertaining to separationof parts or formed into groups. 2. (ARTHRO: Insecta)Having the head, thorax and abdomen set off by constrictions.3. (MOLL: Gastropoda) Whorls of a shell not touchingeach other.disjunction n. [L. disjunctus, disunited] Separation of daughterchromosomes during anaphase of mitosis and meioticdivision.disjunct pallial line (MOLL: Bivalvia) A pallial line broken upinto unequal muscle attachments.disk see discdislocate v.t. [L. dis, without; locus, place] To move out of itsproper place, as when stria bands or lines are in discontinuity.disomic a. [Gr. dis, twice; soma, body] Cells or individuals inthe 2n condition; cells in the n+1 condition.

Online Dictionary of Invertebrate Zoology 299dispersal n. [L. dispergere, to disperse] 1. The act or result ofscattering. 2. The scattering or distribution of organisms inthe biosphere.displacement n. [OF. desplacier, to displace] An abnormal positionof any part due to shifting from its normal position.disposed a. [L. dis, away from; ponere, to place] Distributing,arranged or laid out.dissect v. [L. dissecare, to cut open] 1. To divide or separateinto parts; to cut into pieces for examination. 2. To analyze,to examine.disseminule n. [L. dis, away from; seminare, to sow] One whooriginates colonization.dissepiment(s) n.; n.pl. [L. dissaepire, to separate] 1. A partitioningwall; a septum. 2. (ARTHRO: Insecta) a. The septaof an embryo, separating the coelom-sacs. b. The enclosingmembrane of an obtect pupa. 3. (CNID: Anthozoa) A transversecalcareous plate or partition between the radiatingsepta of coral. 4. (SIPUN) A series of peritoneal tissue situatedtransversely across the coelom.dissilient a. [L. dissilire, to burst asunder] Bursting or springingopen.dissimilation see catabolismdissoconch n. [Gr. dissos, double; konche, shell] (MOLL) Theshell of a second stage larva.dissogeny, dissogony n. [Gr. dissos, double; genos, descent](CTENO) A form of reproduction in an animal of sexual maturityin the larval stage and again as an adult.distacalypteron see antisquamadistad adv. [L. distare, to stand apart] Away from the body, orfrom point of attachment; toward the end farthest from thebody.distadentes n.pl. [L. distare, to stand apart; dentis, tooth] Thedentes distad on the mandible.distal a. [L. distare, to stand apart] Pertaining to any part of astructure farthest from midline of the body or base of attachment;opposed to proximal.

300Maggenti and Gardnerdistal bud (BRYO: Gymnolaemata) The bud arising from thedistal side of the vertical wall of the parent zooid. seebasal bud.distal cell (ARTHRO: Insecta) The cell bounded by the branchesof the crossveins in a wing.distalia n.pl. [L. distare, to stand apart] (ARTHRO: Insecta) Thesegments of an antenna excluding the scape and pedicel.distal process The peripheral process of a sensory nerve cell.distal tubes see marginal tubesdistich n. [Gr. distichos, of two rows] 1. Two vertical rows; tworanked. 2. (NEMATA: Adenophorea) In Mermithida, the stichosomeesophagus with a row of gland cells on either sideof the esophagus and external to it; diplostichous. distichousa. see monostich, stichosome.distichous antennae (ARTHRO: Insecta) Pectinate antennaewith processes issuing from each joint and bending forwardat acute angles.distiproboscis n. [L. distare, to stand apart; proboscis, trunk]The enlarged distal portion of a proboscis.dististipes n. [L. distare, to stand apart; stipes, stock] (AR-THRO) The distal part of the maxillary stipes.dististylus n.; pl. -li [L. distare, to stand apart; Gr. stylos,pillar] (ARTHRO: Insecta) In Culicidae, the distal segment ofthe gonopods; clasp filament.Trema-distome n. [Gr. dis, double; stoma, mouth] (PLATY:toda) A fluke with an oral and ventral sucker.distribution n. [L. distributus, allot, divide] Range of an organismor group of organisms in space and time.ditaxic foot (MOLL: Gastropoda) Foot of Pomatiasidae, dividedby a transverse sulcus (groove-furrow) at about its anteriorthird.Dithra see Bivalviaditrochous a. [Gr. dis, twice; trochis, runner] (ARTHRO: Insecta)Pertaining to Hymenoptera having a two-segmentedtrochanter.diuresis a. [Gr. dia, through; ouron, urine] Pertaining to urine

Online Dictionary of Invertebrate Zoology 301excretion in excess of the usual amount, directly referableto drinking, eating or certain metabolites.diurnal a. [L. diurnus, of the day] Pertaining to animals activeonly during the daytime. see nocturnal, crepuscular.diurnal eyes (ARTHRO: Chelicerata) In spiders, eyes that aredark in color.diurnal rhythm Having a 24 hour periodic cycle. see circadian.divaricate a. [L. divaricatus, spread apart] 1. Forked or dividedinto branches; diverging. 2. (MOLL: Bivalvia) Pertainsto ornamentation consisting of widely divergent costulae orother shell ornamentation.divaricator n. [L. divaricatus, spread apart] 1. A muscle whichcauses parts to open. 2. (BRACHIO) A muscle from theventral valve to the cardinal process which opens the shell.3. (BRYO) One of a pair of muscles which open the mandiblefor an avicularium or an operculum.divergent a. [L. diversus, different] Becoming more separateddistally; extending in different directions from the sameorigin.divergent adaptation Adaptation to different kinds of environmentalinfluence that results in a change from a commonancestral form.diverse a. [L. diversus, different] Being distinct; differing insize or shape; dissimilar; separate.diverticulum n.; pl. -ula [L. devertere, to turn away] An outgrowthor pouch of some sort from the main axis of an organ.divided a. [L. dividere, to separate] Parted or disunited.divided eyes (ARTHRO: Insecta) 1. One in which the ommatidiain one area are different in size and often in pigmentation.2. In many Odonata, the dorsal facets are nearly twice thediameter of the ventral ones. 3. In certain Hemiptera, theventral facets are larger. 4. In some coleopteran waterbeetles, the eye is divided transversely. 5. In certainEphemeroptera, the lateral pair are apposition eyes and thedorsal pair are superposition eyes.

302Maggenti and Gardnerdixenic a. [Gr. dis, two; xenos, guest] Rearing of one or moreindividuals of a single species in association with twoknown species of organisms. see axenic, monoxenic,polyxenic, synxenic, trixenic, xenic.dixenous a. [Gr. dis, two; xenos, guest] Parasitizing two hostspecies. see monoxenous.DNA Deoxyribonucleic aciddocoglossate a. [Gr. dokos, main beam; glossa, tongue](MOLL: Gastropoda) Pertaining to the long radula containinga few strong teeth (up to 12) per transverse row; medianradular tooth may be lacking or fused with lateral teeth toform a strong median tooth; marginal and lateral teeth,when present, are uncinate.dolabriform a. [L. dolabra, ax; forma, shape] Hatchet-shaped.dolichasters n.pl. [Gr. dolichos, long; aster, star] (ARTHRO:Insecta) In Neuroptera larvae, modified setae on the lateralsegmented processes of the dentate mandibles.dolioform, doliioform a. [L. dolium, wine-cask; forma, shape]Barrel-shaped; globose; capacious.doliolaria larva (ECHINOD: Crinoidea) A free-swimming bilaterallysymmetrical larva of the crinoids and a post auriculariaholothurian larva; characterized by possessing a largeapical tuft and several (4 or 5) ciliated bands around thebody; dipluerula. see pentacrinoid.Dollo's rule The principle that evolution is irreversible, i.e.,structures or functions once lost cannot be regained.dome organ A sensillium campaniformia.dominant allele An allele that determines the phenotype of aheterozygote. see recessive allele.dominant character A character from one parent that manifestsitself in offspring to the exclusion of a contrasted (recessive)character from the other parent. see recessivecharacter.dormancy n. [L. dormire, to sleep] A period of inactivity orsuspended animation usually referable to adverse environmentalconditions, but can be genetically controlled.dormant a. [L. dormire, to sleep] Being in a state of torpor or

Online Dictionary of Invertebrate Zoology 303sleep, hibernating, quiescent or aestivating.dorsad adv. [L. dorsum, back; ad, to] Toward the back or top.dorsal a. [L. dorsum, back] 1. Pertaining to the upper surfaceor back of the body. 2. (ARTHRO: Crustacea) In Ostracodsin normal position, the upper part comprising the area thatcontains hinge, eyes, antennules, antennae and stomach.3. (BRACHIO) From the pedicle valve toward the brachialvalve. 4. (ECHINOD) see aboral. 5. (MOLL) a. In Bivalvia,the back edge in the region of the hinge. b. In Gastropoda,the back remote from the aperture; the conical top surfaceof a limpet. 6. (POGON) see adneural.dorsal area 1. (G.T.) 2. (ARTHRO: Crustacea) In Ostracoda,that part of the valve surface adjacent to the dorsal border,comprised of anterodorsal, mid-dorsal and posterodorsalareas. 2. (MOLL) For chitins, see jugal area.dorsal arms of the tentorium (ARTHRO: Insecta) A pair ofdorsal arms arising from the anterior arms; may be attachedto the dorsal wall of the head by short muscles.dorsal blastoderm see serosadorsal blood vessel 1. (ARTHRO: Insecta) The posterior heartand anterior aorta. 2. (ECHI) A dorsal tubular blood vesselin the anterior part of the body cavity often associated withthe foregut; functioning in the transport of blood anteriorlyto the median vessel of the proboscis; sometimes calledthe heart.dorsal bristles see dorsocentral bristlesdorsal cardo (ARTHRO: Crustacea) In Ostracoda, that portionof the peniferum that serves as a hinge by which it articulateswith the zygum.dorsal denticle 1. (G.T.) 2. (ARTHRO: Crustacea) In Ostracoda,a small, solid spinose projection on the dorsal margin;smaller than the dorsal spine.dorsal diaphragm (ARTHRO: Insecta) Muscular sheets of tissueextending from the ventral wall of the heart and vessels tothe laterodorsal parts of the body wall, usually incompletelaterally; it may or may not delineate the pericardial sinusfrom the perivisceral sinus.

304Maggenti and Gardnerdorsal foramen (BRACHIO) A posterior perforation of the cardialplate that may or may not encroach on the beak of thebrachial valve.dorsal gland orifice 1. The opening of any dorsal gland. 2.(ARTHRO: Insecta) In Diaspididae, disc pores and ducts forwax production on the surface of the pygidium.dorsal hair tuft see dorsal tuftdorsalia n.pl. [L. dorsum, back] (GNATHO) Paired sensory bristlesfound dorsally on the head.dorsal lip 1. (G.T.) 2. (ARTHRO: Insecta) In Coccoidea, a chitinizedplate supporting the anal tube.dorsal margin/border 1. (G.T.) 2. (ARTHRO: Crustacea) InOstracoda, part of the valve outline, above or at the hingeline.dorsal ocelli (ARTHRO: Insecta) Simple eyes of adults, thatvary in number from 2 to 3 in different orders.dorsal organ 1. (ANN: Polychaeta) In Orbiniida and Spionida,ciliated sensory tubercles, ridges, or bands located on thedorsal surface of the segments. see lateral organs. 2.(ARTHRO: Crustacea) Thickened glandular area of hypodermon the dorsal surface in the posterior or anterior part of thecephalon. 3. (ARTHRO: Insecta) A distinct mass of cells inthe dorsal part of an embryo.dorsal ostioles (ARTHRO: Insecta) In Pseudococcidae, the dorsaltranverse, slit-like openings on the pronotum and thesixth abdominal segment.dorsal plate 1. (ARTHRO: Chelicerata) In Mesostigmata, thedorsal plate on the body. 2. (ARTHRO: Crustacea) In Decapoda,a spindle-shaped division of the carapace. 3. (AR-THRO: Insecta) a. In Buprestidae larva, the plate or disk onthe dorsal surface of the enlarged segment back of thehead. b. In some Diaspididae, slightly to elaboratelybranched marginal pygidial processes with none to manymicroducts.dorsal pores (ARTHRO: Insecta) In Coccoidea, the outlet ofwax glands; the ceratubae.dorsal scale 1. (G.T.) 2. (ARTHRO: Insecta) a. The wax and

Online Dictionary of Invertebrate Zoology 305exuviae cover resting tentlike over the body of armoredscale. b. Usually two peglike cibarial setae borne lateraland/or posterior to the anterior hard palate of the clypeopalatumof mosquitoes.dorsal setae 1. (G.T.) 2. (ARTHRO: Insecta) Usually two peglikecibarial setae borne lateral and/or posterior to theanterior hard palate of the clypeopalatum of mosquitoes.dorsal shield (ECHINOD: Asterozoa) In Ophiurida, the ossiclesalong the mid-line of the aboral arm surface; dorsal armplate.dorsal sinus 1. (G.T.) 2. (ARTHRO: Insecta) The blood spaceenclosed by the dorsal diaphragm and the heart; dorsalpericardial sinus; pericardial cavity.dorsal spine 1. (G.T.) 2. (ARTHRO: Crustacea) In Ostracoda,sometimes prominent, solid or hollow, pointed projectionon the dorsal valve margin.dorsal spur 1. (G.T.) 2. (ARTHRO: Insecta) In Syrphidae larvae,a pointed spine or ridge-like elevation of the posteriorspiracular plate mesad to the circular plate.dorsal star (ECHINOD: Crinoidea) In some Comatulida, a stellatehollow around the aboral pole of the centrodorsal ossicle.dorsal stylet (ARTHRO: Insecta) In Anoplura, one of two styletsthat are retracted within the trophic pouch.dorsal tentorial arm (ARTHRO: Insecta) Thought to be an outgrowthof the anterior arm, which it joins near the junctionof the anterior and posterior arm; frequently reduced ormore or less consolidated in Diptera.dorsal tubercles see submarginal tuberclesdorsal tubular spinnerets see dorsal poresdorsal tuft (ARTHRO: Insecta) In mosquito larvae, a tuft oflong setae on the dorsum of the ninth segment of the abdomen.dorsal valve see brachial valvedorsal vessel 1. The dorsal blood vessel. 2. (SIPUN) see contractilevessel.

306Maggenti and Gardnerdorsiferous a. [L. dorsum, back; ferre, to carry] Carryingyoung or eggs upon the back.dorsiventral see dorsoventraldorso-alar region (ARTHRO: Insecta) In Diptera, that areabetween the transverse suture and the scutellum, and thebase of the wing and the dorsocentral region.dorsocaudad adv. [L. dorsum, back; cauda, tail] Toward thedorsal surface and caudal end of the body.dorsocentral a. [L. dorsum, back; centralis, midpoint] 1. Pertainingto the mid-dorsal surface. 2. (ECHINOD) Pertainingto the aboral surface.dorsocentral bristles (ARTHRO: Insecta) In Diptera, a longitudinalrow of bristles on the mesonotum, laterad of theacrostichal bristles; absent in many groups.dorsocentrals see dorsocentral bristlesdorso-humeral region (ARTHRO: Insecta) The humeri of Diptera.dorsomedian a. [L. dorsum, back; medius, middle] Pertainingto the true middle line on the dorsum of an individual.dorsomedian groove (ARTHRO: Crustacea) In certain Decapoda,a longitudinal groove extending from the tip of therostrum to the posterior carapace margin dorsomedially.dorsomesal a. [L. dorsum, back; Gr. mesos, middle] Being atthe top and along the midline.dorsomeson n. [L. dorsum, back; Gr. mesos, middle] Wherethe meson meets with the dorsal surface of the body.dorso-pleural line (ARTHRO: Insecta) The line of separationbetween the dorsum and the limb bases of the body, oftenmarked by a fold or groove.dorsopleural suture (ARTHRO: Insecta) In Diptera, a sutureseparating the mesonotum from the pleuron.dorsoscutellar bristles (ARTHRO: Insecta) In Diptera, a pair ofbristles on the dorsal portion of the scutellum, one on eachside of the midline.dorsotentoria n. [L. dorsum, back; tentorium, tent] (ARTHRO:Insecta) The dorsal arms of the tentorium.

Online Dictionary of Invertebrate Zoology 307dorsoventral a. [L. dorsum, back; venter, belly] In the axis ordirection from the dorsal toward the ventral sufaces; bifacial;dorsiventral.dorsoventralis posterior (ARTHRO: Crustacea) In Decapoda, aprominent muscle connecting the head apodemes with theinner surface of the carapace posterior to the cervicalgroove.dorsum n. [L. dorsum, back] The back or upper surface of anorganism.dorylaner n. [Gr. dory, spear; aner, male] (ARTHRO: Insecta)A large male form of the driver and legionary ants, characterizedby large, modified mandibles, long cylindricalgaster and singular genitalia.dorylophile n. [Gr. dory, spear; philos, loving] Any obligatoryguest of army ants belonging to the Dorylini.double haploid A haploid possessing a complete genome fromeach of two species. see snyhaploid.double helix Form of DNA proposed by Watson and Crick,made of two chains of nucleotides arranged spirally aroundeach other.double recessive A cell or organism showing the recessivephenotype.doublure n. [F. doublure, lining] (ARTHRO) The reflected marginof a carapace, as in mantis shrimp, horseshoe crabsand trilobites.Doyere's cone The final conical termination of a nerve fiberentering a muscle; an end plate.drepanoid a. [Gr. drepane, sickle] Sickle-shaped; falcate; drepaniform.drill n. [D. drillen, to bore, drill] (MOLL: Gastropoda) A snailthat preys upon other mollusks by penetrating the shellwith a drilling apparatus. see radula.dromotropic a. [Gr. dromos, race; tropein, to turn] 1. Bent ina spiral. 2. An influence affecting the conductivity of anerve fiber.drone n. [A.S. dran, the male bee] (ARTHRO: Insecta) A malesocial bee, especially a male honeybee or bumblebee.

308Maggenti and GardnerD-shaped larval stage (MOLL) A larva in the form of a D, theback of which is the long, straight hinge; protostracum.duct n. [L. ductare, to lead] 1. The tubular outlet of a gland forexternal secretion. 2. Any tube that conveys fluids or othersubstances.ductule n. [L. dim. ductare, to lead] A small duct, or the beginningportion of a duct.ductus n. [L. ductare, to lead] A duct.ductus bursae (ARTHRO: Insecta) A tube in female Lepidopteraconnecting the ostium with the bursa copulatrix.ductus ejaculatorius The median ectodermal exit tube of themale genital system.ductus entericus (NEMATA) A duct between osmium anduvette in the demanian system.ductus obturatus (ARTHRO: Insecta) In Siphonaptera, aprimitive genital character of certain females that functionsas a spermathecal duct.ductus uterinus (NEMATA) A duct between the uterus and thedemanian system.Dufour's gland (ARTHRO: Insecta) In Hymenoptera, an abdominalgland of the sting apparatus that supposedly secretsa liquid which when applied to cell walls, forms a thin,cellophane-like, transparent, or waxy lining which mayfunction as a chemical cue for nesting, maintaining humiditycontrol, a defense against microbial infection and/orfood source.dulosis n. [Gr. doulosis, servitude] (ARTHRO: Insecta) Ant slaveryin which a parasitic ant species raids the nests of anotherspecies to capture brood (usually pupae) to rear asenslaved nestmates.duodecathecal a. [L. duodecim, twelve; Gr. theke, case](ANN: Polychaeta) Pertaining to having 12 spermathecae,usually in 6 pairs.duodenum n. [ML. duodenum, the first part of the small intestine]The anterior intestine.dupion n. [F. doupion, double] (ARTHRO: Insecta) In Lepidoptera,a double cocoon spun by two silkworms; the silk from

Online Dictionary of Invertebrate Zoology 309such cocoons.duplaglossa n. [L. duplex, double; Gr. glossa, tongue] (AR-THRO: Insecta) A forked or divided glossa.duplex a. [L. duplex, double] Pertaining to a polyploid havingtwo dominant alleles for a given genetic locus (AAa); doubled.duplicate a. [L. duplex, double] Double; twofold.duplicato-pectinate (ARTHRO: Insecta) A bipectinate antennawith branches alternately long and short.duplicature n. [L. duplex, double] 1. A doubling; a fold. 2.(ARTHRO: Crustacea) In Ostracoda, the calcified inner lamellaof a shell that extends along the free margin of thevalve and is fused to the outer lamella.duplicature muscle fibers (BRYO) Muscle fibers that widenthe anterior end of the tentacle sheath, through which thelophophore passes during protrusion and serves as fixatorligaments for protruded polypide.duplivincular ligament (MOLL: Bivalvia) A ligament consistingof a series of bands attaching it to narrow grooves in thecardinal area of the valve.duraphagous a. [L. durus, hard; Gr. phagein, to eat] Pertainingto animals that break shells to eat the animal inside;sclerophagus.dyad n. [Gr. dyas, two] 1. Two chromatids that make up onechromosome in the first meiotic division. 2. A pair of cellscaused by aberrant meiotic division.Dyar's law The theory that various parts of the body increasein linear dimensions by a ratio that is constant for the species.dynamic a. [Gr. dynamis, power] Producing motion or activity.see static.dysodont a. [Gr. dys, bad; odos, tooth] (MOLL: Bivalvia) Havingsmall, weak teeth close to the beak.dysphotic a. [Gr. dys, bad; phos, light] Dim; zone betweeneuphotic and aphotic zones in light penetration of water.dyssaprobes n.pl. [Gr. dys, bad; sappros, putrid; bios, life]

310Maggenti and Gardner(NEMATA) Microbiotrophic nematodes able to invade andobtain nourishment from healthy plants.dystrophic a. [Gr. dys, bad; trophein, to nourish] 1. Defectivenourishment. 2. A lake high in undecomposed organicmatter.Dzierzon's rule (ARTHRO: Insecta) In social Hymenoptera, sexdetermination in which fertilized eggs become females andunfertilized eggs become males.

Eear see auricleeaves n.pl. [A.S. efes, lower border of a roof] (MOLL: Polyplacophora)Portions of the tegmentum just over the linewhere the insertion plates and the sutural laminae project.eave tissue (MOLL: Polyplacophora) Composition of the shellthat forms the eaves; either porcelaneous or riddled withmicroscopic tubules (spongy).eburnean a. [L. eburneus, ivory] Made of, or like ivory; ivorywhite.ecalcarate a. [Gr. ek, out of; L. calcar, spur] Lacking spurs orcalcaria.ecarinate a. [Gr. ek, out of; L. carina, keel] Without a keel orcarina.ecaudate a. [Gr. ek, out of; L. cauda, tail] Lacking a cauda ortail-like process or structure; excaudate.ecaudate wing (ARTHRO: Insecta) A wing lacking a tail-likeprocess.ecbolic see hydrelacticeccentric a. [Gr. ek, out of; kentron, center] 1. Deviation fromthe regular. 2. (MOLL) Having an operculum with growth onone side of the nucleus only, and to one side of the center.ecdemic a. [Gr. ekdemos, away from home] Disease broughtinto a region from outside; neither endemic nor epidemic.ecdysial cleavage line see epicranial sutureecdysial fluid see molting fluidecdysial glands see prothoracic glandsecdysial membrane (ARTHRO: Insecta) A thin membraneformed from the lateral lamellae of the old procuticle that istanned by the polyphenols and phenoloxidase associatedwith the new outer epicuticle during molting.ecdysial tube (ARTHRO: Insecta) In some Diptera and Coleop-

312Maggenti and Gardnertera, a simple cuticular tube formed around the old spiracleand through which the old spiracle and trachea are pulledduring molting.ecdysis n., pl. -ses [Gr. ekdysis, getting out of] Molting, theprocess of shedding cuticle or exoskeleton. see molt,apolysis, endysis.ecdysone n. [Gr. ekdysis, getting out of] (ARTHRO) A hormonethat initates changes in cells associated with molting, producedby a secretion of the prothoracotrophic hormonefrom the median neurosecretory cells of insects, and the Y-gland of crustaceans.ecdysotrophic cycle (ARTHRO) Alternation of blood feedingand molting in mites, ticks, and hemimetabolous insects.ecesis n. [Gr. ek, out of; -esis, denotes action] The migrationof organisms into a new habitat.echinate a. [Gr. echinos, spiny] Set with prickles; spinous;having some or all of the surface of the body covered withspines.echinating spicule (PORIF) A megasclere that protrudes froma fiber or spicule tract.Echinodermata, echinoderms n.; n.pl. [Gr. echinos, spiny;derma, skin] Phylum of marine coelomate animals with basicpentaradiate symmetry in the adult, with a calcareousendoskeleton and a water vascular system.echinopaedium see dipleurulaechinostome cercaria (PLATY: Trematoda) A cercaria having acollar with spines around the margin of the head and a longslender tail.echiopluteus larva Sea-urchin larva.Echiura, echiurans n.; n.pl. [Gr. echis, serpent; oura, tail] Aphylum of soft-bodied, unsegmented, sac-like almost exclusivelymarine invertebrates with a large fluid-filled bodycavity; related to Sipuncula and somewhat resemblingthem.ecitophile a. [NL. Eciton, a genus of ants; L. philos, loving](ARTHRO: Insecta) An obligatory guest of the tribe Ecitonini.ecium see zooecium

Online Dictionary of Invertebrate Zoology 313eclectic a. [Gr. eklektos, selected] Selecting from various systems,doctrines, or sources.eclipsed antigen An antigen borne by a parasite that is commonto both the host and the parasite, genetically of parasiticorigin.eclosion n. [F. eclosion, emerge] The act or process ofemerging from the egg or pupal case; to eclose.ecoclimate a. [Gr. oikos, house; klima, region] Total of meteorologicalfactors within a habitat.ecocline n. [Gr. oikos, house; klinein, to slope] Continuousgradient of characters in response to variation in ecologicalconditions.ecogeographical rules The formulation of regularities in geographicvariation of characters correlated with environmentalconditions.ecological isolation Interbreeding between two or more sympatricpopulations is prevented by mating in different ecologicalniches. see geographic isolation/barriers isolate.ecology n. [Gr. oikos, house; logos, discourse] The study ofinterrelationships among organisms themselves and theirenvironment; bionomics; hexicology; mesology; poikology.ecomorph n. [Gr. oikos, house; morphe, form] A growth formcaused by a special environment; infraspecific variation.ecomorphic a.economic density The number of individuals per unit of habitatspace; also called specific density.ecoparasite see ecositeecophene n. [Gr. oikos, house; phainein, to appear] The rangeof phenotypes produced by one genotype within the limitsof the habitat under which it is found in nature.ecophenotype n. [Gr. oikos, house; phainein, to appear; typos,type] A nongenetic modification of the phenotype byspecific ecological conditions, esp. habitat variation. ecophenotypica.ecosite n. [Gr. oikos, house; sitos, food] A microparasite towhich its host is immune under normal conditions; eco-

314Maggenti and Gardnerparasite.ecospecies n. [Gr. oikos, house; L. species, kind] A group ofpopulations in an ecological niche that are among themselves,and with other ecospecies, capable of interbreedingwithout loss of fertility or vigor in the offspring; an ecotype.ecosystem n. [Gr. oikos, house; systema, an ordered arrangementof things] Any entity or natural unit that includesliving and non-living parts interacting to produce astable system in which the exchange of materials betweenthe living and non-living parts follows circular paths; thebiotic community and its habitat.ecotone n. [Gr. oikos, house; tonos, stretch, brace] A transitionarea between two adjacent ecological communities orbiomes; usually containing many organisms from both, aswell as some characteristic of (sometimes restricted to) theecotone.ecotype n. [Gr. oikos, house; typos, type] A local race arisingas a result of genotypical response to a particular habitat;an ecospecies.ecsoma n. [Gr. ek, out of; soma, body] (PLATY: Trematoda)The telescoping posterior part of the body.ectad adv. [Gr. ektos, outside; L. ad, toward] From within towardthe exterior. see entad.ectadenia n.pl. [Gr. ektos, outside; aden, gland] (ARTHRO: Insecta)A male accessory gland, ectodermal in origin;ectodene glands. see mesadenia.ectal a. [Gr. ektos, outside] Exterior; outer surface of the bodyor body parts.ectally adv. [Gr. ektos, outside] Near to or towards the bodywall. see ental.ectoblast n. [Gr. ektos, outside; blastos, bud] The outer wallof a cell; ectoderm; epiblast.ectochone n. [Gr. ektos, outside; chone, funnel-shaped hollow](PORIF) A funnel-shaped chamber into which the ostiaempty.ectocochleate a. [Gr. ektos, outside; L. cochlea, spiral] (MOLL)An externally coiled shell, as in Nautiloidea.

Online Dictionary of Invertebrate Zoology 315ectocommensal n. [Gr. ektos, outside; L. cum, together;mensa, table] A commensal symbiont that lives on theouter surface of its host.ectocrine a. [Gr. ektos, outside; krinein, to separate] Anychemical released into the environment that includes allelochemics,pheromones, foods, and respiratory gases.ectocyst n. [Gr. ektos, outside; kystis, bladder] (BRYO) Theouter layer of the zooecium.ectoderm n. [Gr. ektos, outside; derma, skin] The outer embryoniclayer from which the epidermis of the body walland nerve tissue are derived. ectodermal a. see choanoderm.ectognathous condition Mouthparts external to the head, notenclosed; ectotrophous. see entognathous condition.ectohormones see pheromoneectolecithal a. [Gr. ektos, outside; lekithos, yolk of an egg](PLATY: Turbellaria) Having cleavage modified by a specialcondition whereby yolk is stored in separate cells surroundingthe oocytes as opposed to entolecithal as seen inother animal phyla whose eggs contain yolk.ectomere n. [Gr. ektos, outside; meros, part] A blastomereforming the ectoderm.ectomesenchyme n. [Gr. ektos, outside; mesos, middle;chyma, anything poured] 1. A structure with organizedcells that functions in epithelial interfaces, muscular sheets,and neuroid networks. 2. (PORIF) All components except forthe flagellated cells.ectomesoderm n. [Gr. ektos, outside; mesos, middle; derma,skin] Mesoderm derived chiefly from the ectoderm duringearly embryology of animals; forming mesenchyme predominentlyin Porifera, Ctenophora and in certain mollusksand annelids.ectoneural a. [Gr. ektos, outside; neuron, nerve] (ECHINOD)Pertaining to the oral part of the nervous system (sensoryand motor).ectooecium n. [Gr. ektos, outside; oikos, house] (BRYO) Theouter layer of the oecial wall; usually calcified.

316Maggenti and Gardnerectoparasite n. [Gr. ektos, outside; para, beside; sitos, food]A parasite feeding on a host from the exterior. ectoparasitica.ectophagous a. [Gr. ektos, outside; phagein, to eat] Feedingexternally.ectophallus n. [Gr. ektos, outside; phallos, penis] (ARTHRO:Insecta) The outer phalic wall. see endophallus.ectopic a. [Gr. ek, out of; topos, place] 1. Occurring in an abnormalplace. 2. A parasite in an organ in which it does notnormally live. see entopic.ectoplasm n. [Gr. ektos, outside; plasma, to form or mold] Anexternal or cortical layer of protoplasm in a cell. see endoplasm.ectoproct n. [Gr. ektos, outside; proktos, anus] (ARTHRO: Insecta)In certain Neuroptera, a plate of the anal segment,including the fused anoprocess, cerci and catoprocess.Ectoprocta, ectoprocts see Bryozoaectoptygma see serosaectosomal spicule (PORIF) A spicule occurring in the ectosomalregion.ectosome n. [Gr. ektos, outside; soma, body] (PORIF) Theouter region that consists of dermal membrane and subdermalspaces, but is not supported by any special skeleton;pinacoderm.ectospermalege n. [Gr. ektos, outside; sperma, seed; legein,to gather] (ARTHRO: Insecta) In females, one to two cuticularpouches, variable in position, functioning for the receptionof the male clasper and penis. see Ribaga's organ.ectostracum n. [Gr. ektos, outside; ostrakon, shell] (ARTHRO:Chelicerata) 1. In acarology, the outermost layer of thechitonostracum layer that when sclerotized is normally colored;stains with acid dyes. see chitonostracum. 2. Themiddle layer of integument of arachnids.ectosymbion(t) n. [Gr. ektos, outside; symbiosis, life together;on, being] A symbiont that lives on or among itshosts. see endosymbiont.

Online Dictionary of Invertebrate Zoology 317ectothermal n. [Gr. ektos, outside; therme, heat] The bodytemperature is determined by that of the environment;poikilothermal.ectotrophous see ectognathous conditionectozoon n. [Gr. ektos, outside; zoon, animal] An ectoparasite.ecumenical a. [Gr. oikoumenikos, world-wide] World-wide inextent; cosmopolitan. see pandemic.edaphic a. [Gr. edaphos, soil] Relating to, or belonging to thesoil or substratum.edaphic factors The influence of soil properties on organisms.edaphon n. [Gr. edaphos, soil] Soil flora and fauna. see geobios.edeagus see aedeagusedentate a. [L. ex, without; dens, tooth] Being devoid of teethor folds. edentulous a.edge effect The tendency to have greater variety and densityof organisms in the boundary zone between communities.editum n. [L. editus, high, lofty] (ARTHRO: Insecta) In maleLepidoptera, a small, rounded, hairy prominence arisingfrom the harpe.edoeagus see aedeaguseffector a. [L. efficere, to execute] A structure specialized forthe activation of a particular form of response, i.e., movementor secretion.efferent a. [L. ex, out of; ferre, to carry] Conducting or carriedoutward; discharging. see afferent.efferent channels (ARTHRO: Crustacea) Passageways throughwhich water moves away from gills and out of the branchialregion.efferent nerve A nerve that conducts from a nerve center towardthe periphery; the axon of a motor neuron that conductsimpulses to the effectors.effete a. [L. effetus, exhausted] No longer capable of fertility;barren.

318Maggenti and Gardnereffluvium n.; pl. -via [L. ex, out of; fluere, to flow] A noxioussmell or invisible emanation.effuse a. [L. ex, out of; fluere, to flow] (MOLL: Gastropoda)Pertaining to the condition of the shell aperture when themargin is interrupted by a short spout for a siphonal outlet.eflected a. [L. ex, out of; flectere, to bend] Bent outwardsomewhat angularly.egest v.t. [L. egestus, discharged] To eliminate solid materialfrom a cell or from the enteron.egesta n.pl. [L. egestus, discharged] The total amount of substancesand fluids discharged from the body.egg-burster (ARTHRO: Insecta) Various cuticular structuresthat aid in hatching by rupturing the egg membranes; eggtooth; hatching spine; ruptor ovi; hatching tooth.egg-calyx (ARTHRO: Insecta) The dilation of the oviduct at theopening of the ovarian tubes.egg-cap A cap, or operculum joined to the body of an eggalong a line of weakness that facilitates hatching.egg-case The case or covering of an egg or egg-mass.egg funnel see female funnelsegg guide (ARTHRO: Insecta) A median caudal process of thesubgenital plate.egg-membrane Internal egg envelope or lining, thin, tough,flexible and colorless.egg-pod (ARTHRO: Insecta) Frothy secretions that form theegg-mass of grasshoppers and the gelatinous sheath ofdipteran eggs.egg-pouch see oothecaegg-tooth see egg-bursteregg-tube see ovarian tubeegg-valve see egg guideejaculate n. [L. ex, out of; jacere, to throw] Emitted seminalfluid; ejected fluid from the body.ejaculatory bulb (ARTHRO: Insecta) 1. In Lepidoptera, thedistal part of the ejaculatory duct, cephalad of the scle-

Online Dictionary of Invertebrate Zoology 319rotized aedeagus. 2. In Diptera, a syringe-like, stronglymuscledstructure, of the ejaculatory duct.ejaculatory duct The terminal portion of the male sperm duct.elabrate a. [L. ex, out of; labrum, lip] Without a labrum.elaphocaris larva (ARTHRO: Crustacea) A third protozoealstage or postnaupliar stage, leading to the acathosoma(mysis) stage.elastes n.pl. [Gr. elastikos, rebounding] (ARTHRO: Insecta) Theabdominal flexion organs of the bristletail apterygote insects.elastic a. [Gr. elastikos, rebounding] Capable of resuming theoriginal shape; flexible.elastic membrane (MOLL) A membrane between the radularmembrane and the pharyngeal epithelium, secreted by thelatter and found in the part of the radula which is in use.elate a. [L. elatus, high] Elevated; lifted up.elater n. [Gr. elater, driver] (ARTHRO: Insecta) In Collembola,the furcula or springing organ.elateriform larva (ARTHRO: Insecta) A slender, heavily sclerotizedlarva with short thoracic legs, and with few bodyhairs; resembles a wireworm.Elatobranchiata see BivalviaElatocephala see Bivalviaelattostase n. [Gr. elatton, smaller; stasis, position] (ARTHRO:Chelicerata) A rare stase of prelarva or larva in which themouthparts are subject to regression in that though themouthparts are intact, they are unable to function, or thelack of chelicerae and palps, closure of the mouth, and regressionof the pharynx. elattostasic a. see hypopus.elbowed antenna (ARTHRO: Insecta) An antenna with the firstsegment elongated and the remaining segments coming offthe first segment in an obtuse angle; a geniculate antenna.electrotropism, electropism n. [Gr. elektron, amber; trope,turn] Movement of an organism as determined by the directionof an external electric current; galvanotropism.eleocyte, elaeocyte n. [Gr. elaion, any oil; kytos, container]

320Maggenti and Gardner(ANN) Free fatty globules, yellow or transparent, inodorousor evil-smelling, in the coelom; emitted by the dorsal poreswhen the worm is irritated.eleutherorhabdic a. [Gr. eleutheros, free; rhabdos, rod](MOLL: Bivalvia) Pertaining to ctenidia with each filamenthaving approximately two ciliated disks that interlockholding the filaments in position; junctions by ciliateddisks. see synaptorhabdic.eleutherotogony n. [Gr. eleutheros, free; gonos, offspring](ARTHRO: Insecta) In embryology, having the back formedwithout participation of the membranes.elevated a. [L. elevatus, raised] High in proportion to diameter;higher than surrounding areas.eleutherozoic a. [Gr. eleutheros, free; zoe, life] Free-living.elevator see levationelimination n. [L. eliminare, to turn out of doors] The castingout or discharging of excretory waste or foreign substancesfrom the body.elinguata n. [L. ex, out of; lingua, tongue] (ARTHRO: Insecta)Having maxillae and labium united at the base. see synista.elite n. [MF. elit, to choose] (ARTHRO: Insecta) A member of acolony showing greater than average initiative and activity.ellipsoidal see ellipticalelliptical a. [Gr. elleipsis, lack, defect] Oblong with roundedends, oval in shape.elongate v. [L. elongatus, prolonged] To lengthen or stretchout.elongate antenna (ARTHRO: Insecta) An antenna equaling thebody length.elute a. [L. ex, out; lutus, washed] With barely distinguishablemarking.elytra pl. of elytronelytral ligula (ARTHRO: Insecta) In beetles, a tongue andgroove joint at the midline of the elytra which meet andhold them together.

Online Dictionary of Invertebrate Zoology 321elytriform a. [Gr. elytron, sheath; L. forma, shape] Shapedlike or resembling an elytron.elytrin n. [Gr. elytron, sheath; L. -ine, compound] (ARTHRO:Insecta) In Coleoptera, the chitinized composition of thebody surface covering.elytron n.; pl. -tra [Gr. elytron, sheath] 1. (ANN: Polychaeta)The numerous modified setae in the form of scales orplates. 2. (ARTHRO: Insecta) A thickened, leathery, orhorny fore wing or wing cover of certain insects. see hemelytron.3. Tegmen.elytrophore n. [Gr. elytron, sheath; phoreus, bearer] (ANN) Aprocess on the prostomium that bears an elytron.emandibulate a. [L. ex, out of; mandibula, jaw] Lacking welldeveloped mandibules.emarginate a. [L. emarginatus, notched at the apex] 1. Havinga margin or apex notched or indented. 2. (MOLL) Havingthe margin of the outer lip notched or variously excavated.embolium n.; pl. -lia [Gr. embolos, wedge] (ARTHRO: Insecta)1. In the hemipteran hemeletron, the narrow costal part ofa wing, separated from the rest of the corium by a suture.2. A basal enlargement in the fore wing. embolar a.embolus n. [Gr. embolos, wedge] (ARTHRO: Chelicerata) 1.The distal division of the palpus of some spiders. 2. The intromittentportion of the male copulatory organ, containinga portion of the ejaculatory duct of spiders.emboly n. [Gr. embole, anything inserted] The formation of agastrula by the process of invagination.embossed a. [ME. embossen, to hide] Ornamented with araised pattern.embryo n.; pl. embryos [Gr. embryon, fetus] A young organismbefore emerging from the egg, or the body of themother.embryogenesis n. [Gr. embryon, fetus; genesis, beginning]Formation and development of an embryo from an egg;embrogeny.embryology n. [Gr. embryon, fetus; logos, discourse] The

322Maggenti and Gardnerstudy of the formation, early growth and development ofliving organisms.embryonic a. [Gr. embryon, fetus] 1. Pertaining to an embryo.2. (MOLL: Bivalvia) Pertaining to a larval stage, as the freeswimmingembryo of an oyster.embryonic fission (BRYO) Division of the first embryo intosecondary and tertiary embryos. see polyembryony.embryonic shell (GASTRO) That part of the shell formed beforehatching.embryophore n. [Gr. embryon, fetus; phoreus, bearer] 1.(ENTO) The vestibular wall anterior to the anal cone towhich the stalks of the eggs and embryos are attached. 2.(PLATY: Cestoda) The protective shell covering the developingonchosphere of some tapeworms.emendation n. [L. emendatus, corrected] In nomenclature, anintentional change of the spelling of a previously publishedzoological name.emergence n. [L. emergere, to come up] (ARTHRO: Insecta)The act of the adult winged insect leaving the pupal case,cocoon, or the last nymphal skin.Emery's rule (ARTHRO: Insecta) The dulotic ants and the parasiticants, both temporary and permanent, that generallyoriginate from closely related forms that serve them ashosts.emigration n. [L. emigrare, to move out] Moving from onepermanent nesting area to another.eminence n. [L. eminens, projecting] A ridge or projection ona surface.emmet n. [ME. emete, ant] (ARTHRO: Insecta) An ant.empodial hair (ARTHRO: Insecta) A bristle or hair on the tarsusor tibia of scale insects. see empodium.empodium n.; pl. -dia [Gr. en, in; pous, foot] (ARTHRO: Insecta)A median bristle-, spine- or lobe-like process arisingventrally at the apex of the last tarsal segment, usuallyfrom the unguitractor plate. see arolium, digitules.enamel n. [OF. esmaillier, to coat with enamel] (MOLL: Gastropoda)The glossy substance which forms the inductura of

Online Dictionary of Invertebrate Zoology 323the shell.enantiomorphic a. [Gr. enantios, opposite; morphe, form]Alike but contraposed as a mirror image.enarthrosis n. [Gr. en, in; arthron, joint] An articulation; aball and socket joint.encapsulation n. [Gr. en, in; L. dim. capsa, box] 1. Enclosedin a capsule or membrane. 2. An animal host surroundingand walling off internal parasites; capsules often involveblood cells, or melanin formation.encephala a. [Gr. encephalos, brain] (MOLL) Pertaining tobearing a head and usually protected by a spiral shell.encephalon n. [Gr. encephalos, brain] The brain.encrusting colony (BRYO) A colony in which most individualsare attached to the substrate.encyst v.t. [Gr. en, in; kystis, bladder] To form a cyst, or becomeenclosed within. see excyst.endemic a. [Gr. endemos, native] 1. Confined to a given region;indigenous, native. 2. Any disease occurring at thenormal or expected level. see epidemic, pandemic.end-hook (ARTHRO: Insecta) In Odonata, a small hook at theinner border of the lateral lobes of the labium.endite n. [Gr. endon, within] 1. The inner lobe of any limbsegment. 2. (ARTHRO: Chelicerata) The plate borne by thecoxa of the pedipalps of most spiders, that functions as acrushing jaw. 3. (ARTHRO: Crustacea) The inwardly (medially)directed lobe of the precoxa, coxa, basis, or ischium.endite lobes (ARTHRO: Insecta) The lacinia and galea on theinner apical angle of the stipes.endobiotic a. [Gr. endon, within; bios, life] Living in the cellsor tissues of another living organism. see exobiotic.endoblast see endodermendocardium n. [Gr. endon, within; kardia, heart] The membranelining the inner surface of the heart.endochorion n. [Gr. endon, within; chorion, membrane] Theinner layer of the chorion of an egg shell. see exochorion.endocoele, endocoel n. [Gr. endon, within; koilos, hollow]

324Maggenti and Gardner(CNID: Anthozoa) 1. Situated on the inner-wall (visceralside) of the coelom. 2. Part of a gastrovascular cavity betweenpaired mesentaries. endocoelar a. see exocoele.endocommensal n. [Gr. endon, within; L. cum, with; mensa,table] A commensal symbiont that lives inside its host.endocranium n. [Gr. endon, within; kranion, skull] The innersurface of the cranium.endocrine glands Ductless glands which produce internalhormonal secretions that are released directly into theblood or hemolymph. see exocrine glands.endocrinology n. [Gr. endon, within; krinein, to separate; logos,discourse] Study of endocrine glands and secretionsand their various effects, e.g., molting, metamorphosis andoocyte production.endocuticle, endocuticula n. [Gr. endon, within; L. dim. cutis,skin] The innermost softer, elastic layer of the cuticule.endocyclic a. [Gr. endon, within; kyklos, circle] (ECHINOD:Echinoidea] Pertaining to a test with rounded profile,peristome and periproct central at the oral and aboral polesrespectively; periproct encircled by apical system of plates.endocyst n. [Gr. endon, within; kystis, bladder] (BRYO) A softlayer lining a zooid; used to include both epidermis andperitoneum or peritoneum alone.endocytosis n. [Gr. endon, within; kytos, container] Ingestionof particulate matter or fluid by phagocytosis or pinocytosis.endoderm n. [Gr. endon, within; derma, skin] 1. The innermostcell layer of the embryo forming the epithelium of thearchenteron, endoblast, entoderm, and hypoblast. 2.(CNID) Layer of cells lining the gastrovascular cavity. 3.(PORIF) see pinacoderm.endodyogeny n. [Gr. endon, within; dyas, two; genos, offspring]The formation of only two daughter cells surroundedby their own membrane, while still in the mothercell. see endopolyogeny.endoenzymes n.pl. [Gr. endon, within; en, in; zyme, yeast]Intracellular enzymes.

Online Dictionary of Invertebrate Zoology 325endogamy n. [Gr. endon, within; gamos, marriage] Inbreeding;sexual reproduction in which mating partners areclosely related. see exogamy, autogamy.endogastric a. [Gr. endon, within; gaster, stomach] (MOLL:Gastropoda) Pertaining to the normal adult coiled so as toextend backward from the aperture over the extrudedhead-foot mass.endogean a. [Gr. endon, within; gaia, the earth] 1. Interstitialsoil dwellers. 2. (ANN: Oligochaeta) Earthworms dwellingwithin the soil. see epigean, hypogean.endogenous a. [Gr. endon, within; genes, producing] Pertainingto development from within; internal origin. endogenyn. see exogenous.endognath, endognathite n. [Gr. endon, within; gnathos,jaw] (ARTHRO: Crustacea) The endopod (inner and principalbranch) of the maxilliped.endolabium n. [Gr. endon, within; L. labium, lip] (ARTHRO)The inner surface of the labium; the well developed hypopharynx.endolecithal see entolecithalendolymph n. [Gr. endon, within; L. lympha, water] (MOLL:Cephalopoda) The fluid in the inner sac of the statocyst ofOctopods and Vampyroteuthis ; in squid and cuttlefish, theonly fluid filling the single walled statocyst sac.endolysis n. [Gr. endon, within; lyein, to dissolve] Dissolutionof the cytoplasm of a cell.endomembrane n. [Gr. endon, within; L. membrana, skin]Membrane inside a cell; endoplasmic reticulum, golgi bodies,vesicles and other structures.endomesoderm n. [Gr. endon, within; mesos, middle; derma,skin] Mesoderm derived from the endoderm during embryologyof animals.endomitosis n.; pl. -ses [Gr. endon, within; mitos, thread]Mitosis within the nuclear envelope without nuclear or cytoplasmicdivision.endoneurium n. [Gr. endon, within; neuron, nerve] Supportingfibers within a nerve.

326Maggenti and Gardnerendooecium n. [Gr. endon, within; oikos, house] (BRYO) Theinner layer of the ooecial wall, usually membranous.endoparamere n. [Gr. endon, within; para, beside; meros,part] (ARTHRO: Insecta) The lamina phalli of Caelifera.endoparasite n. [Gr. endon, within; para, beside; sitos, food]A parasite that lives inside its host. endoparasitic a.endophagy n. [Gr. endon, within; phagein, to eat] The internalfeeding of endoparasites.endophallic cavity (ARTHRO: Insecta) In male Ensifera, thecavity into which the gonopore opens; for Caelifera, seespermatophore sac.endophallus n. [Gr. endon, within; phallos, penis] (ARTHRO:Insecta) The inner wall, sac or tube of the aedeagus, whichis a continuation of the ejaculatory duct.endophragm n. [Gr. endon, within; phragma, partition] (AR-THRO: Crustacea) In some Decapoda, a wall formed by unionof opposed apodemes (cephalic and thoracic) formingpart of the endoskeleton; an arthrophragm.endophragmal skeleton (ARTHRO: Crustacea) A complex internalstructure composed of fused apodemes, providingthe framework for muscle attachment.endophytic a. [Gr. endon, within; phyton, plant] Living withinthe tissues of plants.endophytic oviposition (ARTHRO: Insecta) In certain Odonataa form of oviposition in which they insert their eggs bymaking slits in plants or mud.endopinacocyte n. [Gr. endon, within; pinax, tablet; kytos,container] (PORIF) Cells that form the internal epitheliumlining the canals.endoplasm n. [Gr. endon, within; plasma, to form or mold]The inner or central part of the cytoplasm of a cell. seeectoplasm.endoplasmic reticulum A network of double membranes continuouswith the cell membrane and nuclear membrane; iflined with ribosomes called rough, if unlined called smooth.endopleural ridge see pleural ridge

Online Dictionary of Invertebrate Zoology 327endopleurite n. [Gr. endon, within; pleuron, side] 1. (ARTHRO)A sclerotized infolding between pleurites. 2. (ARTHRO:Crustacea) In Decapoda, a lateral apodeme of the endoskeleton.endoplica see implexendopod(ite) n. [Gr. endon, within; pous, foot] (ARTHRO:Crustacea) The inner ramus of a biramous appendage; themain shaft of that appendage. see exopodite.endopolyogeny n. [Gr. endon, within; polys, many; genos,offspring] Formation of many daughter cells, each surroundedby its own membrane, while still in the mothercell. see endodyogeny.endopolyploid n. [Gr. endon, within; polys, many; aploos,onefold] Cells whose chromosome number has been increasedby endomitosis.Endoprocta, endoprocts see EntoproctaEndopterygota n. [Gr. endon, within; pteron, wing] (ARTHRO:Insecta) In some classifications a division of insects withcomplete metamorphosis. see Holometabola; Exopterygota.endopterygote n. [Gr. endon, within; pteron, wing] (ARTHRO:Insecta) A condition of internal wing bud development, orany insect secondarily wingless but derived from such anancestor; associated with holometabolous insects.endopuncta n.; pl. -ae [Gr. endon, within; L. punctus, point](BRACHIO) An internal cavity in the shell which does notpenetrate all the way through; caeca extend into these depressions.see pseudopunta.endosiphuncle n. [Gr. endon, within; siphon, pipe] (MOLL:Cephalopoda) A tube leading from the protoconch to thesiphuncle.endoskeleton n. [Gr. endon, within; skeleton, dried body] Askeleton or internal supporting structure of the body or anapodeme for muscle attachment. endoskeletal a. seeexoskeleton.endosmosis n. [Gr. endon, within; osmos, a pushing] Osmoticdiffusion toward the inside.

328Maggenti and Gardnerendosome n. [Gr. endon, within; soma, body] (PORIF) All areasof a sponge except for the ectosomal structures.endospine see papillaendosternal ridge (ARTHRO: Insecta) A Y-shaped furca ofhigher insects, formed by the two apophyses of the eusternumarising together in the midline and only separatinginternally.endosternite n. [Gr. endon, within; sternon, chest] 1. (AR-THRO) In various arthropods, an internal sclerotized ridge,plate or other process of the cephalic exoskeleton thatfunctions for muscle and connective tissue attachment;sometimes called entosternite. 2. (ARTHRO: Crustacea) a.In Notostraca, the mesodermal plate beneath the anteriorportion of the alimentary canal. b. In certain Decapoda, afirm calcareous plate of the anterior thorax between thenerve cord and alimentary canal. 3. (ARTHRO: Insecta) seeapophyses.endostome n. [Gr. endon, within; stoma, mouth] (ARTHRO:Crustacea) In some brachyuran Decapoda, a platelike partof the buccal frame; a palate.endostracum n. [Gr. endon, within; ostrakon, shell] 1. (AR-THRO: Chelicerata) For arachnids, see epiostracum. 2. (AR-THRO: Insecta) The endocuticle. 3. (MOLL) The inner layerof a shell.endostyle n. [Gr. endon, within; stylos, pillar] (MOLL) A specialgland on the ctenidial axis, that produces mucus used fortransport of particles to the mouth.endosymbion(t) n. [Gr. endon, within; symbiosis, life together;on, being] An internal symbiont. see ectosymbiont.endotergite see phragmaendotheca n.; pl. -thecae [Gr. endon, within; theke, case]The inner wall of a theca.endothermal see homoiothermalendothorax n. [Gr. endon, within; thorax, chest] Internalstructure or processes of a thorax.endotoichal ooecium (BRYO) An ooecium which appears to be

Online Dictionary of Invertebrate Zoology 329inside the distal zooid, but opens separately to the exterior.endotokia matricida see matricidal hatchingendotoky n. [Gr. endon, within; tokos, birth] A form of reproductionin which the eggs develop within the body of themother. see exotoky.endotoxin n. [Gr. endon, within; toxikon, poison] A substanceproduced by microorganisms which is confined within themicrobial cell. see exotoxin.endotrachea n. [Gr. endon, within; trachia, windpipe] (AR-THRO: Insecta) The inner surface or lining of the trachealtubes. see intima.endozoic a. [Gr. endon, within; zoon, animal] Living within orpassing through an animal. see entozoic, epizoic.endozone n. [Gr. endon, within; zone, belt] (BRYO: Stenolaemata)The inner parts of zooids in a colony with weak wallsand skeletons.endozooidal ooecium (BRYO) An ooecium opening below theoperculum of the parent zooid.endysis n. [Gr. endysis, putting on] The development of a newcuticle. see molt.energid n. [Gr. energos, active] Nucleated cytoplasmic aggregationscontaining all the apparatus necessary for life.enervose a. [L. ex, out of; nervus, sinew] 1. Without veins. 2.(ARTHRO: Insecta) Lacking wing veins.engraved a. [OF. engraver, cut] Having superficial irregularimpressed lines; exsculptate.ennomoclones n.pl. [Gr. ennea, nine; klon, twig] (PORIF)Megasclere spicules of the dicranoclone or sphaeroclonetype.ensate a. [L. ensis, sword] Ensiform; sword-shaped.ensheathed a. [Gr. en, in; A.S. sceath, case] 1. Enclosed byor inserted as in a sheath. 2. During development, cuticlepreceding the molt is retained into the next stage.ensiform a. [L. ensis, sword; forma, shape] Sword-shaped;two-edged and tapering toward a point.entad adv. [Gr. entos, within; L. ad, toward] Extending in-

330Maggenti and Gardnerwardly from the exterior; internally. see ectad.ental a. [Gr. entos, within] Away from the body wall, towardthe center of the body. see ectal.entelechy n.; pl. -chies [Gr. en, in; telos, end; echein, tohold] 1. An actuality or realization as opposed to potentiality.2. A vital force or agent directing growth and life.enteric a. [Gr. enteron, intestine] Pertaining to the enteron oralimentary canal.enterocoel, enterocoele n. [Gr. enteron, intestine; koilos,hollow] Coelom that arises as an outpocketing of the archenteron.enterocoelic a.enterocoely n. [Gr. enteron, intestine; koilos, hollow] Theprocess of forming the perivisceral cavity.enteroic a. [Gr. enteron, intestine] (ANN) Pertaining to the excretorysystem when it opens into the gut lumen. seeexoic.enteron n. [Gr. enteron, intestine] The digestive cavity ofmulticellular animals.enteronephric a. [Gr. enteron, intestine; nephros, kidney](ANN: Oligochaeta) Having nephridia opening into the gutlumen. see exonephric.enterosegmental organs (ANN: Oligochaeta) In Moniligastrida,paired structures containing a bundle of glandulartubes bound together by a delicate connective tissue investmenton the dorsal face of the post-gizzard gut.enterostome n. [Gr. enteron, intestine; stoma, mouth] (CNID)Aboral opening of the actinopharynx leading to the gastrovascularcavity.enterozoa see entozoaentire a. [L. integer, complete] 1. Without emargination; havinga smooth margin. 2. (ARTHRO: Insecta) Pertaining to awing with an unbroken margin. 3. (MOLL: Gastropoda)When the aperture margin is uninterrupted by a siphonalcanal, sinus or crenulation.entoblast see endodermentobranchiate a. [Gr. entos, within; branchia, gills] Having

Online Dictionary of Invertebrate Zoology 331internal gills.entocodon n. [Gr. entos, within; kodon, bell] (CNID: Hydrozoa)The primordium of the subumbrella in the development ofmedusae from the gonophore.entoderm see endodermentognathous condition (ARTHRO: Insecta) In Collembola,Diplura and Protura, the mouthparts which lie in a cavitywithin the head. see ectognathous condition.entolecithal a. [Gr. entos, within; lekithos, yolk of an egg](PLATY: Turbellaria) A type of egg where the yolk is storedwithin the oocytes as opposed to ectolecithal; sometimesreferred to as endolecithal.entoloma n. [Gr. entos, within; loma, fringe] (ARTHRO: Insecta)The inner margin of a wing.entomiasis n. [Gr. entomon, insect; -iasis, a diseased condition]A lesion in the tissues of animals caused by insects.entomochoric a. [Gr. entomon, insect; chorein, to spread]Dispersed by insects, such as fungal spores and nematodes.entomochore, entomochory n.entomogenous a. [Gr. entomon, insect; genee, producing]Pertaining to micro-organisms growing in or on the bodiesof insects.entomography n. [Gr. entomon, insect; graphein, to write]The description and life history of an insect.entomolin see chitinentomology n. [Gr. entomon, insect; logos, discourse] Thatbranch of zoology dealing with insects.entomoparasitic a. [Gr. entomon, insect; para, beside; sitos,food] Refers to insect parasites. see entomogenous, entomophilic,entomophagous.entomophagous a. [Gr. entomon, insect; phagein, to eat] Insectivorous;the eating of insects or their parts.entomophilic, entomophilous a. [Gr. entomon, insect; philos,loving] 1. Pertaining to associations between insectsand plant microorganisms, protozoa, and nematodes. 2.Being pollinated by the agency of insects.

332Maggenti and Gardnerentomophobia n. [Gr. entomon, insect; phobos, fear] Havingan abnormal fear of insects.entomophyte, entophyte n. [Gr. entomon, insect; phyton,plant] A fungus living on or in the body of an insect. entomophytica.entomosis n. [Gr. entomon, insect; -osis suff. denoting a conditionusually morbid] An insect borne disease.Entomostraca, entomostracan n. [Gr. entomon, insect; ostrakon,shell] Formerly considered a single natural group ofCrustacea including Brachiopoda, Ostracoda, Copepoda,Branchiura and Cirripeda which is no longer acceptable tosystematists.entomotaxy n. [Gr. entomon, insect; taxis, arrangement] Theart of preserving and mounting insects.emtomotomist n. [Gr. entomon, insect; temnein, to cut] Astudent of entomotomy.entomotomy n. [Gr. entomon, insect; temnein, to cut] The artof insect dissection; dealing with internal structures of insects.entomurochrome n. [Gr. entomon, insect; ouron, urine;chroma, color] (ARTHRO: Insecta) The color pigments of theurine of insects.entoneural a. [Gr. entos, within; neuron, nerve] (ECHINOD)Pertaining to the aboral ring and nerves.entoparasite see endoparasiteentopic a. [Gr. en, in; topos, place] Occurring in the normalplace. see ectopic.entopleuron see pleural apophysisentoprocessus n. [Gr. entos, within; L. procedere, to go forward](ARTHRO: Insecta) In Neuroptera, a pair of lateralprocesses of the gonarcus.Entoprocta, entoprocts n.; n.pl. [Gr. entos, within; proktos,anus] A small phylum of solitary or colonial animals, havinga flame cell protonephridial excretory system and a loopedintestine with both the mouth and anus opening within thecircle of tentacles; formerly a class of Bryozoa.

Online Dictionary of Invertebrate Zoology 333entosaccal cavity (BRYO) That part of the body cavity containingthe digestive and reproductive systems.entosternite see endosterniteentosternum n.; pl. -sterna [Gr. entos, within; sternon,chest] (ARTHRO) The internal processes or system of processesof the sternum.entotergum n. [Gr. entos, within; L. tergum, back] (ARTHRO:Insecta) A large V-shaped ridge of the thorax on the undersurfaceof the notum.entothorax n. [Gr. entos, within; thorax, chest] (ARTHRO: Insecta)The apodemes or processes that extend inwardlyfrom the sternal sclerites; an apophysis. see endothorax.entotrophous see entognathous conditionEntotropha see apteraentozoa n.pl., sing. entozoon [Gr. entos, within; zoon, animal]The internal parasites collectively. entozoal a., entozoana. & n.entozoic a. [Gr. entos, within; zoon, animal] Living within anotheranimal; an internal parasite. see endozoic, epizoic.enucleate v. [L. ex, out of; nucleus, kernel] 1. To remove anentire organ, etc. 2. To destroy or remove the nucleus of acell.envelope n. [OF. enveloper, wrap up] (ARTHRO: Insecta) Asheath surrounding the nest of a social wasp.environment n. [F. environ, about] The totality of physical,chemical and biotic conditions surrounding an entire organism.enzootic disease A disease which is constantly present in apopulation of lower animals, although usually at a lowmaintenance level.enzyme n. [Gr. en, in; zyme, yeast] An organic catalyst producedby a living organism.Eogaea n. [Gr. eos, dawn; gaia, earth] Seldom used zoogeographicterm; including Africa, South America andAustralia. see Caenogaea.eoplasmatocyte n. [Gr. eos, dawn; plasma, formed or

334Maggenti and Gardnermolded; kytos, container] (ARTHRO: Insecta) A form ofplasmatocyte with conspicuous acidophilic nucleus and lightbasophilic cytoplasm.eoplasmatocytoid a. [Gr. eos, dawn; plasma, formed ormolded; kytos, container; eidos, like] (ARTHRO: Insecta) Aform of plasmatocyte intermediate to the eoplasmatocyteand microplasmatocyte.eosinophil a. [Gr. eos, dawn; philos, loving] A polymorphonuclearleukocyte or other granulocytes whose cytoplasm hasan affinity for eosin dye.eosinophilia n. [Gr. eos, dawn; philos, loving] With an elevatedeosinophil count in the circulating blood, resultingfrom chronic parasite infection or other diseases.epacme n. [Gr. epi, upon; akme, top] The evolutionary phylogenyof a group of organisms before reaching its highestpoint.epalpate a. [L. ex, out of; palpus, feeler] Lacking palpi; expalpate.epandrium, epiandrium n.; pl. -dria [Gr. epi, upon; aner,male] (ARTHRO: Insecta) In male Diptera, the tergite of the9th segment, maybe reduced or enlarged, sometimesbearing surstyli.epaulet, epaulett n.; pl. epaulets, epaulettes [F. dim. epaule,shoulder] 1. (ARTHRO: Insecta) a. In Diptera, scleritesat the base of the costa. b. In Hymenoptera, the tegula. c.In Lepidoptera, the sclerotized separation of the tympanumfrom the membranous dorsoposterior portion of theepimeron, variable in shape between species; the nodularsclerite. 2. (CNID: Scyphozoa) Branched or knobbed processesof the oral arms. 3. (ECHINOD: Echinoidea) Crescenticridges of cilia of the sea urchin nymph. 4. (NEMATA) A specializedshield-shaped band of cephalic cuticle, not to beconfused with cordons.epedaphic a. [Gr. epi, upon; edaphos, soil] Pertaining to, ordependent upon climatic conditions.epharmonic a. [Gr. epi, upon; harmonia, a fitting together]Pertaining to the adaptation of an organism or species toits environment. epharmony n.

Online Dictionary of Invertebrate Zoology 335epharmosis n. [Gr. epi, upon; harmonia, a fitting together]The method of adaptation of organisms to a new environment.ephebic a. [Gr. epi, upon; hebe, puberty] 1. Mature. 2. (AR-THRO: Insecta) The adult; between the neanic and geronticstage; the winged adult stage. 3. (BRYO) Zooids laid downduring the phase of astogenic repetition.ephemeral n. [Gr. ephemeros, living only a day] A short-livedanimal species, especially insects.ephippium n.; pl. ephippia [L. ephippium, saddle] (ARTHRO:Crustacea) Exuvia of some female cladocerans with one toseveral eggs enclosed, capable of withstanding dessication;a vehicle of dispersal. ephippial a.ephyra n.; pl. ephyre, ephyrae, ephyrula [Gr. Ephyra, nameof a sea nymph] (CNID: Scyphozoa) A small free-swimmingmedusa arising by asexual division (transverse fission) of astrobila; a monodisk.epiandrous glands (ARTHRO: Chelicerata) A group of glandsfound in most male spiders that add to the sperm web asmall white mat on which the drop of sperm is deposited.epibenthos n. [Gr. epi, upon; benthos, depth of the sea] Thefauna of the sea bottom between low tide line and 100fathoms.epibiont see epicoleepibiotic a. [Gr. epibionai, to survive] 1. Endemic species thatare relicts of former fauna. 2. Growing on the surface ofother animals. see hypobiotic.epiblast n. [Gr. epi, upon; blastos, bud] Ectoderm, the outergerm layer in early embryos; ectoblast.epiboly, epibole n. [Gr. epibole, placing upon] The growth ofone structure around another during embryonic development.epibolic a.epibranchial lobe or area (ARTHRO: Crustacea) In Decapoda,the anterior part of the branchial region of the carapace.epibranchial space (ARTHRO: Crustacea) In Decapoda, thatpart of the gill chamber above or external to the gills.epicaridum, epicaridium n. [Gr. epi, upon; kardis, shrimp]

336Maggenti and Gardner(ARTHRO: Crustacea) The first larval stage of a parasiticepicaridean; a microniscus.epicnemis n. [Gr. epi, upon; kneme, leg] (ARTHRO: Chelicerata)A tibial accessory joint of arachnids.epicnemium see prepectusepicole n. [Gr. epi, upon; L. colere, to inhabit] An animal thatlives on the surface of another animal and neither harmsnor helps that animal.epicondyle n. [Gr. epi, upon; kondylos, knuckle] (ARTHRO: Insecta)The cephalic or dorsal swelling of the proximal endof the mandible, articulating with a socket in the gena orpostgena.epicranial plate (ARTHRO: Insecta) In larval forms, a plate-likestructure forming the epicraniumepicranial stem (ARTHRO: Insecta) The coronal suture.epicranial suture (ARTHRO: Insecta) In larval forms, the dorsalY-shaped line of the cranium normally associated withmolts, but may persist in adults and form a true sulcus;ecdysial cleavage line.epicranium n. [Gr. epi, upon; kranion, skull] (ARTHRO: Insecta)The upper part of of the head, from the face to theneck; the calva. epicranial a.epicuticle, epicuticula n. [Gr. epi, upon; L. dim. cutis, skin]1. (ACANTHO) See glycocalyx. 2. (ARTHRO) The thin, outermostnonchitinous exterior layer of arthropod cuticle. 3.(ARTHRO: Chelicerata) For mites see epiostracum.epidemic n. [Gr. epi, upon; demos, the people] 1. A rapidlyspreading attack of disease in a population. 2. A diseaselevel higher than expected for a designated area. see endemic.epidemiology n. [Gr. epi, upon; demos, the people; logos,discourse] A science that deals with all ecological aspects ofdisease including transmission, distribution, prevalence,and incidence.epiderma n [Gr. epi, upon; derma, skin] An abnormal outgrowthof the skin.epidermis n. [Gr. epi, upon; derma, skin] 1. The cellular layer

Online Dictionary of Invertebrate Zoology 337of the body wall that secretes the cuticle; the hypodermis.2. (BRYO) Secretes cuticle and calcium carbonate of theskeleton. 3. (MOLL) The periostracum. epidermal a.epididymis n. [Gr. epi, upon; didymos, testicle] (ARTHRO: Insecta)The coiled part of the vas deferens.epifauna n. [Gr. epi, upon; L. Faunas, deity of herds andfields] Any animal living on the surface deposits of theocean. see infauna.epifrontal fold (BRYO: Gymnolaemata) In Umbonulidae, a foldof the exterior body wall and body cavity arching over thefrontal wall.epigaen see epigeanepigamic a. [Gr. epi, upon; gamos, marriage] Serving to attractindividuals of the opposite sex during courtship; thecolors displayed during courtship.epigastric furrow (ARTHRO: Chelicerata) A transverse ventralsuture near the anterior end of the abdomen of spiders,along which lie the opening of the book lungs and in themiddle the reproductive organs.epigastric lobe or area (ARTHRO: Crustacea) In Decapoda,the anterior extension of the gastric region of the carapace.epigastrium n. [Gr. epi, upon; gaster, stomach] 1. (ARTHRO:Chelicerata) In spiders, the ventral portion of the opisthosoma.2. (ARTHRO: Insecta) The ventral side of the mesoandmetathorax.epigean, epigaen a. [Gr. epi, upon; gaia, earth] Living at orabove the soil surface; epigeic; epigenous. see endogean,hypogean.epigenesis n. [Gr. epi, upon; genesis, beginning] The theorythat morphological complexity develops gradually from anessentially formless egg during embryology; during the18th and 19th century debates, epigenesis represented thetheory that complexity must be directed by a vital forcefrom outside the system for normal development.epigenetics n. [Gr. epi, upon; genesis, beginning] That branchof biology that deals with the causal analysis of development.

338Maggenti and Gardnerepigenotype n. [Gr. epi, upon; genesis, beginning; L. typus,type] The chain of interactions among genes resulting inthe phenotype; the developmental system.epiglossa see epipharynxepiglottis n. [Gr. epi, upon; glottis, mouth of the windpipe] 1.(ARTHRO: Insecta) The epipharynx. 2. (BRYO) The epistome.epigynial plate see epigynumepigynum, epigynium n.; pl. -yna [Gr. epi, upon; gyne,woman] (ARTHRO: Chelicerata) 1. A sclerotized structure ofcertain female spiders and mites, variable in form, coveringthe genital opening. 2. In mites also referred to as epigynialplate or genital plate.epilabrum n.; pl. -labra [Gr. epi, upon; L. labrum, lip] (AR-THRO) In Myriapoda, a sclerite on each side of the labrum.epilimnion n. [Gr. epi, upon; limne, lake] The upper layer ofwater found in deep lakes. see thermocline andhypolimnion.epilobe n. [Gr. epi, upon; L. lobus, a rounded projection] (AR-THRO: Insecta) A lateral appendage of the mentum ofground beetles.epilobous a. [Gr. epi, upon; L. lobus, a rounded projection](ANN: Oligochaeta) A prostomium that is continued by atongue into the peristomium but without reaching the divisionbetween segments 1 and 2.epimegetic a. [Gr. epi, upon; megas, large] (ARTHRO: Insecta)Being the largest in a series of polymorphic forms.epimera pl. epimeronepimeral fold (ARTHRO: Crustacea) In Decapoda, the foldedendopleurites connected to the branchiostegite that formsthe branchial chamber.epimeral parapterum (ARTHRO: Insecta) The posterior basalarsclerite between the pleural wing process and theepimeron of the wing bearing segment.epimeral suture (ARTHRO: Insecta) The caudal portion of thesternopleural suture.

Online Dictionary of Invertebrate Zoology 339epimere n. [Gr. epi, upon; meros, part] 1. (ARTHRO: Crustacea)A dorsolateral, flat overhanging keel on the somiteswhich may form a carapace, flattened shield or clam-shellvalves. 2. (ARTHRO: Insecta) In Lepidoptera, a dorsal processof the phallobase.epimeron n.; pl. -ra [Gr. epi, upon; meros, part] 1. (ARTHRO)In Arachnida and Diplopoda, a ventral plate to which thebasal segment of the leg is attached; a coxal plate. 2. (AR-THRO: Crustacea) See epimere. 3. (ARTHRO: Insecta) Thatportion of a thoracic pleuron posterior to the pleural suture;for Diptera, see mesepimeron.epimorphosis n. [Gr. epi, upon; morphosis, form] 1. With thesame form in successive stages of growth. see anamorphosis,metamorphosis. 2. Larval forms which are suppressedor passed before hatching, emerging as the adultbody form. 3. (ANN: Oligochaeta) A type of regenerationthat results in the addition of new tissues and/or parts atthe level of amputation. epimorphic a., epimorpha n.epineural canal (ECHINOD) A canal or sinus between each radialnerve and the epidermis.epineural sinus (ARTHRO: Insecta) In embryology, the developmentof primary body cavity between the upper surfaceof the embryo and the yolk.epineurium n. [Gr. epi, upon; neuron, nerve] 1. Outermostconnective tissue sheath on the nerve. 2. (ARTHRO: Insecta)The fibrous connecting tissue that invests a nerveganglion.epinotal spines (ARTHRO: Insecta) In Formicoidea, the spineson the first abdominal segment that protect the pedicel.epinotum n. [Gr. epi, upon; notos, back] (ARTHRO: Insecta) InFormicoidea, the thoracic dorsum posterior to themesonotum, consisting of the metanotum and propodeum.see propodeum.epiopticon see medullaepiostracum n. [Gr. epi, upon; ostrakon, shell] (ARTHRO: Chelicerata)1. A thin elastic, colorless layer of the cuticle ofarachnids which overlies the ectostracum layer; further dividedinto two layers: inner, dense and proteinaceous, and

340Maggenti and Gardnerouter, cuticulin. 2. The upper layer of cuticle of arachnids.epipelagic a. [Gr. epi, upon; pelagos, sea] Pertaining to suspendedorganisms inhabiting an aquatic environment betweenthe surface and a depth of 200 m. see mesopelagic,bathypelagic.epiphallus n. [Gr. epi, upon; phallos, penis] 1. (ARTHRO: Insecta)a. In male Orthoptera, a plate on top of the genitalcomplex. b. In male Dictyoptera, a pair of valves dorsad ofthe phallus. 2. (MOLL: Gastropoda) A very muscular part ofthe sperm duct proximal to the penis sheath which participatesin the formation of spermatophores.epipharyngeal wall (ARTHRO: Insecta) The inner surfaces ofthe labrum and clypeal regions of the head.epipharynx n. [Gr. epi, upon; pharynx, throat] (ARTHRO: Insecta)A small medium lobe on the interior surface of thelabrum or clypeus. epipharyngeal a.epiphragm n. [Gr. epi, upon; phragma, partition] (MOLL: Gastropoda)In land snails, a sheet of dried mucus across theaperture preventing loss of moisture during aestivation orhibernation.epiphysis n.; pl. -ses [Gr. epi, upon; phyein, cause to grow]1. (ARTHRO: Insecta) In Lepidoptera, a lamellate spur orprocess on the inner surface of the fore tibia bearing adense brushlike array of setae. 2. (ECHINOD: Echinoidea)One of 5 small peripheral bars in Aristotle's lantern.epipleura n.; pl. -rae [Gr. epi, upon; pleura, side] (ARTHRO:Insecta) In Coleoptera, the infolded lateral edge of theelytra.epipleural sclerites (ARTHRO: Insecta) One or two smallsclerites in the membranous area between the thoracicpleura and the wing bases that are important to wingmovement due to muscle attachment.epipleurum n. [Gr. epi, upon; pleuron, side] (ARTHRO: Insecta)1. Among coleopterous larvae the lateral area abovethe ventrolateral suture and below the dorsolateral suture.2. In ichneumonid Hymenoptera, the thin margin of thesecond and following abdominal segments.epiploon see caul

Online Dictionary of Invertebrate Zoology 341epipodial plate (ARTHRO: Crustacea) In Ostracoda, a setaceousrespiratory plate on the maxilla or the fifth limb.epipod(ite) n. [Gr. epi, upon; pous, foot] (ARTHRO: Crustacea)A laterally directed exite of the protopod, usually branchialin function; a laterally directed ramus of the coxa; gillseparator. see exite.epipodium n.; pl. -dia [Gr. epi, upon; pous, foot] (MOLL: Gastropoda)Lateral grooves between foot and mantle, withtentacles and integumentary sensory organs, usually flat.epiproct n. [Gr. epi, upon; proktos, anus] (ARTHRO: Insecta) Aprocess or appendage situated above the anus; the dorsalpart of the eleventh abdominal segment. see suranalplate.epiprosoma n. [Gr. epi, upon; pro, before; soma, body] (AR-THRO: Chelicerata) In Acari, a body division consisting ofgnathosoma and aspidosoma.epiptygma n.; pl. -mata [Gr. epiptygma, overflap] (NEMATA)Anterior and posterior cuticular flaps associated with thevulval opening of some female nematodes. see hypoptygma.epipygium n. [Gr. epi, upon; pyge, rump] (ARTHRO: Insecta) Adorsal arch in the last abdominal segment.epirrhysa n.pl., sing. -sum [Gr. epirrheein, to flow into] (PO-RIF) The inhalent canals. see prosochete, aporrhysa.episematic a. [Gr. epi, upon; sema, sign] A term used to designatedistinctive markings which serve as a recognitionsignal. see pseudepisematic color; sematic.episite n. [Gr. epi, upon; sitos, food] A predator able to completeits life cycle by devouring a succession of victims.epistasis n. [Gr. epi, upon; stasis, a standing] When one geneinterferes with the phenotypic expression of another nonallelicgene (or genes), producing a phenotype determinedby the former and not by the latter when both genes occurtogether in the genotype.episternal lateral see pre-episternumepisternal paraptera (ARTHRO: Insecta) One or two anteriorbasalar sclerites in front of the pleural process in the mem-

342Maggenti and Gardnerbrane at the base of the wings; indistinctly separated fromthe episternum.episternal suture (ARTHRO: Insecta) The anterior part of thesternopleural suture.episternum n.; pl. episterna [Gr. epi, upon; sternon, chest]1. (ARTHRO: Crustacea) In Decapoda, the posterolateralprojection of various sterna. 2. (ARTHRO: Insecta) The areaof a thoracic pleuron anterior to the pleural suture. episternala.epistoma see epistomeepistomal ridge (ARTHRO: Insecta) The cranial inflection of theepistomal sulcus.epistomal sulcus or suture (ARTHRO: Insecta) The groovesituated between the frons and clypeus that unites with theanterior ends of the subgenal sulcus extending to the anteriortentorial pits.epistome, epistoma, epistomis, epistomum n. [Gr. epi,upon; stoma, mouth] 1. (ARTHRO: Chelicerata) See tectum,cervix. 2. (ARTHRO: Crustacea) In brachyuran Decapoda, aplate of varying shape between the labrum and bases ofthe antennae; sternum of antennal somite. 3. (ARTHRO: Insecta)a. In Diptera, the oral margin; that part of the faceabove the mouth. b. In Odonata, the clypeus. c. In certainColeoptera, the reduced frontoclypeal region. see peristome.4. (BRYO: Phylactolaemata) A small, movable lip-likelobe of tissue and coelom overhanging the mouth.epitheca n. [Gr. epi, upon; theke, case] (CNID) The externallayer surrounding the theca in many corals.epithelial layer 1. Any layer of cells, one surface of which islining a tube or cavity. 2. (BRYO) A single layer of cells oftwo types: secretory cells and fat storage cells.epithelial syncytium Multinucleated epithelial cells.epithelial tissues Surface tissues in which the cells formregular layers, containing very little intercellular material.epitheliomuscular a. [Gr. epi, upon; thele, nipple; L. musculosus,fleshy] (CNID) Pertaining to epithelium with a longitudinalcontractile fiber at the base; myoepithelial.

Online Dictionary of Invertebrate Zoology 343epithelium n., pl. -lums, -lia [Gr. epi, upon; thele, nipple] Anepithelial tissue, covering an external or internal surface.epithelial a.epitoke n. [Gr. epi, upon; tokos, birth] (ANN: Polychaeta) Theposterior sexual portion of certain marine worms. seeatoke.epitoky n. [Gr. epi, upon; tokos, birth] (ANN: Polychaeta) Reproductionof certain dimorphic swarming worms in whichstructural modifications such as enlarged eyes, nonfunctionalgut and modification of parapodia for swimming occur;also called hetero-forms: heteronereis, heterosyllid.see heteronereid.epitorma n.; pl. -mae [Gr. epi, upon; tormos, socket] (AR-THRO: Insecta) In scarabaeoid larvae, a rod extending fromthe inner end of the laeotorma. a. Epitorma anterior, whendirected toward the apex of the epipharynx. b. Epitormaposterior when directed in the opposite direction.epizoic a. [Gr. epi, upon; zoon, animal] Pertaining to an organismliving on, or attached to the body of another animal.see endozoic.epizoicide n. [Gr. epi, upon; zoon, animal; L. caedere, to kill]An agent that destroys epizoa.epizoon n.; pl. epizoa [Gr. epi, upon; zoon, animal] An animalparasite living upon the exterior of the body of the host; anexternal parasite.epizootic a. [Gr. epi, upon; zoon, animal] An outbreak of diseasein animals in which there is an unusually large numberof cases; identical to an epidemic in humans.epizootiology n. [Gr. epi, upon; zoon, animal; logos, discourse]The field concerned with the study of diseases ofanimals involved in an epizootic outbreak.epizygal n. [Gr. epi, upon; zygon, yolk] (ECHINOD: Crinoidea)The distal member of a syzygial pair of brachials. see hypozygal.epizygial a.epizygum n.; pl. epizyga [Gr. epi, upon; zygon, yolk] (AR-THRO: Insecta) In certain beetle larvae, an elongate plateor bar extending from the zygum toward the clithrum onthe right of the epipharynx, or embodied in the tylus; may

344Maggenti and Gardnerbe present when clithrum is absent.epoch n. [Gr. epoche, stop] Subdivision of a period or divisionin geologic time.epomia n.; pl. -ae [Gr. epomidios, on the shoulder] (ARTHRO:Insecta) 1. The margin of the propleural furrow in whichthe front femur is inserted. 2. In ichneumonid Hymenoptera,a carina on the side of the pronotum, obliquelycrossing the trough in the side of the pronotum.epupillate a. [L. ex, out of; pupilla, pupil of eye] Without apupil or color spot; pertaining to ocellate spots.equal weighting Treating all taxonomic characters as equallyimportant.equatorial plate Plane where chromosomes gather duringmetaphase of mitosis or meiosis.equidistant a. [L. aequus, uniform; distantia, remoteness]Equally spaced from any two or more points.equilateral shell (MOLL: Bivalvia) With the shell parts equal oralmost equal anterior and posterior to the beak.equilibrating a. [L. aequus, uniform; libra, balance] Balancingequally.equimeric a. [L. aequus, uniform; Gr. meros, part] (ANN: Oligochaeta)Pertaining to regenerates having the same numberof segments as had been amputated. equimery n.equipedal a. [L. aequus, uniform; pes, foot] Possessing pairsof equal feet.equipotent a. [L. aequus, uniform; potens, powerful] Differingcell parts or organs capable of performing like functions.equivalve a. [L. aequus, uniform; valva, leaf of a folding door](MOLL: Bivalvia) When two valves (shells) are the sameshape and of equal size.era n. [L. aera, epoch] A division of geologic time, such as Palaeozoic,etc.; divided into periods.eradiate v. [L. ex, out of; radiatus, rayed] To shoot forth asrays of light; to radiate.erectopatent a. [L. erectus, upright; patens, open] (ARTHRO:Insecta) Pertaining to having the fore wings erect and the

Online Dictionary of Invertebrate Zoology 345hind wings partially spread during resting.ereisma n. [Gr. ereisma, prop] (ARTHRO: Insecta) The furculain Sminthurus which has a fanlike structure.eremobic a. [Gr. eremos, solitary; bios, life] Living a solitaryexistence.eremochaetous a. [Gr. eremos, solitary; chaite, mane] Lackingthe normal arrangement of bristles.eremology n. [Gr. eremia, desert; logos, discourse] A scienceconcerned with the desert and its phenomena.eremophilous a. [Gr. eremia, desert; philos, loving] Desertloving; pertaining to animals that live in deserts or arid regions.eremosymbiont n. [Gr. eremos, solitary; syn, together; bios,life] A species living in an ant nest for protection, not takingor contributing anything.ergastic a. [Gr. ergastikos, fit for working] Pertaining to theintegration or union of parts during evolution. see metaplasm.ergastoplasm n. [Gr. ergaesthai, working; plasma, form ormold] 1. Granular endoplasmic reticulum. 2. A former conceptionof cytoplasm, the fibrillar or flocculent massesfound in many gland cells and elsewhere.ergatandromorph n. [Gr. ergates, worker; aner, man; morphe,form] (ARTHRO: Insecta) An abnormal ant possessingthe worker characteristics, combined with qualities of themale. see ergatogynandromorph.ergataner see ergatomorphic maleergate n. [Gr. ergates, worker] (ARTHRO: Insecta) A type ofworker ant.ergatogynandromorph n. [Gr. ergates, worker; gyne, female;andros, male; morphe, form] (ARTHRO: Insecta) Amosaic form of ant possessing qualities of male andworker. see ergatandromorph.ergatogyne n. [Gr. ergates, worker; gyne, female] (ARTHRO:Insecta) A form intermediate between the worker andqueen.

346Maggenti and Gardnerergatoid male see ergatomorphic maleergatoid reproductive or ergatoid (ARTHRO: Insecta) Supplementaryreproductive termite, usually larval in appearancewith a distinctive rounded head; tertiary reproductive;apterous neote(i)nic.ergatomorphic male (ARTHRO: Insecta) A social insect withnormal male genitalia and a worker-like body; an ergatoidmale; an ergataner.ergatotelic type (ARTHRO: Insecta) A group of social insects,including the honey-bees in which the queen manifests onlysecondary instincts, while the workers retain the primaryinstincts. see gynaecotelic type.ergonomics n. [Gr. ergon, work; nomos, law] (ARTHRO: Insecta)The quantitative study of the distribution of workperformance and efficiency of social insects.ericeticolous a. [Gr. erike, heath; L. colere, to inhabit] Inhabitinga heath or similar environment.erichthus larva (ARTHRO: Crustacea) In Hoplocardia, a megalopatype larva of mantis shrimp in the families Lysiosquillidaeand Gonodactylidae.erosion n. [L. erosus; eaten away] 1. Wearing away of soil becauseof wind, water, or gravitational action. 2. (MOLL:Gastropoda) The disintergration of the apex of the shell.errantia n. [L. errere, to wander] 1. Mobile organisms. 2.(ANN: Polychaeta) Sometimes used as a taxonomic group.eruca n.; pl. erucae [L. eruca, caterpillar] (ARTHRO: Insecta) Acaterpillar or other insect larva similar in appearance.eruciform a. [L. eruca, caterpillar; forma, shape] (ARTHRO: Insecta)Having a body shaped like a caterpillar: cylindricalbody, well developed head, thoracic legs, and abdominalprolegs. see polypod larva.eruciform larva (ARTHRO: Insecta) The larval instar of certainHymenoptera and Lepidoptera, caterpillar-like larva with awell-developed head capsule, true legs and often abdominalprolegs.erucism n. [L. eruca, caterpillar; -ismus, denoting condition](ARTHRO: Insecta) Poisoning or rash caused by caterpillars

Online Dictionary of Invertebrate Zoology 347or pupae. see lepidopterism, paraerucism, metaerucism,cryptotoxic, phanerotoxic.erucivorous a. [L. eruca, caterpillar; vorare, to devour] (AR-THRO: Insecta) The eating of or on caterpillars.eructation n. [L. ex, out of; ructare, to belch] The emitting ofcontents from the intestine via the mouth.eruptive cell see spherule celleryoneicus larva (ARTHRO: Crustacea) In Eryonoidea, a larvalstage with almost spherical carapace with many spines andabdomen shorter than carapace.exploratory trail (ARTHRO: Insecta) An odor trail laid by advanceworkers of a foraging group of social insects.explosive cell see spherule cellexplosive evolution and speciation Rapid formation of numeroustypes from a single or a few types.exsculptate a. [L. ex, out of; sculpere, to carve] Having moreor less irregular longitudinal lines with grooves between.exscutellate see escutellateexserted a. [L. exsertus, projecting] Protruding or projectingfrom the body.exsertile a. [L. exsertus, projecting] Capable of being exertedor extruded.exsheath v. [L. ex, out of; A.S. sceath, case] To escape fromthe residual membrane (egg shell) of a previous developmentalstage.exsules n. [L. exule, exile] (ARTHRO: Insecta) In apterousAdelges on the secondary host, give rise parthenogeneticallyto the neosistens form.extend v. [L. ex, out of; tendere, to stretch] To spread orstretch out.extensile a. [L. ex, out of; tendere, to stretch] Capable of beingextended, stretched or spread.extension plate see unguitractor plateextension sole (ARTHRO: Insecta) The pad-like pulvillus.extensor muscle see unguitractor

348Maggenti and Gardnerextenso-tendon see unguitractor tendonextenuate v. [L. ex, out of; tenuis, thin] To make or becomethin or slender; to diminish.exterior a. [L. exterus, out] Situated away from the centralaxis; outward; outside.exterior skeletal wall (BRYO: Gymnolaemata) InCheilostomata, a skeletal wall which calcifies against thecuticle; the membrane forming this wall expands thecoelomic volume of the colony.exterior wall (BRYO) Body wall that increases the size of thezooid body and colony.external a. [L. exterus, outside] Outward; that part away fromthe center of the body.external buttress see buttressexternal cortical layer (NEMATA) The outermost stratum ofthe cuticle, comprised of a dense outer area, an inner lessdense area, and a thinner area.external exocuticle (NEMATA) In derived forms, a subdivisonof the exocuticle.external genitalia The organs involved with sexual matingand the deposition of eggs.external medullary mass see medullaexternal muscle (BRYO) A muscle extending from a body wallacross the body cavity, to the lophophore or to the gut.external parameres (ARTHRO: Insecta) All male externalgenital appendages.external parasite An ectoparasite.external respiration The process of gaseous exchange betweenan organism and its environment.external secretion Any secretion to the outside of the body orinto the cavity of the enteron.external statocysts (ARTHRO: Insecta) Special hair structuresfor the retention of the air supply that are adapted to underwaterlife.external thickening see buttress

Online Dictionary of Invertebrate Zoology 349externomedial vein (ARTHRO: Insecta) 1. In Hymenoptera,the radius. 2. In Orthoptera, the media.externomedian nerve (ARTHRO: Insecta) The humeral anddiscoidal veins collectively.exteroceptors n.pl. [L. exterus, outside; capere, to take]Sense organs situated externally which respond to conditionsin the external environment, as opposed to interoceptors.extogenous see exogenousextra-axial skeleton (PORIF) Skeletal elements that surroundor arise from an axial region.extracellular a. [L. extra, outside; cellula, little cell] Pertainsto being outside of the cell but within the organism.extracellular digestion Digestion of food within a cavity ofthe digestive system.extraconic a. [L. extra, outside; Gr. konos, cone] Almost conical,but with concave sides. see coeloconoid.extracorporeal a. [L. extra, outside; corpus, body] Occurringoutside of the body.extracorporeal digestion A mode of feeding whereby someparasites and predators release esophageal or salivary secretionsinto the host or prey that predigests the internalcontents of the host or prey.extrados n. [L. extra, outside; F. dos, the back] The exteriorcurve of an arch. see intrados.extraembryonic a. [L. extra, outside; Gr. embryon, fetus]Outside the body of the embryo.extraembryonic field see serosaextraenteric a. [L. extra, outside; Gr. enteron, intestine] Outsidethe enteron.extranidal a. [L. extra, outside; nidus, nest] (ARTHRO: Insecta)In social insects, outside the nest or hive.extranuclear a. [L. extra, outside; nucleus, kernel] Structuresor processes found outside the nucleus.extraocular a. [L. extra, outside; oculus, eye] Away from orbeyond the eyes.

350Maggenti and Gardnerextraoral a. [L. extra, outside; os, mouth] Away from or beyondthe mouth.extrapallial space (MOLL: Bivalvia) A narrow muscus-filledspace between the mantle lobe and the valve of the shell.extratentacular budding (CNID: Anthozoa) Development ofnew polyps of a zoantharian colony from the tissue betweenexisting ones.extratropical a. [L. extra, outside; tropicus, solstice] Outsideof the tropics; not in the tropics.extrazooidal a. [L. extra, outside; Gr. zoon, animal] (BRYO) Acolony structure, protective or supportive in function, thatremains outside zooidal boundries.extremity n.; pl. -ties [L. extremus, outermost] The remotestpart or point from the base.extrinsic a. [L. extrorsus, in an outward direction] 1. Not in ora part of a body or congregation; external. 2. Environmentalinfluences on a population. see intrinsic.extrinsic articulation One in which the articulating surface ofcontact is outside of the skeletal parts. see intrinsic articulation.extrinsic muscles Muscles which move an organ (leg, etc.),but that originate outside of it. see intrinsic muscles.extrorse a. [Gr. extrorsus, in an outward direction] Turning orfacing outwards; toward the outside. see introrse.extrude v. [L. ex, out of; trusus, thrust] To turn; to force out.extrusion n.exudate n. [L. exsudo, discharge by sweating] Any flow fromthe body or organ through pores or openings by naturaldischarge.exudatoria n. [L. exsudo, discharge by sweating] (ARTHRO:Insecta) Finger-like appendages of certain larvae of antsand termites that produce secretions attractive to theworkers.exude v. [L. exsudo, discharge by sweating] To ooze moistureor other liquids through minute openings.exumbilicate a. [L. ex, out of; umbilicus, navel] Lacking an

Online Dictionary of Invertebrate Zoology 351umbilicus.exumbrella n. [L. ex, out of; dim. umbra, shade] (CNID: Scyphozoa)The convex aboral surface of a medusa or jellyfish.see subumbrella.exuvia n.; n.pl. exuviae [L. exuvia, cast] The cast parts of thecuticle; cuticle shed at a molt; usually used only in theplural.exuvial glands Certain epidermal glands associated with themolting fluid during ecdysis at molting.exuvial space (ARTHRO: Insecta) An area between the epidermisand the cuticle into which the molting enzymes are secretedafter apolysis.exuviate v. [L. exuvia, cast] To cast skin or shell; to molt.eye n. [A.S. eage, eye] An organ of sight; a photoreceptor; acompound eye; an ocellus.eye-bridge (ARTHRO: Insecta) In Diptera, eyes dorsally joinedabove the antennae by a narrow line of facets.eye brush see prosartemaeye cap (ARTHRO: Insecta) In Lepidoptera, a structure overhangingor capping the compound eye.eyespots n.pl. [A.S. eage, eye; ME. spotte, spotted] Pigmentedareas in many invertebrates to which are attributedvarious functions: a simple eye or visual organ (ocellus);intimidation of predators; to deflect attention to the leastvulnerable parts of the body; a sensory organ.eyestalk see ocular peduncle

FF 1 First filial generation, arising from a cross, subsequent generationsabbreviated F 2 , F 3 , etc. see P 1 .face n. [L. facies, countenance] 1. The surface of anything. 2.(ARTHRO: Insecta) The front of a verticle head between thecompound eye above the mouth to vertex. a. In Hymenopterabetween antennae and clypeus. b. In Diptera, belowthe frontal suture, often having grooves or fovea below theantennae; the mesofacial plate. c. In Ephemeroptera, thefused front and vertex; facies.facet n. [F. facette, small face] 1. A small surface. 2. (ARTHRO:Insecta) The external surface or part of a compound eyeunit or ommatidium.facette n. [F. facette, small face] (ARTHRO: Pentastomida) Afunnel-shaped opening through the inner membrane complexof the egg into which the product of the dorsal organis deposited.facetted eye see compound eyefacial angle (ARTHRO: Insecta) The angle formed by the pointof union of the face and vertex.facial bristles see oral vibrissaefacial carina (ARTHRO: Insecta) One of the carinae of thefrontal costa and of the accessory carinae of the face. a. InOrthoptera, one of the accessory carinae. b. In Diptera, thesingle median facial ridge separating the antennal grooves.facial depression (ARTHRO: Insecta) 1. The antennal groove.2. For Diptera, the middle of the face; the facial plate.facialium see vibrissal ridgefacial orbit (ARTHRO: Insecta) On the head, the region next tothe mesal margin of a compound eye.facial plate (ARTHRO: Insecta) In Diptera, the central part ofthe face.facial quadrangle (ARTHRO: Insecta) In bees, the quadrangle

Online Dictionary of Invertebrate Zoology 353formed by the eyes laterally, and between their apex andbelow by a line between their lower points.facial ridge see vibrissal ridgefacies see facefacio-orbital bristles (ARTHRO: Insecta) In Diptera, bristles oneach side near the orbit, may extend to the gena or cheek;orbital bristles. see genal bristles.factor n. [L. facere, to do, to make] 1. An agent or causativeagent in genetics determining development of a hereditarycharacter in offspring. 2. (PORIF) A cell surface-active proteoglycanaffecting the stability of cell-to-cell adhesion.facultative n. [L. facultas, capability] The ability to live underdifferent conditions. see obligate.facultative meiotic parthenogenesis The diploid chromosomalcomplement in the reduced oocytes is restored by fusionof the second polar nucleus with the egg pronucleus.see automictic meiotic parthenogenesis.facultative parasite 1. A parasitic organism that can developinside a host, but still retains the ability to complete a freelivinglife cycle in the outside environment. 2. Organismsnormally free-living that may become parasitic under specialenvironmental conditions. see obligate parasite.facultative symbiont A symbiont that establishes a relationshipwith a host only if the opportunity presents itself. seeobligate symbiont.faeces see fecesFahrenholz's rule Common ancestors of present day parasiteswere themselves parasites of the common ancestors ofpresent day hosts; parasite phylogeny mirrors host phylogeny.falcate a. [L. falx, sickle] Sickle-shaped, hooked or new moonshaped.falces n.pl.; sing. falx, falcis [L. falx, sickle] 1. (ARTHRO: Chelicerata)Falces used to denote chelicerae of ticks; cheliceraeof certain arachnids. 2. (ARTHRO: Insecta) In lycanidbutterflies, when present, paired, sclerotized, curved armsarticulated with the caudal margin of the tegumen ventrad

354Maggenti and Gardnerof the uncus, and extending ventro-caudad.falciform a. [L. falx, sickle; forma, shape] Having the shape ofa sickle; curved like a sickle.falciger n. [L. falx, sickle; gerere, to carry] (ANN) A compound,distally blunt, curved seta.falculate a. [L. dim. falx, sickle] Curved with a sharp point.falsadentes see cibarial teethfalse head (ARTHRO: Insecta) In some syrphid fly larvae, abroad globulose or hood-like cephalic segment(s) with avisible constriction behind.false legs see prolegs or spurious legsfalse umbilicus (MOLL: Gastropoda) A cavity or depression inthe base of the last whorl of the shell; a pseudumbilicus.famulus n.; pl. -li [L. famulus, servant] (ARTHRO: Chelicerata)In Acari, microsensory seta found on the genu, tibia andtarsi.fan n. [A.S. fann, fr. L. vannus, fan] 1. A segment or processflattened and spread triangularly or in a semicircle, appearingfan-like. 2. (ANN: Polychaeta) The parapodia on thel4th, 15th, or 16th segments. 3. (CNID: Anthozoa) A colonyof zooids. 4. A flabellum.fang n. [A.S. fang, seizure] (ARTHRO: Chelicerata) The clawlikedistal segment of the chelicera of spiders.farctate a. [L. farctus, filled] Fully filled; distended; to swellout.farinaceous a. [L. farina, flour] 1. Mealy. 2. (ARTHRO: Insecta)Has been used to describe powdery looking insect surfacesand wings; pulverulent; pollinose.fascia n., pl. -ciae [L. fascia, bundle] 1. A broad and well-definedband of color; striped. 2. Marked with transversebands of color. see vitta. 3. A layer of connective tissuecovering an organ or attaching a muscle. fasciate a.fascicle, fasciculus n.; pl. -li, -les [L. dim. fascia, bundle] 1.A small bundle or tuft. 2. A bundle of nerve or muscle fibers.3. (ANN) A bundle of setae originating from a commonmuscular source, normally two dorsolateral and two

Online Dictionary of Invertebrate Zoology 355ventrolateral fasciculi per segment. 4. (ARTHRO) A styletbundle or combination of mouthparts of blood-feeding arthropodsthat function to pierce the skin. 5. (CNID) Tubesintergrown together to form a stem or branches. 6. (MOLL:Polyplacophora) A bundle of hairs or bristles against eachvalve end. 7. (PORIF) Fibers intertwined in bundles to producecomplex interlocking tracts.fasciole n. [L. dim. fascia, bundle] 1. (CNID: Echinoidea) InSpatangidae, a small band of minute spine-bearing tuberclesused to produce water currents in the burrow forfeeding, respiration and excretion. 2. (MOLL: Gastropoda) Aspiral band formed by the successive growth lines on theedges of a canal.fascio-maculata Having spots arranged in bands.fascio-punctate Ornamented with colored points arranged inbands.fastening or fixing muscle (SIPUN) A thin strand or filamentof muscle joining or attaching some part of the alimentarycanal, (the esophagus or posterior region of the intestine)to the body wall.fastigiate a. [L. fastigium, gable end] Arranged into a conicalbundle.fastigium n. [L. fastigium, gable end] (ARTHRO: Insecta) InOrthoptera, the anterior dorsal surface of the vertex ofgrasshoppers.fat body Aggregated cells that store food reserves, storage forexcretory materials, or light producing organ; a center inwhich many metabolic processes occur.fate map Diagrammatic method of indicating the fate of embryoniccells.fauces n.pl. [L. fauces, gullet] That portion of the interior of aspiral shell that can be viewed by looking into the aperture.fauna n. [L. Faunus, diety of herds and fields] The animal lifeof a region. see flora, biota.faunal region An area where certain groups of animals arefound.faveolate a. [L. favus, honeycomb] Pitted; having depressions

356Maggenti and Gardneror cells resembling a honeycomb; favose.feces n.pl. [L. faex, dregs] Pertaining to sediment, refuse orexcrement.fecula n. [L. dim. faex, dregs] (ARTHRO: Insecta) Excrement.fecundate v.t. [L. fecundus, fruitful] To fertilize; to impregnate.fecundity n. [L. fecundus, fruitful] The potential reproductivecapacity as measured by the quantity of gametes, particularlyeggs, produced.feedback mechanism Regulation mechanism in cells by whichthe final product of a metabolic reaction inhibits furtherproduction of that product.feeding zooid (BRYO) A zooid that at some developmentalstage feeds and provides nourishment to the entire colony.feeler n. [A.S. felan, to feel] A tactile organ of many invertebrates.felt chamber (ARTHRO: Insecta) A spongy structure within thespiracular chamber of larval trypetid flies, thought to act asan air filter.felt setae (ANN: Polychaeta) In scale worms, threadlike setaethat arise from the notopodia and trail back over the dorsalsurface of the animal.female ducts see gonoduct, oviductfemale encystment see matricidal hatchingfemale funnel (ANN: Oligochaeta) Enlargement of the entalend of an oviduct of earthworms that facilitates entry of theova on their way to the exterior.female pores (ANN: Oligochaeta) The external apertures of thefemale ducts of earthworms.femoro-alary organs (ARTHRO: Insecta) A stridulatory apparatus.femorogenu n. [L. femur, thigh; genu, knee] (ARTHRO: Chelicerata)In mites, a leg segment resulting from the fusion ofthe femur and genu.femorotibial joint (ARTHRO) One of the two primary bendingsof a typical leg, pertains to the femur and the tibia. see

Online Dictionary of Invertebrate Zoology 357coxotrochanteral joint.femur n. [L. femur, thigh] 1. (ARTHRO: Chelicerata) a. In spiders,the thigh; normally the stoutest segment, articulatingto the body through the trochanter and coxa and bearingthe patella and remaining leg segments at the distal end.b. In mites, segment of palp and legs, between the trochanterand genu; sometimes divided into femur 1 (proximal)and femur 2 (distal). 2. (ARTHRO: Insecta) The largestand stoutest part of the leg of most adults; the third segment,located between the trochanter and the tibia.fenestra n.; pl. -trae [L. fenestra, window] 1. A small opening;a window. 2. An opening through a shell; a foramen.3. (ARTHRO: Insecta) a. Transparent spots or marks on thewings. b. In Orthoptera, a small membranous area at thebase of an antennae of a cockroach. c. In Isoptera, a cavityon the head; a fontanel. d. The membranous base of theommatidia at the junction with the optic nerve of a compoundeye; a transparent ocellate spot in an eye. e. Inmale Odonata, the genital opening on the ventral surface ofabdominal segment 11. see fontanelle. 4. (BRYO: Gymnolaemata)In Cheilostomata, an open space or mesh in reticulatezoaria. 5. (NEMATA) a. In Secernentea, the thinmembranous area surrounding or on either side of thevulva of a cyst forming nematode (Heterodera spp.). b. Insome marine Adenophorea, the openings in subcuticularhelmets through which sensory nerves pass. fenestratea., fenestration n.fenestrate colony (BRYO) An erect colony in which thebranches form a reticulate pattern.fenestrella n. [L. dim. fenestra, window] (ARTHRO: Insecta) InOrthoptera, a transparent spot in the anal area of the anteriorwings. see fenestra.fenestrule n. [L. dim. fenestra, window] (BRYO) A small openingbetween branches of a fenestrate colony.fente n. [F. fente, a hole] (MOLL: Bivalvia) An opening or slitnear the hinges when the valves are closed.feral a. [L. ferus, wild, untamed] Undomesticated; wild; uncultivated.

358Maggenti and Gardnerferment see enzymefermentation chambers (ARTHRO: Insecta) A tube or pouch inthe hind gut where food materials are broken down byvarious bacteria or protozoa.ferreous a. [L. ferreus, of iron] The color metallic gray resemblingpolished iron.ferruginous a. [L. ferrugineus, like iron rust] Rusty red-brownin color.ferrule n. [L. dim. viria, bracelet] (NEMATA) A ring or bushingmaking a tight joint between the odontostyle and odontophore.fertile a. [L. fertilis, fruitful] Producing viable gametes, capableof producing viable eggs or living offspring. fertility n.fertilization n. [L. fertilis, fruitful] Fusion of two gametes, especiallyof their nuclei, to produce a zygote.fertilization cone Protuberance on an ovum where the spermatozoonfuses with the ovum.fertilization membrane A delicate membrane that growsoutward from the point of contact of the egg and spermatozoonand rapidly covers the surface of the egg.fertilizin n. [L. fertilis, fruitful] A chemical causing species specificattachment of spermatozoon to ovum.festivus a. [L. festivus, holiday, feast] Having a variety of colors.festoon n. [F. feston, garland] Garlands hanging in curves.festoons n.pl. [F. feston, garland] (ARTHRO: Chelicerata)Sclerites on the posterior margin of the opisthosoma ofcertain hard ticks.fetid a. [L. fetidus, stinking] Having a disagreeable odor;malodorous.fiber n. [L. fibra, thread] 1. Any thread-like structure. 2. (PO-RIF) A column more homogeneous than a tract.fiber layers (NEMATA) Cuticular strata of dense connective-liketissue that is oblique, ribbonlike, possibly spiral (mesocuticle).fibril n.; pl. -llae [L. dim. of fibra, thread] Small fibers or

Online Dictionary of Invertebrate Zoology 359threads within cells.fibrillar layer (NEMATA) In ascarids, a cuticular stratum thatconsists of a condensation of spongy matrix forming aclosely woven network between the internal cortical layerand the matrix layer.fibrin n. [L. fibra, thread] A fibrous protein that constitutesmuscular tissue and facilitates blood clotting or coagulation.fibrinogen n. [L. fibra, thread; gigno, producing] A proteinsubstance of the blood and other body fluids facilitating theproduction of fibrin.fibrocyte n. [L. fibra, thread; Gr. kytos, container] Elongatedcells derived from connective tissue cells, the fibroblasts,functioning in the production of fibrous tissue.fibroin n. [L. fibra, thread] (ARTHRO) 1. A protein found in silkand webs. 2. (ARTHRO: Insecta) In Bombyx, a unique proteincontaining an unusual amount of the simpler aminoacids glycine and alanine.fibroplasm n. [L. fibra, thread; Gr. plasma, molded] (NEMATA)That portion of a muscle cell differentiated into contractilefibers. see sarcoplasm.fibrous ligament (MOLL: Bivalvia) The fibrous part of a ligamentin which the conchiolin is impregnated with calciumcarbonate; elastic to compression.fibula see jugal lobefide v.t. [L. fidus, trustworthy] Used to indicate that the authorhas not seen the work or specimen cited.filament plate (ARTHRO: Insecta) In early embryology, a differentiatedsheet of cells connecting the genital and heartrudiments on the same side of the body.filamentary appendage (ARTHRO: Crustacea) In Cirripedia, amembranous process at the base of the cirrus.filaria n. [L. filum, thread] (NEMATA: Secernentea) Microfilaria(Spirurida), motile embryo found in the subcutaneous tissue,blood or lymph systems of many animals and man.filariform larva (NEMATA: Secernentea) A post-feeding stagelarva characterized by its delicate, elongate structure and

360Maggenti and Gardnerits slim, capillary esophagus.filate a. [L. filum, thread] Threadlike, slender, and without appendages.filator n. [L. filum, thread] (ARTHRO: Insecta) The silk spinningapparatus of caterpillars. see spinnerets.file n. [A.S. fil, feo, file] (ARTHRO: Insecta) A filelike, roughridge on the ventral side of the tegmen, near the base, thatfunctions as a part of the stridulating mechanism in cricketsand long-horned grasshoppers.filiation n. [L. filius, -ia, son, daughter] The relationship of offspring;lineage. filial a.filibranch gill (MOLL: Bivalvia) Gills with bars of tissues betweenthe limbs of the "U" at intervals with filaments attachedto adjacent filaments by specialized ciliary junctions;functioning in inhalent and feeding-ventilating currents.filicornia n. [L. filum, thread; cornu, horn] (ARTHRO: Insecta)Insects with filiform antennae, e.g., the coleopteranAdephaga.filiform a. [L. filum, thread] 1. Hairlike or threadlike. 2. (CNID)Used to describe thread-like tentacles tapering to a point.Filippi's glands see Lyonnet's glandsfillets n. [L. filum, thread] Bands of fibers; any raised rib.filose a. [L. filum, thread] Having a threadlike appendage, orterminating in a threadlike process.filter apparatus (ARTHRO: Insecta) Opposing rows of taperingprocesses of some spiracular atrial walls, clothed with interlacinghairs, that permits passage of air and preventsforeign particles or water from penetrating into the atrium.filter chamber An area that serves to filter suspended matter.filter feeder An animal that feeds on small particles which itfilters from the surrounding medium.filum terminale (ARTHRO: Insecta) In Thysanura, tergite XIprolonged into a bristle.fimbria n.; pl. -briae [L. fimbriatus, fringed] 1. A fringe-likestructure. 2. (ARTHRO: Insecta) Ciliated hair terminating

Online Dictionary of Invertebrate Zoology 361any part.fimbriate a. [L. fimbriatus, fringed] 1. With finger-like projections;having a fringed or puckered margin. 2. (ARTHRO:Insecta) An antenna with joints bearing a lateral hair. 3.(MOLL: Gastropoda) A shell with an irregular margin.fin n. [A.S. finn, fin] An extension of the body of an aquaticanimal used in locomotion or steering.finger n. [A.S. finger, finger] 1. Any structure resembling orused like a finger. 2. (ARTHRO: Crustacea) a. In Decapoda,one of the scissor-like blades at the end of the cheliped,usually one is movable and one fixed. b. In Ostracoda, adorsal and ventral process of the male copulatory apparatuswhich are thought to be tacticle organs and may alsoassist in directing or holding certain structures duringcopulation.finger guard (ARTHRO: Crustacea) In male Ostracoda genitalia,an extension of the ventral cardo alongside the dorsal andventral fingers.firmatopore n. [L. firmus, strong; porus, hole] (BRYO: Stenolaemata)In Tubuliporina, a degenerate zooid that appearsas a slender, proximally directed tubule.first antenna see antennulefirst axillary (ARTHRO: Insecta) The sclerite that articulateswith the anterior notal process; its anterior necklike portionabuts the base of the subcostal wing vein.first incisura (ARTHRO: Insecta) In scale insects, the pygidialmarginal notch on the meson between the median pair oflobes.first maxilla see maxillulaefirst maxillae (ARTHRO: Insecta) The second pair of appendagesbelonging to the mouth, posterior to the mandibles orjaws; the maxillae.first phragma (ARTHRO: Insecta) A transverse apodeme ofDiptera, under the anterior promontory of the mesonotumand internally connecting the antepronota.first reviser The first author to publish a definite choice of oneamong two or more conflicting names or zoological inter-

362Maggenti and Gardnerpretations that are equally available under the ICZN.first segment The nearest segment of any segmented appendagenearest the body at point of attachment.first species rule Authors that specify the first species namedin a new genus to be the type of that genus; generally theworks of older authors in which no generic type was specified.first thoracic spiracle (ARTHRO: Insecta) The mesothoracicspiracle, sometimes dislocated into the posterior part of theprothorax.first trochanter (ARTHRO: Insecta) The first segment of a telopodite;the basipodite.fissate a. [L. fissus, cleft] Cleft or split; having fissures orcracks.fissile a. [L. fissus, cleft] Capable of being divided or separatedinto layers; divided into parallel lamellae.fission n. [L. fissus, cleft] The splitting of a single chromosomeinto two chromosomes; splitting of one organism into twoorganisms. see fusion.fissiparous a. [L. fissus, cleft; parere, to produce] Reproductionor propagation by fission.fissure n. [L. fissura, cleft] A narrow opening, slit, furrow orgroove separating adjacent tissues, parts or organs.fistula n.; pl. -las [L. fistula, pipe] 1. A reed, pipe or tube. 2.(ARTHRO: Insecta) The proboscis of Lepidoptera. fistular a.fix v. [L. fixus, bind] To kill and preserve specimens for observationand retention.fixation n. [L. fixus, bind] (MOLL: Bivalvia) The process of animalspermanently attaching themselves to the substrate.fixative n. [L. fixus, bind] A chemical compound which has thequality of fixing and preserving specimens for observationand retention.fixed finger (ARTHRO: Crustacea) The distal immovable part ofthe propodus of the chela; the pollex.fixed hairs see microtrichiafixed jaw (ARTHRO: Chelicerata) In Acari, the distal (fixed) part

Online Dictionary of Invertebrate Zoology 363of the cheliceral segment.fixed-wall colony (BRYO: Stenolaemata) Feeding zooids withoral walls attached to the body apertures.flabellate a. [L. flabellum, fan] Having fanlike processes orprojections. flabelliform a.flabellum n.; pl. -la [L. flabellum, fan] 1. Any leaflike or fanlikeprocess. 2. (ARTHRO: Crustacea) The thin distal exite ofa branchiopod; or epipodite of a thoracopod. 3. (ARTHRO:Insecta) A transparent distal lobe of the glossa of bees;bouton.flaccid a. [L. flaccus, flabby] Lacking firmness or elasticity;limp; limber.flagellate a. [L. flagellum, whip] 1. Having flagella or whip-likestructures. 2. Having a lash-like appendage as the terminalpart of an antenna.flagellated chamber (PORIF) Cavities lined with coanocytes.flagelliform a. [L. flagellum, whip; forma, form] Flagella-like;whip-like; lash-like.flagellomere n. [L. flagellum, whip; Gr. meros, part] (ARTHRO:Insecta) In Diptera, an individual subdivision or unit of theantennal flagellum; in mosquitoes 13-14 flagellomeres.flagellum n.; pl. -lums, -lla [L. flagellum, whip] 1. Any ofvarious whiplike appendages. 2. A protoplasmic process,longer than a cilium, whose movements usually effect locomotionof the cell. 3. The whip-like tip of the male copulatoryorgan in some invertebrates. 4. (ARTHRO: Crustacea)The multiarticulate distal portion of the antennule, antenna,or exopod. 5. (ARTHRO: Insecta) The distal portion of an insectantenna beyond the second segment (pedicel). seeflagellomere. 6. (PORIF) A long projection from a cell,used as a propeller.flame bulb Common name for solenocytes.flame cell see solenocyteflammaules n.pl. [L. flammula, blaze; Gr. aule, court] Havingspots of color resembling a small flame; reddish, tingedwith red.flange n. [OF. flangier, flank] 1. A projecting rim, edge, or ex-

364Maggenti and Gardnerternal or internal rib; a guide attachment for another partor organ. 2. (ARTHRO: Crustacea) In ostracods, a ridgealong the valve margin formed by projection of the outerlamella as a narrow brim. 3. (NEMATA) Posteriorly slopingthickening or knob at the base of the odontostyle extension.flank n. [OF. flanc, side] (MOLL: Bivalvia) The middle of thevalve surface, bounded posteriorly by the posterior ridge.flaring a. [Uncertain] To open, spread or project outward;spreading from within toward outward; a lip.flatworms Classes Trematoda, Turbellaria and Cestoda; Platyhelminthes.flavescent a. [L. flavus, yellow] A yellow color.flavid a. [L. flavus, yellow] Golden yellow; sulphur yellow.flavones n.pl. [L. flavus, yellow] Plant pigments that can beincorporated into the tissues of insects which contribute totheir coloration. see anthocyanins, anthoxanthins,carotene pigments.flavous see flavidfleshy filament (ARTHRO: Insecta) A flexible, attenuate processof the body wall on some butterfly larvae.flex v. [L. flectere, to bend] To bend or curve back.flexor a. [L. flectere, to bend] Pertains to muscle that serves tobend a limb at an articulation.flexor surface A surface brought closer together when ajointed structure is bent at a joint.flexuous a. [L. flexuosus, full of turns] Having gentle turns andwindings in opposite directions; zigzag.flexure n. [L. flexura, a winding] 1. A bending. 2. (MOLL) Theprogressing folding or warping of one or both valves.float n. [A.S. flotian, float] An air filled sac used for buoyancyby an organism or its eggs.floatoblast n. [A.S. flotian, float; Gr. blastos, bud] (BRYO) Astatoblast with a peripheral pneumatic annulus, with orwithout marginal hooks.flocculent a.; pl. -li [L. floccus, lock of wool] Covered with a

Online Dictionary of Invertebrate Zoology 365soft, waxy substance, often resembling wool; clinging togetherin bunches.flocculus n.; pl. -li [L. floccus, lock of wool] (ARTHRO: Insecta)In Hymenoptera, a tuft of hairs on the posterior coxa.flora n. [L. flos, flower] The plants or plant life of a region. seefauna, biota.floricome n. [L. flos, flower; coma, hair] (PORIF) An elaboratelybranched hexaster spicule.floscelle n. [L. flos, flower] (ECHINOD: Echinoidea) A flowerlikestructure composed of bourrelets and phyllodes aroundthe mouth.flosculus n. [L. dim. flos, flower] (ARTHRO: Insecta) A small,crescent shaped, tubular anal organ with a central style,found in certain lantern flies (Fulgoridae).fluted a. [OF. flaute] A channeled or grooved area.fluviatile a. [L. fluviatilis, of a stream] Living in rivers; growingnear or inhabiting rivers or fresh water.fly-blow (ARTHRO: Insecta) An egg or larva of flesh flies.focus n.; pl. foci [L. focus, central point] A particular region ofdisease; a localized region.fold n. [A.S. folde, a fold] 1. A doubling or folding. 2.(BRACHIO) A major external elevation of the valve surface,convex in transverse profile and radial from the umbo. 3. a.(MOLL: Bivalvia) A broad undulation in the shell surfacewhich is directed radially or comarginally. b. (MOLL: Gastropoda)The spirally wound ridge on the interior of a shellwall. see columellar fold, parietal fold.folded membrane (ARTHRO: Insecta) In Cicadidae, a specializedmembraneous area of the anterior wall of the ventralcavity of the sound-producing organ.foliaceous a. [L. folium, leaf] Leaflike in appearance.foliate a. [L. folium, leaf] Foliaceous; leaves, consisting oflaminae or thin plates.folioles a. [L. dim. folium, leaf] Having leaflike processes extendingfrom a margin or protuberance.folium n. [L. folium, leaf] (ARTHRO: Chelicerata) A pigmented

366Maggenti and Gardnerdesign or pattern on the abdominal dorsum of some spiders.follicle n. [L. dim. follis, windbag] Any small cavity, sac ortube.follicle cells Epithelial cells surrounding the oocytes in thevitellarium, that in some species secrete on its externalsurface the chorion and perhaps function in a nutritionalrole.follicular a. [L. dim. follis, windbag] Pertaining to or havingfollicles.folliculate a. [L. dim. follis, windbag] Having, consisting of, orenclosed in a follicle or follicles.fontanelle, fontanel n. [F. fontannella, little fountain] (AR-THRO: Insecta) In Isoptera, when present, a small circularor slit-shaped orifice of the frontal or cephalic gland nearthe center of the head, through which a liquid is emitted; afrontal pore.food n. [A.S. foda, fodder] Any material that an organism obtainsfrom the environment that yields energy or suppliesmatter for its growth.food bodies (ARTHRO: Insecta) In Hymenoptera, secretions onthe seeds and leaves of some plants used by ants as food.food chain Food energy transferred from plants through a sequenceof organisms in which each is food of a later memberof the sequence.food channels see food meatusfood cycle see food webfood meatus (ARTHRO: Insecta) In Diptera, a channel formedby the juxtaposition of the mouthparts of mosquitoes anteriorto the cibarium.food web Interlocking pattern of food chains in a community;typical food web composed of plants, herbivores, carnivores,omnivores, and detritus feeders.foot n.; pl. feet [A.S. fot, foot] 1. An organ of locomotion orattachment. 2. (ARTHRO: Insecta) The tarsus. 3. (MOLL) a.The muscular undersurface of the body. b. In Bivalvia, themuscular, protrusible structure extending from the body

Online Dictionary of Invertebrate Zoology 367mid-line; used for burrowing. 4. (ROTIF) The foot or tail,with or without toes.foot-shaped loop see cubito-anal loopforamen n.; pl. -ramina, -ramens [L. foramen, hole] 1. Asmall opening, orifice or perforation through a bone, shell,membrane or partition. 2. (ARTHRO: Insecta) The openingof an insect cocoon. 3. (BRACHIO) A round opening at ornear the beak facilitating the extension of the pedicle.foramen magnum (ARTHRO: Insecta) The opening on theposterior side of the head, giving passage to the internalstructures that extend from the head to the thorax; the occipitalforamen.foramina pl. foramenforceps n.; pl. & sing. [L. forceps, pincers] 1. (ARTHRO) Hookor pincer-like processes terminating the abdomen of variousarthropods which function as weapons in predation orfor defense, for holding the mate during courtship, or evenfor cleaning the body or folding the wings. 2. (ARTHRO:Crustacea) The chelipeds. 3. (PORIF) Tongs-shaped.forcipate a. [L. forceps, pincers] Bearing forceps or similarstructures.forcipate mastax (ROTIF) Slender, elongate trophi formed byrami and fulcrum (incus).forcipiform a. [L. forceps, pincers; forma, shape] Forcepsshaped.fore n. [A.S. for, fore] The front; the anterior.forebrain n. [A.S. for, fore; braegen, brain] (ARTHRO: Insecta)The protocerebrum.foregut n. [A.S. for, fore; gut, channel] The anterior portion ofthe alimentary tract, from the mouth to the midgut. seestomodeum.forehead n. [A.S. for, fore; heafod, head] (ARTHRO: Insecta)The frons.foreleg n. [A.S. for, fore; ON. leggr, leg] (ARTHRO: Insecta)One of a pair of legs on the prothorax.forfex n. [L. forfex, shears] A pair of shears.

368Maggenti and Gardnerforficiform a. [L. forfex, shears; forma, shape] 1. Scissorshaped.2. (ECHINOD: Asteroidea) The pedicellaria of certainstarfish.forficulate a. [L. dim. forfex, shears] Scissor-shaped; forked;furcate.form n. [L. forma, shape] 1. An image or likeness. 2. A termfor a single individual, phenon, or taxon. see group.formaldehyde A colorless gas with a pungent odor; forms a40% solution in water (formalin) which is used as a fixative,preservative and for hardening tissues; formalin.formalin The 40% solution of formaldehyde in water; used asa preservative and for hardening tissues.formation n. [L. forma, shape; -tion, process] A definite typeof habitation, i.e., tundra, coniferous forest, prairie, rainforest, etc.formative cells see prohemocyteformic a. [L. formica, ant] (ARTHRO: Insecta) Of or pertainingto ants.formic acid An organic acid naturally occurring in some hymenopteraninsects.formicary n.; pl. -ies [L. formica, ant] (ARTHRO: Insecta) Anant's nest or dwelling; an ant-hill; a formicarium.fornent prep. [A.S. for, fore; efen, even] Opposite to; facing;alongside.fornicated a. [L. fornix, vault] Concave within, convex without;arched; vaulted.fornix n.; pl. fornices [L. fornix, vault] 1. An arch or fold. 2.(ARTHRO: Crustacea) A ridge in the lateral part of thecephalon above insertion of antennal muscles in waterfleas. 3. (MOLL: Bivalvia) The cavity on the inside under thehinge; the upper or convex shell of an oyster. fornical a.fossa n.; pl. -sae [L. fossa, ditch] A depression or cavity.fosse n.; pl. -ses [L. fossa, ditch] (CNID: Anthozoa) A groovebetween the collar and base of the capitulum in sea anemones.fossette n. [L. dim. fossa, ditch] 1. A small, hollow, dimple or

Online Dictionary of Invertebrate Zoology 369depression. 2. (MOLL: Bivalvia) Any socket; for example asocket for a cardinal tooth. 3. (PLATY: Cestoda) A ciliated,sensory pit.fossil n. [L. fossilis, dug out] An organic relic of a previousgeological period preserved by natural means in rock orsofter sediments which afford information as to the characterof the original organism.fossoria n. [L. fossor, digger] 1. (ARTHRO: Insecta) Insectsthat burrow or dig, i.e., mole crickets, digger wasps, etc. 2.(NEMATA) The cheilostomal, outwardly movable teeth.fossorial a. [L. fossor, digger] Fitted for or having the habit ofdigging.fossula n.; pl. -lae; fossule, fossulet [L. dim. fossa, ditch] 1.A shallow fossa. 2. (ARTHRO: Insecta) Grooves on the heador sides of the prothorax, in which the antennae are concealed;a foveola. 3. (MOLL: Gastropoda) A shallow lineardepression of the inner lip in some Cypraeidae.fossulate a. [L. dim. fossa, ditch] Having slight hollows orgrooves.founder cells 1. Daughter cells from the early cleavages of thezygote, with potential to form the individual tissues and organsof the body. 2. (PORIF) Cells responsible for ray lengthduring the secretion of calcareous spicules.founder principle/effect The principle that when founderspopulate a new colony as an isolated entity, the populationwill contain only a small fraction of the total genetic variationof the parental population.fourth axillary (ARTHRO: Insecta) In Hymenoptera and Orthopterawings, an axillary sclerite between the posteriornotal process and the third axillary sclerite.fovea n.; pl. -ae [L. fovea, pit] A small depression, pit, pocket;a fossa. foveolate a.foveola n.; pl. -lae [L. dim. fovea, pit] 1. An extremely smallpit; a small fovea. 2. (ARTHRO: Insecta) A small pit intowhich the antennae are inserted.fractate a. [L. frangere, to break] Displaced; bent at an angle.fractate antenna (ARTHRO: Insecta) An antenna with one very

370Maggenti and Gardnerlong joint with other annuli attached at angles.fracture n. [L. frangere, to break] (ARTHRO: Insecta) The sutureon the hemelytra of Heteroptera that separates thecuneus from the corium.fragile a. [L. frangere, to break] Easily broken; delicate; thinand brittle.fragmentation n. [L. frangere, to break] 1. Separated in partsor fragments. 2. Amitotic division. 3. (BRYO) Asexual productionof a colony from a single or group of zooids fromanother colony.frame n. [A.S. framian, fashion, prepare] (ECHINOD) A structurecomposed of pentagonal rings of small ossicles on thedistal end of the tube feet.frass n. [Ger. fressen, to devour] Insect larval excrement usuallymixed with plant fragments.free a. [A.S. freo, freedom] Unrestrained; motile; not attached.free edge (ARTHRO: Crustacea) The line of contact of an ostracodshell between closed valves, except along hinge linemarking the distal limit of the contact margin.free-living Not attached or parasitic; capable of independentmovement and existence. see sessile.free margin (ARTHRO: Crustacea) All parts of an ostracod shellmargin, except hingement.free mesodermal cell see hemocytefree pupa see exarate pupafree-swimming Swimming about; not sessile.free-walled colony (BRYO: Stenolaemata) A colony coveredloosely by membranous exterior walls that are not attachedat oral apertures.free-wax cell (ARTHRO: Insecta) Cells found in the hemolymphof Aphididae and Coccoidea.frenate wing coupling (ARTHRO: Insecta) Lepidopterous wingcoupling with a well developed frenulum that engages witha catch or retinaculum on the underside of the fore wing,securing the wings together.frenulum n.; pl. -la [L. dim. frenum, bridle] 1. (ARTHRO: In-

Online Dictionary of Invertebrate Zoology 371secta) The strong spine or group of bristles on the humeralangle of the hind wing, that projects beneath the fore wing,uniting them in flight; frenum. 2. (CNID) Gelatinous foldsupporting the subumbrella of certain jellyfish. 3. (POGON)A v-shaped cuticular thickening held in an epidermalgroove that functions as an adhesive device; also calledbridle.frenulum hook (ARTHRO: Insecta) A cuticular clasp (retinaculum)that functions in wing coupling.frenum n.; pl. frenna [L. frenum, bridle] 1. Any fold of skin ortissue supporting an organ. 2. (ARTHRO: Crustacea) Membranousbilateral fold of the carapace of barnacles thatholds eggs. 3. (ARTHRO: Insecta) The frenulum.frilled organ (PLATY: Cestoda) A posterior attachment organ inthe order Gyrocotylidea.fringe n. [L. fimbria, border] 1. To furnish or adorn. 2. Hair,scales or other processes extending beyond the margin,usually of equal length. 3. (MOLL: Bivalvia) Periostracumextending passed the calcareous shell.fringed plates see pectinaefringe scale (ARTHRO: Insecta) Any scale in the wing fringe.frogga see articular panfrondose a. [L. frondis, of leaves] More or less divided intoleaf-like expansions, as certain mollusks or bryozoans.frons n.; pl. frontes [L. frons, fore part of anything, face] 1.(ARTHRO: Insecta) The head sclerite bounded by the postfrontalsuture dorsally and the epistomal suture ventrally;the frons is delimited in various ways by different authorsand in different insects and stages. see front, facies. 2.(SIPUN) see cerebral organs, digitate processes.front n. [L. frons, fore part of anything, face] 1. The forehead;face. 2. (ARTHRO: Crustacea) In Decapoda, that part of abrachyuran carapace between the orbits. 3. (ARTHRO: Insecta)a. That portion of a cranium between the antennae,eyes, and ocelli; the frons. b. In ants, the facial area abovethe clypeus between the frontal carinae; dorsally it passeswithout definite boundary into the vertex.

372Maggenti and Gardnerfrontal a. [L. frons, fore part of anything, face] 1. Of or pertainingto the front or forehead. 2. (BRYO) Pertaining to theexposed or orifice-bearing sides of the zooecial chambers.frontal appendages (ARTHRO: Crustacea) In Anostraca, pairedfilaments arising from the bases of the antennae, but independentof them.frontal area (ARTHRO: Insecta) The small median triangularplate of ants, on the anterior surface of the head, justabove the clypeus.frontal band (ARTHRO: Crustacea) A glandular adhesion organof parasitic copepods, in the frontal region, used for attachmentto the host.frontal bristles (ARTHRO: Insecta) In Diptera, a row of bristleson each side of the boundry between the median, frontalvitta or plate and the eye orbit.frontal budding (BRYO: Gymnolaemata) Buds arising from thefrontal wall or associated structure.frontal carina (ARTHRO: Insecta) A carina, or ridge, formingthe medial boundary of the antennal fossa.frontal closure (BRYO: Gymnolaemata) In Cheilostomata, calcifiedfrontal and oral walls which were membranous in theautozooid originally.frontal condyle (ARTHRO: Insecta) A process of the frons thatarticulates with the dorsal fossa of the mandible.frontal costa (ARTHRO: Insecta) In Orthoptera, a prominentvertical ridge of the head; a carina.frontal crest (ARTHRO: Insecta) In Hymenoptera, an elevationextending across the head above the antennal sockets.frontal dilators of the pharynx (ARTHRO: Insecta) The muscleswhich run from the frons to the pharynx.frontal disc (ARTHRO: Insecta) In larval Diptera, a projectinghistoblast upon which develops the rudiment of an antenna.frontal eye see frontal organfrontal eye complex (ARTHRO: Crustacea) The eyes or reducedeyes innervated from the nauplius eye center. see

Online Dictionary of Invertebrate Zoology 373organ of Bellonci, frontal organ.frontal fissure (ARTHRO: Insecta) In Diptera, the line extendingfrom the crescent-shaped sclerite above the antennaeto the border of the mouth.frontal ganglion (ARTHRO: Insecta) The median ganglionabove the esophagus, in front of the brain, connected bynerves to the tritocerebral lobe on either side.frontal gland (ARTHRO: Insecta) In Isoptera, a large mediangland beneath the integument of the head in certain soldier-termites,opening through the fontanelle or frontalpore, which produces secretions.frontalia n. [L. frons, front] 1. (ARTHRO: Insecta) For Diptera,see frontal vitta. 2. (GNATHO) Paired sensory bristles on theanterior part of the head.frontal lobes (ARTHRO: Insecta) 1. In Psyllidae, two lobes orprotrusions divided by a suture in which an ocellus is situated.2. In Formicoidea, lateral projection of the frontal carina.frontal lunule (ARTHRO: Insecta) In Diptera, the lunar-shapedsclerite above the base of the antennae and below thefrontal suture.frontal membrane (BRYO: Gymnolaemata) In Cheilostomata,membrane of the frontal wall in autozooids.frontal orbit see facial orbitfrontal orbits see genovertical platesfrontal organ (ARTHRO: Crustacea) a. Sensory cells on theanterior surface of the cephalon of malacostracans; thehaft organ or frontal eye in non-malacostracans. b. TheBellonci organ of ostracods. see organ of Bellonci, frontaleye complex, x-organ.frontal plane A plane or section parallel to the body main axisand at right angles to the sagittal plane; horizontal plane.frontal plate (ARTHRO: Crustacea) In brachyuran Decapoda, amodified rostrum with a downward projecting processunited with the epistome.frontal plate of the tentorium (ARTHRO: Insecta) The plateformed by fused anterior arms of the tentorium.

374Maggenti and Gardnerfrontal pore see fontanellefrontal/pretentorial pits (ARTHRO: Insecta) The internal invaginationsof the anterior arms of the tentorium.frontal region (ARTHRO: Crustacea) The anteromedian part ofa carapace including the rostrum and the region behind it.frontal ridge (ARTHRO: Insecta) 1. An anteriorly directed ridgeon the dorsal margin of the eye. 2. For mosquitoes, seepostfrontal ridge.frontal sail (MOLL: Gastropoda) In Prosobranchia, an erecttransverse fold on the anterior part of the head which maybe simple or formed into scallops, tubercles, or projections.frontal seta 1. (ARTHRO: Diplopoda) One of a pair of setae oneither side of the median line of the frontal surface of thehead. 2. (ARTHRO: Insecta) One of two setae on the fronsof caterpillars.frontal shield (BRYO: Gymnolaemata) In Cheilostomata, theskeletal structure of the frontal or body wall that supportsand protects the retracted organs of an autozooid.frontal stripe (ARTHRO: Insecta) In Diptera, a membranous ordiscolored area on the middle front.frontal suture (ARTHRO: Insecta) 1. One of two sutures arisingat the anterior end of the coronal suture which extendsventrad toward the epistomal suture. 2. In Diptera, a sutureshaped like an inverted "U", having the base crossingthe face above the bases of the antennae, and the armsextending downward on each side of the face; a ptilinalsuture.frontal tentacles (MOLL: Gastropoda) In Opisthobranchia,tentacles just posterior to the mouth; cephalic tentacles.frontal triangle (ARTHRO: Insecta) In holoptic flies, the trianglebetween the eyes and the antennae, the apex beingabove.frontal tubercle see nasusfrontal tuft (ARTHRO: Insecta) In Hymenoptera, a group ofelongate simple setae and fusiform scales arising at theinterocular space and the adjacent portion of the vertex.frontal vesicle (ARTHRO: Insecta) In Odonata, a protuberance

Online Dictionary of Invertebrate Zoology 375between the compound eyes, bearing the ocelli.frontal vitta (ARTHRO: Insecta) In Diptera, an area on thehead between the antennae and the ocelli; the frontalia.frontal wall (BRYO) An external wall supporting the oral wallwholly or partly.frontoclypeal area (ARTHRO: Insecta) The front of the head,that is divided by the epistomal sulcus (or suture) into thefrons above and the clypeus below.frontoclypeal sulcus or suture see epistomal suturefrontoclypeus n. [L. frons, forehead; clypeus, shield] (AR-THRO: Insecta) The line (sulcus or suture) between thecombined clypeus and frons which is not externally visible.frontoclypeal a.frontogenal suture (ARTHRO: Insecta) A more or less verticalsuture on the front of the head, between the frons and thegena. see subantennal suture.frontolateral horn (ARTHRO: Crustacea) In Cirripedia nauplii, apair of tubular frontolateral extensions of cuticle.fronto-orbital bristles (ARTHRO: Insecta) In Diptera, bristleson the front, next to the eyes.froth glands (ARTHRO: Insecta) In nymphal Cercopidae, themodified Malpighian tubules.frugivorous a. [L. frux, fruit; vorare, to devour] Feeding uponfruit.fry n.; sing. & pl. [ME. fry, offspring] 1. Young or offspring. 2.The recently hatched brood of oysters.fugacious a. [L. fugere, to flee] Having a tendency to disappear;not permanent; perishing early; lasting a short while.fugaciously adv.; fugaciousness n.fulcral a. [L. fulcrum, support] Of or pertaining to a fulcrum.fulcral plates (ARTHRO: Insecta) In aculeate Hymenoptera, seetriangular plates; for Diptera see clypeal phragma.fulcrant trochanter (ARTHRO: Insecta) A trochantin traversingthe femur, but not intervening between it and the coxa.fulcrate mastax (ROTIF) A mastax with an elongate fulcrum,having a pair of leaf-like manubria attached anteriorly.

376Maggenti and Gardnerfulcro-cranial muscle (ARTHRO: Insecta) 1. A muscle arisingfrom the postoccipital phragma or ridge and inserted on thefulcrum in the thysanuran Lepismodes and mayfly nymphs.2. In the blattoid Periplaneta and lower apterygotes, amuscle arising from each of the posterior tentorial arms.fulcrum n.; pl. fulcrums [L. fulcrum, support] 1. Any structurethat props or supports another. 2. (ARTHRO: Insecta)a. In Heteroptera, the trochantin. b. In lower hemimetabolousinsects, a sclerotized fulcrum formed by two ligualsclerites joined proximally on the ventral surface of the hypopharynx.c. In Diptera and Hymenoptera, the horny partof the lingula. 3. (MOLL: Bivalvia) That portion to which thecartilage is attached; chondrophore. 4. (ROTIF) The unpairedtrophus of the mastax.fulgid a. [L. fulgidus, shining] Appearing red with bright metallicreflections.fulguration n. [L. fulgurare, to flash] The act of flashing aslightning; to emit flashes.fuliginous a. [LL. fuligo, soot] Of or pertaining to soot orsmoke; having the color of soot; dark colored, sootyopaque brown.fultella n. [L. dim. fultura, prop] (ARTHRO: Insecta) In Diptera,the aedeagal apodeme of male Tephritidae possessing apair of lateral processes extending to the hypandrium.fultelliform a. [L. dim. fultura, prop; forma, shape] (ARTHRO:Insecta) Having the fultella at least partially fused with themedian internal surface of the hypandrium.fultura n.; pl. -ae [L. fultura, prop] (ARTHRO: Insecta) In maleLepidoptera, a rectangular sclerite (paired) extending intothe abdomen from sternite 9. see suspensorium.fulturae of hypopharynx (ARTHRO: Chilopoda) Two ventralplates posteriorly attached to the margin of the cranium,and mesally extended forward as a tapering arm againstthe side of the hypopharynx; hypopharyngeal supports.fultura inferior (ARTHRO: Insecta) In male Lepidoptera, sclerotizedstructures situated on the ventral diaphragm, includingthe ventral part of the anellus and juxta.fultura penis (ARTHRO: Insecta) In male Lepidoptera, the

Online Dictionary of Invertebrate Zoology 377sclerotized structures of the diaphragm, namely, the fulturainferior and the fultura superior.fultura superior (ARTHRO: Insecta) In male Lepidoptera,sclerotized structures situated on the dorsal part of thediaphragm, including the dorsal part of the anellus andtranstilla.fulvous a. [L. fulvus, tawny yellow] Having low saturation andmedian brilliance; orange, reddish yellow, tawny, rust coloror reddish brown.function v. [L. functio, perform] The activity or action of anypart of an organism. functional a.functional haplometrosis (ARTHRO: Insecta) A colony inwhich an initial pleometrotic association of females undergoesa change, resulting in a haplometrotic society of theoriginal females, presided over by one of them; functionalmonogyny. see permanent haplometrosis, temporaryhaplometrosis.fundament n. [L. fundamentum, foundation] The primordium.fundatrigenia n. [L. fundare, to found; Gr. genos, descent](ARTHRO: Insecta) In Homoptera, the wingless, viviparousparthenogenetic Aphidae and Phylloxeridae females, theoffspring of a fundatrix, that lives on the primary host.fundatrix n.; pl. -trices [L. fundare, to found] (ARTHRO: Insecta)The wingless, viviparous, parthenogenetic femaleAphidae, Phylloxeridae and Adelgidae that hatches fromoverwintered eggs and founds a new colony. see fundatrigenia,alienicola, migrante, gallicola.fundatrix spuria see agamic, migrantefundus n. [L. fundus, bottom] The base or bottom, as in thebottom of a hollow organ.fungicolous a. [L. fungus, mushroom; colare, to inhabit] Livingin or on fungi.fungiform a. [L. fungus, mushroom; forma, shape] Mushroomshaped.fungivorous a. [L. fungus, mushroom; vorare, to devour]Feeding on or devouring fungus mycelium; mycetophagous;mycophagous.

378Maggenti and Gardnerfungus garden Fungi cultivated within the nest of higher termitesor fungus ants for use as food. see ambrosia, beebread.fungus-growing beetle (ARTHRO: Insecta) Any beetle thatfeeds on symbiotic fungi, i.e., ambrosia beetles, etc.funicular strand (BRYO: Gymnolaemata) Tissue crossing allbody cavities; in males and hermaphrodites producessperm.funiculate a. [L. funiculus, little cord] Having or forming a funiculus.funiculus, funicle n.; pl. -li [L. funiculus, little cord] 1. (AR-THRO: Insecta) a. The middle antennal segments betweenthe scape and the club. b. The main tendon of the abdomen.c. In Hymenoptera, the ligament connecting the propodeumto the petiole. 2. (BRYO) A strand of tissue thatattaches the digestive tract to the body wall or communicationpores, thus extending from zooid to zooid throughoutthe colony. 3. (MOLL: Gastropoda) A narrow ridge ofcallus spiraling from the upper lip into the umbilicus.funnel n. [L. infundibulum, funnel] 1. (ANN: Oligochaeta) Internalopening of both male and female genital ducts. seefemale and male funnel. 2. (ARTHRO: Insecta) See peritrophicmembrane. 3. (MOLL: Cephalopoda) a. A specializedsiphon from the mantle cavity providing locomotion by propulsion.b. For Nautiloidea, see hyponome.funnel organ (MOLL: Cephalopoda) A glandular structure onthe dorsal side of the funnel, slightly behind the valve;Verrill's organ.funnel shaped see infundibulumfurca n.; pl. -cae [L. furca, fork] 1. Any forked process. 2.(ARTHRO: Crustacea) The caudal furca; cercopod. 3. (AR-THRO: Insecta) a. The cercopods; the forked sternal processarising from the thoracic sternum of pterygote insectsformed by the sternal apophyses, supported on a mediuminflection; referred to as pro-, meso, or metafurca. b. InCollembola, the modified abdominal jumping appendages.see furcula. c. In some male Lepidoptera, the sclerotizedstructure of the juxta. d. For furca of the labellum, see la-

Online Dictionary of Invertebrate Zoology 379bellar sclerite.furcae maxillares see superlinguaefurcal arms see sternal apophysesfurcal ramus see caudal ramusfurcapectinae see pectinafurcasternal suture (ARTHRO: Insecta) In pterygote insects,the internal median longitudinal line formed at the point ofmeeting the mesopleurosternal ridges of opposite sides andconfluent with the mesosternal ridge.furcasternum n. [L. furca, fork; sternum, breast] (ARTHRO:Insecta) 1. In apterygote insects, that area of the thoracicsternum separated from the basisternum by the sternacosta.2. In pterygote insects, the bases of the sternalapophyses form the furca, the sternacosta is lost, and theseparation of the basisternum and furcasternum is usuallyobscure.furcate a. [L. furca, fork] Forked; having two divergentbranches from a common base.furcate plates see pectinafurcella see spinafurcilia n. [L. dim. furca, fork] (ARTHRO: Crustacea) InEuphausiacea, the larval stage following the calyptopis(mysis type) with stalked and movable compound eyes andwith thoracic and abdominal appendages; antennae notused for locomotion.furcina n. [L. dim. furca, fork] (ARTHRO: Insecta) The outersurface of the sternum bearing an invaginated furca. seefurcasternal suture.furcocercous cercariae (PLATY: Trematoda) Cercariae withforked tails into which the body is not retractable; dividedinto several groups: 1. Bucephalus group (includinggasterostomes). 2. Lophocercous group (apharyngeate,monostome cercariae). 3. Apharyngeate or ocellate group.4. Pharyngeate, nonocellate group. 5. Suckerless apharyngeategroup.furcocystocercous cercariae see cysticercariae cercariae

380Maggenti and Gardnerfurcula n.; pl. -lae [L. dim. furca, fork] (ARTHRO: Insecta) 1.The forked springing apparatus of springtails; furca. 2. InHymenoptera, a small sclerite of the anterior sting basewhich depresses, raises and rotates the sting of bees. furculara.furculate a. [L. dim. furca, fork] Having a furcula.furrow n. [A.S. furh, trench] A groove separating parts, divisionsor segments of an invertebrate body.furrow spines (ECHINOD: Asteroidea) Spines on the adambulacralplates that protect the ambulacral furrow.fuscescent a. [L. fuscus, dusky] Having a dusky or somberhue.fuscous a. [L. fuscus, dsky] Brown or grayish black; dusky.fused a. [L. fundere, to pour] Pertaining to being united,blended or run together.fused phobal mass (ARTHRO: Insecta) In certain scarabaeoidlarvae, the large, coalesced group of phobae located oneach side of the pedium, slightly anterior to the tormae.fused-wall colony see fixed-wall colonyfusiform a. [L. fusus, spindle; forma, shape] 1. Spindleshaped,tapering almost equally toward both ends. 2.(MOLL: Gastropoda) Of or pertaining to univalves having along canal and an equally long spire, tapering from themiddle toward both ends.fusion n. [L. fusus, spindle] A joining together of adjacentstructures, parts or sclerites.fusion layer (MOLL: Bivalvia) That part of the ligament secretedby the mantle.fusoid a. [L. fusus, spindle] Spindle-shaped; fusiform.fusulae, fusules n.pl. [L. dim. fusus, spindle] (ARTHRO) Minuteupright cylinders with a tapering spine on the base of thespinnerets; the spinning tubes of the silk glands in variousarthropods.fusus amphidialis see sensilla pouch

Ggalea n. [L. galea, helmet] 1. (ARTHRO: Chelicerata) A moveableprocess on the digit of the chelicera of pseudoscorpions,used to spin silken cocoons for protection duringmolting, hibernation, or the brooding of eggs. 2. (ARTHRO:Crustacea) Outer distal hoodlike lobe of the second segmentof the maxillula. 3. (ARTHRO: Insecta) a. The outerlobe of the maxilla borne by the stipes; may be present orabsent. b. Basis for coiled tongue in Lepidoptera.galea palpiformis (ARTHRO: Insecta) The galea composed ofcylindrical joints as distinguished from the lacinia.gallery n.; pl. -leries [ML. galilaea, gallery] A passage or corridormade by an animal.gallicola n. [L. galla, gall; colere, to inhabit] (ARTHRO: Insecta)Form of phylloxeran fundatrix that forms leaf galls.gallicolae migrantes (ARTHRO: Insecta) Winged gall-makingform of Phylloxeridae or Adelgidae that migrate to an intermediatehost.gallicolae nonmigrantes (ARTHRO: Insecta) Apterous Adelgidaethat remain on the primary host and produce fundatricesparthenogenetically.gallicolous a. [L. galla, gall; colere, to inhabit] Producers orinquilines dwelling in plant galls.galliphagous a. [L. galla, gall; Gr. phagein, to eat] Feedingupon galls or gall tissue.galvanotaxis n. [Luigi Galvani, pert. electricity; Gr. taxis, arrangement]A taxis in which an electric current is the directivefactor.galvanotropism n. [Luigi Galvani, pert. electricity; Gr. tropein,to turn] Tropism in which an electric current is the orientingfactor; electrotropism.gametangiogamy n. [Gr. gamete, wife; dim. angos, vessel]The union of gametangia.

382Maggenti and Gardnergametangium n.; pl. -ia [Gr. gamete, wife; angos, vessel] Astructure producing gametes.gamete n. [Gr. gamete, wife] A cell that unites with anothercell in sexual reproduction.gametocyte n. [Gr. gamete, wife; kytos, container] 1. Aspermatocyte or oocyte. 2. Sexual stage of the malarialparasite in the blood which upon being taken into the mosquitohost may produce gametes. see microgametocyte,macrogametocyte.gametogamy n. [Gr. gamete, wife; gamos, marriage] Union oftwo single celled gametes to form the zygote.gametogenesis n [Gr. gamete, wife; genesis, beginning]Gamete formation by which oogonia become ova andspermatogonia become sperm; gametogeny; gonogenesis.see oogenesis; spermatogenesis.gametogenetic generation A sexual generation as opposedto a parthenogenetic generation.gametogeny see gametogenesisgametogonium see gametocytegametogony n. [Gr. gamete, wife; gonos, seed] A phase inthe development cycle of the malarial parasite in the redblood cells of man in which the two sexes of gametocytesare formed.gametotoky n. [Gr. gamete, wife; tokos, birth] Parthenogenesisin which unfertilized eggs develop into either sex; deuterotoky;amphitoky; arrhenotoky.gamma taxonomy Taxonomy that uses all available biologicalinformation ranging from intraspecific population studies tothe study of speciation, evolutionary rates and trends;systematics. see alpha taxonomy, beta taxonomy.gamobium n. [Gr. gamos, marriage; bios, life] The sexualgeneration in alternation of generations. see agamobium.gamodeme n. [Gr. gamos, marriage; demos, people] An isolatedinbreeding community.gamogenesis n. [Gr. gamos, marriage; genesis, beginning]Sexual reproduction. gamogonic a. see agamogenesis.

Online Dictionary of Invertebrate Zoology 383gamogony see gamogenesisgamones n. [Gr. gamos, marriage; -one, mimics ending ofhormone] A group of biological agents that cause initiationof fertilization.gamophase see haplophaseganglia allata see corpora allataganglion n.; pl. -glia [Gr. ganglion, swelling] A discrete groupof nerve cell bodies acting as a center of nervous influence.gangliate a.ganglionic center Where two or more ganglia of adjoiningsegments coalesce.ganglionic commissure A nerve cord connecting any two adjacentganglia.ganglionic layer see laminaganglionic plate see laminaganglion ventriculare (ARTHRO: Insecta) The ganglion in frontof the proventriculus.gap n. [ON. gap] 1. Discontinuity. 2. A narrow unstained regionin a chromosome representing chromosome structuralchanges caused by mutagens.gaper a. [ON. gapa, yawn, gape] 1. An invertebrate thatgapes. 2. (MOLL: Bivalvia) In oysters, used to denote adead or dying individual with gaping valves and some remainingmeat. see gaping.gaping a. [ON. gapa, yawn, gape] (MOLL: Bivalvia) Pertainingto an opening along the margin of a shell that does notnaturally shut tightly together, i.e., soft shelled clams;gapers. see gaper.gaseous exchange The exchange of gases between an organismand its environment.gaseous plastron see plastrongas gland (CNID: Hydrozoa) In Siphonophora, glandular epitheliumthat secretes an air-like gas into a float.gaster n. [Gr. gaster, stomach] 1. Stomach. 2. (ARTHRO: Insecta)The major part of the abdomen behind the pedicel inthreadwaisted Hymenoptera.

384Maggenti and Gardnergasterostome n. [Gr. gaster, stomach; stoma, mouth] (PLATY:Trematoda) Cercaria in which the sucker is on the midventralsurface.gasterotheca n. [Gr. gaster, stomach; theke, case] (ARTHRO:Insecta) Part of the theca or pupa case surrounding theabdomen. see somatotheca.gastraea n. [Gr. gaster, stomach] Hypothetical adult ancestorof higher animals that all have the gastrula as a commonstage in their early ontogeny.gastraeum n. [Gr. gaster, stomach] The ventral side of abody.gastral cavity see spongocoelgastral groove (ARTHRO: Insecta) A longitudinal furrow in themid-line of the ventral plate of some eggs.gastralia n. [Gr. gaster, stomach] (PORIF: Hexactinellida) Microscleresbeneath the inner cell layer.gastral layer or membrane (PORIF) Choanocytes lining theinternal cavity.gastral ray (PORIF) One of the quadriradiates embedded in thewall and projecting into the central gastral cavity.gastric filament (CNID) A filament lined with nematocysts thatkill living prey entering the stomach of a jellyfish.gastric grooves (ARTHRO: Crustacea) In Stomatopoda, thelongitudinal pair of grooves, extending from the base of therostrum to the posterior margin of the carapace.gastric mill (ARTHRO: Crustacea) 1. Thickened and calcifiedparts in the cardiac stomach lining composed of moveablearticulated ossicles used to break up food. 2. In Acrothoracica,chitinous triturating apparatus in the foregut; masticatorystomach.gastric ossicles (ARTHRO: Crustacea) The teeth of the gastricmill.gastric ostium (CNID) Gastric pouch opening of jellyfish.gastric pouch (CNID) One of four enlargements of the stomachof a jellyfish.gastric region (ARTHRO: Crustacea) In Decapoda, the median

Online Dictionary of Invertebrate Zoology 385part anterior to the cervical groove and posterior to thefrontal region.gastric shield (MOLL: Bivalvia) A sclerotized plate that lines apart of the stomach, that aids the crystalline style by abrasion,thus releasing carbohydrate digesting enzymes.gastric tooth (ARTHRO: Crustacea) In Decapoda, a tooth onthe midline of the carapace anterior to the cervical groove.gastrilegous a. [Gr. gaster, stomach; L. legere, to collect](ARTHRO: Insecta) Pertaining to bearing pollen baskets beneaththe abdomen.gastrocoele n. [Gr. gaster, stomach; koilos, hollow] The gastrulationcavity; archenteron.gastrocoelus n.; pl. -li [Gr. gaster, stomach; koilos, hollow](ARTHRO: Insecta) In Hymenoptera, transverse impressionsat both sides of the base of the 2nd gastral tergite; includesthyridium.gastrodermis n. [Gr. gaster, stomach; derma, skin] 1. A onecell thick lining of the digestive tract of coelenterates,ctenophors and platyhelminths. 2. Endoderm.gastro-ileal fold (ARTHRO: Insecta) A circular valve-like foldseparating the intestine and the chylific stomach or ventricle.gastrolith n. [Gr. gaster, stomach; lithos, stone] (ARTHRO:Crustacea) In Decapoda, a discoidal calcareous nodule,commonly found in the stomodeum.gastroorbital carina (ARTHRO: Crustacea) In Decapoda, anarrow carapace ridge extending posteriorly from the supraorbitalspine; supraorbital.gastroorbital groove (ARTHRO: Crustacea) In Decapoda, ashort, longitudinal carapace groove branching from thecervical groove at the level of the orbit and directed towardit.Gastropoda, gastropods n.; n.pl. [Gr. gaster, stomach; pous,foot] A class of asymmetrical univalve mollusks with stomachsituated in the region of the foot, shell in one piece,often spirally coiled, that live in the sea, fresh water, andon land, and are either herbivorous or carnivorous.

386Maggenti and Gardnergastropores n. [Gr. gaster, stomach; poros, hole] (CNID: Hydrozoa)In Milleporina and Stylasterina, the larger pores inthe coenosteum through which gastrozooids protrude.Gastrotricha, gastrotrichs n.; n.pl. [Gr. gaster, stomach;thrix, hair] A phylum of aquatic micrometazoans that areoblong, strap-shaped to ovoid tenpin-shaped and bear locomotorcilia on the flattened venter.gastrovascular cavity A body cavity in which functions ofboth digestion and circulation occur.gastrovascular system The digestive-excretory system without-pouchings and canals.gastrozooid n. [Gr. gaster, stomach; zoon, animal] (CNID: Hydrozoa)In some colonial cnidarians, a hydroid modified forfeeding and digestion, also called siphons; in most species,they fulfill the defensive functions of the colony. see dactylozooid.gastrula n. [Gr. dim. gaster, stomach] Embryonic stage resemblinga sac with an outer layer of epiblastic cells (ectoderm)and an inner layer of hypoblastic cells (endodermand mesoderm); the enclosed cavity is the archenteron orgastrocoel. gastrular a.gathering hairs (ARTHRO: Insecta) The small hairs coveringthe glossa and the fringe of stouter bristles on the labellumof bees.Gause's rule see competitive exclusiongelatigenous a. [L. gelatus, congealed; genos, origin] Producinggelatin.gelatin, gelatine n. [L. gelatus, congealed] A jelly-like substance(gel) obtained from animal tissue; also loosely appliedto secretions of animals.gelatinous matrix An external glandular substance secretedby some invertebrates, into which the eggs are embeddedor deposited.geminate a. [L. geminus, two-fold] To double; occurring inpairs; twins.gemma n.; pl. -mae [L. gemma, bud] A bud or bud-like organicgrowth.

Online Dictionary of Invertebrate Zoology 387gemmation n. [L. gemma, bud] 1. The act of reproducing bybudding. 2. Marked with bright colored spots. gemmate a.gemmipara n., pl. gemmipares [L. gemma, bud; parere, tobeget] A form of asexual reproduction where animals reproduceby budding, as hydroids, bryozoans and sponges.gemmule n. [L. gemma, bud] 1. A bud-like outgrowth that becomesan independent individual. 2. (PORIF) Composed of amass of archaeocytes charged with reserves and enclosedin a non-cellular protective envelope. 2. Historically a particleof heredity, hypothesized by Darwin, carried in the cellsand able to move to the sex cells that allowed environmentto influence inheritance directly.gemmulostasin n. [L. gemma, bud; stasis, standing] (PORIF)An inhibitor of gemmule germination.gena n.; pl. genae [L. gena, cheek] (ARTHRO: Insecta) 1. Thatpart of an insect head on each side below the eyes, borderedby the frontal suture, and behind the eyes, by theoccipital suture. 2. In Diptera, the region lying between theface and the lower margin of the eye on either side;parafacials or genal groove. 3. In Hymenoptera, the lateralportions of the head between the eyes and the insertions ofthe mandibles of Formicidae. genal a.genacerore see wax glandsgenal bristles (ARTHRO: Insecta) In Diptera, bristles on thegenal groove at the lower corner of the eye.genal carina (ARTHRO: Insecta) In ichneumonid Hymenoptera,the lower end of the occipital carina, ending at the oral carinaor the lower mandibular socket.genal comb (ARTHRO: Insecta) In Siphonaptera, a row ofstrong spines borne on the anteroventral border of thehead; genal ctenidium. see ctenidium.genal ctenidium see ctenidiumgenal groove (ARTHRO: Insecta) In Diptera, a depressed andgroove-like area near the ventral limits of the ptilinal sutureand the juncture of the gena and parafacial; cheekgroove; transverse impression.genal orbit (ARTHRO: Insecta) That area of an orbit adjacent to

388Maggenti and Gardnerthe ventral margin of a compound eye.genaponta n. [L. gena, cheek; pons, bridge] (ARTHRO: Insecta)In specialized Hymenoptera, a bridge composed ofthe fused postgenae that closes the underside of the headbehind the mouth.genatasinus see genital pouchgene n. [Gr. genos, birth, origin] A hereditary determiner; theunit of inheritance, carried in a chromosome that is transmittedfrom one generation to another in the gametes andthat controls the development of characters in the new individual;the factor.gene action Gene expression by control of specificity and rateof biosynthetic processes, particularly proteins.gene activation Differential expression of genes caused bydeactivation, etc., of specific genes by products of the cell.gene flow The exchange of genetic factors between populationsof the same species owing to dispersal of zygotes orgametes.gene frequency The percentage of all alleles at a given locusin a population represented by a specific allele.gene interaction Interaction between genes that produces aparticular phenotype.gene location The distance between genes on a chromosomemap.gene locus pl. loci The position of a gene in a chromosome.gene map The graphical linear arrangement of mutational sitesin the gene itself.gene mutation Heritable change within a gene.gene pool The totality of the genes of a given population ofsexually reproducing organisms existing at a given time.generalized a. [L. genus, kind] A comparative term used inbiology in contrast to specialized or cenogenetic, indicatingan ancient or long-standing character when compared withone or more newly evolved.generation n. [L. generare, to beget] The length of time fromany given stage in the life cycle of an organism to the same

Online Dictionary of Invertebrate Zoology 389stage in the offspring.generative a. [L. generare, to beget] Pertains to somatic cellgeneration as distinct from germ cells or gametes.generitype Obs. see type speciesgenerotype Obs. see type speciesgenesiology n. [Gr. genesis, descent; logos, discourse] Thescience of generation or heredity.Gene's organ (ARTHRO: Chelicerata) In female Ixodida, a cephalicglandular organ which functions only during egglaying.gene splicing see splicinggenetic assimilation The fixation of a genetic character beinginfluenced by artificial environmental changes, not evidentin the original phenotype.genetic balance Harmonious interaction of genes ensuringnormal development of the organism; genic balance.genetic code Genetic information that is encoded into DNAand transcribed to messenger RNA which forms peptides bygenetic translation.genetic drift Genetic changes in isolated populations causedby random phenomena rather than by natural selection.see population, local.genetic engineering Manipulation of DNA from different speciesto form recombinant DNA including genes from bothspecies.genetic equilibrium Condition of gene frequencies and genotypesin large populations that remain stable from generationto generation.genetic homeostasis The tendency of a population to balanceits genetic composition and to resist sudden changes.genetic isolation Having sterility barriers preventing interbreedingbetween two or more populations.genetic map A chromosome map; relative distance betweengenes on a chromosome measured by crossing over andrecombinations; may be recombination of genes (chromosomemap) or within genes (gene map).

390Maggenti and Gardnergenetic polymorphism The long-term common occurrence of2 or more genotypes in a population which cannot be accountedfor by recurrent mutation.genetics n. [Gr. genesis, beginning] The science of heredityand variation.genetic variability Inheritable variation caused by geneticchange not by environment.genic balance see genetic balancegenicular a. [L. dim. genu, knee] Pertaining to the region ofthe knee.geniculate n. [L. dim. genu, knee] 1. Bent; elbowed; bent inan obtuse angle. 2. (ARTHRO) The antenna of arthropods,i.e., insects and crustaceans. 3. (ARTHRO: Chelicerata) Thebase of the chelicerae in some spiders.genital a. [L. gignere, to beget] Pertaining to the reproductiveorgans or the process of generation.genital aperture 1. The genital opening. 2. (NEMATA) When acloaca is present, the anus.genital area (BRACHIO) That part of the shell underlain by saccategonocoel or posterior part of the digitate or lemniscategonocoel.genital armature Those portions of the reproductive systemdirectly involved in copulation.genital atrium (PLATY) A small cavity in the body wall intowhich the male and female genital ducts open.genital bursa 1. (ECHINOD: Ophiuroidea) A genitorespiratorysac into which the gonads open; also used in respirationand brooding of larvae in brooding forms. 2. See bursacopulatrix.genital canal (ECHINOD: Crinoidea) A canal in the arms inwhich the genital tube and cord lie.genital chaeta (ANN) A seta that functions in sexual reproduction;spermathecal chaeta; penial chaeta; penial seta.genital chamber (ARTHRO: Insecta) A copulatory invagination.a. In females, sometimes forms a tubular vagina that isoften developed to form a bursa copulatrix. b. In males, a

Online Dictionary of Invertebrate Zoology 391ventral invagination containing the phallic organs.genital coelom (MOLL) The lamina of the gonads.genital cone (ARTHRO: Crustacea) Single or paired testesopenings on the eighth thoracic sternite of males.genital cord see genital rachis/cordgenital disc (ARTHRO: Insecta) The imaginal disc from whichthe reproductive duct system and the external genitalia areformed in the vinegar fly, Drosophila .genital duct see gonoductgenital fossa see fenestragenital groove 1. (ARTHRO: Chelicerata) In some female spiders,a cleft posterior to the epigynum into which the fertilizationduct opens and through which the eggs pass. 2.(ECHI) A depression, with or without setae, extending fromthe nephridopore(s) to the mouth on the ventral surface.genital hamule/hook see hamular hook, hamulus anterioris,hamulus posteriorisgenitalia n.pl. [L. genitalis, pert. to procreation] 1. The sexualorgans and associated structures. 2. (ARTHRO: Chelicerata)In male and female spiders, the sclerotized genital structures.3. (ARTHRO: Insecta) Usually applied to the externalsexual organs; gonapophyses.genital lobe (ARTHRO: Insecta) In Odonata genitalia, a lobe ofthe postero-lateral angles of the second abdominal segment.genital opening 1. (ARTHRO: Chelicerata) a. In Acari, originallya transverse slit or trifid orifice associated with segmenteight. b. In many actinotrochid Acari, it is found in the progenitalchamber where it is named the eugenital opening.2. (MOLL: Bivalvia) Opening for gonadal products leadinginto the cloacal passage.genital organs The reproductive organs.genital papilla/papillae 1. (ANN) A protuberance below theneuropodium where a reproductive duct opens. 2. (AR-THRO: Chelicerata) Endite of an opisthosomatic appendage;shaped like an erectile papilla or verruca in Acari. 3. (AR-THRO: Crustacea) In some males, long genital processes on

392Maggenti and Gardnerthe 5th or 8th thoracomere that provides openings for thevasa deferentia and a pair of accessory glands. 4. (ARTHRO:Insecta) see papilla genitalis. 5. (NEMATA) Sensory nerveterminations, variable in size, form and arrangement on ornear the male tail.genital plates 1. (ARTHRO: Chelicerata) see epigynum. 2.(ECHINOD: Echinoidea) Plates surrounding the periproct.genital pleurae see genital ridgegenital pore Genital opening.genital pouch (ARTHRO: Insecta) In certain Diptera, a pouchbelow the hypandrium receiving the tips of the surstyli andcerci.genital primordium In embryology, the originating cellsleading to the development of the reproductive system.genital rachis/cord (ECHINOD: Crinoidea) Strands of gonocytesin the genital canal that traverse the arms to the gonad.genital ridge (ARTHRO: Insecta) In embryology, thickenings ofthe viseral (splanchnic) wall of the mesoderm in the abdominalregion of the body in which the gonadal rudimentslie.genital region see urogastric lobe or areagenital sac see preputial sacgenital segments 1. Body segments that bear copulatory organs.2. (ANN) Usually segments X and XI. 3. (ARTHRO: Insecta)In males, abdominal segment IX; in females, abdominalsegments VIII and IX.genital setae see genital papillae, genital chaetagenital spike (ARTHRO: Insecta) In Coccidae, the penis sheath.genital stolon see axial glandgenital styles see genostylesgenital sucker (PLATY: Trematoda) A sucker around the genitalpore.genital supplements see supplementsgenital tracheae (ARTHRO: Chelicerata) In Acari, tracheae

Online Dictionary of Invertebrate Zoology 393from the progenital chamber resembling gland ducts andoften ending in caecae; the respiratory function is notproven.genital tube (ECHINOD: Crinoidea) Suspended in the genitalcanal and carrying the rachis or genital cord.genital tuft see brushesgenital tumescences (ANN: Oligochaeta) In Lumbricidae,modified epidermis through which follicles of genital setaeopen.genital valve see lateral gonapophysesgenital wings see genital ridgesgenitointestinal canal 1. (NEMATA) see demanian system. 2.(PLATY: Trematoda) A duct connecting the oviduct and intestineof certain Polyopisthocotylea monogeneans.genito-urinary see urogenitalgenocline n. [Gr. genos, race; klinein, to slope] Change withina continuous population in frequencies of genotypes in differentgeographical areas.genocopy n. [Gr. genos, race; L. copia, abundance] Productionof the same phenotype by different genes (mimetic genes).genodeme n. [Gr. genos, race; demos, people] A deme.genoholotype n. [Gr. genos, race; holos, whole; typos, type]A typical species specified by the author as the generictype.genolectotype n. [Gr. genos, race; lektos, chosen; typos,type] The type of a genus selected from a series of speciesplaced in the genus subsequent to the description.genome n. [Gr. genos, race; soma, body] The genes carriedby a single gamete; the genetic contents of the chromosomes.genostyles n.pl. [Gr. genos, race; stylos, pillar] (ARTHRO: Insecta)In male Ephemeroptera, genital projections (consistingof 1-7 segments) initiated from the posterior cornersof the 9th segment, functioning during copulation.genosyntype n. [Gr. genos, race; syn-, together; typos, type]Any one of a series of species that a genus is based upon

394Maggenti and Gardnerwhen no one species was established as type. see type.genotype n. [Gr. genos, race; typos, type] 1. The genetic constitutionof an organism or taxon, regardless of the outwardappearance (phenotype) of the same. 2. Incorrectsynonym for type species.genovertical plate (ARTHRO: Insecta) In Diptera, the area onthe head above the antenna and next to the compoundeye; the orbital plate; the parafrontals.genu n.; pl. genua [L. genu, knee] 1. Any structure or organwith a knee-like bend. 2. (ARTHRO: Chelicerata) In Acari,the segment between the femur and tibia that is activatedby its own muscles and tendons, corresponding with thepatella in other groups of Chelicerata.genus n.; pl. genera [L. genus, race] A taxon including onespecies or a group of species from a presumed commonancestor, separated from related similar genera by a decidedgap; a taxonomic category above species and nextbelow the family group.genus novum A new genus, never before described; gen. nov.geobionts n. [Gr. ge, earth; bios, life; on, a being] Organismsthat permanently inhabit the soil and thereby affect itsstructure. see geocoles.geobios n. [Gr. ge, earth; bios, life] Soil life; terrestrial life.see edaphon.geochronology n. [Gr. ge, earth; chronos, time; logos, discourse]The measurement of time in relation to the evolutionof the earth.geocline see clinegeocoles a. [Gr. ge, earth; L. cola, inhabitant] Animals thatspend only a part of their lives in the soil and affect itsstructure, aeration, etc. see geobionts.Geoffroyism see Lamarckismgeographical distribution The range of a species.geographical isolation/barriers A population or group ofpopulations prevented by geographic barriers from freegene exchange with other populations of the same species;a geographic isolate. see climatic isolation.

Online Dictionary of Invertebrate Zoology 395geographic race A geographically delimited race; usually asubspecies.geographic variation The differences between spatially segregatedpopulations of a species.geology n.; pl. -gies [Gr. ge, earth; logos, discourse] The sciencewhich treats of the structure and history of the earth.geometrid a. [Gr. ge, earth; metron, measure] (ARTHRO: Insecta)A larva whose movements resemble a looping motionmoving tail to head, such as the geometrid moth larva(Geometridae) "measuring worms"; geometroid. see rectigrade.geophagous a. [Gr. ge, earth; phagein, to eat] Feeding onearth.geophilous a. [Gr. ge, earth; philein, to love] Living in or onthe ground; ground loving, as land snails.geotaxis n.; pl. -taxes [Gr. ge, earth; taxis, arrangement] Atactic response with the force of gravitation as the stimulus.a. Positive geotaxis : toward the force of gravitation. b.Negative geotaxis : away from the force of gravitation.geotropism n. [Gr. ge, earth; tropos, turn] Movement determinedby the direction of gravitational force. geotropic a.see tropism.geoxenes n. [Gr. ge, earth; xenos, stranger] Organism occurringonly occasionally in the soil showing little effect on thesoil structure. see geobionts.geratology n. [Gr. geras, old age; logos, discourse] Study ofdegeneration and decadence of species with age. see gerontology.germarium n. [L. germen, bud] 1. The distal chamber of anovarial or testicular tube containing the oogonia or spermatogonia.2. An ovary. 3. An egg or sperm producing partof a gonad. see insect ovary types.germ-balls 1. (ARTHRO: Insecta) Reproductive cells in somelarvae from which other young larvae may be produced. 2.(PLATY: Trematoda) Embryos in the redial stage.germ band (ARTHRO) In egg, the thickened area from whichthe embryo is produced; embryonic rudiment; germ disc;

396Maggenti and Gardnerprimitive streak.germ cells A reproductive cell in a multicellular organism. seesomatic cells.germiduct n. [L. germen, bud; ducere, to lead] (PLATY: Trematoda)The oviduct.germigen n. [L. germen, bud; Gr. genos, offspring] (PLATY:Trematoda) The ovary.germinal a. [L. germen, bud] Pertaining to a germ cell or embryonicstructure. see soma.germinal cell Cells which produce gametes through meiosis,i.e., oocytes in females, spermatocytes in males; productsof the germinal primordium.germinal disc see germ bandgerminal layers Primary cell of the embryo: ectoderm, mesoderm,and endoderm, from which tissues and organs of theadult are formed; germ layer.germinal mutations Genetic alteration in cells destined to becomegerm cells.germinal spot The nucleolus of an ovum.germinal streak The primitive streak. see germ band.germinal variations A variation caused by some modificationin the germ cells.germinal vesicle The diploid nucleus of a primary oocyte beforeformation of polar bodies.germinal zone That part of an ovarial or testicular tube wherethe oogonia or spermatogonia divide.germ layer see germinal layersgermogen n. [L. germen, bud; genes, born] (MESO: Rhombozoa)The central part of an infusorigen in the developmentof an axoblast.germovitallarium n.; pl. -vitellaria [L. germen, bud; vitellus,yolk] (PLATY) Having the ovary differentiated into yolk- andegg-producing regions.germ plasm Genetic material which forms the physical basis ofinheritance and is passed from generation to generation.

Online Dictionary of Invertebrate Zoology 397germ tract The complete detailed history of the germ cellsfrom one generation to the next.gerontic a. [Gr. gerontos, old man] Pertaining to decadence;old age; deteriorating.gerontogeous a. [Gr. gerontos, old man; ge, earth] Belongingto the Old World or Eastern Hemisphere. see neogeic.gerontology n. [Gr. gerontos, old man; logos, discourse] Thestudy of aging.gerontomorphosis n. [Gr. gerontos, old man; morphe, form]Evolution involving specialization and diminishing capacityfor further evolutionary change.gestation n. [L. gestare, to bear] In viviparous animals, theperiod from conception to birth.geusid n. [Gr. geusis, taste] (NEMATA) Gustatory organ.giant bud (BRYO: Gymnolaemata) Unpartitioned distal endgrowth in which the side walls grow faster than the internaltransverse walls.giant cell A term applied to a host response in which a multinucleatemass of protoplasm or cytoplasm often acts as apreferred feeding site or "nurse cell". see coenocyte,syncytium, lysigenoma, teratocyte.giant chromosome (ARTHRO: Insecta) In Diptera, a very largechromosome bundle that arises by repeated endoreplicationof single chromatids.giant fiber Enlarged nerve fibers that transmit rapid impulsesin certain mollusks, crustaceans, annelids, pogonaphoransand insects; giant fibre.gibber n. [L. gibbus, humped] A swelling or enlargement; arounded protuberance.gibbous, gibbose a. [L. gibbus, humped] Very convex; humpbacked;embossed; swollen; a protuberance.Gicklhorn's organ (ARTHRO: Crustacea) In Copepods, pairedphotoreceptors having two cells that closely resembleretinula cells, found in proximity to the frontal eye.gigantism n. [Gr. gigas, giant] Excessive growth of an organor a complete organism to a large size.

398Maggenti and Gardnergigeriate a. [L. gigerium, gizzard] (ANN) Having one or moregizzards in the digestive system.gill n. [ME. gile, gill] 1. An external respiratory organ of variousaquatic invertebrates. 2. (ARTHRO) Brachia or plastron. 3.(ECHINOD: Echinoidea) The plastron. 4. (MOLL) Thectenidium.gill bailer see scaphognathitegill bar (MOLL: Bivalvia) Dorsoventral rodlike thickenings of agill lamellae.gill book see book gillgill chamber see branchial chambergill filaments 1. Finger-like subdivisions of gills of various invertebrates.2. (ANN) Finger-like extensions of the bodywall that function in respiration.gill lamellae (MOLL: Bivalvia) Thin plates making up a gill.gill plume (MOLL: Gastropoda) Gill or ctenidium.gill retractor (MOLL: Bivalvia) When present, a muscle attachingone of the gills to the shell.gill separator see epipoditegill tuft A group of mainly lateral, filamentous gills.Gilson's glands (ARTHRO: Insecta) In Trichoptera, thoracicglands homologized to coxal glands or nephridia.ginglymus n. [Gr. ginglymos, hinge-joint] (ARTHRO: Insecta)In dicondylic jaws, a cavity or groove of the mandible thathinges on a convex process of the clypeus forming the anteriorjoint.gin-traps (ARTHRO: Insecta) In certain coleopteran larvae, localsclerotization of opposable edges of adjacent abdominalsegments, supposed organs of defense against arthropodpredators.girdle n. [A.S. gyrdel, a girdle] (MOLL: Polyplacophora) Flexiblemuscular integument, plain or leathery, or variously ornamented,holding the chiton valves in place; perinotum; girdle.gizzard n. [OF. gezier, gizzard] 1. A grinding chamber of variousinvertebrates. 2. (ANN: Oligochaeta) A muscular area of

Online Dictionary of Invertebrate Zoology 399the digestive system between intestine and crop. 3. (AR-THRO) For Insecta and Crustacea, see proventriculus. 4.(BRYO: Gymnolaemata) In Ctenostomata, an elongate orspherical inner part of the cardia with pointed or roundedplates or teeth. 5. (ECHI) The short, muscular region of theposterior foregut usually marked by ringed or annularstriations. 6. (MOLL) A thickened muscular stomach, orlined with calcareous plates for crushing food.glabella n. [L. dim. glaber, bald] (ARTHRO: Trilobita) A thickened,median elevated cephalic shield of trilobites.glabrous a. [L. glaber, bald] Smooth, free of hair.gladiolus n. [L. dim. gladius, sword] The mesosternum.gladius n. [L. gladius, sword] (MOLL: Cephalopoda) In Sepiidae,Octopoda, and Teuthoidea, the horny endoskeleton orpen of endocochleates; the internal shell.glairy a. [L. clarus, clear] Pertaining to glair, or white of anegg.gland n. [L. dim. glans, acorn] An organ or cell specialized forsecretion, either for use in the body or for excretion.gland cell A single secreting cell.glandiform a. [L. dim. glans, acorn; forma, shape] Acornshaped.glandilemma n. [L. dim. glans, acorn; Gr. lemma, skin] Thecapsule of a gland.gland of Leiblein (MOLL) A gland connected to the modifiedesophagus by a duct that secretes a strong proteolytic enzymein some predaceous mollusks and carbohydrase invegetarians.gland orifice Any external opening for gland secretion.gland shields (ANN: Polychaeta) In tube-builders, a pair oflarge mucous-secreting pads which lay down a coating onthe inner surface of the tube.glands of Batelli (ARTHRO: Insecta) In Hemiptera, large hypodermalglands in the Cercopidae; formerly believed to producethe spittle.glands of Filippi see Lyonnet's gland

400Maggenti and Gardnerglands of Morren see calciferous glandsgland spines (ARTHRO: Insecta) In Diaspidinae, small to largespines that are conical, bifid, or somewhat fimbriate at thetip and have one or more ducts that extend to the tip ofthe spine; pectines; plates; squamae.gland tubercules (ARTHRO: Insecta) In Diaspidinae, a glandspine that is short, basally swollen and sclerotized.glanduba n.; pl. -ae [L. dim. glans, acorn] (ARTHRO: Insecta)In Hymenoptera, chitinized ring openings of the cutaneouswax glands found in most sawfly larvae.glandulae accessoriae (ARTHRO: Insecta) The accessoryglands of the reproductive organs.glandular a. [L. dim. glans, acorn] Having or bearing a glandor gland cell, i.e., hair, spines, etc.glandular bristles/hairs 1. Stout and rigid glandular setae. 2.(ARTHRO: Insecta) In Lepidoptera, the urticating hairs.glandular organ (SIPUN) A prominent structure on the ventral,median part of the oral disc of pelagosphera larvae; lipgland.glans n. [L. dim. glans, acorn] (SIPUN) The acorn-shaped posteriorextremity of the trunk of some species.glassy a. [A.S. glaes, glass] Vitreous; transparent; pellucid;clear.glaucothoe n. [Gr. glaukos, grey; thos, swift] (ARTHRO: Crustacea)In Decapoda, a postlarval stage in the developmentof Paguridae, equivalent to a megalopa.glaucous a. [L. glaucus, bluish-green] Sea-green or pale bluish-greenin color.glenoid cavity 1. A depression for the fit of a condyle. 2. (AR-THRO: Chelicerata) In Acari, part of a condylar articulation.glia, glial cells, gliacytes n. [Gr. glia, glue] Nonnerve cells inthe brain or glanglion, that may support the life processesof the neurons; neuroglia.globate, globated a. [L. globus, ball] Globose; spherical.globoferous cell (PORIF) A cell having a prominent array ofparacrystalline components.

Online Dictionary of Invertebrate Zoology 401globose, globular a. [L. globus, ball] Spherical; globe shaped.globuli cells (ARTHRO: Insecta) Specialized association cells ofthe brain, small in size with round nuclei rich in chromatin.globulin n. [L. dim. of globus, ball] A class of proteins whichare insoluble in water, but soluble in saline solutions, orwater soluble proteins with globulin-like physical properties.globulus n.; pl. -li [L. globulus, small ball] (ARTHRO: Pauropoda)One jointed globular or two joined pear-shaped sensoryorgans on the antennae.glochidium n.; pl. -dia [Gr. glochis, arrow-point; idion, dim](MOLL: Bivalvia) In Unionoida, the modified parasitic larva,with or without hooks, of certain fresh water clams.glochis n.; pl. glochines [Gr. glochis, arrow-point] 1. Abarbed hair, bristle, spine or point. 2. (MOLL: Gastropoda)The protrusible radula.glomerate a. [L. glomus, ball] Massed or compacted into acluster.glomerule see glomerulusglomerulus n.; pl. -li [L. dim. glomus, ball] A tuft or cluster ofblood vessels or nerve fibers.glossa n. [Gr. glossa, tongue] (ARTHRO: Insecta) One of a pairof terminal lingular lobes of the labium of certain insects,between the paraglossae; the medium ligula. a. In adultHymenoptera, the fused glossae that form the tongue. b.In Thysanoptera, the median ligula that forms the apical tipof the wall of the mouth cone.glossarium see labrum-epipharynxglossate a. [Gr. glossa, tongue] Furnished with a tongue-likestructure.glossotheca n. [Gr. glossa, tongue; theke, case] (ARTHRO: Insecta)The pupa integument covering the tongue; atongue-case.glottis n. [Gr. glotta, tongue] The opening from the pharynxinto the trachea.glottoid apparatus (NEMATA) A toothed projection at the base

402Maggenti and Gardnerof the esophastome utilized in rhabditid species and genericidentification.glucoprotein n. [Gr. gleukos, sweet; proteion, primary] A substancein which hexosamine containing polysaccharide ischemically united with peptides. see glycoprotein, mucoprotein.glue cell see adhesive cellsglumes n.pl. [L. gluma, husk] (ARTHRO: Insecta) In Hymenoptera,longitudinal ridges on the flagellar segments ofmany wasps.glutinants n.pl. [L. gluten, glue] (CNID) A type of nematocyst;the holotrichous and atrichous isorhizas.glutinose, glutinous a. [L. glutinosus, sticky] Having a slimyor sticky surface.glycocalyx n. [Gr. glykys, sweet; kalyx, covering] 1. A filamentouslayer containing carbohydrate, found on the outersurface of many cells. 2. (ACANTHO) Formerly known asepicuticle.glycogen n. [Gr. glykys, sweet; genes, born] A branch-chainedpolysaccharide; a major stored food substance of mostanimals, fungi and bacteria.glycogenesis n. [Gr. glykys, sweet; gennaein, to produce]Formation of glycogen from glucose.glycogenolysis n. [Gr. glykys, sweet; genes, born; lyein, tobreak up] The breakdown of glycogen.glycolysis n. [Gr. glykys, sweet; lyein, to break up] The enzymaticbreakdown of glucose to lactic acid or pyruvic acidwith the release of energy in the form of high energy phosphatebonds.glycoprotein n. [Gr. glykys, sweet; proteion, primary] Glucoproteinwhose hexosamine content is less than 4%.glymma n.; pl. -ae (ARTHRO: Insecta) In ichneumonid Hymenoptera,one of a pair of lateral fovae between the base andspiracles of the petiolar segment; may be small and shallowor large and almost meeting in midline.gnathal a. [Gr. gnathos, jaw] Pertaining to the jaws.

Online Dictionary of Invertebrate Zoology 403gnathal lobe 1. (ARTHRO: Crustacea) The masticatory endite ofthe mandible; the masticatory process. 2. (ARTHRO: Diplopoda)The third or most distal part of the mandible; bearingthe teeth and grinding surfaces.gnathal pouch (ARTHRO: Insecta) a. The concave surface belowthe oral plate; the oral chamber. b. In Hymenoptera,used as a receptacle for food particles and detritus in ants.gnathal region/segments (ARTHRO: Insecta) The gnathocephalon.gnathites n.pl. [Gr. gnathos, jaw] (ARTHRO: Insecta) Themouth parts; the buccal appendages.gnathobase n. [Gr. gnathos, jaw; basis, base] 1. (ARTHRO)One of a pair of endites used to manipulate or move food intrilobites, and some crustaceans. 2. (ARTHRO: Chelicerata)In arachnids, the projection from the coxa of a leg or palp,used in crushing food. 3. (ARTHRO: Insecta) A lobe or projectionof a basal segment of an appendage near themouth, used in eating.gnathocephalon n. [Gr. gnathos, jaw; kephale, head] (AR-THRO: Insecta) That part of the head formed by the gnathalsegments and the procephalic lobes.gnathochilarium n. [Gr. gnathos, jaw; dim. cheilarion, lip](ARTHRO: Diplopoda) A plate-like mouth structure; thoughtto be the fused maxillae and labium.gnathopod(ite) n. [Gr. gnathos, jaw; pous, foot] (ARTHRO:Crustacea) Prehensile appendages. a. The maxilliped. b. InAmphipoda, the first and second pereopods, chelate orsubchelate; the gnathopodite; subchela.gnathos see subscaphiumgnathosoma n. [Gr. gnathos, jaw; soma, body] (ARTHRO:Chelicerata) The anterior of two basic regions of the bodyof a mite or tick bearing the mouth parts; a capitulumpseudotagma.gnathostegite n. [Gr. gnathos, jaw; stegos, roof] (ARTHRO:Crustacea) One of a pair of plates covering the mouthparts.Gnathostomulida n. [Gr. gnathos, jaw; stoma, mouth] A

404Maggenti and Gardnerphylum of microscopic, free-living marine worms that areacoelomate bilateria with a mono-ciliated skin epithelium,jaws and a muscular pharyngeal apparatus; commonlycalled jaw-worms.gnathothorax n. [Gr. gnathos, jaw; thorax, breast] (ARTHRO:Crustacea) Having the first, sometimes also the second,thoracic somites fused with the cephalon; the cephalon andpereon.gnotobiote n. [Gr. gnostos, known; bios, life] A known microorganismliving in or on a host.gnotobiotic culture The breeding or culturing of organisms bythemselves or in association with other known kinds of organisms.see agnotobiotic culture.gnotobiotics n.pl. [Gr. gnostos, known; bios, life] A field ofbiology involving breeding or culturing of organisms bythemselves or together with other known kinds of organisms.gnotobiotic a. see agnotobiotic culture.goblet cell see calyciform cellgoblets n.pl. [OF. goblete] (ARTHRO: Chelicerata) Stigmatalplate markings of certain hard ticks.Golgi bodies [=dictyosomes=golgiosomes or internal reticularapparatus] Organelle found in most eukaryote cells consistingof a stack (dictyosome) of flat sacs (cisternae), involvedin secretion.golgio-kinesis Distribution of Golgi bodies during mitosis.gonad n. [Gr. gone, that which produces seed] A reproductiveorgan; a testis, ovary, ovotestis, or their generative tissue.gonadial a.gonadotropin, gonadotrophin n. [Gr. gone, that which producesseed; tropos, direction] A substance that stimulatesthe gonads to develop.gonaduct see gonoductgonangium n. [Gr. gone, that which produces seed; angeion,capsule] (CNID: Hydrozoa) In colonials, the gonotheca andenclosed blastostyle with gonophores.gonangulum n. [Gr. gone, that which produces seed; L.angulus, angle] (ARTHRO: Insecta) A small sclerite attached

Online Dictionary of Invertebrate Zoology 405to the base of the first gonapophysis articulating with thesecond gonocoxa and the tergum of segment 9 in Lepisma;in others fused with the first gonocoxa or with tergum 9.gonapophysis n.; pl. -yses [Gr. gone, that which producesseed; apo, from; phyein, to grow] 1. (ARTHRO: Crustacea)In male Syncarida, a median process from the base of thefirst or second pleopod. 2. (ARTHRO: Insecta) a. The slendercurving processes that form the shaft of the ovipositor;may be leaf- or flap-like or modified to form the sting. b.Also applied to certain paired genital appendages in themale.gonarcus n. [Gr. gone, that which produces seed; L. arcus,bow] (ARTHRO: Insecta) In male Neuroptera, an archshapedstructure below the anal segment and above theaedeagus.gonatocerous condition (ARTHRO: Insecta) In some adultColeoptera, bearing a geniculate antenna with a long scapeand compact club. see orthocerous condition.gone n. [Gr. gone, that which produces seed] Any germ cellarising by meiosis.gongylidia n.pl.; sing. -ium [Gr. gongylos, ball] Spherical orellipsoidal swellings at the tips of the hyphae that are cultivatedby the Attine ants; a group of gongylidia is sometimesreferred to as a staphyla.goniatite n. [Gr. gonia, angle] (MOLL: Cephalopoda) ExtinctPaleozoic ammonoid cephalopod existing in the Middle DevonianPeriod.gonoblast n. [Gr. gone, that which produces seed; blastos,bud] A reproductive cell or bud.gonocalyx n. [Gr. gone, that which produces seed; kalyx,cover] (CNID) The bell of a medusa-like gonophore.gonochorism n. [Gr. gone, that which produces seed; chorismos,separation] The possession of functional gonads ofone sex only (male or female); dioecious. gonochoristica.gonochoristic a. [Gr. gone, that which produces seed; chorismos,separation] Unisexual; producing distinct malesand females. see hermaphrodite.

406Maggenti and Gardnergonocoel n. [Gr. gone, that which produces seed; koilos, hollow]The cavity containing the gonads.gonocoxa, gonocoxite n.; pl. -ae [Gr. gone, that which producesseed; L. coxa, hip] (ARTHRO: Insecta) The coxite ofthe gonopod. see second valvifers.gonocoxopodites n.pl. [Gr. gone, that which produces seed;L. coxa, hip; pous, foot] (ARTHRO: Insecta) In Siphonaptera,a pair of 2-segmented claspers associated with the9th tergum and median intromittant organ.gonodendron n. [Gr. gone, that which produces seed; dendron,tree] (CNID: Hydrozoa) In Siphonophora, a branchingstructure bearing grapelike clusters of gonophores that arenot set free.gonoducts n.pl. [Gr. gone, that which produces seed; L. ductus,led] 1. The ducts through which the gametes reach theexterior, oviduct in females, vas deferens in males. 2.(ECHI) see nephridium.gonogensis see gametogenesisgonomery n. [Gr. gone, that which produces seed; meros,part] (ARTHRO: Insecta) The separate grouping of maternaland paternal chromosomes during cleavage in some embryos.gonopalpon n. [Gr. gone, that which produces seed; L. palpare,to touch] (CNID: Hydrozoa) In Siphonophora, tentacle-likedactylozooids associated with gonophores.gonopericardial canal (MOLL: Solengastres) A canal from gonadsto the pericardium.gonophore n. [Gr. gone, that which produces seed; phoreus,bearer] (CNID: Hydrozoa) In Hydroida, a structure thatproduces gametes and is a sporosac, medusa or any intermediatestage.gonoplac n. [Gr. gone; that which produces seed; plax, plate](ARTHRO: Insecta) A process of the second gonocoxa; maybe a separate sclerite and may form a sheath around thegonapophyses; 3rd valvula.gonopod n. [Gr. gone, that which produces seed; pous, foot](ARTHRO) The appendages serving as genital segments, or

Online Dictionary of Invertebrate Zoology 407associated segments modified for reproductive purposes,i.e., chelicera, palp, leg, pleopod.gonopody n. [Gr. gone, that which produces seed; pous, foot]A type of internal fertilization whereby the male sperm istransferred by an appendage to the female genital organs;sperm transfer which is nearly direct. see podospermia,tocospermia.gonopore n. [Gr. gone, that which produces seed; poros,channel] 1. The external opening of the reproductive organs.2. (ARTHRO: Crustacea) The sexual pore. 3. (NEMATA)The vulva in females; the anus or cloacal opening in males.gonosome n. [Gr. gone, that which produces seed; soma,body] (CNID: Hydrozoa) All gonophores of a colony collectively.see trophosome.gonosomite see genital segmentgonostyle n. [Gr. gone, that which produces seed; stylos, pillar](CNID: Hydrozoa) The blastostyle; gonodendron.gonostylus n.; pl. gonostylii [Gr. gone, that which producesseed; stylos, pillar] (ARTHRO: Insecta) The stylus of agenital segment; harpago; style; stylus; paramere.gonotheca n. [Gr. gone, that which produces seed; theke,case] (CNID: Hydrozoa) In Leptomedusae, a vase-like coveringof the stalklike blastostyles.gonotreme n. [Gr. gone, that which produces seed; trema,hole] (ARTHRO: Insecta) The female gonopore, oviporus(secondary gonopore), or vulva; in males, the gonopore.gonotrophic concordancy (ARTHRO: Insecta) In certain mosquitoes,discontinuation, or only occasional ingesting ofblood meals after ovulation has stopped. see gonotrophicdissociation.gonotrophic dissociation (ARTHRO: Insecta) In certain mosquitoes,the continuation of ingesting blood meals afterovulation has stopped. see gonotrophic concordancy.gonotyl n. [Gr. gone, that which produces seed; tylos, knob](PLATY: Trematoda) In digenetic forms, a sucker or otherperigenital specialization associated with the genital atrium.gonozooecium n. [Gr. gone, that which produces seed; zoon,

408Maggenti and Gardneranimals; oikos, house] (BRYO: Stenolaemata) An enlargedpolymorph that serves as a brood chamber for eggs.gonozooid, gynozooid n. [Gr. gone, that which producesseed; zoon, animal; eidos, form] 1. (BRYO) A zooid modifiedas a brood chamber. 2. (CNID: Hydrozoa) A gonophoreor individual specialized for reproduction in a colony.gorgeret n. [Gr. Gorgos, terrible] 1. A barblike structure. 2.(ARTHRO: Insecta) The sting of a honey bee. 3. (NEMATA)The barb on the spicule.gorgonin n. [Gr. Gorgos, terrible] (CNID: Anthozoa) A proteinaceoushorny material forming the axial skeleton of seafans and sea whips.Gotte's larva (PLATY: Turbellaria) In Stylochus, a "Muller's"-type larva with the exception of four instead of eight lobes.Graber's organ (ARTHRO: Insecta) In tabanid larvae, a pyriformsac containing a series of capsules that opens at thesurface between the last two segments, thought to be sensoryin function; may be seen through the integument ofliving larvae.gracile a. [L. gracilis, slender] Gracefully slender or thin.gradate a. [L. gradus, step] Regularly increasing in size; arrangedin a series; blending of colors.grade n. [L. gradus, step] A group of organisms similar in levelof organization.graft n. [OF. greffe, graft] Act of grafting, or joining a part ofan organism with another.grained a. [L. granum, grain] Dotted with small tubercules.graminaceous a. [L. gramen, grass] Grass-colored.graminicolous a. [L. gramen, grass; colere, to dwell] Livingon grasses.graminivorous a. [L. gramen, grass; vorare, to devour]Grass-eating.granose a. [L. granum, grain] Like a string of grains; moniliform.granulated a. [L. dim. granum, grain] Covered with grains orsmall tubercles.

Online Dictionary of Invertebrate Zoology 409granular eosinophilic cell see granular hemocytegranular hemocyte Hemocytes that vary in size and shape,phagocytic in function, characterized by possession of acidophilicgranules in the cytoplasm. see granulocyte.granular leucocyte see granular hemocytegranular spheres see granulocytegranule n. [L. dim. granum, grain] 1. A very small or minuteelevation. 2. (ARTHRO: Insecta) Grain-like, short, thick,dark seta of beetles.granulocyte n. [L. dim. granum, grain; Gr. kytos, container] Ahemocyte variable in size and shape, granular contents ofsulfated, periodate-reactive sialomucin and other glycoproteinsor neutral mucopolysaccharides, and sometimeslipid droplets may be present.granulose a. [L. dim. granum, grain] Roughened with granules,or grain-like elevations.granum tinctorium see kermesgraphiohexaster n. [Gr. graphe, writing; hex, six; aster, star](PORIF) A six-rayed spicule with long filamentous processesfrom four of the rays.graptolite n. [Gr. graptos, painted; lithos, stone] A fossilgroup of pelagic, colonial animals with chitinous exoskeletons,consisting of simple or branched stems (rhabdosomes)toothed along one or both edges.grasping spines (CHAETO) Chitinous spines on the posteriorpart of the head used for food catching; prehensile spines;seizing jaws.gravid n. [L. gravidus, pregnant] Containing an egg or eggs,as a gravid pinworm, or gravid proglottid of a tapeworm.gray cell (PORIF) A cell with spherical basiphilic granules andmany glycogen rosettes.greater ocellars see ocellar bristlesgreen gland (ARTHRO: Crustacea) Excretory glands on the antennaeof crayfish and other Malacostraca; antennal gland.green pigments (ARTHRO: Insecta) A synthesized pigmentthat gives a green color to the blood and epidermal cells,

410Maggenti and Gardnereven without chlorophyll. see insectoverdin.gregaria n. [L. grex, flock] (ARTHRO: Insecta) The high densityphase of locusts and some caterpillars during which theyare gregarious and/or migratory. see solitaria.gregarious a. [L. grex, flock] Habitually associating in groupsor colonies.grege, greige see silkgres see sericingressorial a. [L. gressus, step] Adapted for walking.gribble n. (ARTHRO: Chelicerata) A small wood-boring isopod ofthe Limnoriidae.griseous a. [ML. griseus, gray] A white color mottled withblack or brown; light gray; bluish gray.grooming n. [OF. gromet, servant] To make neat; the cleaningof an animal by itself or others.group n. [F. groupe] A number of related taxa; a series ofclosely related species within a genus. see complex.group effect Alteration in behavior within a species or groupby nondirected signals.group predation Hunting and securing prey by groups of cooperatinganimals, i.e., army ants.growing-molt A molt that results in a larger size, but nochanges in characters or form.growing tip or point (BRYO) Proliferating distal extremities ofthe colony.growth n. [A.S. growan] 1. The development of an organismby assimilation. 2. A morbid formation, as a tumor.growth hormone Any of various growth promoting hormones.growth lines (MOLL: Gastropoda) Surface marking of the shell,denoting a former position of the outer lip.growth period In germ cell development, the period in whichthey increase greatly in size and during which synapsis occursand the tetrads are formed.growth ring see annotinategrowth rugae (MOLL) Irregular ridges or undulations on the

Online Dictionary of Invertebrate Zoology 411shell surface determined by former positions of the outerlip which show slowed or stopped growth. see growthlines.growth squamae (MOLL: Bivalvia) Scaly extensions of theshell surface parallel to the growth lines.growth stage The intermitotic growth stage of a cell; restingstage; resting cell.growth thread (MOLL: Bivalvia) A threadlike growth line.growth welt (MOLL: Bivalvia) An elongate shell elevation parallelto the growth lines.grub n. [ME. grubben, dig] (ARTHRO: Insecta) A legless larva;certain U- or C-shaped larvae generally found among theColeoptera and Hymenoptera.gryphaeate a. (MOLL: Bivalvia) Shell with left valve stronglyconvex with its dorsal part incurved and the right valve flat,as in the genus Gryphea ; gryphaeiform; gryph-shaped.guanine n. [Ab.Am. huanu, dung] A purine base present inDNA and RNA, found in fish scales, animals, plants and excreta.gubernaculum n.; pl. -la [L. dim. gubernare, to guide] 1.(CNID: Hydrozoa) Hydroida, protoplasmic strands connectingthe blastostyle and internal marsupium to the gonothecalwall; possibly functioning in nutrition or as a device forkeeping the internal marsupium in position. 2. (NEMATA) Asclerotized trough-shaped structure of the dorsal wall ofthe spicular pouch, near the distal portion of the spicules;functions for reinforcement of the dorsal wall. a. Retractorgubernaculi muscles extend from the gubernaculum to thedorsal or lateral body wall. b. Seductor gubernaculi musclesextend from the lateral walls of the body to the gubernaculum.guest n. [A.S. gaest] Animal living within the nest or den ofothers; a social symbiont.gula n. [L. gula, gullet] 1. (ARTHRO: Diplopoda) The reducedsternite of the first trunk segment forming the posteriorpart of the gnathochilarium; the hypostoma. 2. (ARTHRO:Insecta) A median ventral plate of the head, extendingfrom the submentum to the posterior tentorial pits; gular

412Maggenti and Gardnerplate.gulacava see gular pitgulamental plate (ARTHRO: Insecta) The basal labial plateformed by fusion of the gula and submental regions.gulamentum n. [L. gula, gullet; mentum, chin] (ARTHRO: Insecta)The plate formed by the fusion of the gula and submentum.gular a. [L. gula, gullet] 1. Pertaining to the throat or gula. 2.(MOLL) Pertaining to the innermost part of the shell aperture.gular pit (ARTHRO: Insecta) The infolding of a posterior arm ofthe tentorium.gular suture (ARTHRO: Insecta) 1. Longitudinal sutures oneach side of the gula or middle piece of the throat. 2. InColeoptera, marking the inflection of the posterior arms ofthe tentorium.gullet n. [L. gula, gullet] The esophagus.gustatory a. [L. gustus, taste] Pertaining to the sense of taste.see chemoreceptor.gut n. [A.S. gut] The intestinal tract; the alimentary canal, orpart of.gut sinus (ANN: Polychaeta) In some species, a thin-walledchamber around the gut filled with blood.gutta n. [L. gutta, a drop or spot] A roundish spot or markingof color. guttate a.gutter n. [OF. gutiere, a gutter] (MOLL: Gastropoda) An elongateprojection beyond the mouth.guttiform a. [L. gutta, a drop or spot; forma, shape] Dropshaped.gymnoblastic a. [Gr. gymnos, bare; blastos, bud] (CNID: Hydrozoa)Lacking hydrothecae and gonothecae, as some colonialforms.gymnocephalous cercaria (PLATY: Trematoda) Cercaria withoutornamentation, lacking spines or stylets on the anteriorend or in the oral sucker; with equal sized oral and ventralsuckers; no tail fin (Fasciolidae).

Online Dictionary of Invertebrate Zoology 413gymnocoel n. [Gr. gymnos, bare; koilos, hollow] A body cavitypossessing no special lining cells other than tissue borderingcavities such as epidermis or gastrodermis.gymnocyst n. [Gr. gymnos, bare; kystis, bladder] 1. (BRYO) Asimple type of wall morphology that adds exterior walls tothe ends of interior walls, thereby separating adjacent zooidsthat remain in communication through interzooidalpores. gymnocystal a. see cryptocyst. 2. (BRYO: Gymnolaemata)In cheilostomates, continuous or partial frontalshield formed by calcification of the zooidal frontal wall orby cuticle covered spots on the frontal wall.gymnocystidean n. [Gr. gymnos, bare; kystis, bladder](BRYO: Gymnolaemata) An Ascophora cheilostomate withautozooids having gymnocysts as frontal shields.gymnocyte n. [Gr. gymnos, bare; kytos, container] A cell withno cell wall. see lepocyte.gymnodomous a. [Gr. gymnos, bare; L. domus, house] (AR-THRO: Insecta) Pertaining to nests, especially of socialwasps lacking an envelope. see calyptodomous.gymnogastra n. [Gr. gymnos, bare; gaster, stomach] Havingthe venter or belly visible. see cryptogastra.Gymnolaemata, gymnolaemates n.; n.pl. [Gr. gymnos,bare; laimos, throat] Largest class of mainly marine Bryozoaprimatively cylindrical, but most commonly flattenedand lozenge-shaped, with a circular lophophore and lackingan epistome.gymnoparia n.; pl. -ariae [Gr. gymnos, bare; pareion, cheek](ARTHRO: Insecta) In scarabaeoid larvae, that part of theparia without bristles posterior to the acroparia and betweenthe acanthoparia and chaetoparia.gymnopterous a. [Gr. gymnos, bare; pteron, wing] (ARTHRO:Insecta) Lacking scales on wings.gynaecoid see gynecoidgynaecomorphic male see gynecanergynaecophoral canal (PLATY: Trematoda) A longitudinal infoldedgroove in the ventral surface of male schistosomeflukes where the female usually resides.

414Maggenti and Gardnergynaecotelic type (ARTHRO: Insecta) One of the two groups ofsocial insects in which the queen manifests the prototypefemale, with all the primary instincts, including those of theworker caste until after the colony is established when shethen becomes an egg-laying machine. see ergatotelictype.gynander see gynandromorphgynandrarchy n. [Gr. gyne, woman; aner, male; archon,leader] (ARTHRO: Insecta) Social organization among insectsdiffering from gynarchy in that the male takes part inestablishing the colony.gynandromorph n. [Gr. gyne, woman; aner, male; morphe,form] An individual in which male and female somaticcharacters exist; bilateral gynandromorphs, with the leftand right halves of different sex; sex mosaic. see intersex,chimera.gynandromorphism n. [Gr. gyne, woman; aner, male; morphe,form] The condition of being a gynandromorph. gynandromorphica.gynandry n. [Gr. gyne, woman; aner, male] Hermaphroditism;also, the condition of a female approximating to the maletype of physique.gynarchy n. [Gr. gyne, woman; archon, leader] (ARTHRO: Insecta)In social insects, a colony organization in which afemale initiates and dominates.gynecaner, gynaecaner n. [Gr. gynaiko, womanly; aner,male] (ARTHRO: Insecta) In Hymenoptera, a male ant ofcertain parasitic and workerless genera that resembles afemale rather than a worker, but having the same numberof antennal joints and according to the genus may bewingless; a gynaecomorphic male.gynecoid n. [Gr. gynaiko, womanly; eidos, like] (ARTHRO: Insecta)In Hymenoptera, a large egg laying worker ant.gynecophore see gynaecophoral canalgynergate n. [Gr. gyne, woman; ergate, worker] (ARTHRO: Insecta)A female containing patches of tissue of both thequeen and worker castes.

Online Dictionary of Invertebrate Zoology 415gynes n.pl. [Gr. gyne, woman] (ARTHRO: Insecta) 1. In bees, apotential or actual queen. 2. Especially potential queens ofhoneybees. 3. Certain halictid bees that are first gynes,later to become workers or queens.gynetype n. [Gr. gyne, woman; typos, type] A designated femaletype specimen.gynocophoral canal see gynaecophoral canalgynogenesis n. [Gr. gyne, woman; genesis, descent] Femaleparthenogenesis; pseudogamy; development of a haploidindividual possessing only the maternal chromosome set.see androgenesis.gynomerogony n. [Gr. gyne, woman; meros, part; gonos,seed] Development of an egg fragment containing only thefemale nucleus (maternal chromosomes).gynosynhesmia n. [Gr. gyne, woman; syn, together; hesmos,swarm] A group of females gathering together during matingseason. see androsynhesmia, synhesmia.gynozooid n. [Gr. gyne, woman; zoon, animal] A femalegonozooid.gyrate, gyral a. [L. gyrare, to turn about] Circular or spiralmovement; curved.gyration n. [L. gyrare, to turn about] 1. Rotating or whirlingmovement. 2. (MOLL) One of the whorls on a spiral shell.gyratory a. [L. gyrare, to turn about] Moving in a circle; circularor rotary motion.gyre n. [L. gyrare, to turn about] Coiling; chromosome coiling.gyri-cerebrales (ARTHRO: Insecta) Esophageal ganglion lobesin embryos.

Hhabitat n. [L. habitare, to dwell] The particular kind of environmentwhere a race, species or individual lives.habitat selection The capability of a dispersing individual toselect a particular (species-specific) environment.habitat type The ecotype.habitude n. [L. habitus, condition] General appearance orconformation of an animal.habroderes n.pl. [Gr. habros, graceful; deire, neck] (KINOR) InEchinoderidae, the fourth juvenile stage to adulthood inwhich the midterminal spine is missing, and a series ofmolts results in the loss of posterior middorsal spines untilthe adult complement is reached.hackled band (ARTHRO: Chelicerata) In cribellate spiders,composite threads spun by the cribellum and combed bythe calamistrum setae.haem- for words not found here see hemhaemocoelesee hemocoelhaemocyte see hemocytehaemolymph see hemolymphhaemostatic diaphragm or membrane (ARTHRO) In somearthropods, an obstruction device between femur and trochanterpreventing fluid loss after autotomy; an occlusivediaphragm.haemoxanthine n. [Gr. haima, blood; xanthos, yellow] (AR-THRO: Insecta) An albuminoid protein in the hemolymph,providing oxygen and nutritive materials.haft organ see frontal organhair n. [A.S. haer, hairy] Seta; chaeta; trichome. see pubescence.hair pads (ARTHRO: Insecta) 1. A group of sensory hairs combinedto form pads near joints together with internal pro-

Online Dictionary of Invertebrate Zoology 417prioceptors that are involved in the normal bearing of thelimbs; also involved for measuring the vector of externalforces, and contributing to orientation of the animal. 2. Apad on the compound eyes of the honey bee and betweenthe eyes of locusts controlling the self-generated flightspeed.hair plates see hair padshaliotoid a. [Gr. hals, salt, sea; otos, ear; eidos, like] Earshaped.Haller's organ (ARTHRO: Insecta) A complex sensory setal fieldwithin one or more pits, on the dorsal aspect of tarsus I ofticks and mites, providing sites for contact or olfactorychemoreception.halmatometamorphosis n. [Gr. halmatos, leap; metamorphosis,transform, change] (ARTHRO: Insecta) The processof degeneration of larval structures and development ofspecialized structures adapted for arthropod endoparasiticlife.halocline n. [Gr. hals, salt, sea; klinein, to slope] That area ofsharp vertical salinity change in the ocean or other salinewater.halophile n. [Gr. hals, salt, sea; philos, love] An organismadapted to living in a salty environment.halter n.; pl. halteres [Gr. halter, balancer] (ARTHRO: Insecta)In Diptera, sense organs consisting of a basal lobe, a stalkand an end knob on each side of the metathorax, representinga reduced hind wing; balancers.hamabiosis see neutralismhamate, hamiform a. [L. hamus, hook] Hooked; bent at theend resembling a hook; aduncate.hamatype n. [Gr. hama, together; typos, type] Obs. A specimenfrom the type lot of a species, not specified as aholotype or paratype; a special group of topotypes.hammock n. [Sp. hamaca, swinging couch] (ARTHRO: Insecta)Has been used to describe the hammock-like covering of acaterpillar.hampe n. [F. shank, stalk] (CNID) The basal tube portion of the

418Maggenti and Gardnernematocyst; the butt.hamula n. [L. hamulus, little hook] (ARTHRO: Insecta) A trigger-likehook securing the springing organ (furcula) ofspringtails; a retinaculum.hamular hook (ARTHRO: Insecta) In some male Odonata, acurved hook receiving the end of the basal lobe of theposterior hamuli.hamulohalterae n.pl. [L. hamulus, little hook; Gr. halter, balancer](ARTHRO: Insecta) In Homoptera, giant mealybughalters developed from the metathoracic wing-buds furnishedwith one or more hooklets that engage in a basalpocket of the corresponding fore wing.hamulus n., pl. -li [L. hamulus, little hook] 1. A hook or hooklikeprocess. 2. (ARTHRO: Insecta) a. In certain Hymenoptera,a row of minute hooks along the costal margin of thehind wing to unite the front and hind wings in flight; hasbeen spelled humule. b. In male Odonata, one of a pair ofanterior(is) and posterior(is) clasps of the genitalia (fenestra)for grasping the female. c. In Siphonaptera, one of apair of movable sclerites originating from the lateral wall ofthe aedeagal palliolum. 3. (PLATY: Trematoda) In monogeneticforms, large hooks on the opisthaptor; anchors.hamus n.; pl. hami [L., hook] (ARTHRO: Insecta) 1. In Heteroptera,an abrupt spur-like vein in the hind wings. 2. InLepidoptera, the retinaculum.Hancock's glands (ARTHRO: Insecta) In Orthoptera, large,glandular, sex-attractant pits of male tree crickets that secretea fluid which the female ingests during the matingact.Hancock`s organ (MOLL: Gastropoda) A succession of parallelfolds on each side of the mouth in the groove between thecephalic shield and the foot in some Opisthobranchia; lateralsensory areas.hapaloderes n.pl. [Gr. hapalos, tender; deire, neck] (KINOR)The first three juvenile stages of Echinoderidae in which amidterminal, lateral and middorsal spines are present. seehabroderes.haplobiont n. [Gr. haplos, simple; bios, life] An organism

Online Dictionary of Invertebrate Zoology 419characterized by one morphological distinct generation.haplo-diploidy (ARTHRO: Insecta) A normal reduction divisionoccurring in the oocyte, fertilized eggs developing into females,unfertilized eggs into males; characteristic of Hymenopteraand some other groups of insects.haploid a. [Gr. haplos, single] Having one set of chromosomes;gametes are usually haploid. see diploid.haplometrosis n. [Gr. haplos, single; metros, mother] (AR-THRO: Insecta) In Hymenoptera, the founding of a new colonyby a single fertilized, egg laying queen; monometrosis.haplometrotic a. see temporary haplometrosis, pleometrosis.haploneme a. [Gr. haplos, single; nema, thread] (CNID) Bearingthreads of uniform diameter or slightly dilated at thebase, but without a hampe; nematocysts, anisorhizas andisorhizas.haploneural a. [Gr. haplos, single; neuron, nerve] Suppliedwith one simple nerve.haplont n. [Gr. haplos, simple; -on, individual] An organismwith haploid somatic nuclei; monoplont.haplophase n. [Gr. haplos, single; phasis, look] The haploidphase or generation of the life cycle (meiosis to fertilization);gamophase. see diplophase.haplosis n. [Gr. haplos, single; -sis, act of] Meiotic reduction.haptolachus n. [Gr. haptos, fasten or join; lachos, part] (AR-THRO: Insecta) In scarbaeoid larvae, that part of the posteriorepipharynx behind the pedium, usually below thecrepis, comprised of the nesia, sensillae and crepis; proximalsensory area.haptomerum n.; pl. haptomeri [Gr. haptos, fasten or join;meron, a part] (ARTHRO: Insecta) The medio-anterior regionof the epipharynx of scarbaeoid larvae composed generallyof sensory spots, sometimes setiferous.haptor n. [Gr. haptos, fasten or join] 1. Organ of attachment;an acetabulum. 2. (PLATY: Trematoda) The pre-oral, oral orventral sucker.Hardy-Weinberg law The law stating that the frequency of

420Maggenti and Gardnergenes in a large randomly mating population remains constantin the absence of mutation, migration and selection.harmonic growth see Przibram's ruleharmonic mean Reciprocal of the arithmatic mean.harmosis n. [Gr. harmosis, adapting] Total response of an organismto a stimulus; includes reaction and adaptation.harpagones n. pl.; sing. harpago [Gr. harpage, grapplinghook] (ARTHRO: Insecta) 1. Moveable periphallic processesof males located on the ninth abdominal segment usuallyhaving a clasping function. 2. In mosquitoes, basal lobeson the mesal margin of the dorsal surface of the gonocoxites;the basal dorsomesal lobes. 3. The harpes of Lepidoptera.harpes n.pl. [Gr. harpes, sickle] (ARTHRO: Insecta) In Lepidoptera,a part of the male genitalia being one or moreprocesses; clasper.harpoon seta (ANN) A stout pointed seta with recurved barbsnear the apex.hastate a. [L. hasta, spear] 1. Triangular or spear-shaped withthe base diverging on each side into an acute lobe. 2. (PO-RIF) Pertaining to spicules of uniform diameter coming toan abrupt, sharp point.hastisetae n.pl. [L. hasta, spear; seta, bristle] (ARTHRO: Insecta)Spear-headed setae found especially in tufts on tergitesof the caudal segments of some larval dermestid beetles.hatching n. [ME. hacchen] Emergence from an egg shell.hatching membrane The embryonic cuticle between the larvalcuticle and the chorion that is shed during hatching orshortly afterward.hatching spines/tooth see egg bursterhaustellate a. [L. dim. haustus, sucking] For sucking; possessinga haustellum.haustellum n. [L. dim. haustus, sucking] A part of a beak orproboscis; mouthparts specialized for sucking.haustrulum n. [L. dim. haustrum, pump] (NEMATA: Se-

Online Dictionary of Invertebrate Zoology 421cernentea) The cavity of the valvular apparatus in theposterior bulb of rhabditid esophagi.Hautkorper see skin bodiesHayes' plate/sense cone see nesiumH-band The region in the center of the A-band of a sarcomerecharacterized by myosin filaments and absence of actinfilaments.head n. [A.S. haefod] 1. The anterior body region. 2. (ANN:Polychaeta) The prostomium and peristomium. 3. (ARTHRO)Bearing the eyes, antennae and mouth parts. 4. (NEMATA)Comprising the lips and sensory organs, oral opening andsupporting head skeleton.head apodeme (ARTHRO: Crustacea) In crayfish, fused endopleuriteand endosternite forming an area for muscle attachmentat the anterior end of the skeleton.head bulb see ballonetshead-fans (ARTHRO: Insecta) In Diptera, fan-like rays on themain part of the torma of mature larva of Simuliidae thatfunction as filtering organs in running water, or a rakingfunction in Crozetia .head gland (PLATY: Trematoda) Glands of circaria which producea secretion emitted into the matrix of the tegumentthat is thought to function in the postpenetration adjustmentof the schistosomula.head valve (MOLL: Polyplacophora) The anterior valve of chitons.heart n. [A.S. heorte] Sometimes used to describe the pulsatingdorsal blood vessel.heart chamber (ARTHRO: Insecta) One of the segmentalswellings of the dorsal blood vessel; ventricle.heautotype n. [Gr. heautou, of itself; typos, image] A specimenused by the original describer as an illustration of hisspecies and compared with the type or cotype; a hypotype.hectocotylus, heterocotylus n. [Gr. hekaton, hundred; kotyle,a cup] (MOLL: Cephalopoda) A penislike process orarm utilized in spermatophore transfer to the mantle cavityof the female, in some species breaking off in the process.

422Maggenti and Gardnerheel n. [A.S. hela, heel] (ARTHRO: Insecta) In Hymenopteralarvae, padlike prolongation of the base of the tarsungulusopposing the claw.height n. [A.S. hiehthu, height] 1. (MOLL: Gastropoda) Thelength parallel to the shell axis through the columella. 2.(MOLL: Bivalvia) The greatest vertical dimension throughthe beak at right angles to a line bisecting the adductorscars; altitude.heli pl. of helushelical a. [Gr. helix, a spiral] Spirally coiled; heliciform.helicocone a. [Gr. helix, a spiral; konos, cone-like] (MOLL:Gastropoda) An expanding cone-like spiral tube that is theform of most shells.heliophil, heliophilic, heliophilous a. [Gr. helios, sun;philein, to love] Thriving in a high intensity of light.heliophobic n. [Gr. helios, sun; phobos, fear] Shade loving.heliotaxis n. [Gr. helios, sun; taxis, arrangement] Taxis withsunlight as the stimulus. see phototaxis.heliotropism n. [Gr. helios, sun; trope, a turning] Tropismwith sunlight as the stimulus.helix n.; pl. helices [Gr. helix, a spiral] Having a spiral form.helmet n. [OF. helme] (NEMATA) An internal thickening in thecephalic region, often setoff by a groove, and denoted by alack of ornamentation of the anterior exterior cuticle. seecane.helminth n. [Gr. helmins, worm] Any parasitic worm of vertebrates.helminthiasis n. [Gr. helmins, worm; -iasis, disease] A wormdisease induced in or on a host.helminthic a. [Gr. helmins, worm] Pertaining to worms.Helminthology n. [Gr. helmins, worm; logos, discourse] Abranch of zoology dealing with the natural history of parasiticworms, especially flatworms and roundworms.helocerous a. [Gr. helos, nail; keros, horn] Having a clavateantenna.helotism n. [Gr. Heilotes, slave class] Symbiosis in which one

Online Dictionary of Invertebrate Zoology 423animal enslaves another forcing it to labour on its own behalf.see consortism.helus n.; pl. heli [Gr. helos, nail] (ARTHRO: Insecta) In scarabaeoidlarvae, a coarse fixed spine located near the haptomerum.hemal a. [Gr. haima, blood] Pertaining to blood.hemapoiesis see hematopoiesishematal see hemalhematocyte, hematacyte see hemocytehematodocha, haematodocha n. [Gr. haima, blood; doche,receptacle] (ARTHRO: Chelicerata) A fibro-elastic sac at thebase of the palpus of certain male spiders that fills withhemolymph and becomes distended during pairing.hematogenic, hematogenous a. [Gr. haima, blood; genos,birth] 1. Forming blood, hematopoietic. 2. Relating to anythingproduced from, derived from, or transported by theblood.hematophagus see hemophagushematopoiesis n. [Gr. haima, blood; poietes, maker] Theformation of blood cells; also spelled haematopoiesis, haemopoiesis,hemopoiesis.hemelytron n.; pl. -tra [Gr. hemisys, half; elytron, sheath](ARTHRO: Insecta) A fore wing in which only the basal portionis hardened; wing-covers; also spelled hemelytran,hemelytrum, hemielytron. hemelytral a. see elytron,tegmen.hemerophilic a. [Gr. hemeros, cultivated; philos, loving]Having the ability to withstand culture and human interferencewith the environment. see hemerophobic.hemerophobic a. [Gr. hemeros, cultivated; phobos, fear]Lacking the ability to withstand culture and human interferencewith the environment. see hemerophilic.hemianamorphosis n. [Gr. hemisys, half; ana, on; morphe,form] Post-embryonic development beginning as anamorphicand later becomes epimorphic.hemibranch n. [Gr. hemisys, half; branchos, gill] Gill filaments

424Maggenti and Gardneronly on one side; demibranch.hemicephalous a. [Gr. hemisys, half; kephale, head] (AR-THRO: Insecta) Referring to dipteran larvae with reducedhead capsule retractable within the thorax; an intermediatecondition between eucephalous and acephalous; hemicephalic.hemidesmosome n. [Gr. hemisys, half; desmos, bond; soma,body] Attachment process of the epidermal cell to the cuticle;process from the cuticle to which microtubules are attached.see desmosome, tonofibrillae.Hemimetabola n. [Gr. hemisys, half; metabole, change] A divisionof insects in some classifications (=Exopterygota) inwhich the nymphs live an aquatic life as opposed to theadult form.hemimetabolous metamorphosis (ARTHRO: Insecta) Simpleor gradual metamorphosis in which the nymphs are generallysimilar in body form to the adults, but resemble theadults more with each instar.hemiomphalous a. [Gr. hemisys, half; omphalos, the navel](MOLL: Gastropoda) Having the opening of the umbilicuspartly plugged.hemiphragms n.pl. [Gr. hemisys, half; phragma, wall] (BRYO:Stenolaemata) Shelf-like skeletal projections into the zooidliving chamber alternating from opposite sides of the zooecia;hemiphragms in any single zooid usually comparable inmorphology. see hemisepta.hemipneustic a. [Gr. hemisys, half; pnein, to breath] Having8 functional spiracles. see polypneustic.hemiseptum n.; pl. hemisepta [Gr. hemisys, half; L. septum,wall] (BRYO: Stenolaemata) Shelf-like projections into zooidliving chambers; usually on proximal walls, but also in pairson proximal and distal walls which differ in morphology.see hemiphragms.hemispondylium n.; pl. -ia [Gr. hemisys, half; spondylos,back] (BRACHIO) In Thecideidae, one of two small platesattached to a medium septum and not to the valve floor orside walls, bearing the median adductor muscles.hemisyrinx n. [Gr. hemisys, half; syrinx, pipe] (BRACHIO) A

Online Dictionary of Invertebrate Zoology 425median, conical chamber on the spondylium floor, posteriorlymarked by a pair of lateral ridges.hemitergite n. [Gr. hemisys, half; L. tergum, back] (ARTHRO:Insecta) 1. Any tergite that is divided into two plates. 2.Adult male Embiidae with tergum 10 divided into a pair ofasymmetrical plates. 3. In female Apoidea, the divided 7thgastral tergum.hemitrope a. [Gr. hemisys, half; tropos, a turn] Being halfturned around; half inverted.hemizonid n. [Gr. hemisys, half; L. zona, girdle] (NEMATA: Secernentea)A nerve commissure from the nerve ring that ishighly refractive at the point it joins the ventral nerve cordnear the excretory pore. see cephalids, hemizonion,caudalid.hemizonion n. [Gr. hemisys, half; L. zona, girdle] (NEMATA:Secernentea) A small nerve commissure slightly posteriorto the hemizonid.hemizygous a. [Gr. hemisys, half; zygon, yoke] A gene withno allele; gene in a haploid organism; sex linked gene as inxy-xx; gene in a part of a chromosome where the correspondingpart has been deleted.hemocoel, haemocoele n. [Gr. haima, blood; koilos, hollow]1. (ARTHRO) The main body cavity, the embryonic developmentof which differs from that of a true coelom, butwhich includes a vestige of that true coelom that emanatesfrom the blood spaces of the embryo, or remnants of theblastocoel after invasion of the latter by the mesoderm. 2.(MOLL) The main body cavity.hemocoelous viviparity, haemocoelous (ARTHRO: Insecta) Aform of viviparity in which development occurs in thehemocoel.hemocyanin n. [Gr. haima, blood; kyanos, dark blue] A blueoxygen carrying respiratory protein containing copper inthe prosthetic group instead of iron; found in many invertebratespecies.hemocyte, haemocyte n. [Gr. haima, blood; kytos, container]A mesodermal cell, sessile or circulating, in the hemocoelor hemolymph of insects and other invertebrates. see

426Maggenti and Gardnergranular hemocyte.hemocytoblast see prohemocytehemocytopoietic organs see hemopoietic organshemoglobin n. [Gr. haima, blood; L. globos, sphere] A redoxygen respiratory protein with iron in the prosthetic groupwith molecular weights varying from 17,000 to 2,750,000,differing in absorption spectrum and oxygen-combiningproperties.hemolymph, haemolymph n. [Gr. haima, blood; L. lympha,water] 1. (ARTHRO) Fluid within the hemocoel. 2. (NEMATA)The pseudocoelomic fluid.hemolysis, haemolysis n. [Gr. haima, blood; lyein, to dissolve]The breakdown or destruction of red blood corpuscles.hemolytic a.hemophagous a. [Gr. haima, blood; phagein, to eat] Ingestingblood.hemopoietic a. [Gr. haima, blood; poietes, maker] Pertainingto any blood forming cell or organ.hemopoietic organs (ARTHRO: Insecta) Discrete encapsulatedorgans, reported in Hemiptera, Coleoptera, Diptera, Lepidopteraand Hymenoptera, functioning in the formation ofblood cells; hemocytopoietic organs; also spelled haemopoietic.hemozoin n. [Gr. haima, blood; zoon, animal] A pigmentfound in a host produced by a malarial parasite from thehemoglobin of the host.henidium n. [Gr. dim. henos, one] (BRACHIO) Deltidial platesthat lose the line of fusion during growth.Hensen gland (MOLL: Cephalopoda) A gland found in the headnear the eyes that synthesize leucocytes; white body.hepatic a. [L. hepaticus, liver] Pertaining to liver; liver colored.hepatic caecum/cecum pl. caeca/ceca Pouchlike diverticulumgenerally connected with the mesenteron in many invertebrates.see hepatopancreas.hepatic cells see nephrocyteshepatic groove (ARTHRO: Crustacea) In Decapoda, a groove

Online Dictionary of Invertebrate Zoology 427connecting cervical, postcervical and branchiocardiacgrooves.hepatic pouches see caecumhepatic region (ARTHRO: Crustacea) In Decapoda, an areacontiguous with antennal, cardiac and ptergostomial regions.hepatic spine (ARTHRO: Crustacea) In Decapoda, located belowand behind the lower branch of the cervical groove.hepatopancreas n. [Gr. hepar, liver; pan, all; kreas, flesh] Abranched digestive gland of the cephalothorax of variousinvertebrates, functioning as both liver and pancreas.herbivore n. [L. herba, plant; vorare, to eat] Animals that feedon plants. herbivorous a.hereditary a. [L. hereditas, heirship] Biological traits transmittedfrom one generation to another.heredity n. [L. hereditas, heirship] The transmission of genesfrom parents to offspring, controlling biological traits.hermaphrodite n. [Gr. hermaphroditos, combining bothsexes] An individual bearing recognizable male and femaletissues and producing male and female gametes at someperiod of the life cycle; monoecious; androgynous; ambisexual;ambosexous; protandry. see intersex. hermaphroditica.hermaphroditic duct (MOLL: Gastropoda) In Pulmonata, theduct that connects the ovotestes and carrefour area.hermaphroditism n. [Gr. hermaphroditos, combining bothsexes] Possession of gonads of both sexes by a single individual;autocopulation.hermatype corals (CNID) Reef building species of corals. hermatypica. see ahermatype corals.hesmosis see swarmingheteractinal a. [Gr. heteros, different; aktis, ray] (PORIF) Spiculeshaving a disc of six to eight rays in one plane and asingle perpendicular ray.heterauxesis n. [Gr. heteros, different; auxesis, growth] Disproportionategrowth of a structure in relation to the rest of

428Maggenti and Gardnerthe body; heterogonic or allometric growth. see bradyauxesis,isauxesis, tachyauxesis.heteroacanthus armature (PLATY: Cestoda) Hooks arrangedin semicircles from the internal surface to the externalsurface of the tentacles without chainettes. a. Atypica :differing numbers of hook rows on the internal and externalsurface of the tentacles. b. Typica : same number of hookrows, etc.heteroallelic a. [Gr. heteros, different; allelon, reciprocal]Genes having mutations at different mutational sites (nonidenticalalleles). see homoallelic.heteroausecic coefficient see allometric coefficientheteroblastic a. [Gr. heteros, different; blastos, bud] Similarorgans arising from different germ layers in different species.see homoblastic.heteroblastic change Rapidly altered structures during transitionfrom juvenile to adult.heterobrachial a. [Gr. heteros, different; brachion, arm]Chromosome arms of unequal length.heterocentric a. [Gr. heteros, different; kentron, midpoint]Dicentric chromosomes or chromatids whose centromeresare of unequal strength; frequently behave as monocentricchromosomes.heterochelate a. [Gr. heteros, different; chele, claw] (ARTHRO:Crustacea) Having the chelae of left and right chelipedsvarying in size and shape.heterochromatin n. [Gr. heteros, different; chroma, color]Non or poorly staining part of the chromosome inactive inheredity, as contrasted with euchromatin. heterchromatica.heterochrome a. [Gr. heteros, different; chroma, color] Havingdifferent colors. see homochrome.heterochromosome n. [Gr. heteros, different; chroma, color;soma, body] 1. Any chromosome differing from the autosomesin size, shape or behavior. 2. A sex-chromosome;an allosome.heterochronism n. [Gr. heteros, different; chronos, time]

Online Dictionary of Invertebrate Zoology 429Changes in the relative time of appearance and rate of developmentfor characters already present in ancestors.heterochronic a.heteroclite n. [Gr. heteros, differrent; clitos, hill] (MOLL: Bivalvia)A folded or twisted commissural plane.heterocotylus see hectocotylusheterodactyl a. [Gr. heteros, different; daktylos, finger] (AR-THRO: Chelicerata) Having claws, apoteles or ungues differingfrom each other. heterodactyly n. see homodactylheterodont a. [Gr. heteros, different; odous, tooth] Having avariety of tooth types.heterodynamic a. [Gr. heteros, different; dynamis, power]Genes not simultaneously influencing the same developmentalprocess.heterodynamic life cycle 1. A life cycle in which there is aperiod of dormancy. 2. A life cycle that includes a rest periodnot caused by environmental conditions. see homodynamiclife cycle.heteroecious, heteroicous a. [Gr. heteros, different; oikos,house] Parasitic upon two unlike hosts, either by successivegenerations or in a single life history. see metoeciousparasite; heteroxenous.heterogamete see anisogametesheterogametic a. [Gr. heteros, different; gamete, spouse]Pertains to the sexual form that gives rise to two differenttypes of sexual gametes in meiosis; in xy and xo systemsthis is usually male; digametic. see homogametic.heterogamy n. [Gr. heteros, different; gamos, marriage] 1.Alternation of bisexual with parthenogenetic reproduction.2. The preference of an individual to mate with an unlikephenotype or genotype. see homogamy. 3. see anisogamy.heterogeneous a. [Gr. heteros, different; genos, kind] Possessingdifferent characteristics. see homogeneous.heterogenesis n. [Gr. heteros, different; genesis, descent]Form of reproduction that has sexual and asexual orparthenogenetic forms; alternation of generations; xeno-

430Maggenti and Gardnergenesis. see metagenesis.heterogenetic a. [Gr. heteros, different; genesis, descent]Pertaining to meiotic chromosome pairing in hybrids whenpairs are derived from different ancestors. see homogenetic,heterogonic life cycle.heterogenic a. [Gr. heteros, different; genos, race] Containingmore than one allele of a gene.heterogomph n. [Gr. heteros, different; gomphos, peg] (ANN)A compound seta with an asymmetrical joint between shaftand blade. see homogomph.heterogonic coefficient see allometric coefficientheterogonic life cycle Life cycle involving alternation of parasiticand free-living generations. see homogonic life cycle.heterogony n. [Gr. heteros, different; gonos, seed] 1. Studyof relative growth. see allometric growth. 2. Alternationof generations. see heterogamy. 3. Both males and femalespresent in a colony.heterogynous a. [Gr. heteros, different; gyne, woman] Havingmore than one type of female.heteroideus a. [Gr. heteros, different; idios, personal] (AR-THRO: Insecta) Pertaining to larvae with a mesoseries ofcrochets bearing a well developed median series of hooksflanked on each end by smaller or rudimentary crochets.see homoideus.heterology n. [Gr. heteros, different; logos, discourse] Thelack of similarity between structures due to different componentsor of a different derivation. see anology, homology.heterolysis n. [Gr. heteros, different; lysis, loosen] Disintegrationof a cell or tissue by an external agent, either bylysins or enzymes. see autolysis.heteromedusoid a. [Gr. heteros, different; Medousa, Medusa](CNID: Hydrozoa) In Hydroida, a sessile gonophore of astyloid type.heteromerous a. [Gr. heteros, different; meros, part] 1. Nonuniformityin number of parts between organisms of the

Online Dictionary of Invertebrate Zoology 431same species, or organs on the same individual. see homeomerous.2. (ARTHRO: Insecta) In Coleoptera, the tarsiare usually 5,5,4 segments in both sexes, occasionally4,4,4, and rarely 3,4,4 in males, very rarely 3,3,3.Heterometabola n. [Gr. heteros, different; metabole, change]In some classifications the division of Exopterygota excludingHemimetabola.heterometabolous, metamorphosis a. [Gr. heteros, different;metabole, change] (ARTHRO: Insecta) Developing by incompleteor direct metamorphosis where there is no pupalstage; the immature resemble adult insects and are knownas nymphs.heteromorph n. [Gr. heteros, different; morphe, form] (AR-THRO: Crustacea) An adult female dimorphic ostracod, recognizableby carapace structure.heteromorphic a. [Gr. heteros, different; morphe, form] 1.Deviating from the normal form. 2. At different life stagesprogressing to another form; heteromorphous 3. Homologouschromosomes differing in size or form.heteromorphosis n.; pl. -ses [Gr. heteros, different; morphosis,forming] The replacement of an organ or part in an abnormalposition, especially one lost or removed; homoeosis.see homomorphosis.heteromorphous a. [Gr. heteros, different; morphe, form] 1.Heteromorphic. 2. (ARTHRO: Insecta) Successive instarswith differing forms and marked differences in development.see hypermetamorphosis.heteromorphous armature (PLATY: Cestoda) Hooks thatchange radically in size and shape from internal to externalsurface of the tentacle.heteromyarian a. [Gr. heteros, different; mys, muscle] (MOLL:Bivalvia) Having adductor muscles unequally developed.see homomyarian.heteroneme n. [Gr. heteros, different; nema, thread] (CNID) Anematocyst with an open tip with a definite hampe.heteronereid n. [Gr. heteros, different; Neris, family Nerididae](ANN: Polychaeta) A specialized, free swimming, sexuallydimorphic marine worm that gives off sex products into

432Maggenti and Gardnerthe water and dies after spawning. see epitoky.heteronereis see epitokyheteronomous a. [Gr. heteros, different; nomos, usage] Havingunlike segments; differing in development or function.heteronomous hyperparasitoid (ARTHRO: Insecta) In Hymenoptera,a species in Adelinidae in which the female developsas a hyperparasitoid of one host, while the male developsas a normal parasitoid on another host; an adelphoparasite.see diaphagous parasitoid, heterotrophicparasitoid.heteronomous parasitoid (ARTHRO: Insecta) In Hymenopteraspecies Aphelinidae, a parasitoid exhibiting heteronomy.heteronomous segmentation Relative dissimilarity and specializationof certain body segments. see homonomous.heteronychia n. [Gr. heteros, different; onyx, claw] (ARTHRO:Chelicerata) One or more legs with a different number ofclaws than the other legs in a particular mite stase.heteropalpi n.pl. [Gr. heteros, different; L. palpus, feeler](ARTHRO: Insecta) Palpi that differ in number of segmentsbetween male and female.heteroparthenogenesis n. [Gr. heteros, different; parthenos,virgin; genesis, beginning] Cyclic parthenogenesis.heteroploid a. [Gr. heteros, different; aploos, onefold; eidos,form] Designating a chromosome number deviating fromthe somatic number characteristic of the species; chromosomenumbers may be either euploid or aneuploid.heteropod a. [Gr. heteros, different; pous, foot] (MOLL: Gastropoda)Pertains to pelagic snails with a compressed footadapted for swimming.heteropycnosis, heteropyknosis n. [Gr. heteros, different;pyknos, dense] Certain chromosomes or regions of chromosomesthat are out of phase in their coiling cycle andstaining properties. heteropycnotic, heteropyknotic a.heterorhabdic a. [Gr. heteros, different; rhabdos, rod] (MOLL:Bivalvia) Pertaining to plicate lamellibranchiate gill in whichthe filament in the bottom of the depression between twosuccessive plicae is longer than the other filaments. see

Online Dictionary of Invertebrate Zoology 433homorhabdic.heterosis n. [Gr. heteros, different; -sis, process of] Selectivesuperiority of heterozygotes; hybrid vigor.heterosomal a. [Gr. heteros, different; soma, body] Chromosomalstructural changes involving two or more nonhomologouschromosomes.heterosome n. [Gr. heteros, different; soma, body] Sex chromosome;a heterochromosome.heterostrophic a. [Gr. heteros, different; strophe, turn](MOLL: Gastropoda) Pertaining to a protoconch when thewhorls appear to be coiled in the opposite direction tothose of the teloconch.heterosyllid see epitokyheterotaxis n. [Gr. heteros, different; taxis, arrangement] Abnormalarrangement of parts or organs.heterotopy n. [Gr. heteros, different; topos, place] Phyleticchange in the location from which an organ differentiates inontogeny. heterotropic a.heterotrichous anisorhiza (CNID) A nematocyst open at thetip with a slightly swollen base, with spines on the wholethread, but those at the base are larger.heterotroph n. [Gr. heteros, different; trophe, nourishment]An organism requiring organic compounds among the foodsubstances as its source of carbon; organotroph; sometimesused as synonymous with chemoheterotroph. heterotrophica. see autotrophic.heterotrophic parasitoid (ARTHRO: Insecta) In Hymenoptera,a species in Adelinidae in which the male is a parasitoid ofa different host species than the female. see diaphagousparasitoid, heteronomous hyperparasitoid.heterotropic a. [Gr. heteros, different; tropos, turn] Sexchromosome that does not have an exactly homologouspartner (xx-xy or xx-xo).heterotypic a. [Gr. heteros, different; typos, shape] Pertainingto the first meiotic division (meiosis) in which the bivalentchromosomes separate and are reduced in number. seehomeotypic.

434Maggenti and Gardnerheteroxenous a. [Gr. heteros, different; xenos, host] Havingmore than one host during a parasite's life cycle.heterozooid n. [Gr. heteros, different; zoon, animal] (BRYO:Gymnolaemata) A specialized zooid that forms stolons, attachmentdiscs, rootlike structures and other such vegetativeparts of the colony; a bryozoan, such as an aviculariumor a rhizoid.heterozygosity n. [Gr. heteros, different; zygon, yolk] Conditionof bearing differing genetic alleles at the same loci ofthe two parental chromosomes. see homozygosity.heterozygous a. [Gr. heteros, different; zygon, yolk] Pertainingto an individual with different genetic alleles at thecorresponding loci of the two parental chromosomes. heterozygoten. see homozygous.hexacanth a. [Gr. hex, six; akantha, thorn] (PLATY: Cestoda) Asix-hooked mature embryo, or larva, hatching from theegg; an onchosphere.hexachaetous a. [Gr. hex, six; chaite, hair] (ARTHRO: Insecta)In Diptera, describing the bundle of 6 needlelike mouthparts(stylets).hexactinal a. [Gr. hex, six; aktis, ray] (PORIF) Referring to a 6rayed spicule occurring in only the class Hexactinellida.hexactine n.hexagonal a. [Gr. hex, six; gonia, corner, angle] Having 6sides and 6 angles.hexamerous a. [Gr. hex, six; meros, part] Having 6 radiallyarranged parts or multiples of 6.hexanephric a. [Gr. hex, six; nephros, kidney] Having 6 kidneys,or structures utilized as kidneys.hexapod a. [Gr. hex, six; pous, foot] 1. Having 3 pairs of legs.2. (ARTHRO: Chelicerata) In larval mites, having or using 3pairs of legs. hexapody n. see octopod.Hexapoda see Insectahexaradiate a. [Gr. hex, six; L. radius, rod] Projecting outwardin 6 directions.hexaster n. [Gr. hex, six; aster, star] (PORIF) A type ofhexatine with branching rays producing star-shaped fig-

Online Dictionary of Invertebrate Zoology 435ures.hexicology see ecologyhexose n. [Gr. hex, six; -ose, indicates carbohydrate] Monosaccharideshaving 6 carbon atoms, including glucose andfructose.hexuronic acid Vitamin C.hiatus n.; pl. hiatuses, hiatus [L. hiare, to gape] 1. Anopening, gap or foramen. 2. An opening in an egg shell. 3.(NEMATA) see opercular plug.hibernaculum n.; pl. -la [L. hibernaculum, winter residence]1. A case or covering. 2. (BRYO) Winter bud in a few freshwaterforms that survive the winter and form a new colonyin the spring. 3. (ARTHRO: Insecta) A case or covering inwhich larvae hide or hibernate; a winter cocoon.hibernal a. [L. hibernus, winter] Occurring in winter.hibernation n. [L. hibernus, winter] A form of suspended animationor inactivity in organisms during unfavorable winterconditions. see aestivation.hibernestivation n. [L. hibernus, winter; aestivus, of summer]A period of rest or inactivity during unfavorable conditionsextending through both hot and cool seasons, especially inthe monsoon tropics, i.e., certain annelids.Hicks' bottles (ARTHRO: Insecta) Campaniform sensillae ofbees and ants located in the antennae in the shape of depressionsor pits, and thought to be auditory in function;sensilla campaniformia.Hicks' papillae (ARTHRO: Insecta) In Diptera, campaniformsensilla on the haltere base sensitive to vertical forcesduring flight.hierarchy n. [Gr. hieros, holy; archon, leader] 1. In classification,the system of ranks that indicates the categorical levelof various taxa. 2. A social ranking system in a colony.hill see formicaryhind angle see anal anglehind-gut n. [A.S. hindan; gut] The posterior ectodermal portionof the alimentary tract (canal) between the mid-gut

436Maggenti and Gardnerand the anus. see proctodeum.hind head (ARTHRO: Insecta) In Mallophaga, behind the mandiblesand antennae.hindunguis n. [A.S. hindan; L. unguis, claw] (ARTHRO: Insecta)In mosquitoes, the posterior unguis of one of thehindlegs.hinge n. [ME. heng, hinge] 1. The point of articulation of amoveable joint. 2. (ARTHRO: Insecta) The maxilla, cardo; inmosquitoes, between the upper and lower vaginal lips. 3.(MOLL: Bivalvia) An interlocking toothed device upon whichthe shells articulate.hinge ligament Elastic substance interlocking the valves of abivalve shell.hinge line 1. (ARTHRO: Crustacea) The middorsal line of junctionbetween two valves of the carapace permitting movementbetween them. 2. (BRACHIO/MOLL: Bivalvia) The externalline of meeting of the brachial and pedicle valves;movement of the shells occurs here; hinge axis.hingement n. [ME. heng, hinge; L. mentum, tool] (ARTHRO:Crustacea) A collective term for the structures comprisingarticulations of ostracods.hinge nodes (ARTHRO: Crustacea) Localized thickening of theright valve hinge.hinge plate see cardinal platformhinge selvage (ARTHRO: Crustacea) In Ostracoda, a single ridgeextending along the free margin of the carapace, whenvalves are closed, fitting into the selvage groove of the oppositevalve; keeps valves from slipping sideways acrosseach other.hinge teeth 1. (BRACHIO) The tooth part of the articulating deviceon the ventral valve in the form of small projectionsalong the free edge of the palintrope. 2. (MOLL: Bivalvia) Aseries of shelly structures near the dorsal margin and fittinginto a socket in the opposite valve; functioning inholding valves in position when closed.hirsute a. [L. hirsutus, rough, shaggy] Bearing coarse hairs orhair-like processes; shaggy.

Online Dictionary of Invertebrate Zoology 437hirudinin n. [L. hirudo, leech] (ANN: Hirudinoidea) An anticoagulantsecretion of leeches.hispid a. [L. hispidus, hairy, prickly] Covered with rough hairsor minute spines.hispidulous a. [L. dim. hispidus, hairy, prickly] Minutely hispid.histoblast n. [Gr. histos, tissue; blastos, bud] The imaginaldisc.histochemistry n. [Gr. histos, tissue; chemeia, transmutation]The microscopic study of the chemical characteristics of tissues.histogenesis n. [Gr. histos, tissue; genesis, beginning] 1. Theformation and development of tissues from the undifferentiatedcells of the germ layers of the embryo. 2. (ARTHRO:Insecta) In holometabolic forms, histogenesis follows afterhistolysis of larval organs during the quiescent late larval orpupal stadia. see histolysis. histogenesis a.histohematin, histohaematin see cytochromehistology n. [Gr. histos, tissue; logos, discourse] The microscopicstudy of the detailed structure of the organs and tissuesof organisms.histolysis n. [Gr. histos, tissue; lyein, to loosen] 1. Breakdownof cells and tissues. 2. (ARTHRO: Insecta) The breakdown oflarval tissues during the quiescent late larval or pupalstages in holometabolic forms.histones n. [Gr. histos, tissue; -one, ketone] The basic proteinsassociated with DNA; the major general structuralproteins of chromatin, however, they can also act as depressorsof template activity.histopathology n. [Gr. histos, tissue; pathos, suffering; logos,discourse] The study of abnormal microscopic changes inthe tissue structure of an organism.histozoic a. [Gr. histos, tissue; zoon, animal] Dwelling withinthe tissues of a host.histrichoglossate a. [Gr. hystrix, porcupine; glossa, tongue](MOLL: Gastropoda) Referring to the radula, consisting ofnumerous types or categories of teeth: a median central

438Maggenti and Gardnertooth plus several kinds of lateral and marginal teeth, inretrograde oblique position, often in bristlelike fascicles.hive aura/odor see nest odorhive n. [A.S. hyf,] (ARTHRO: Insecta) A man-made nest forhoneybees.holandric a. [Gr. holos, whole; aner, male] 1. Describing sexdeterminategenes that are manifest only in the male sex.2. (ANN: Oligochaeta) Classical term that originally meantthe placement of testes in segments x-xi.holandry n. [Gr. holos, whole; aner, male] 1. The condition ofbearing the normal number of testes. 2. (ANN: Oligochaeta)Earthworms with two pair of testes, one pair in segment xand another pair in segment xi. see proandry, metandry.holarctic region A zoogeographical region encompassing thepalaeartic and nearctic regions.holaspis larva (ARTHRO: Trilobita) Final larval stage in whichthe general adult structures are present and with succeedingmolts minor changes and increase of size. see protaspisand meraspis larva.holidic a. [Gr. holos, whole; -idios, distinct] Said of a mediumthat has exactly known chemical constituents other thanpurified inert materials before compounding; a defined medium.holism n. [Gr. holos, whole; -ismos, denoting condition] 1. Thephilosophic principle that the determining factors in nature,especially evolution, are wholes, such as organisms and notthe sum of their parts. 2. Accentuating the organic functionalrelation between parts and wholes. holistic a.holobenthic a. [Gr. holos, whole; benthos, sea-bottom] Refersto animals living their whole life on or near sea-bottom.holoblastic division The type of cleavage in which the entireegg cell is divided.holochroal a. [Gr. holos, whole; chroa, body surface] (AR-THRO) Refers to a compound eye with narrow facets andpolygonal lenses, as in most crustacean and insect eyes.see schizochroal.holocoen n. [Gr. holos, whole; koinos, common] The whole

Online Dictionary of Invertebrate Zoology 439environment, the biocoen and abiocoen; the ecosystem.holocrine a. [Gr. holos, whole; krinein, to separate] The disintegrationof a gland in order to release secretions. seemerocrine.holocyclic a. [Gr. holos, whole; kyklos, circle] Pertaining toalternation of generations. see anholocyclic.holoenzyme n. [Gr. holos, whole; en, in; zyme, yeast] A completefunctional enzyme consisting of an apoenzyme and acoenzyme taken together. see apoenzyme.hologamy n. [Gr. holos, whole; gamos, marriage] Conditionwhere gametes and somatic cells are similar; macrogamy.holognathous a. [Gr. holos, whole; gnathos, jaw] (MOLL:Gastropoda) Possessing a jaw of one piece construction, ascertain terrestrial forms.hologynic a. [Gr. holos, whole; gyne, woman] A term describingsex-limited characters which are manifest only inthe female sex. see holandric.hologynous a. [Gr. holos, whole; gyne, woman] (ANN) A classicalterm pertaining to ovaries restricted to segments xiiand xiii or a homeotic equivalent.hologyny n. [Gr. holos, whole; gyne, woman] The state orcondition of being hologynous.holoic see meganephridiaHolometabola n. [Gr. holos, whole; metabole, change] Dominantsuperorder of insects, distributed worldwide, that includesthe vast majority of insect families, genera and specieswith complete metamorphosis and wing pads formedby invagination; in some classifications Endopterygota.holometabolous metamorphosis (ARTHRO: Insecta) Metamorphosiswith a larva, pupa and adult; complete metamorphosis.see paurometabolous.holomyarian a. [Gr. holos, whole; mys, muscle] (NEMATA) Describingthe longitudinal muscle cells indistinguishable asindividual cells so as to appear like a single band as viewedin transverse section. This term was discarded in nematologywhen Butschli in 1873 showed that, by definition, noexamples exist. see meromyarian, polymyarian.

440Maggenti and Gardnerholonephridia see meganephridiaholoparalectotype n. [Gr. holos, whole; para, near; lektos,choose; typos, type] Any specimen from the original materialthat is later established as a paratype, it must be of thesame sex described by the author.holoparasite n. [Gr. holos, whole; parasitos, parasite] An obligateparasite.holophyletic a. [Gr. holos, whole; phyle, tribe] Denoting amonophyletic group that contains all of the descendants ofthe most recent common ancestor of that group. see monophyletic.holophyly see holophyleticholopneustic a. [Gr. holos, whole; pneustikos, of breathing]Having 10 functional spiracles. see polypneustic.holoptic a. [Gr. holos, whole; optikos, eye] (ARTHRO: Insecta)Having eyes dorsally contiguous along the midline. see dichoptic.holosericeous a. [Gr. holos, whole; serikos, silken] Coveredwith minute silky or shiny hair-like structures.holostomatous a. [Gr. holos, whole; stoma, mouth] (MOLL:Gastropoda) Having the mouth of the shell rounded or entire,uninterrupted by siphonal canal, notch, or by otherextension. holostomate n.holotaxy n. [Gr. holos, whole; taxis, arrangement] The presenceof all the organs or structures typically present in aparticular organism.Holothuroidea, holothuriids n., n.pl. [Gr. holothurion, seacucumber]Soft bodied, bottom-dwelling echinoderms, livingmostly in sand and mud where they lie buried, withtheir tentacles sticking up into clearer water.holotrichous isorhiza (CNID: Hydrozoa) A nematocyst withtubes spiney throughout. see atrichous isorhiza, basitrichousisorhiza.holotrichy n. [Gr. holos, whole; trichos, hair] Pertaining to invertebratespossessing all of the setae normally present intheir natural group. see hypertrichy.holotype n. [Gr. holos, whole; typos, type] The single speci-

Online Dictionary of Invertebrate Zoology 441men designated or indicated as the type specimen by theoriginal author at the time of original publication of a species.holozoic a. [Gr. holos, whole; zoon, animal] Obtaining organicfood materials by active ingestion of organisms or particles.holozygote n. [Gr. holos, whole; zygos, yolked] Zygote.homelytra n. [Gr. homos, same; elytron, cover] Elytra similaror equal to each other.homeoacanthous armature (PLATY: Cestoda) Homeomorphoushooks in spirals or in quincunxes on the tentacles.homeochilidium, homoeochilidium n. [Gr. homoios, like;dim. cheilos, lip] (BRACHIO) An external triangular platethat closes most or only the apical part of the notothyrium.homeochronous, homoechronous a. [Gr. homoios, like;chronos, time] Variation occurring at the same age in offspringas in the parent.homeodeltidium, homoeodeltidium n. [Gr. homoios, like;4th letter, delta; dim. thyrion, door] (BRACHIO) A convextriangular plate closing most or only the apical part of thedelthyrium.homeomerous see homoeomeroushomeomorph n. [Gr. homoios, like; morphe, form] Two unrelatedtaxa that are superficially alike.homeomorphous armature (PLATY: Cestoda) Hooks of sameshape and size in a row.homeosis see homoeosishomeostasis n. [Gr. homoios, like; stasis, a placing] Tendencyof a system to maintain a dynamic equilibrium; when disturbedthe animal's own regulatory mechanisms will restoreequilibrium.homeostrophic a. [Gr. homoios, like; strophe, turn] (MOLL:Gastropoda) Having whorls of the teloconch and the protoconchcoiled in the same direction.homeotely n. [Gr. homoios, like; telos, end, finish] Evolutionfrom homologous parts which have no resemblance to theoriginal structure; homeotic mutant.

442Maggenti and Gardnerhomeotype n. [Gr. homoios, like; typos, type] Taxonomic typefor a specimen that has been compared with the holotypeby another author and determined to be conspecific with it.homeotypic a. [Gr. homoios, like; typos, type] Referring tothe second meiotic division.homing ability The ability permitting return to the originalpoint of departure.homo- for those not found here, see homeo-.homoallelic a. [Gr. homos, same; allelon, reciprocal] Geneshaving mutations at the same site; homoallelic pairs do notyield recombinants. see heteroallelic.homoblastic a. [Gr. homos, same; blastos, bud] Similar organsarising from similar germ layers in different species;having direct embryonic development. see heteroblastic.homochrome a. [Gr. homos, same; chroma, color] Having onecolor or hue. see heterochrome.homochromy n. [Gr. homos, same; chroma, color] 1. Of thesame or uniform color. 2. (ARTHRO: Insecta) A phenomenonin which certain insects tend to have a general resemblanceto the prevailing color of the environment. see anticrypticcolor.homodactyl a. [Gr. homos, same; daktylos, finger] (ARTHRO)Pertaining to a claw similar in shape to the lateral claws(ungues). see heterodactyl.homodont see isodonthomodynamic a. [Gr. homos, same; dynamis, power] Pertainingto different genes simultaneously influencing thesame developmental process; opposed to heterodynamic.homodynamic life cycle 1. A life cycle in which there is continuousdevelopment; not interrupted by a diapause. 2. Alife cycle in which dormancy can only be caused by adverseenvironmental conditions. see heterodynamic life cycle.homodynamous a. [Gr. homos, same; dynamis, power] Directdevelopment without a resting stage.homoecious a. [Gr. homos, same; oikos, home] Denoting theutilization of the same host during the entire life cycle.

Online Dictionary of Invertebrate Zoology 443homoeochilidium see homeochilidiumhomoeodeltidium see homeodeltidiumhomoeomerous, homeomerous a. [Gr. homoios, like;meros, part] (ARTHRO) Pertaining to having the same numberof tarsal segments on all legs; isomerous. see heteromerous.homoeosis n. [Gr. homoios, like; -osis, formation] The replacementof an appendage with another part, by modificationor regeneration; metamorphosis. homoeotic a.homoeotype n. [Gr. homoios, like; typos, type] Specimen acceptedto be identical with the holotype, lectotype, paratypes,or syntypes of its species.homoesis n. [Gr. homoios, like] Presence of an organ, or pairsof organs, or a series of organs, in a segment or series ofsegments, other than those in which normally found.homogametic a. [Gr. homos, same; gamete, wife] Pertainingto sexual form that gives rise to the same type of sexualgamete in meiosis; in xx-xy and xx-xo systems usuallyfound in the female. see heterogametic.homogamy n. [Gr. homos, same; gamos, marriage] The preferenceof a mating individual for another with similar phenotypeor genotype. see heterogamy.homogeneous a. [Gr. homos, same; genos, race] Of the samekind or nature. see heterogeneous.homogenetic a. [Gr. homos, same; genesis, beginning] Pertainingto meiotic chromosome pairing in hybrids whenpairs are derived from the same ancestor. see heterogenetic.homogenic a. [Gr. homos, same; genos, race] Having onlyone allele of a gene or gene pair.homogenous a. [Gr. homos, same; genos, race] Having a resemblancein structure due to a common progenitor.homogeny n. [Gr. homos, same; genos, race] With analogousparts or organs due to descent from the same ancestraltype; homology. see homoplasy.homogomph n. [Gr. homos, same; gomphos, peg] (ANN) Acompound seta having a symmetrical joint between shaft

444Maggenti and Gardnerand blade. see heterogomph.homogonic life cycle Life cycle in which all generations arefree-living or all are parasitic; there is no (or little) alternationof the two. see hetergonic life cycle.homoideus a. [Gr. homoios, like; idios, personal] (ARTHRO:Insecta) In larvae, denoting a mesoseries of crochetsbearing well developed hooks throughout the entire series;homogeneous. see heteroideus.homoiosmotic a. [Gr. homoios, like; osmose, impulse] Said oforganisms maintaining constant internal osmotic pressure.homoiothermal a. [Gr. homoios, like; thermos, warm] Pertainingto warm-blooded animals having a relatively constantbody temperature due to their surrounding environment.see poikilothermal.homolecithal egg An egg-cell with a relatively small amountof yolk evenly distributed through the cytoplasm.homologue, homology n. [Gr. homologos, agreeing] 1. Featuresor organs in two or more taxa that can be tracedback to the same (or an equivalent) feature in the commonancester of these taxa. see analogy, heterology. 2. Basicsimilarity of organs or other structures that have had similarembryonic origin, but have developed in different waysfor different purposes.homomorpha, homorpha n. [Gr. homos, same; morphe,form] Larvae resembling the adults.homomorphic a. [Gr. homos, same; morphe, form] Beingsimilar in appearance or form.homomorphosis n. [Gr. homos, same; morphosis, forming] Inregeneration, when the reformed part or structure is similarto the part removed. see heteromorphosis.homomyarian see isomyarianhomonomous a. [Gr. homos, same; nomos, usage] Beingsimilar in form, function or development. see heteronomous.homonomous segmentation Relative similarity in body segmentsarranged on a transverse axis. see heteronomoussegmentation.

Online Dictionary of Invertebrate Zoology 445homonym n. [Gr. homos, same; onyma, name] The same independentlyproposed generic or specific name for thesame or different taxa. see senior homonym, juniorhomonym.homoplast n. [Gr. homos, same; plastos, formed] An idorgancomposed of similar plastids. see alloplast.homoplasy, homoplassy n. [Gr. homos, same; plastos,formed] Resemblance between parts or organs betweendifferent organisms due to evolutionary convergence or ofparallel evolution. homoplastic a. see homogeny.homopterous a. [Gr. homos, same; pteron, wing] (ARTHRO:Insecta) Having the anterior and posterior pairs of wingsalike.homorhabdic a. [Gr. homos, same; rhabdos, rod] (MOLL: Bivalvia)Pertaining to lamellibranch gill filaments that arearranged in a flat, uniform series. see heterorhabdic.homorpha see homomorphahomosequential a. [Gr. homos, same; L. sequor, follow] Pertainingto species with identical karyotypes.homostase n. [Gr. homos, same; stasis, a standing] Stasewhich differs only slightly from its neighboring stases.homotaxis n. [Gr. homos, same; taxis, arrangement] An assemblageor succession of species in different strata or regions,may or may not be contemporaneous.homotene a. [Gr. homos, same; L. tenere, to hold] Retainingthe primitive form. homotenous a.homothermis see homoiothermalhomotrichous anisorhiza (CNID) A nematocyst open at thetip with a slightly swollen base, and with spines of equallength along the thread.homotype n. [Gr. homos, same; typos, type] A structure correspondingto a structure on the opposite side of the body;reverse symmetry; homeotype. see enantiomorphic.homotypic a. [Gr. homos, same; typos, type] 1. Pertaining tothe second meiotic division (meiosis). 2. Exhibiting homotypy.

446Maggenti and Gardnerhomotypy n. [Gr. homos, same; typos, type] The similarity orequality of body structures along the main axis. see enantiomorphic.homozygosity n. [Gr. homos, same; zygon, yoke] Quality orcondition of bearing two identical alleles at one or more lociin homologous chromosome segments. see heterozygosity.homozygote n. [Gr. homos, same; zygon, yoke] One who exhibitshomozygosity. see heterozygote.homozygous a. [Gr. homos, same; zygon, yoke] Pertains tohaving identical alleles in the corresponding loci of homologouschromosomes; therefore breeding true. see heterozygous.honey n. [ME. honey] Thickened partially digested secretionfrom nectar of flowers produced by honeybees by enzymaticaction and used as food for larvae.honeycomb n. [A.S. hunigcamb] 1. A waxen structure built bybees in their nests consisting of an aggregation of hexagonalcells used as breeding cells for larvae and the storageof honey. 2. Any structure resembling a honeycomb.honey dew A sweetish liquid excreted by aphids or other homopterousinsects.honeypot (ARTHRO: Insecta) A wax container deposited insidethe entrance of the nest cavity filled with nectar by a solitaryqueen bumblebee when establishing a colony.honey stomach (ARTHRO: Insecta) A thin-walled enlargementof the esophagus (crop) in which the honeybee transportsnectar.honey tube see corniclehood n. [A.S. hod] 1. A color marking or expansion suggestinga hood. 2. (ARTHRO: Chelicerata) In beetle mites, the dorsalwall of the camerostome that extends over the capitulum.3. (ARTHRO: Insecta) a. In notodontoid and noctuoid Lepidoptera,a counter-tympanal cavity that expands laterallyto form a covering for the tympanal cavity posteriorly. b. Intingid Hemiptera, the dorsal elevated longitudinal carinae.4. (CHAETO) A body-wall fold with a coelomic sac which canbe drawn over the head. 5. (MOLL: Cephalopoda) In Nauti-

Online Dictionary of Invertebrate Zoology 447loidea, thickened membrane of fused sheaths of the dorsaltentacles, which serve for protection when the animal isretracted into the shell.hooded seta (ANN: Polychaeta) A stout, blunt or apicallytoothed seta with the apex protected by a delicate chitinousguard; a hook.hood protractor (CHAETO) An unpaired muscle that is found inthe free edge of the hood that acts as a sphincter muscle topull the hood over the head; protractor preputii.hood retractor (CHAETO) One of a pair of curved musclesoriginating on connective tissue beneath the brain and attachingto the neck plates (collarette) which retract thehood from the head; retractor preputii.hook glands (ARTHRO: Pentastomida) The paired longitudinalglands that unite anteriorly to form the head gland.hook, hooklets see hamulus, uncushoplochaetellin a. [Gr. hoplon, implement; chaite, hair] (ANN:Oligochaeta) Denoting earthworm male terminalia in whichone pair of sperm ducts open together with the prostaticducts of segment xvii or close to the prostatic pores, theother pair of sperm ducts similarly associated with theprostates of segment xix.horiodimorphism n. [Gr. horios, in season; dis, twice; morphe,form] Seasonal dimorphism.horismology n. [Gr. horos, boundry; logos, discourse] (AR-THRO: Insecta) Scientific description of the neuration of insectswings. see orismology.horizontal a. [Gr. horizon, bounding] Laying in a plane at rightangles to a primary axis; parallel with the horizon.horizontal classification Classification focusing on groupingspecies in a similar stage of evolution, rather than locationon the same phyletic line. see vertical classification.horme n. [Gr. horme, impulse, impetus] 1. Behavioral activitydirected toward a goal. 2. In living cells or organisms apurposive behavior, urge or drive.hormone n. [Gr. hormao, instigate] A chemical regulator orcoordinator secretion having some specific effect on me-

448Maggenti and Gardnertabolism, development, or response of the organism orsome particular part of it.horn n. [A.S. horn] 1. A stiff, pointed, unbranched cuticularprocess. 2. (ARTHRO: Insecta) a. A long handlelike processof the first gastric tergite of Innostemman wasps, thatcurves up and over the mesoscutum and houses the retractedovipositor. b. In the plural sometimes refers to antennae.horny a. [A.S. horn] Thickened or hardened.horny corals (CNID: Anthozoa) In the order Gorgonacea,commonly called sea fans or sea whips, with extensiveskeleton composed of a horny protein material, gorgonin.horotelic a. [Gr. horos, boundry; telos, completion] Pertainingto evolution proceeding at the standard rate. seetachytelic, bradytelic.host n. [L. hospes, guest or host] Any living organism in or onwhich a parasite lives, and/or feeds.host selection principle A theoretical hypothesis that femaleorganisms that breed on two or more hosts will return tothe host on which she was reared to reproduce.host specificity The degree to which a parasite is able to maturein one or more host species.Hoyle's organ (MOLL: Cephalopoda) In embryonic Sepia, adistinct set of cells in an anchor-shaped complex at the siteof the shell sac closure; a hatching gland that produces aproteolytic enzyme that dissolves the chorion and surroundingenvelope.humeral a. [L. humerus, shoulder] 1. Pertaining to or situatedon the shoulder. 2. (ARTHRO: Insecta) The anterior basalportion of an insect wing.humeral angle (ARTHRO: Insecta) 1. The basal anterior angleor portion of a wing. 2. The outer anterior angle of the elytrumof beetles.humeral bristles (ARTHRO: Insecta) In Diptera, the bristles onthe humeral callus.humeral callus (ARTHRO: Insecta) In Diptera, a more or lessrounded tuberculate anterior lateral angle of the thoracic

Online Dictionary of Invertebrate Zoology 449notum.humeral carina (ARTHRO: Insecta) In Coleoptera, an elevatedkeel-like ridge on the outer anterior angle of an elytron.humeral cross vein A cross vein between the base of a wingand the apex of the subcosta.humeral lobe (ARTHRO: Insecta) The base of the costal marginof the hind wing that overlaps the fore wing in some primitiveforms that serves to prevent the wings from movingout of phase.humeral nerve (ARTHRO: Insecta) A transverse nerve in thewing between the costal and subcostal veins.humeral plate (ARTHRO: Insecta) 1. In Odonata, a large platehinged to the tergum and supported by an arm from thepleural wing process. 2. In Hymenoptera (wasps and honeybees), a small plate separated from the metanotum anteriorlyand laterally which bears the anterior notal wing processof the hind wing. 3. In mosquitoes, an anterior preaxillarysclerite of the wing base supporting the costa.humeral suture see mesopleural suture, basal suturehumeral vein (ARTHRO: Insecta) A branch of the subcosta thatserves to strengthen the humeral angle of the hind wing.humerus n.; pl. humeri [L. humerus, shoulder] (ARTHRO: Insecta)The shoulder.humor n. [L. humor, fluid] Any body fluid, natural or morbid.hyaline a. [Gr. hyalos, glass] Clear, transparent or glassy.hyaline cells see granulocytehyalogen n. [Gr. hyalos, glass; genes, producing] Insolublesubstances found in animal tissues and related to mucoids.hyaloplasm, hyaloplasma n. [Gr. hyalos, glass; plasma,formed or molded] 1. The base substance of cytoplasm inwhich organelles are found. 2. (ARTHRO: Insecta) The clearnon-contractile matter (sarcoplasm) of a muscle in whichthe organelles are found.hyalopterous a. [Gr. hyalos, glass; pteron, wing] (ARTHRO:Insecta) Having transparent wings as the clear winged aegeridmoths.

450Maggenti and Gardnerhybrid n. [L. hybrida, a crossbred animal] The offspring of twoforms or species that are genetically dissimilar; a heterozygote.see cross.hybridization n. [L. hybrida, a crossbred animal] The crossingof individuals belonging to two unlike natural populations,or to different species.hybrid vigour see heterosishydatid cyst (PLATY: Cestoda) Metacestode of Echinococcus,with many protoscolices, some budding inside secondarybrood cysts.hydatid sand (PLATY: Cestoda) Free protoscolices forming thesediment in a hydatid cyst.hydranth n. [Gr. hydor, water; anthos, flower] (CNID: Hydrozoa)A nutritive zooid in a colony; the hydroid polyp, bearinga mouth, digestive cavity and tentacles.hydrarch a. [Gr. hydor, water; arche, beginning] A series ofchanges in time from newly formed pond or lake to landwith climax vegetation; an ecological succession.hydra-tuba n. [Gr. hydor, water; tuba, horn] (CNID: Scyphozoa)A simple polyp-like stage that may produce a fewmore polyps, but all bud off larvae known as ephyrae,which bud like a hydra. see scyphistoma.hydrelatic a. [Gr. hydor, water; elaunein, to set in motion] Ofor pertaining to the effects stimulation of glands have onactive transport of inorganic solutes and water.hydric a. [Gr. hydor, water] 1. Having an abundant supply ofmoisture. 2. Pertaining to or containing hydrogen.hydrobiology n. [Gr. hydor, water; bios, life; logos, discourse]Study of aquatic plants and animals.hydrobiont n. [Gr. hydor, water; bion, living] An organismthat lives mainly in water.hydrocarbon n. [Gr. hydor, water; L. carbo, coal] A chemicalcompound of hydrogen and carbon, usually in the proportionof C-H 20 .hydrocaulus n.; pl. -cauli [Gr. hydor, water; kaulos, stem](CNID: Hydrozoa) The simple or branched upright portion ofa hydroid colony; stem.

Online Dictionary of Invertebrate Zoology 451hydrochoric a. [Gr. hydor, water; chorein, to spread] Pertainsto dispersal by water; being dependent on water for dissemination.hydrocircus n. [Gr. hydor, water; kirkos, circle] (ECHINOD)The hydrocoelic ring surrounding the mouth.hydrocladium n.; pl. -ia [Gr. hydor, water; klados, branch](CNID: Hydrozoa) The lateral growing branch of the hydrocaulus;the secondary branches.hydrocoel n. [Gr. hydor, water; koilos, hollow] (ECHINOD) Partof the embryonic coelom which develops into the watervascular system.hydrocoles n.pl. [Gr. hydor, water; L. colere, to dwell] Organismsliving in water or a wet environment.hydrocyst see dactylozooidhydroecium n. [Gr. hydor, water; oikos, house] (CNID: Hydrozoa)A sheath-like extension that protects the zone of thesiphonophoran bell from adjacent bells.hydrofuge n. [Gr. hydor, water; L. fugere, to flee] (ARTHRO:Insecta) 1. Water repelling hairs. 2. The outer surface ofthe chorion of eggs, as well as the cuticles, respiratory siphonsand hairs.hydroid n. [Gr. hydor, water; eidos, like] (CNID) Polyp of coelenterates;any member of the Hydroida.hydrolysis n.; pl. -es [Gr. hydor, water; lyein, to dissolve] Reactionof water with substances to produce simpler compoundsas starch reduction to sugars or with inorganiccompounds to produce acid, basic or neutral reactions insolution.hydrophanous a. [Gr. hydor, water; phanerus, visible] Becomingtransparent when immersed in water.hydrophile hair (ARTHRO: Insecta) A water-attracting hair asopposed to a hydrophobe hair.hydrophilous a. [Gr. hydor, water; philein, to love] Moistureloving;hygrophilous.hydrophobe hair (ARTHRO: Insecta) A hair with resistance towetting, thus making a 90° angle of contact with the watersurface. see hydrophile hair.

452Maggenti and Gardnerhydrophyllum n.; pl. -lia [Gr. hydor, water; phyllon, leaf](CNID: Hydrozoa) A thick, gelatinous, helmet-shaped orleaf-like medusoid containing a simple or branched gastrovascularcanal, protective in function; a phyllozooid; abract.hydrophyton n. [Gr. hydor, water; phyton, plant] (CNID: Hydrozoa)A hydroid colony complete with root-like organ,stem and branches.hydroplanula n. [Gr. hydor, water; L. dim. planus, flat] (CNID)Larval stage between the planula and actinula larvalstages.hydropolyp n. [Gr. hydor, water; F. polype, polyp] (CNID: Hydrozoa)A single polyp of a hydroid colony. see hydrula.hydropore n. [Gr. hydor, water; poros, hole] (ECHINOD) Insome modern larvae and some extinct forms, the openinginto the left axocoel anterior to the hydrocoel, i.e., the canalextending from the axocoel to the surface.hydropyle n. [Gr. hydor, water; pyle, orifice] (ARTHRO: Insecta)A specialized structure of an egg for the uptake ofwater; the thickened region of the serosal epicuticle over alayer of endocuticle, thinner than elsewhere.hydrorhiza n. [Gr. hydor, water; rhiza, root] (CNID: Hydrozoa)A tubular or ribbon-like basal attachment of a colony anchoringthe colony to the substrate; the stalk of the colony.hydrosere n. [Gr. hydor, water; serere, to join] A sere originatingin water. see lithosere, xerosere.hydrosome (=hydrosoma) a. [Gr. hydor, water; soma, body](CNID) A hydra-like stage.hydrosphere n. [Gr. hydor, water; sphaira, ball] Aqueous envelopeof the earth.hydrospire n. [Gr. hydor, water; L. spira, coil] (ECHINOD) Inextinct Blastoidea, respiratory structures in the form ofpouches at the side of the ambulacral grooves.hydrostatic a. [Gr. hydor, water; statikos, cause to stand] 1.Of or pertaining to the pressure of water. 2. (ARTHRO: Insecta)Pertains to floats, as air sacs in larval aquatic insects.

Online Dictionary of Invertebrate Zoology 453hydrostatic organs (ARTHRO: Insecta) In some larval Culicidae,pigmented, crecent-shaped organs found laterally onthe thorax and near the tail.hydrostatic system (BRYO: Gymnolaemata) A method of protrusionof the lophophore in some autozooids; made up offlexible frontal wall or infolded frontal wall sac and attachedparietal muscles which contract and raise the lophophoreby hydrostatic pressure in the autozooid.hydrostome n. [Gr. hydor, water; stoma, mouth] (CNID: Hydrozoa)The mouth of a polyp.hydrotaxis n. [Gr. hydor, water; taxis, arrangement] A taxis inresponse to a moisture gradient initiating stimulus.hydrotheca n. [Gr. hydor, water; theke, case] (CNID: Hydrozoa)Peridermal cups into which most or all of the hydranthcan retract, may be provided with an operculum; in someThecata, the cup may be reduced to a mere platform supportingthe hydranth.hydrotropism n. [Gr. hydor, water; tropos, turn] The responseof an organism to water stimulus.Hydrozoa, hydrozoans n.; n.pl. [Gr. hydor, water; zoon,animal] Class of the phylum Cnidaria having both polyp andmedusal stages.hydrula n. [Gr. hydor, water] A simple hypothetical polyp. seehydropolyp.hygric a. [Gr. hygros, wet] Tolerating or being adapted to humidconditions.hygrokinesis n. [Gr. hygros, wet; kinesis, movement] Orientationdue to differences in humidity.hygrometabolism n. [Gr. hygros, wet; metabole, change] Theinfluence on metabolism by humidity.hygropetric a. [Gr. hygros, wet; petros, stone] Pertaining tothe fauna of submerged rocks.hygrophilous see hydrophiloushygroreceptor a. [Gr. hygros, wet; L. recipere, to receive] Asensory cell or structure that is sensitive to moisture.hygroscopic a. [Gr. hygros, wet; skopein, to view] Moisture

454Maggenti and Gardnersensitive; retaining moisture; accumulating moisture.hygrotaxis see hydrotaxishygrotropism see hydrotropismhylogamy n. [Gr. hyle, material; gamos, marriage] The fusionof gametes; syngamy.hylophagous a. [Gr. hyle, wood; phagein, to eat] Wood eating,as some insects.hylotomous a. [Gr. hyle, wood; temnein, to cut] Cuttingwood, as some insects.hymen n. [Gr. hymen] Membrane.hyoid sclerite (ARTHRO: Insecta) A small sclerite near the baseof the labrum in many cyclorrhaphous flies.hyote spines (MOLL: Bivalvia) Variably shaped (founded, earshaped),hollow, tubular spines open at their tips and ontheir flanks, arising from the thin edges of the shell marginof oysters; typical of Hyotissa Hyotis (Linne, 1758).hypandrium n.; pl. -dria [Gr. hypo, under; aner, male] (AR-THRO: Insecta) The plate below the genitalia of males, usuallyin abdominal sternum 8 or 9. see subgenital plate.hyperandric a. [Gr. hyper, above; andros, male] (ANN: Oligochaeta)In earthworms, having additional testes otherthan those of segments x-xi. hyperandry n.hyperapolysis n. [Gr. hyper, above; apo, separation; lyein, todissolve] (PLATY: Cestoda) Detachment of a juvenile tapewormproglottid before eggs are formed.hyperdiploid see hyperploidhypergamesis n. [Gr. hyper, above; gamos, marriage] Spermdigested by blood cells or phagocytes, thought to be of nutritionalvalue.hypergynous a. [Gr. hyper, above; gyne, woman] (ANN: Oligochaeta)In earthworms, having additional ovaries otherthan those of segments xii-xiii. hypergyny n.hyperhaline a. [Gr. hyper, above; hals, sea] Pertaining towaters above the salinity of normal sea water; above 40parts per thousand. see hypohaline.hyperhaploid see hyperploid

Online Dictionary of Invertebrate Zoology 455hypermeric a. [Gr. hyper, above; meros, part] (ANN: Oligochaeta)Said of regenerate earthworms, which reproducemore segments than originally removed. hypermery n.see hypomeric.hypermetamorphosis n. [Gr. hyper, above; meta, after;morphosis, forming] 1. In the broad sense, refers tochange of form throughout the life history. 2. (ARTHRO: Insecta)A type of metamorphosis development in which differentlarval insect instars have markedly dissimilar bodyforms. see heteromorphous.hyperparasite n. [Gr. hyper, above; parasitos, one who eatsat the table of another] An organism parasitic upon anotherparasite.hyperplasia n. [Gr. hyper, above; plasis, a molding] An increasein the number of functional units of an organ (organelle,cell, tissue). hyperplasic a. see hypertrophy.hyperploid a. [Gr. hyper, above; aploos, onefold] Cells or individualshaving more chromosomes (or segments) than thecharacteristic euploid number. see hypoploid, aneuploid,monoploid, polyploid.hyperpneustic a. [Gr. hyper, above; pneustikos, of breathing](ARTHRO: Insecta) In some Diplura, pertaining to thegreater number of thoracic spiracles.hyperstomial ooecium (BRYO) An ooecium that rests on or ispartly embedded in the distal zooid with opening above theoperculum of the mother zooid.hyperstrophic a. [Gr. hyper, above; strophe, twist] (MOLL:Gastropoda) In dextrally organized gastropods, characterizedby genitalia on right, but shell falsely sinistral, beingactually ultradextral, or vice versa.hypertely n. [Gr. hyper, above; telos, completion] Ornamentationor coloration without apparent purpose.hypertrichy n. [Gr. hyper, above; trichos, hair] Presence ofsetae in greater numbers than those present in its naturalgroup of invertebrates. see holotrichy.hypertrophy n. [Gr. hyper, above; trophe, nourishment] Theenlargement of an organ due to the increase in the size ofits constituent cells. see atrophy.

456Maggenti and Gardnerhypistoma see hypopharynxhypnody n. [Gr. hypnodes, drowsy] A resting stage of someorganisms.hypnosis n. [Gr. hypnos, sleep] A state of fatigue or inhibitiondue to excessive mechanical stimuli affecting the nervoussystem; reflex immobilization. see stereokinesis.hypnote n. [Gr. hypnos, sleep] An organism in a dormant condition.hypnotheca see prepupahypnotoxin n. [Gr. hypnos, sleep; toxikon, poison] (CNID) Aproteinaceous toxin released from a penetrant nematocyst.hypobenthos n. [Gr. hypo, under; benthos, sea bottom] Seabottom fauna below 1000 m, corresponds roughly tobathyal and abyssal benthic dwellers. see epibenthos.hypobiotic a. [Gr. hypo, under; bios, life] Pertaining to organismsthat live under objects or projections. see epibiotic.hypoblast n. [Gr. hypo, under; blastos, bud] Endoderm inearly embryos, entoderm. see endoderm.hypobranchial gland (MOLL) Single or paired glandular epidermalareas of the roof of the mantle cavity.hypobranchial space (ARTHRO: Crustacea) The area of thelower gill chamber, (below gills).hypocerebral ganglion (ARTHRO: Insecta) An expansion ofthe recurrent nerve in the anterior division of the autonomicnervous system. see occipital ganglion.hypodactyl n. [Gr. hypo, under; daktylos, finger] (ARTHRO:Insecta) The modified labium of Hemiptera.hypoderm see hypodermishypodermal a. [Gr. hypo, under; L. dermis, skin] Of or relatingto the hypodermis.hypodermal chord (NEMATA) Dorsal, ventral or lateral longitudinalthickenings of the hypodermis, generally internal.hypodermal glands (NEMATA) Glands of hypodermal originthat may serve as excretory glands.hypodermic envelope see peripodial sac

Online Dictionary of Invertebrate Zoology 457hypodermis n. [Gr. hypo, under; L. dermis, skin] The cellular,subcuticular layer that secretes the cuticle of annelids,nematodes, arthropods (see epidermis), and various otherinvertebrates; hypoblast.hypodigm n. [Gr. hypo, under; deigma, specimen] The entirematerial of a species available to the taxonomist.hypodiploid see hypoploidhypogean, hypogaen a. [Gr. hypo, under; gaia, the earth] 1.Living in the soil; endogean. 2. (ARTHRO: Insecta) Soildwellers except for nuptial flight.hypoglossa n. [Gr. hypo, under; glossa, tongue] (ARTHRO: Insecta)In brachycerous and cyclorrhaphous Diptera, thedorsal wall of the premental plate, formed by the sclerotizedventral side of the prementum.hypoglossis n. [Gr. hypo, under; glossa, tongue] (ARTHRO:Insecta) The under portion of the tongue.hypoglottis n. [Gr. hypo, under; glottis, mouth of windpipe](ARTHRO: Insecta) In Coleoptera, the sclerite between thementum and labium.hypognathous a. [Gr. hypo, under; gnathos, jaw] (ARTHRO:Insecta) When the head is joined to the thorax so themouth parts are directed ventrally. see prognathous, opisthognathous.hypogynium n. [Gr. hypo, under; gyne, female] (ARTHRO: Insecta)The eighth abdominal sternite of a female; formerly,the genital plate.hypohaline a. [Gr. hypo, under; hals, sea] Pertaining to watersunder the salinity of normal sea water; below 30 partsper thousand; brackish. see hyperhaline, euhaline.hypohaploid see hypoploidhypolimnion n. [Gr. hypo, under; limne, lake] The bottomstratum in deep lakes containing low oxygen and near absenceof living organisms. see epilimnion, thermocline.hypolithic a. [Gr. hypo, under; lithos, stone] Living beneathstones.hypomegetic a. [Gr. hypo, under; megas, great] Pertaining tothe smallest in a series of polymorphic organisms.

458Maggenti and Gardnerhypomere n. [Gr. hypo, under; meros, part] 1. (ARTHRO: Insecta)a. The ventral process of the phallobase. b. Inflexededge of the pronotum and raised margin of the epipleura ofbeetles. 2. (PORIF) The basal portion of certain sponges inwhich no flagellated chambers develop.hypomeric a. [Gr. hypo, under; meros, part] (ANN: Oligochaeta)A condition of regenerates with fewer segmentsthan had been removed. see hypermeric.hypomeron see hypomerehypomorph n. [Gr. hypo, under; morphe, form] An allele thatfunctions more weakly when compared with wild-type alleles;a leaky gene.hyponeural a. [Gr. hypo, under; neuron, nerve] (ECHINOD)Part of the nervous system deeper and more weakly developedthan the ectoneural system.hyponeuston n. [Gr. hypo, under; neustos, swimming] Anyorganism that swims or floats near the surface of the water.hyponome n. [Gr. hyponome, tunnel] (MOLL: Cephalopoda) Aventral funnel consisting of two unfused lappetlike folds; inNautiloidea, functions in bringing oxygen to the gills in themantle cavity, and secondarily as a powerful locomotororgan.see funnel.hyponomic sinus (MOLL: Cephalopoda) In Nautiloidea, a largeconcave sinus ventrally in the head-foot shell opening,marking the location of the hyponome.hyponym n. [Gr. hypo, under; onym, name] A generic namenot based on a type species; a provisional or temporaryname.hypoparatype n. [Gr. hypo, under; para, beside; typos, type]Any specimen originally used to indicate a new species butnot chosen as the type specimen. see holotype, paratype.hypophare see hypomerehypopharyngeal glands (ARTHRO: Insecta) In bees, pairedglands in the facial part of the head that open through thelateral areas of the hypopharynx; pharyngeal glands; food

Online Dictionary of Invertebrate Zoology 459glands.hypopharynx n. [Gr. hypo, under; pharyngx, pharynx] 1. (AR-THRO: Chelicerata) The chitinous plate situated on the labiumin certain Acari. 2. (ARTHRO: Crustacea) The metastoma.3. (ARTHRO: Insecta) a. A median mouth-part structureanterior to the labium, usually associated with thesalivary glands by ducts. b. A tongue-like lobe that arisesfrom the mouth-cavity floor and serves as a sensory apparatusfor taste, variously modified for feeding in manygroups; ligua; glossa. hypopharyngeal a.hypophragm see operculumhypopi pl. hypopushypoplasia n. [Gr. hypo, under; plasis, a molding] Developmentaldeficiency of an organ system, organ, or tissue. hypoplastica.hypoplax n. [Gr. hypo, under; plax, plate] (MOLL) A long,narrow, calcareous ventral plate covering the gape betweenthe two valves on the ventral margin, joined to the valvesby a chitinous fold.hopopleural bristles (ARTHRO: Insecta) In Diptera, a row ofbristles, usually vertical, on the hypopleuron, above thehind coxae.hypopleurite n. [Gr. hypo, under; pleura, side] (ARTHRO: Insecta)The lower plate of a divided pleuron.hypopleuron n. [Gr. hypo, under; pleura, side] (ARTHRO: Insecta)1. The region below the metapleuron. 2. In Diptera,the lower part of the mesepimeron.hypoploid a. [Gr. hypo, under; aploos, onefold; eides, form]Cells or individuals with one or more chromosomes or segmentsdeleted. see hyperploid.hypopneustic see hemipneustichypopolyploid see hypoploidhypoptera, hypoptere see tegulahypoptygma n. [Gr. hypo, under; ptygma, anything folded](NEMATA) Anterior and posterior cuticular flaps of the cloacalopening in some males. see epiptygma.

460Maggenti and Gardnerhypopus n.; pl. hypopi [Gr. hypo, under; pous, foot] (AR-THRO: Chelicerata) 1. In Acari, the second nymphal stage.2. The non-feeding deutonymph of Acaridida; either active,phoretic nymphs or rather inactive resistant nymphs. hypop(i)ala.hypopygial spine (ARTHRO: Insecta) The caudal spine endingof the hypopygium of some female cynipid wasps.hypopygium n. [Gr. hypo, under; pyge, rump] (ARTHRO: Insecta)The last ventral plate; sometimes including attachedsegments of the postabdomen; terminalia; genital segments(commonly used for Diptera). see pygofer.hyposcleritic a. [Gr. hypo, under; skleros, hard] (ARTHRO:Chelicerata) A region only partially sclerotized in mites.hypostasis n. [Gr. hypo, under; stasis, a standing] A non-allelicrecessive gene, interferred with by an epistatic gene.hypostegal coelom (BRYO: Gymnolaemata) In Cheilostomata,part of the body cavity separated from the principle bodycavity of the zooid; it may communicate with the principlebody cavity by pores or remain confluent with it at somepoint.hypostegal epithelium (BRYO: Stenolaemata) In free-walledforms, epithelium that lays down extrazooidal skeleton.hypostegia see hypostegal coelomhypostigmatic cell (ARTHRO: Insecta) In three neuropteranPermian families, a greatly elongated cell behind the fusionof the subcosta and radius 1.hypostoma see hypostomehypostomal bridge (ARTHRO: Insecta) 1. Union of the hypostomataof the two sides meeting in the midline belowthe occipital foramen which is continuous with the postocciput.2. In Diptera, the parts of the genae joined ventrallybetween the compound eyes.hypostomal carinae (ARTHRO: Insecta) The margin of theproboscidial fossa of bees, which turn laterally toward thebases of the mandibles at their anterior end.hypostomal sclerite see intermediate scleritehypostomal suture (ARTHRO: Insecta) Part of the subgenal

Online Dictionary of Invertebrate Zoology 461sulcus behind the mandible.hypostome, hypostoma n. [Gr. hypo, under; stoma, mouth]1. (ARTHRO: Chelicerata) In Acari, forming the ventral-medianwall of the gnathosoma; fused with the pedipalps inmost groups, but in ticks a toothed structure between thepedipalps. 2. (ARTHRO: Crustacea) The metastoma. 3. (AR-THRO: Diplopoda) The gula. 4. (ARTHRO: Insecta) The anteroventralpart of the head including between the antennae,eyes and mouth of Diptera; the ventral part of thehead of Hemiptera. 5. (ARTHRO: Trilobita) The median preoralplate or labrum.hypostracum n. [Gr. hypo, under; ostrakon, shell] 1. (AR-THRO: Chelicerata) In Acari, the inner cuticular layer, usuallypigmented with basic dyes. 2. (MOLL: Bivalvia) a. Innerlayer of shell wall laid down by the mantle. b. That part ofthe shell secreted at muscle attachments. see myostracum.3. (MOLL: Polyplacophora) In chitons, the lowestventral calcareous layer of a valve.hyposulculus n. [Gr. hypo, under; L. dim. sulcus, furrow](CNID: Anthozoa) The groove in the siphonoglyph.hypothesis n.; pl. -ses [Gr. hypothesis, theory] A tentativeproposition explaining the occurrence of a phenomenoneither asserted as provisional conjecture to guide an investigationor accepted as highly probable in view of establishedfacts.hypotome n. [Gr. hypo, under; tome, a cutting] (ARTHRO: Insecta)In Hymenoptera, sternum ix.hypotype n. [Gr. hypo, under; typos, type] A specimen, otherthan the type, upon which a subsequent or supplementarydescription or figure is based; an apotype; a plesiotype.hypovalvae n.pl. [Gr. hypo, under; L. valva, leaf of a foldingdoor] (ARTHRO: Insecta) In Mecoptera, a bi- or trilobedsubgenital plate formed from the larval ix sternum.hypozygal n. [Gr. hypo, under; zygon, pair] (ECHINOD: Crinoidea)The proximal member of a syzygial pair of brachials.see epizygal.hysteresis n. [Gr. hysteros, after] (CNID) A lag in adjustmentat one level in response to stress at another level such as

462Maggenti and Gardnerchromosome coiling or storm damage response of corals.hysterodehiscence n. [Gr. hysteros, after; L. dehiscere, tosplit open] (ARTHRO: Chelicerata) In Acari, dehiscence orsplitting of the cuticle in the posterior part of the body; inhatching the animal moves backward.hysterosoma n. [Gr. hysteros, after; soma, body] (ARTHRO:Chelicerata) Combination of the metapodosomal and theopisthosomal segments of the body of a tick or mite; pseudotagma.hysterotely n. [Gr. hysteros, after; telos, end] (ARTHRO: Insecta)Retention of larval characteristics in pupa or adult.see neotony.hystrichoglossate a. [Gr. hysterix, porcupine; glossa, tongue](MOLL: Gastropoda) Referring to a radula of the rhipidoglossatetype with tufts of bristles.hyther n. [Gr. hydor, water; therme, heat] The combined effecton an organism of moisture and temperature.H-zone see H-band

II-band That zone of the sarcomere composed of actin alone.I-cells (CNID) The interstitial cells.ichnotaxon n. [Gr. ichnos, track; taxis, arrangement] A taxonbased on fossilized impressions, tracks, trails, and burrowsmade by an animal, but not part of that animal.ichthyophagous a. [Gr. ichtys, fish; phagein, to eat] Eating,or subsisting on fish.iconotype n. [Gr. eikon, image; typos, type] A graphic reproductionof a type.icotype n. [Gr. eikos, to be like; typos, type] A representativespecimen serving for purpose of identification, but has notbeen used in published literature.ICZN The International Code of Zoological Nomenclature.ideotype n. [Gr. idios, personal; typos, form] A specimennamed by the author after comparison with the type species.see type.idiobiology n. [Gr. idios, personal; bios, life; logos, discourse]The biology of an individual organism.idiochromatin n. [Gr. idios, personal; chroma, color] Nuclearchromatin thought to function as structural support forgenes.idiochromosome n. [Gr. idios, distinct; chroma, color; soma,body] A sex chromosome.idiocuticular a. [Gr. idios, personal; L. cuticula, cuticle] Of orpertaining to characteristics of a cuticle; produced in thecuticle such as the microtrichia of insect epicuticle.idiogamy n. [Gr. idios, distinct; gamos, marriage] Self-fertilization.idiogram n. [Gr. idios, distinct; gramma, drawing] A diagrammaticrepresentation of chromosome morphology.idiomorphic a. [Gr. idios, personal; morphe, form] (MOLL: Bi-

464Maggenti and Gardnervalvia) The normal form of valves; not distorted by crowdingor attachment to the substrate; automorphic.idionymy n. [Gr. idios, personal; onyma, name] State of anorgan which makes it possible to receive its own distinctnomenclatorial designation, either in ontogeny, or a comparativestudy of a natural group. idionymous a.idioplasm n. [Gr. idios, personal; plasma, formed or molded]All of the hereditary determinants of an organism, both nuclearand cytoplasmic; germ plasm; idiotype. see genotype.idiosoma n. [Gr. idios, personal; soma, body] (ARTHRO: Chelicerata)In mites or ticks, the posterior of the two basicparts of the body, prosoma and opisthosoma; pseudotagma.idiosome n. [Gr. idios, personal; soma, body] 1. A purportedultimate element of living matter; micelle. 2. The sphere orregion of differing cytoplasm viscosity surrounding thecentrosome, surrounding Golgi apparatus and mitochondria.idiosphaerotheca n. [Gr. idios, personal; sphaira, globe;theke, sac] A vesicle containing the acrosome of spermcells.idiotaxonomy n. [Gr. idios, personal; taxis, arrangement;nomos, law] Taxonomic study of individuals, populations,species and higher taxa; traditional taxonomy.idiotaxy n. [Gr. idios, personal; taxis, arrangement] Homonomousorgans having a common relative placement, evenwith secondary multiplication.idiotrichy n. [Gr. idios, personal; trichos, hair] Homonomoussetae which share a common relative placement even inthe case of secondary multiplication.idiotype n. [Gr. idios, personal; typos, type] Genotype; idioplasm.idorgan n. [Gr. idios, personal; organon, organ] A morphologicalmulticellular unit composing an organ, antimere, ormetamere, absent of characters of an individual or colony.ileocecal a. [L. ileum, flank; caecus, blind] (ARTHRO: Insecta)

Online Dictionary of Invertebrate Zoology 465Pertaining to the valve at the junction of the large andsmall intestine.ileum n. [L. ileum, flank] (ARTHRO: Insecta) 1. An undifferentiatedtube running back to the rectum; the anterior part ofthe hind-gut. 2. In termites in the form of a pouch in whichflagellate protozoa live.imaginal a. [L. imago, image] (ARTHRO: Insecta) Pertaining tothe adult or imago.imaginal disc, bud or cell (ARTHRO: Insecta) In holometabolousforms, embryonic tissue which remains undifferentiateduntil they give rise to the imago (adult) structures.imagination n. [L. imago, image] (ARTHRO: Insecta) The developmentof an imago or adult.imagine see imagoimago n. [L. imago, image] (ARTHRO: Insecta) 1. The adult orreproductive stage. 2. In termites, applied only to the adultprimary reproductives. imaginal a.imagochrysalis n. [L. imago, image; Gr. chrysallis, chrysalis](ARTHRO: Chelicerata) In the chigger mite life cycle, a quiescentstage between the nymph and adult.imbricate plates (ARTHRO: Crustacea) In Cirripedia, the lowerlateral, lower latus, and lower latera.imbrication n. [L. imbricare, to cover with tiles] An overlappingat the margins as of tiles or shingles. imbricate a.immaculate a. [L. in, not; maculatus, spotted] Without coloredspots or marks.immarginate a. [L. in, not; marginatus, to enclose with a border]Without a definite rim or margin; having no coloredrim or margin.immature a. [L. in, not; maturus, ripe] Any developmentalstages preceding the adult.immersed a. [L. in, not; mergere, to dip] Inserted, imbeddedor hidden, as a part or organ.immunity n. [L. immunis, free] The ability of an organism toresist a pathogen; a type of resistance to disease.immunogenic a. [L. immunis, free; gennaein, to produce]

466Maggenti and GardnerPertaining to a type of substance that stimulates productionof antibody or cell-mediated immunity.imperfect mesentaries (CNID: Anthozoa) Mesentaries spanningthe gastrovascular space, but not reaching the actinopharynx.see perfect mesentaries.imperforate a. [L. in, not; perforatus, to bore through] 1. Notperforated; lacking an opening or aperture. 2. (MOLL: Gastropoda)see anomphalous.implex n. [L. implexus, plaited] (ARTHRO: Insecta) Integumentalinfolding for muscle attachment; endoplica.implicate a. [L. implicare, to entangle] To infold or twist together.impregnation n. [L. impraegnare, to cause to conceive] Tomake pregnant; the introduction of sperm cells; fecundate.impressed a. [L. in, on; premere, to press] 1. Produced bypressure; depressed areas or markings. 2. (MOLL: Gastropoda)A suture of a shell having both adjoined whorl surfacesturned inward adaxially.imprint n. [L. in, on; premere, to press] (MOLL: Bivalvia) Theimpression on the valve of a muscle or gill.impunctate a. [L. in, not; punctum, puncture] Without marks,pits, spots or holes.inaequipartite a. [L. in, not; aequipartus, equal] (MOLL: Bivalvia)Pertaining to bivalves with one end longer than theother.inanition n. [L. inanis, empty] 1. The state of being empty;inane. 2. Exhaustion from lack of nutrients; the physicalcondition resulting from insufficient nutrients. 3. A form ofdormancy brought about by insufficient nutrients.inappendiculate a. [L. in, not; appendix, appendage] Withoutappendages.inarticulate a. [L. in, not; articulatus, jointed] Not jointed orfitted together; lacking distinct body segments.inarticulate hinge (MOLL) Lacking visible teeth or equippedonly with a callosity.inaxon n. [Gr. in, not; axon, axis] A neuron in which the axon

Online Dictionary of Invertebrate Zoology 467branches at a distance from the neurocyte.inbreed v.t. [A.S. in, inward; bredan, nourish] To mate withgenetically similar individuals, particularly with close relatives;endogamy.inbreeding depression A loss of fitness due to severe inbreeding.incased pupa see pupa folliculataincertae sedis Said of a taxon of uncertain taxonomic position.incidence n. [L. incidere, to happen] The number of new casesof a particular disease in a population within a given timeperiod. see prevalence.incidental parasite see accidental parasiteincipient a. [L. incipere, to begin] The beginning or appearance,as a species of animal.incipient species see polymorphismincised a. [L. incisus, cut into] Notched or cut in; sculpturedwith sharp cut grooves.incisor n. [L. incisus, cut into] Adapted for cutting.incisor lobe (ARTHRO: Insecta) A toothed lobe used for biting.incisor process (ARTHRO: Crustacea) The biting portion of thegnathal lobe of the mandible; pars incisiva.incisura n.; pl. -urae [L. incidere, to cut into] 1. A notch, depressionor indentation. 2. (ARTHRO: Insecta) The incisionsin the margin of the terminal segment of scale insects.incisura clavicularis (ARTHRO: Crustacea) In Nephropidae, anincision in the anterolateral margin of the carapace formingtwo lobes partly overlaping that fit around a tubercle orridge of the epistome.incisure n. [L. incidere, to cut into] A cut, gash, impressionline, striation or notch.inclinate a. [L. inclinare, to bend] Bent toward the midline ofthe body.inclivous a. [L. inclivus, sloping] (ARTHRO: Insecta) Term appliedto a transverse wing vein; having the front end nearerthe wing base than the rear. see verticle, reclivous.

468Maggenti and Gardnerinclusion bodies Intracellular bodies, as mitochondria, microsomes,at times viruses, etc.incomplete metamorphosis (ARTHRO: Insecta) In hemimetabolousexoptergotes, the immatures differing from theadult mainly by incomplete development in the wings andgenitalia and develop without quiescent state; directmetamorphosis. see complete metamorphosis.incrassate a. [L. incrassare, to thicken] Thickened; making orbecoming thick or thicker.incremental line see growth lineincrustation n. [L. incrustatus, covered with mud] 1. Encasedwith a crust or hard coat. 2. A deposit of calcareous matterupon a shell. 3. (MOLL: Bivalvia) In oysters, tight attachmentto the substrate.incubation groove (ARTHRO: Insecta) In bumblebees, a broaddepression across the top of the brood comb cell or on topof a group of larvae, into which a lone gyne lies to facilitatewarming of the larvae.incubatory a. [L. in, in; cubare, to lie down] Pertaining toanimals that brood their young.incudate a. [L. incus, anvil] (ROTIF) Type of mastax with stoutforceps-like shape with reduced mallei.incumbent a. [L. incumbere, to lie down upon] Bent downwards;to touch or rest upon.incunabulum n.; pl. -ula [L. incunabulum, cradle] (ARTHRO:Insecta) A cocoon.incurrent a. [L. in, in; currere, to run] 1. A current which flowsinward; afferent. 2. (ARTHRO: Insecta) The ostium of theheart. 3. (MOLL) Inhalant siphons. 4. (PORIF) Canals whichadmit water.incurved a. [L. incurvus, bent] 1. The state of being bowed orcurved inwards. 2. Bent over as the apex in some shells.incus n.; pl. incudes [L. incus, anvil] (ROTIF) Curved plates ofthe mastax, bearing on their medial sides several prongliketeeth; the fulcrum and rami collectively. incudal a. seeuncus.indented a. [L. in, in; dens, tooth] Notched or dented;

Online Dictionary of Invertebrate Zoology 469abruptly pressed inward; a cut or notch in a margin.indeterminate a. [L. in, not; determinare, to limit] Not welldefined; vague; indefinite.index n.; pl. indexes [L. indicare, to point out] A number expressingthe relationship of one quantity to another by expressingthem as ratios of a third quantity.indigenous a. [L. indigena, native] Being native to or originatingin a specified place or country.indigoid biochrome Various blues and purples derived by themetabolism of trytophan found in plants and mollusks.indirect life cycle see heterogonic life cycleindirect nuclear division 1. Typical = mitosis. 2. Atypical =meiosis.inducer n. [L. in, in; ducere, to lead] A small molecule whichcauses an increase in the rate of enzyme synthesis whenpresent.induction n. [L. in, in; ducere, to lead] Increase of the rate ofproduction of an enzyme caused by an inducer molecule.inductor see organizerinductura n. [L. inductura, a coating] (MOLL: Gastropoda)Smooth shelly layer of the shell secreted by the mantle,extending from the inner side of the aperture over the parietalregion, columellar lip, and part or all of the shell exterior.indumentum n. [L. indumentum, garment] Covered by hairs,scales or tufts.indurate a. [L. induratare, to make hard] Hardened.indusium n.; pl. -sia [L. indusium, tunic] (ARTHRO: Insecta) 1.A larva casing. 2. The third covering of embryonic membraneformed from a thickening of the serosa in front of thehead.industrial melanism The evolution of a darkened populationowing to melanistic individuals that blend with their substratein the sooty surroundings of an industrial area.inequal a. [L. in, not; aequus, equal] Having irregular elevationsor depressions.

470Maggenti and Gardnerinequilateral a. [L. in, not; aequus, equal; latus, side] (MOLL:Bivalvia) Shells with unequal sides. see inequivalve.inequilobate a. [L. in, not; aequus, equal; lobus, lobe] Havinglobes of unequal size.inequivalve a. [L. in, not; aequus, equal; valva, leaf of a door](MOLL: Bivalvia) Having one valve larger, or of a differentform from the other.inerm, inermous a. [L. inermis, unarmed] Lacking striae,spines or other sharp processes. see mutic.inert n. [L. iners, idle] Inactive; said of heterochromatin ofchromosomes due to absence of gene mutations or effectson genetic balance; physiologically inactive.infauna n. [L. in, into; Faunus, diety of herds and fields] Bottomburrowing animals of the sea. see epifauna.inferior a. [L. inferior, lower] Situated below, near the base;underneath; behind.inferior anal appendage (ARTHRO: Insecta) In Odonata, thelower one or two terminal abdominal appendages used ingrasping the female at the time of copulation.inferior groove (ARTHRO: Insecta) In Decapoda, a carapacegroove, beginning at the junction of the hepatic and cervicalgrooves toward the lateral margin.inferobranchiate a. [L. inferus, low; Gr. branchia, gills](MOLL) Pertaining to gills under the mantle margin.inferolateral a. [L. inferus, low; latus, side] Being below andat or towards the side.infero-marginal plates (ECHINOD: Asteroidea) The lowermarginal plates that form the outline of the arm. see supero-marginalplates.inferomedian a. [L. inferus, low; medius, middle] Being belowand about the middle.inferoposterior a. [L. inferus, low; posterior, hinder] Belowand behind.infertility n. [F. infertilite] Infertile state or quality; inability toreproduce.infestation n. [L. infestus, disturbed] The living in or on a host

Online Dictionary of Invertebrate Zoology 471by metazoan parasites.infiltration n. [L. in, in; filtrum, felt] Act or process of infilteringor permeating.inflated a. [L. inflatus, inflated] 1. Expanded; distended. 2.(MOLL: Gastropoda) Applied to shells swollen, increasedunduly, distended; ventricose.inflation n. [L. in, in; flare, to blow] (MOLL: Bivalvia) The distancebetween the outermost points of the two valves.inflected a. [L. in, in; flectere, to bend] Turned or bent inwardor downward; inflexed.inflexed a. [L. in, in; fectere, to bend] Curved, bent or directedinward or downward or toward the body axis; inflected.influent a. [L. in, in; fluere, to flow] An animal or plant havingan influence on other living forms.informosome n. [L. in, in; formare, to form; Gr. soma, body]Messenger RNA combined with protein for protection as itmoves from nucleus to cytoplasm.infra-anal flaps see paraproctinfrabasal a. [L. infra, underneath; basis, base] 1. Below abasal structure. 2. (ECHINOD: Crinoidea) Plates aboral tothe basal plates.infrabranchial a. [L. infra, underneath; branchiae, gills] Beingbelow the gills.infrabuccal cavity/chamber (ARTHRO: Insecta) A spheroidalsac beneath the floor of the mouth cavity that opens intothe mouth by means of a short narrow canal, functioning infood storage.infrabuccal slit (ARTHRO: Chelicerata) In Acari, the slit betweenthe two lateral lips seen on the ventral surface of theinfracapitulum.infracalyptral setulae (ARTHRO: Insecta) In tachinid Diptera,fine, bristly hairs below the point of attachment of the calypter(squamae).infracapitular glands (ARTHRO: Chelicerata) In Acari, pairedglands lying in the prosoma and emptying into the cervix.infracapitulum n.; pl. -la [L. infra, underneath; capitulum,

472Maggenti and Gardnersmall head] (ARTHRO: Chelicerata) In Acari, part of thegnathosoma of mites, bearing lips and palpi and containingmouth and pharynx.infraclypeus see anteclypeusinfracoxal a. [L. infra, underneath; coxa, hip] (ARTHRO) Situatedbelow the coxa.infracted a. [L. infractus, break] Bent inward; bent inwardabruptly as if broken.infraepimeron n. [L. infra, underneath; Gr. epi, upon; meros,part] (ARTHRO: Insecta) The lower sclerite of the epimeron;katepimeron.infraepisternum n. [L. infra, underneath; Gr. epi, upon; sternon,chest] (ARTHRO: Insecta) A ventral subdivision of anepisternum.infra-ergatoid form see phthisergateinfraesophageal a. [L. infra, underneath; Gr. oisophagos,gullet] Subesophageal.infragenital a. [L. infra, underneath; genitalis, belonging tobirth] Below the genital opening.inframarginal a. [L. infra, underneath; margo, edge] Behindor below any margin.inframedian a. [L. infra, underneath; medius, middle] Pertainingto a belt or zone along the sea bottom between 50and 100 fathoms in depth.inframedian latus (ARTHRO: Crustacea) In Lepadomorpha Cirripedia,a plate below the upper latus.infraneuston n. [L. infra, underneath; Gr. neustos, floating]Animals that live on the underside of the surface film ofwater.infraocular n. [L. infra, underneath; oculus, eye] Below andbetween the eyes.infraorbital spine (ARTHRO: Crustacea) A spine on the lowerangle of the orbit of a decapod carapace.infraorder n. [L. infra, underneath; ordo, order] An optionalcategory below the suborder.infrasocial a. [L. infra, underneath; socius, companionship]

Online Dictionary of Invertebrate Zoology 473Leading a solitary life; below social. see society.infraspecific n. [L. infra, underneath; species, kind] Within thespecies; usually applied to subspecies.infrastigmatal a. [L. infra, underneath; Gr. stigmata, marks](ARTHRO) Below the stigmata or spiracles.infrasutural a. [L. infra, underneath; sutura, seam] (ARTHRO)Below the seam or suture.infumated a. [L. in, in; fumus, smoke] Clouded with a blackishcolor; smoke colored.infundibulum n.; pl. -ula [L. infundibulum, funnel] 1. A funnel-shapedorgan or part. 2. (CNID: Hydrozoa) The hydroecium.3. (MOLL: Cephalopoda) An exhalant siphonleading out of the mantle cavity. infundibuliform a.infuscate a. [L. in, into; fuscus, dark] Darkened with abrownish tinge; smoky gray-brown.infusoriform larva (MESO: Rhombozoa) In Dicyemida, ciliatedlarva produced by the infusorigen.infusorigen n. [L. infusus, poured into; genos, offspring](MESO: Rhombozoa) A mass of reproductive cells interpretedas being a hermaphroditic gonad within a rhombogen.ingest v. [L. ingestus, taken in] To convey food into a place ofdigestion.ingesta n.pl. [L. ingestus, taken in] The total amount of substancesand fluids taken into the body. see egesta.ingestion n. [L. ingestus, taken in] The act or process ofswallowing or taking in food material into a cell or into theenteron.ingluvial a. [L. ingluvies, crop] (ARTHRO: Insecta) Pertaining tothe ingluvies or crop of insects.ingluvial ganglion (ARTHRO: Insecta) 1. Paired ganglion of thestomodeal nervous system at the posterior end of the foregut.2. In Schistocerca, autonomously exerting influence onmovements of the proventriculus.ingluvies see cropinhalant a. [L. in, into; halere, to breathe] Taking into the

474Maggenti and Gardnerbody, i.e., water or air. see incurrent.inhalant siphon In various invertebrate groups, a tube-likeorgan along which water is drawn into the mantle cavity.inheritance n. [OF. enheritance] The sum of all characters orqualities transmitted by the germ cells from generation togeneration.inherited disease Abnormal characters or qualities predeterminedfrom parent to offspring; an inborn disease.inhibitor n. [L. inhibere, to restrain] Any substance whichchecks or prevents an action or process.injector n. [L. in, in; jacere, to throw] (CNID) A nematocystthat injects venom through a discharged open-ended tube;stomocnide.injury n.; pl. -ries [L. in, not; juris, right] Damage; wound;trauma.ink sac (MOLL: Cephalopoda) A pear-shaped body in the wall ofthe mantle situated near the anus, containing the inkglands which eject a black substance as a defense mechanism.innate a. [L. innatus, inborn] Instinctive behavior; not learned.inner dorsocentral bristles see acrostichal bristlesinner epithelium (BRYO: Stenolaemata) In free-walled forms,an epithelium that secretes the skeleton, including both zooidalskeletal walls and hypostegal extrazooidal skeleton.inner lamina (ARTHRO: Crustacea) In Balanomorpha, the innershell layer of compartmental plates separated by longitudinaltubes from the outer lamina.inner ligament/inner layer of ligament see resiliuminbner line (MOLL: Gastropoda) That part of the peristomeagainst the pillar.inner lip (MOLL: Gastropoda) The inner edge of the aperture ofa univalve shell extending from the foot of the columella tothe suture; columellar and parietal lips collectively. seeouter lip.innervate v. [L. in, in; nervus, tendon] To supply nerves to anorgan or part.

Online Dictionary of Invertebrate Zoology 475inner vesicle see ooecial vesicleinocular antennae (ARTHRO: Insecta) Antennae with basepartly or wholly surrounded by the eye. see eye-bridge.inoculation n. [L. in, in; oculare, to furnish with eyes] 1. Activeor passive introduction of parasites into the body of ahost. 2. Introduction of an inoculum into a culture medium.inoperculate a. [L. in, not; operculum, a cover, lid] Without anoperculum, as a garden snail.inosculate v. [L. in, in; osculum, little mouth] To anastomose.inquiline n. [L. inquilinus, tenant] 1. A commensal organismthat lives habitually on or within the body of another, or inits nest or abode without benefit or damage to either; aguest. see inquilinism. 2. An animal that lives in the homeof another species and derives a share of its food. see inquilinism.3. An insect developing inside a gall producedby another species. inquilinous a.inquilinism n. [L. inquilinus, tenant; -ismus, condition] 1. Therelationship between two organisms sharing an abodewithout benefit or damage to either. 2. (ARTHRO: Insecta)The relationship of a socially parasitic species that spendsits entire life cycle in the nest of a host species; workersare either lacking or scarce and degenerate in behavior;permanent parasitism.inquirende n.pl.; sing. -da [L. in, in; quaerere, to seek] Underinquiry or investigation; needs study.Insecta, insects n.; n.pl. [L. insectum, cut into] A class ofArthropoda generally having a tracheate respiratory system,a single pair of antennae, and the body somitesgrouped into three functional tagmata: the head, thorax(bearing three pairs of legs) and abdomen.insectarium n.; pl. -ia [L. insectum, cut into] A building whereinsects are propagated or the collection contained therein.insectean, insectan a. [L. insectum, cut into] (ARTHRO: Insecta)Referring to or characteristic of insects in general.insectivorous a. [L. insectum, cut into; vorare, to devour]Feeding on insects.insectorubins n.pl. [L. insectum, cut into; ruber, red] Red or

476Maggenti and Gardnerred-brown eye pigments of insects, produced by the oxidationof tryptophane.insect ovary types (ARTHRO: Insecta) There are three types ofovaries: 1. Panoistic. 2. Polytrophic meroistic. 3. Telotrophicmeroistic. see separate entries.insectoverdin n. [L. insectum, cut into; viridis, green] (AR-THRO: Insecta) A blue pigment (usually mesobiliverdin) incombination with carotenoids which produce the green coloringof insects. see green pigments.insect society (ARTHRO: Insecta) Strictly a colony of eusocialinsects.insect sociology (sociobiology) The study of populationcharacteristics related to social behavior in insects.insemination n. [L. inseminare, to sow] The introduction ofspermatozoa into the female reproductive tract. see semination.inserted a. [L. in, in; serere, to join] Joined by natural growth;a muscle attached to a movable part.insertion n. [L. in, in; serere, to join] 1. Movable end of amuscular attachment. 2. Translocation in genetics.insertion plate (MOLL: Polyplacophora) A narrow marginalextension of the articulamentum layer in the head and tailvalves and sides of the intermediate valves, projecting intothe girdle; lamina of insertion.insolation n. [L. in, into; sol, sun] Exposure to the rays of thesun.inspissate v. [L. in, into; spissus, thick, dense] To bringgreater consistency; to thicken.instar n. [L. instar, form] 1. An insect or nematode at a particularlarval period or stage between molts. 2. (ARTHRO:Insecta) Numbered to designate the various periods, i.e.,first instar, second instar, etc.; can be abbreviated 1°, 2°,3°. see stadium.instinct n. [L. instinctus, impulse] A usually invariable complexresponse natural to a species, independent of any previousexperience of the individual.intectate a. [L. in, not; tectum, roof] Lacking a tectum.

Online Dictionary of Invertebrate Zoology 477integration n. [L. integer, whole] (BRYO) Changes in individualzooid morphology brought about by colonial living.integripalliate a. [L. integer, whole; pallium, mantle] (MOLL:Bivalvia) Having a pallial line entire; lacking a sinus, asclams or oysters.integument n. [L. integumentum, covering] The outer coveringof the body.integumental scolophore see scolopaleintegumental vesture or setae (ARTHRO: Insecta) Numerousspines or hairs on the epidermis of syrphid larvae, excludingthe segmental spines.intensity n.; pl. -ties [L. intentus, intent] The total number ofparasites in an individual. see burden.interambulacral areas (ECHINOD: Echinoidea) The radiallyarranged arms (typically 5) that do not bear tube feet orpodia. see ambulacral areas.interambulacral plates (ECHINOD: Crinoidea) Additional calyxplates between the arm bases in stalked crinoids.interantennal setae (ARTHRO: Insecta) In coccids, a group ortransverse row of setae on the ventral aspect of the headbetween the articulation of the antennae.interantennal suture (ARTHRO: Insecta) In Siphonaptera, asuture extending between the bases of the antennae.interantennular septum (ARTHRO: Crustacea) In some Malacostraca,a plate separating antennular cavities; proepistome.interbasal muscle (ECHI) A strong, narrow muscular band oftissue connecting the sheaths of the two ventral setae.interbrachial a. [L. inter, between; brachium, arm] Betweenadjoining arm tips, rays or brachial plates.interbreed n. [L. inter, between; A.S. brod, broad] Individualscapable of actual or potential gene exchange by hybridization.intercalary a. [L. intercalaris, that which is inserted] Insertedor introduced between others; interpolated.intercalary appendages (ARTHRO: Insecta) The rudimentary

478Maggenti and Gardnerpost antennal or premandibular appendages.intercalary segment (ARTHRO: Insecta) The premandibular,tritocerebral segments.intercalary stage (ARTHRO: Diplopoda) A non-reproductivestage between two reproductive stages in which the malegonopods and other secondary sexual structures regress.intercalary vein (ARTHRO: Insecta) 1. An extra longitudinalwing vein of Ephemeroptera. 2. Convex wing vein whichfollows the crest of a ridge. 3. Concave wing vein on thebottom of a furrow. 4. In Diptera, sometimes applied to theposterior branch of the fourth vein.intercalary walls (BRYO: Gymnolaemata) The outer walls ofzooids attached to each other in a linear series.intercellular a. [L. inter, between; dim. cellula, little cell] Lyingbetween cells.intercervical groove (ARTHRO: Crustacea) In Nephropidae, anoblique groove on the carapace that connects the postcervicaland cervical grooves.interchange n. [L. inter, between; combiare, to exchange] Reciprocaltranslocations between nonhomologous chromosomes.intercheliceral gland (ARTHRO: Chelicerata) In Acari, unpairedprosomatic gland emptying between the chelicerae; functionunknown.interchordal areas (NEMATA) The nonthickened regions of thehypodermis devoid of nuclei.interchromomeres n. [L. inter, between; Gr. chroma, color;meros, part] 1. Regions connecting adjacent chromomeres.2. (ARTHRO: Insecta) Lighter staining areas of the giantchromosomes in Diptera.interchromosomal a. [L. inter, between; Gr. chroma, color;soma, body] Reactions between chromosomes.intercostal a. [L. inter, between; costa, a rib] (MOLL) Placedbetween the ribs of a shell.intercostal vein (ARTHRO: Insecta) The subcosta.intercostate n. [L. inter, between; costa, rib or side] (MOLL)

Online Dictionary of Invertebrate Zoology 479Between ribs or ridges.intercoxal process (ARTHRO: Insecta) In Coleoptera, a prosternalprocess, occasionally enlarged, partly concealing thecoxae.interdentum n. [L. inter, between; dens, tooth] (MOLL: Bivalvia)A shelly plate between the pseudocardinal and lateralteeth.interface n. [L. inter, between; facies, countenance] Thecommon surfaces of two bodies.interfrontal bristles (ARTHRO: Insecta) In Diptera, bristles orhairs on the frontal vitta.interfrontalia see frontal vittainterganglionic a. [L. inter, between; Gr. ganglion, swelling]Between and uniting nerve ganglia.intergenic a. [L. inter, between; Gr. genos, race] Changes involvingmore than one gene.interior skeletal wall (BRYO: Gymnolaemata) InCheilostomata, walls growing off the skeletal wall interiorlywhich partition the original coelomic volume of the colony.interior wall (BRYO) Any body wall that partitions the bodycavity into zooids, parts of zooids or extrazooidal parts.interkinesis n. [L. inter, between; Gr. kinesis, movement] Theabbreviated interphase between the first and second meioticdivisions with no chromosomal reproduction.interlabial a. [L. inter, between; labium, lip] (NEMATA) Situatedbetween the lips.interlamellar a. [L. inter, between; lamella, thin plate] Betweenlamellae.interlaminate figure (ARTHRO: Crustacea) In some Balanomorpha,a line or lines extending between epicuticle ofouter lamina through longitudinal septa into the inner laminain sections parallel to base.interlobular incisions see incisuraintermaxilla n. [L. inter, between; maxilla, jaw] (ARTHRO: Insecta)The maxillary lobe.intermedia n. [L. inter, between; medius, middle] (PORIF) Spi-

480Maggenti and Gardnercules between elements of principalia or dictyonalia.intermediate band (disc) see Z-bandintermediate cell see chromophileintermediate denticles (ARTHRO: Crustacea) In Stomatopoda,a row of small projections between the intermediate andsubmedian teeth on the lateroterminal margin of the telson.intermediate host One which alternates with the definitivehost in which the parasite passes through partial development,but not to sexual maturity. see definitive host.intermediate neurons Neurons joining sensory and motorneurons; association neurons.intermediate sclerite (ARTHRO: Insecta) In Diptera, hypostomalsclerites shaped like an "H", joined together by atransverse bar, receiving the opening of the salivary duct.intermediate tooth (ARTHRO: Crustacea) A strong spinelike orblunt projection at the margin of the telson, between submedianand lateral teeth of mantis shrimp.intermediate valve (MOLL: Polyplacophora) Any valve betweenhead and tail valves; median valve; body valve.intermitotic a. [L. inter, between; Gr. mitos, thread] Interphaseof mitotic cell cycle.internal a. [L. internus, within] 1. Located within the limits ofthe surface of something; situated on the side toward themedian plane of the body. 2. (MOLL) Pertaining to shellswhen enclosed within the organism or mantle.internal ligament (MOLL: Bivalvia) The ligament placed withinthe hinge and not visible when the valves are closed.internal parameres (ARTHRO: Insecta) In male genitalia, thepaired sclerotized appendages inside the external parameres.internal respiration The biochemical processes of metabolismthat occur in all living cells that result in energy release.internal rhythm Endogenous rhythm. see circadian.internal ridges (ANN: Hirudinoidea) Fleshy structures of thepharynx; pharynx folds or pods.

Online Dictionary of Invertebrate Zoology 481internal secretion Substance absorbed directly by body fluids.internal triangle see triangleInternational Code of Zoological Nomenclature (ICZN)The official set of regulations and recommendations dealingwith zoological nomenclature.interneuron n. [L. inter, between; Gr. neuron, nerve] Internuncialneuron or association neuron.internode n. [L. inter, between; nodus, swelling] 1. The intervalor part between two nodes or joints. 2. (BRYO) Thatsegment of a jointed colony between surfaces of articulation.3. (CNID: Hydrozoa) A small repeated section of thestem or hydrocladium separated by a constriction of theperisarc.internum n. [L. internus, inside] Medulla of a mitochondrion.internuncial neuron see association neuroninternuncial process (PLATY) The cell processes (trabecula)connecting the perikarya of cestode and trematode tegumentalcells with the distal cytoplasm.interoceptors n. [L. inter, between; (re)capere, to take]Sense organs situated internally that respond to internalconditions, as opposed to exteroceptors.interosculant a. [L. inter, between; osculari, to kiss] Havingcharacters common to 2 or more species or groups.interpetaloid a. [L. inter, between; Gr. petalon, leaf] (ECHI-NOD: Echinoidea) Area between ambulacral areas.interphase n. [L. inter, between; Gr. phasis, state] The periodbetween succeeding mitoses. see interkinesis.interpleural suture (ARTHRO: Insecta) In Odonata, suturebetween the meso- and metapleura.interpleurite n. [L. inter, between; Gr. pleuron, side] (AR-THRO: Insecta) An intersegmentalia between the pleurites.interplical a. [L. inter, between; plicare, to fold] Lying betweenfolds.interradial plates (ECHINOD: Crinoidea) Additional calyx platesbetween the radial plates in stalked crinoids.interradius n.; pl. -radii [L. inter, between; radius, ray,

482Maggenti and Gardnerspoke] 1. Area between radii or perradii in radially symmetricalanimals. 2. (CNID) The second radius.interramal a. [L. inter, between; ramus, branch] Between tworami.interramal cirrus (ANN: Polychaeta) Cirrus on the ventral sideof the notopodium.interrugal a. [L. inter, between; ruga, wrinkle] Between rugae.interrupted a. [L. inter, between; rumpere, to break] Irregular;asymmetrical; broken in continuity.interscutal a. [L. inter, between; scutum, shield] Betweenscuta.intersegmental a. [L. inter, between; segmentum, part] Betweensegments.intersegmental furrow (ANN: Oligochaeta) In pigmented speciesof earthworms, the boundary between two consecutivesegments where epidermis is thinnest and color is lacking.intersegmental groove (ANN: Oligochaeta) In earthworms, acircumferential depression of strongly contracted specimensthat contains the intersegmental furrow.intersegmentalia n.pl.; sing. -lium [L. inter, between; segmentum,part] (ARTHRO: Insecta) 1. Dorsal and ventralplates associated with narrow intersegmental scleriteswhich develop in the intersegmental folds. 2. Setiferous areasassociated with the mesothoracic spiracles in scarabbeetles.intersegmental membrane (ARTHRO: Insecta) The flexibleconjunctiva between two secondary segments where contractionof the longitudinal muscles produce telescoping ofthe segments.interseptal a. [L. inter, between; septum, wall] Spaces betweensepta.intersex n. [L. inter, between; sexus, sex] An individual possessingboth male and female characteristics; sex mosaic.see hermaphrodite.intersomitic a. [L. inter, between; Gr. soma, body] Betweenbody segments or somites.

Online Dictionary of Invertebrate Zoology 483interspaces n. [L. inter, between; spatium, space] 1. Interveningtime or space. 2. (MOLL) Spaces between costa of ashell.interspicular a. [L. inter, between; spiculum, small point]Between spicules.intersterility n. [L. inter, between; sterilis, unfruitful] Crosssterilitybetween groups.intersternite n. [L. inter, between; Gr. sternon, chest] (AR-THRO: Insecta) An intersegmental sclerite, located on theventral side of the thorax; the spinasternum.interstices n.pl. [L. interstitium, space between] A narrowspace between the parts of a body or things close together;a crack, crevice or chink. interstitial a.interstitial cells (CNID) Small undifferentiated epidermal cellswhich may give rise to cnidoblasts or nematocysts.interstrial a. [L. inter, between; stria, groove] 1. Between twostriae. 2. (ARTHRO: Insecta) see elytral intervals.intertentacular organ (BRYO: Gymnolaemata) A small ciliatedtube beneath the tentacle bases of the lophophore throughwhich fertilized eggs pass to the outside.intertergite n. [L. inter, between; tergum, back] An intersegmentbetween tergites.intertidal zone The area bounded by the high and low tidelines; also known as the littoral.intertrochanteric a. [L. inter, between; Gr. trochanter, runner](ARTHRO) Between trochanters.interval n. [L. inter, between; vallum, a wall] 1. The spacebetween elevations or depressions. see interspace. 2.Distance between points. 3. The time between periods ofdevelopment.interzonal a. [L. inter, between; zona, belt] Connection betweenchromatids during separation at anaphase in mitosis.interzooidal budding (BRYO: Stenolaemata) Budding that occursoutside of the living chambers of zooids producing abud nonrelated to an individual parent zooid.interzooidal growth (BRYO: Phylactolaemata) Growth of a

484Maggenti and Gardnerwall between new polypides and parental polypides.interzooidal polymorph (BRYO: Gymnolaemata) Polymorphbetween zooids communicating with two or more zooids ina space smaller than that occupied by an autozooid.intestinal groove (ARTHRO: Crustacea) In Decapoda, marinelobsters with a short, transverse groove of the posteriorcarapace.intestinal region (ARTHRO: Crustacea) In a decapod carapace,a short transverse area behind the cardiac region; posteriorcardiac lobe.intestinal siphon (ECHI) A narrow tube associated with themidgut; an accessory intestine.intestine n. [L. intestina, entrails] The chief digestive portionof the enteron; gut.intima n. [L. intimus, innermost] The internal membranouslining of an organ. intimal a.intorted n. [L. in, in; torquere, to twist] A turning or twistingin any direction from the vertical.in toto In its entirety; entirely; altogether.intra-alar bristles (ARTHRO: Insecta) In Diptera, a row of twoor three bristles between the supra-alar and dorsocentralbristle groups.intracellular a. [L. intra, within; cellula, small cell] Occurringwithin a cell or cells.intrachange n. [L. intra, within; cambiare, to barter] Exchangeof segments within a chromosome resulting inchromosomal structural changes.intracoelomic muscle see external muscleintracristal space Space enclosed by cristae in the mitochondrion.intracuticular skeleton (BRYO: Gymnolaemata) InCheilostomata, skeletal layers between noncellular organicsheets or within organic networks of cuticles of the exteriorwalls.intrados n. [L. intra, within; F. dos, the back] The interiorcurve of an arch. see extrados.

Online Dictionary of Invertebrate Zoology 485intrahemocoelic a. [L. intra, within; Gr. haima, blood; koilos,hollow] Within the hemocoel or perivisceral cavity of an invertebrate.intralecithal cleavage Cleavage where the nuclei undergo severaldivisions within the yolk without concurrent cytokinesis;common in arthropods.intraparies n.; pl. intraparietes [L. intra, within; paries, wall](ARTHRO: Crustacea) In Lepadomorpha, the secondary lateralmargin of the carina.intrapetalous a. [L. intra, within; Gr. petalon, leaf] (ECHINOD)Within the area of the tube feet.intrapulmonary respiration Type of respiration that does notinvolve movements of the outer body wall and is confinedto the respiratory organs.intrasegmental a. [L. intra, within; segmen, piece] Within asegment.intraspicular a. [L. intra, within; spicula, little point] (PORIF)Pertains to spicules completely embedded in spongin.intratentacular budding (CNID: Anthozoa) A zoantharian colonygrowing by asexual reproduction, through the formationof new mouths on the oral disk, resulting in branching,or in linear groups of polyps bearing tentacles mainly onthe outer edges of the row.intrauterine a. [L. intra, within; uterus, womb] 1. Within theuterus. 2. Applied to developing offspring hatching withinthe uterus of the mother. see matricidal hatching.intra vitam Applied to certain stains having the property oftinting cells of living organisms without killing them.intrazooidal budding (BRYO: Stenolaemata) Budding withinthe living chamber of a single zooid.intrazooidal polymorphism (BRYO: Stenolaemata) Two differenttypes of zooids developed in the same living chamber.intrinsic a. [L. intrinsecus, inward] 1. Inherent or within. 2.Cycles of species in a population. 3. Rate of natural increasein a stabilized population. see extrinsic.intrinsic articulation A type of articulation where sclerotic

486Maggenti and Gardnerprolongations within the articular membrane make contact.see extrinsic articulation.intrinsic body wall muscles (BRYO) Circular and longitudinalmuscle layers in the body walls.intrinsic muscles Muscles which move an organ (leg, etc.)that originate within the segment. see extrinsic muscles.introduced a. [L. intro, within; ducere, to lead] Not native butbrought into an area by man.introitus n. [L. introitus, entered] Opening or orifice.intromittent a. [L. intro, within; mettere, to send] Designedfor entering or inserting.intromittent organ A male organ for transfer of seminal fluidinto the female.introrse a. [L. intro, within; versus, turn] Facing or directedinward toward the axis. see extrorse.introvert n. [L. intro, within; versus, turn] (BRYO/SIPUN) Acavity which accepts retractable appendages, e.g., the anteriorcavity that accepts the anterior tentacles.intumescent n. [L. in, in; tumescere, to swell up] A swelling;being swollen or expanded.intussusception n. [L. intus, within; suscipere, to take up]Deposition of new particles of formative material amongthose already present in a tissue or structure. see apposition,accretion.invagination n. [L. in, into; vagina, sheath] An infolding, oringrowth of a sheet or layer of cells forming a pouch or sac,especially in embryos. see emboly.invalid a. [L. invalidus, not strong] Dismissing; without standingin zoological nomenclature.inverse eyes Eyes in which the distal ends of the retinal cellsface the interior of the cup or vesicle. see converse eyes.invertase n. [L. invertere, to turn around; -asis, ending signifyingan enzyme] An enzyme found in many plants andanimal intestines that causes the hydrolysis of sucrose andconverts it into a mixture of glucose and fructose.invertebrate n. [L. in, not; vertebrata, with backbones] Any

Online Dictionary of Invertebrate Zoology 487animal without a backbone or vertebral column.investment n. [L. investire, to clothe] An outer covering of acell, part, or organism.in vitro [L. in, in; vitrum, glass] In the test tube or other artificialenvironment.in vivo [L. in, in; vivere, to live] Occurring within a living organism.involucrum n. [L. involucrum, sheath] (ARTHRO: Insecta) Asheath of cerumen around the brood chamber of stinglessbees.involute a. [L. in, in; volute, spiral] 1. Rolled inwards at marginsor edges. 2. (MOLL) The last whorl of a shell envelopingearlier ones and concealing, or nearly so, the axis orearlier volutions. see convolute, revolute.involution n. [L. in, in; volute, spiral] 1. Act of involving orinfolding. 2. Deterioration or retrograde evolution.ipsilateral a. [L. ipse, same; latus, side] Pertaining to or situatedon the same side. see contralateral.iridescence n. [L. iris, rainbow] A rainbow-like display of interferencecolors that change with variations of the angle ofview, due to diffraction of light reflected from ribbed orfinely striated surfaces. iridescent a.iridophore n. [L. iris, rainbow; Gr. phoreus, bearer] An iridescentchromatophore; an iridocyte.iris n.; pl. irises, irides [L. iris, rainbow] Dark pigment surroundingthe compound eyes of arthropods and the camera-typeeyes of cephalopods.irregular n. [L. in, not; regularis, according to rule] Unequal,curved, bent; not regular.irreversibility rule see Dollo's ruleirritability n. [L. irritare, to provoke] Ability to receive externalimpressions and the power to react to them.irritant n. [L. irritare, to provoke] Any external stimulus thatcan provoke a response.irrorate a. [L. in, not; roris, dew] Covered with minute marks,colors, or minute grains or specks of color.

488Maggenti and Gardnerisauxesis n. [Gr. isos, equal; auxesis, growth] Equality ingrowth; isometry. see bradyauxesis, heterauxesis,tachyauxesis.ischia pl. of ischiumischiocerite n. [Gr. ischion, hip; keras, horn] (ARTHRO: Crustacea)Third segment of an antennal peduncle.ischiomerus a. [Gr. ischion, hip; meros, part] (ARTHRO: Crustacea)Refers to the third (ischium) and fourth (merus)segments of subchelate anterior appendages.ischiopod(ite) n. [Gr. ischion, hip; pous, foot] (ARTHRO) Thethird segment of a generalized limb; the second trochanter,or second segment of the telopodite; prefemur. see ischium.ischium n.; pl. ischia [Gr. ischion, hip] (ARTHRO: Crustacea)The third segment of a pereopod, or first segment of anendopod articulating with the basis; an ischiopodite.islet n. [L. dim. insula, an island] A spot in a plaga differing incolor.isoallele n. [Gr. isos, equal; allelon, one another] An allelewhose effect can only be distinguished from that of a normalallele by special techniques.isobilateral a. [Gr. isos, equal; L. bis, twice; latus, side] Havingbilateral symmetry where a structure can be divisible intwo planes at right angles.isobrachial a. [Gr. isos, equal; brachion, arm] A chromosomein which the centromere occupies the median position.isochela n. [Gr. isos, equal; chele, claw] 1. A chela with twolike parts. 2. (PORIF) A diactinal microsclere with like recurvedhooks, plates, flukes or anchor shaped at each end.see anisochela.isochromosome a. [Gr. isos, equal; chromos, color; soma,body] Monocentric or dicentric chromosome with equal andgenetically identical arms which are mirror images.isocies n.pl. [Gr. isos, equal; L. socius, companion] A group ofassociated organisms with differing taxonomic affinities, attimes used merely in the sense of habitat groups. see associes,consocies, subsocies.

Online Dictionary of Invertebrate Zoology 489isocytous a. [Gr. isos, equal; kytos, container] Having cells ofequal size or height.isodactylous a. [Gr. isos, equal; daktylos, finger] Bearing digitsof equal size.isodiametric a. [Gr. isos, equal; dia, through; metron, measure]Having equal diameters or axes.isodictyal a. [Gr. isos, equal; dictyon, net] (PORIF) Pertainingto a type of skeletal construction with spicules and/or fibersinterlocking in a regular triangular pattern.isodont a. [Gr. isos, equal; odous, tooth] (MOLL: Bivalvia) Withhinge teeth arranged symmetrically; homodont.isoenzyme n. [Gr. isos, equal; en, in; zyme, yeast] An enzymediffering in polymorphic states and isoelectric point, buthaving the same function; an isozyme.isogametes n. [Gr. isos, equal; gamete, spouse] Outwardlysimilar male and female gametes.isogamy n. [Gr. isos, equal; gamos, union] The mutual fertilizationprocess of isogametes.isogenes n. [Gr. isos, equal; genos, race] Lines on a gene mapthat connect points of identical gene frequency.isogenic a. [Gr. isos, equal; genos, race] A group of individualsthat have the same genotype.isoglottid a. [Gr. isos, equal; glottis, mouth of the windpipe](NEMATA) Having metarhabdions situated at the same level.see anisoglottid.isograft n. [Gr. isos, equal; graphion, stylus] Tissue graft betweenanimals of the same genotype.isolate n. [L. insula, island] A breeding population or group ofpopulations isolated from other populations by physiological,behavioral, or geographic barriers.isolation n. [L. insula, island] Separation from similar forms.isolecithal egg An ova with yolk granules randomly distributedthrough the cell; a small amount of yolk; an oligolecithalegg. see centrolecithal egg.isomer n. [Gr. isos, equal; meros, part] Compounds of thesame chemical composition but with different structures.

490Maggenti and Gardnerisomerases n.pl. [Gr. isos, equal; meros, part; -asis, enzyme]Enzymes which convert one chemical compound to another;said to be isomeric compounds.isomeric a. [Gr. isos, equal; meros, part] Equivalent geneswhich can each produce the same phenotype.isomerogamy see isogamyisomerous a. [Gr. isos, equal; meros, part] Having equalnumber of parts, ridges or markings; homoeomerous. seeheteromerous.isometry n. [Gr. isos, equal; metron, measure] Growth of twobody parts remaining constant relative to each other asbody size increases.isomorphic a. [Gr. isos, equal; morphe, form] Alike or identicalin appearance; isomorphous. see anisomorphic.isomorphism n. [Gr. isos, equal; morphe, form] Similarity oforganisms of different ancestry. see heteromorphic.isomyarian condition (MOLL: Bivalvia) Having adductor musclesequal or subequal in size; homomyarian.isonym n. [Gr. isos, equal; onyma, name] The new name of aspecies, or higher classification being based upon the oldername or basinym.isopalpi n.pl.; sing. -us [Gr. isos, equal; L. palpus, feeler]Palpi with the same number of joints.isophene, isophane n. [Gr. isos, equal; phainein, to show] 1.A line connecting points of equal expression of a clinallyvarying character. 2. A line connecting areas in a region atwhich a phenological phenomenon occurs simultaneously.3. Lines at right angles to a cline on a map.isophenon n.; pl. isophena [Gr. isos, equal; phainein, toshow] Maintaining the same form, except sometimes insize, after a growing- or repetition-molt.isophenous a. [Gr. isos, equal; phainein, to show] Showingcharacteristics of a phenotype.isopodus a. [Gr. isos, equal; pous, foot] Having the legs alikeand equal.isopycnosis n. [Gr. isos, equal; pyknos, thick] Chromosome or

Online Dictionary of Invertebrate Zoology 491chromosome regions which do not differ greatly from eachother.isopygous a. [Gr. isos, equal; pyge, rump] Having pygidiumand cephalon equal in size.isorhiza n. [Gr. isos, equal; rhiza, root] (CNID) A form ofnematocyst in which the tube is open and the same diameteralong the tube, responding to mechanical stimuli,and is used in anchoring the animal when it walks on itstentacles. see atrichous isorhiza, holotrichous isorhiza,basitrichous isorhiza.isostrophic a. [Gr. isos, equal; strophe, turn] (MOLL: Gastropoda)Having two faces of the shell symmetrical with respectto a median plane perpendicular to axis.isotomy a. [Gr. isos, equal; temnein, to cut] The process ofregularly repeated bifurcation as in crinoid branchia.isotrophic a. [Gr. isos, equal; tropein, to turn] Singly refracting,as the light stripes of voluntary muscle fibers. see anisotropic.isotype n. [Gr. isos, equal; typus, image] 1. An animal, plantor group frequently found in two or more countries or liferegions. 2. A specimen collected from the type locale orhabitat at the same time as the holotype.isotypical genus A description from more than one congenericspecies.isozyme see isoenzymeisthmiate a. [Gr. isthmos, neck] Connected by an isthmus-likepart.isthmus n. [L. fr. Gr. isthmos, neck, narrow place] (MOLL: Bivalvia)Part of the mantle that secretes the horny uncalcifiedmaterial (conchiolin) of the ligament. 2. (NEMATA) Themiddle part of a muscular esophagus, often constricted; anarrow section of the esophagus.iteroparous a. [L. iterare, to repeat; parere, to bear] Havingthe capability to reproduce two or more times during a lifetime.iteroparity n.

Jjacket cells (MESO: Orthonectida) The ciliated somatoderm;the number of body rings and their arrangement is of taxonomicimportance.jaculatory duct A region of the vas deferens through whichsperm is emitted. see ejaculatory duct.Johnston's organ (ARTHRO: Insecta) A chordotonal organ locatedin the second segment of the antenna and functioningin sound perception, flight speed indicator or waterwave perception.joint n. [L. jungere, to join] An articulation of two successivesegments or parts.Jonstonian organ see Johnston's organjordanon see microspeciesJordan's organ see chaetosematajubate a. [L. jubatus, crested] Fringed with long, mane-likehairs.juga pl. of jugumjugal angle (MOLL: Polyplacophora) The angle formed by thetwo halves of an intermediate valve.jugal area/tract (MOLL: Polyplacophora) The upper surface ofa valve immediately adjacent to the jugum, sometimessculptured differently from the rest of the surface; dorsalarea.jugal bristles (ARTHRO: Insecta) Bristles located on the edgeof the jugal lobe.jugal coverage see valve coveragejugal fold see plica jugalisjugal lobe (ARTHRO: Insecta) A lobe at the base of the forewing that makes contact with the hind wing to prevent thewings from moving out of phase.jugal muscles (MOLL) Thick longitudinal muscles at the base of

Online Dictionary of Invertebrate Zoology 493the radular mass.jugal region 1. (ARTHRO: Crustacea) In Decapoda, the anterolateralpart on the ventral surface, located on oppositesides of the buccal cavity; pterygostomial region. 2. (AR-THRO: Insecta) The posterior basal lobe or area of a wingdemarcated from the vannal region by the jugal fold (plicajugalis).jugal sinus (MOLL: Polyplacophora) A depression between thesutural laminae of chitins.jugal tract (MOLL: Polyplacophora) The tegmentum surface,adjacent to the jugum.jugo-frenate wing coupling (ARTHRO: Insecta) Lepidoptera,wing coupling where the jugum is folded under the forewings and holds the frenular bristles.jugular a. [L. jugulum, collar bone, throat] Of or pertaining tothe throat.jugular sclerites see cervical scleritejugulum n. [L. jugulum, collar bone, throat] (ARTHRO: Insecta)1. The median ventral plate of the head. see gula. 2. Thejugum of the wing.jugum n.; pl. -ga [L. jugum, yoke] 1. (BRACHIO) The medialconnection of the secondary shell between 2 primary lamellaeof the spiralia. 2. (ARTHRO: Insecta) a. In Lepidoptera,a lobe-like process at the base of the fore wings,overlapping the hind wings. b. Two lateral lobes on thehead of certain Heteroptera, bordering the tylus. 3. (MOLL:Polyplacophora) Longitudinal ridge of some intermediatechiton valves that may be sharp or rounded.Julien's organ see coremajuliform a. [ Julus, generic name; L. forma, shape] (ARTHRO:Diplopoda) Having a cylindrical trunk and fused tergites,pleurites, and sternites as in the order Julida.junctional complex Specialized area of adhesive contact betweencells.junior homonym The more currently published of two or moreidentical names for the same or different taxa. see homonym,senior homonym.

494Maggenti and Gardnerjunior synonym The more currently published of two or moreavailable names for the same taxon. see synonyms, seniorsynonym.juvenile a. [L. juvenilis, young] 1. A nonscientific colloquialterm used to denote any stage of development prior toadulthood. 2. Often restricted to that stage immediatelypreceding the sexually mature adult stage. 3. In general,the immature stages resemble the adult in general morphologyexcept for gonadal development.juvenile hormone (ARTHRO: Insecta) A hormone of larvaeproduced by the corpora allata that controls the way thelarval cells differentiate at each molt.juxta n. [L. juxta, near] (ARTHRO: Insecta) 1. In Diptera, aneversible membranous distal section of the male intromittentorgan. 2. In male Lepidoptera, a sclerotized plate atthe base of the aedeagus; sometimes connected to theanellus by a thin median process that is often forked so asto surround the aedeagus; has been used as a synonym ofthe anellus of the aedeagal fulcrum.juxtacardo n. [L. juxta, near; cardo, hinge] (ARTHRO: Insecta)An extension of the cardo from cardo proper toward thesubmentum.juxtacoxal carina (ARTHRO: Insecta) In Ichneumonidae, anarched carina cutting off a lenticular area of the lower partof the metapleura; when complete, the carina arches betweenthe bases of the hind and middle coxae.juxtaposition n. [L. juxta, near; positus, place] A placing orbeing placed side by side.juxtastipes n. [L. juxta, near; stipes, stalk] (ARTHRO: Insecta)An extension of the stipes toward the mentum.

Kkairomone n. [Gr. kairos, fit; hormaein, to exite] A chemicalsubstance, produced or acquired by an organism, that uponcontact with an individual of another species evokes a behaviorialor physiological reaction favorable to the receiverand not to the emitter. see allelochemic.kalymma n. [Gr. kalymma, hood] Matrix material which isthought by some authors to surround the components ofchromosomes.karyochylema see nucleoplasmkaryoclastic a. [Gr. karyon, nucleus; klastos, broken inpieces] Agents that inhibit mitosis without killing the cell.karyogamy n. [Gr. karyon, nucleus; gamos, marriage] Theunion of male and female nuclei during the process of syngamy.karyokinesis n. [Gr. karyon, nucleus; kinesis, movement] Nucleardivision as opposed to cytokinesis.karyolymph see nucleoplasmkaryolysis n. [Gr. karyon, nucleus; lysis, a loosing] Disappearanceof the interphase nucleus at the beginning of karyokinesis;dissolution of the nucleus.karyomere n. [Gr. karyon, nucleus; meros, part] Any of a seriesof micronuclei formed in cells in which the chromosomesdiverge at anaphase.karyon n. [Gr. karyon, nucleus] The cell nucleus.karyoplasm n. [Gr. karyon, nucleus; plasma, formed ormolded] The protoplasm of the nucleus; nucleoplasm.karyorhexis n. [Gr. karyon, nucleus; rhexis, rupture] Nucleardegeneration by nuclear fragmentation.karyosome n. [Gr. karyon, nucleus; soma, body] Irregularclump of chromatin dispersed in the chromatin cell network.karyotheca n. [Gr. karyon, nucleus; theke, a box] Nuclear

496Maggenti and Gardnermembrane.karyotin n. [Gr. karyon, nucleus] Chromatin.karyotype n. [Gr. karyon, nucleus; typos, image] The particularchromosome complement of an individual or species, asdefined by both number and morphology of the chromosomes,usually in mitotic metaphase.katabolism see catabolismkatagenesis n. [Gr. kata, down; genesis, beginning] Retrogressiveevolution.katakinesis see catakinesiskataplexy see cataplexykatatrepsis n. [Gr. kata, down; trepein, to turn] 1. (ARTHRO:Insecta) In blastokinesis, the movement of the embryo insidethe egg from one pole to another. 2. Refers to differentactivities in different groups of insects, i.e., dorsal toventral, ventral to dorsal. 3. Decrease of movement duringblastokinesis. see anatrepsis.katepimeron see infraepimeronkatepisternum see infraepisternumkatharobic a. [Gr. katharos, pure; bios, life] Pertains to livingin clean water.kation see cationKeber's valve (MOLL: Bivalvia) Pericardinal gland, connectingthe pedal and visceral hemocoels.keel n. [A.S. ceol, ship] 1. A prominent ridge or carina. 2.(BRYO) a. In Stenolaemata, a flat median portion of the zooidalwall between sinuses in recumbent part of endozoneor as a synonym of carina. b. In Phylactolaemata, a medianlongitudinal ridge along recumbent tubular colony parts. 3.(MOLL: Gastropoda) A spiral ridge usually marking a changeof slope in the outline of the shell.Keferstein bodies (SIPUN) Small oval bodies on the inner orcoelomic surface of the body wall.kenozooid n. [Gr. kenos, empty; zoon, animal; eidos, like](BRYO) 1. In Stenolaemata, a polymorph without a lophophore,gut, muscles, and orifice. 2. In Gymnolaemata, a

Online Dictionary of Invertebrate Zoology 497polymorph without an orificial wall or equivalent, lophophore,alimentary canal, and usually muscles.kentrogon n. [Gr. kentor, piercer; gone, that which generates](ARTHRO: Crustacea) In Rhizocephala, undifferentiated cellsformed after the cyprid larval molts and its appendagesand carapace are discarded, that penetrates the integumentof a Decapoda host.kentromorphism n. [Gr. kentor, piercer; morphe, form] (AR-THRO: Insecta) A change brought about by environmentalstimuli (high or low population density) in phasmatids, locusts,the larva of Lepidoptera and a few other insects, thatcause coloration and pattern differences, anatomical proportions,physiology and behavioral differences. see gregaria,solitaria.kentron n. [Gr. kentor, piercer] (ARTHRO: Crustacea) In Rhizocephala,a hollow stylet in the anterior body of a kentrogonthat invades the antennule and pierces the integument ofits host.keratin n. [Gr. keras, horn] A sulfur-containing nitrogenouscompound found in animal tissues such as horn, hair andnails.keratinization n. [Gr. keras, horn] Conversion of tissues intokeratin or keratin-like tissue. see cornification.keratose a. [Gr. keras, horn] Having horny fibers in theskeletal structure, as in certain Porifera.kermes (Generic name) A red dye made from the dried bodiesof female coccids of kermococcus ilicis; granum tinctorium.key n. [ME. key] A tabulation of diagnostic characters of organismsmost often in dichotomous couplets facilitatingrapid identification.kidney shaped Shaped like a kidney; reniform.kinaesthesis, kinesthesis n. [Gr. kinein, to move; aisthesis,perception] Perception of movement by internal stimulation;proprioceptors.kinase n. [Gr. kinein, to move; -asis, enzyme] Enzymes thatcatalyse the transfer of high energy groups from a donor toan acceptor; named for acceptor; enzyme which activates a

498Maggenti and Gardnerzymogen.kinesis n. [Gr. kinesis, movement] Responses not directed to avariation in the stimulus or orientation of the body axis tothe source of stimulation; movement resulting from a kinesisis random. see taxis, tropism.kinesodic a. [Gr. kinesis, movement; hodos, way] Conveyingmotor impulses.kinetoblast n. [Gr. kinetos, move; blastos, bud] Outer coveringof aquatic larvae equipped with locomotory cilia.kinetochore see centromerekinetogenesis n. [Gr. kinetos, move; genesis, beginning] Thetheory that animal structure evolution was produced byanimal movements. kinetogenetic a.kinetomere n. [Gr. kinetos, move; meros, part] Chromomere;bead-like chromatin concentrations along a chromosome.kinetonema see centromereking n. [A.S. cyng] (ARTHRO: Insecta) In social Hymenopteraand Isoptera, a primary reproductive male that along withthe queen loses its wings after founding the colony.kingdom n. [A.S. cyngdom] The largest primary taxonomic division;organisms usually divided into three kingdoms,plants, animals and Protista.kinomere see centromerekinoplasm n. [Gr. kinein, to move; plasma, formed or molded]A former name for a distinct type of protoplasm whichtends to form fibrillar structures and is mechanically active.Kinorhyncha, kinorhynchs n., n.pl. [Gr. kinein, to move;rhynchos, snout] A phylum of free-living marine invertebrates,with joined segments and spines; sometimes calledthe Echinoderida or considered a class of Aschelminthes orNemathelminthes.kitchen midden n. [Dan. kjokkenmodding; kitchen leavings]The kitchen refuse heap of sea shells and bones of ancientdwellings along the coast of northern Europe, eastern andwestern United States, and many parts of the world.klinokinesis n. [Gr. klinein, to bend; kinesis, movement] A

Online Dictionary of Invertebrate Zoology 499non-directional response in which the rate of turning dependson the intensity of stimulation; trial-and-error reaction.see orthokinesis.klinotaxis n. [Gr. klinein, to bend; taxis, arrangement] Orientationand movement toward a stimulus by an organism bymoving its head or whole body from side to side symmetrically.see telotaxis, tropotaxis.knee-segment (ARTHRO: Chelicerata) Segment of the legsbetween ascending and descending part; called genu inmites and patella in other chelicerates.Koelliker's canal (MOLL: Cephalopoda) In Incirrata, a smallblind tube that opens into the endolymph sac of the statocyst;function unknown.Koelliker's tufts or organs (MOLL: Cephalophoda) Groups ofstiff bristles on the skin of most embryos and hatching octopods.kolytic a. [Gr. kolytikos, hindering] Inhibiting or inhibitory.koriogamy n. [Gr. koreios, youthful or maiden; gamos, marriage]The impregnation of a female possessing a fully developedvagina and uterus but an immature ovary; coryogamy.Koshevnikov or Koshewnikow gland (ARTHRO: Insecta) Agland consisting of or corresponding to Leydig cells and thesting of numerous bees, that produce an attractant pheromonein honey bee queens.Krause's membrane see Z-band or discKrebs' cycle Energy cycle; stepwise enzymatic oxydation ofsimple sugars to give high energy phosphate bonds (ATP).K-strategist Any species of organism using a survival and reproductivestrategy characterized by low fecundity, lowmortality, longer life, and having populations approachingthe carrying capacity of the environment, controlled bydensity-dependent factors. see R-stratigist.kyphorhabd n. [Gr. kyphos, humpbacked; rhabdo, rod] (PO-RIF) A strongyle with a row of tubercles along one side.

Llabella pl. of labellumlabellar abductor apodeme (ARTHRO: Insecta) In Diptera, asmall cuticular process below the inner basal margin ofeach labellum, where the labellar abductor muscle attaches.labellar basal sclerites (ARTHRO: Insecta) In Diptera, ventralsclerites in the membranous articulation between theprementum and the labella of the labium; basal sclerite.labellar mesial sclerite (ARTHRO: Insecta) In Diptera, twonarrow sclerotized strips on the inner surface of each labellum;mesial sclerite.labellar sclerite (ARTHRO: Insecta) In Diptera, one of severalcuticular plates of each labellum; the prominent basalsclerite; the furca of the labellum.labellum n.; pl. -la [L. dim. labrum, lip] (ARTHRO: Insecta)One of variously expanded apexes of the labium; the boutonor flabellum of bees.labial a. [L. dim. labrum, lip] Pertaining to lip or labium.labial area (MOLL: Gastropoda) The flattened or callus-coatedsurface extending from inner lip of the shell.labial disc (NEMATA) A circular elevation of cuticle surroundingthe oral opening; perioral disc.labial glands (ARTHRO: Insecta) Salivary glands in the majorityof insects, situated below the anterior part of the alimentarycanal; ducts originating from these glands uniteinto a common duct (salivary canal) which opens near thebase of the labium or hypopharynx.labial gutter see premental gutterlabial kidneys see labial nephridialabial lumen see premental gutterlabial mask (ARTHRO: Insecta) A modification of the labium ofdragonfly larvae in which the pre- and post-mentum are

Online Dictionary of Invertebrate Zoology 501elongated and the palps modified into grasping organs forcatching prey.labial nephridia (ARTHRO: Insecta) Tubules in the head ofCollembola and Thysanura, whose terminal sac may playsome excretory role.labial palp/palpus pl. -pi 1. (ARTHRO: Insecta) One of a pairof small feelerlike structures borne on the labium. seemaxillary palp. 2. (MOLL: Bivalvia) One of 4 structures (2on each side of the mouth) derived from the velum bywhich the larva swims and collects food.labial plate (ARTHRO: Insecta) A sclerotized, serrated platederived from the labium of larvae of aquatic Diptera;mental plate.labial stipes see labiostipeslabial suture (ARTHRO: Insecta) Suture on the labium betweenthe postmentum and the prementum.labial veil see oral lappetslabiate a. [L. labium, lip] Having lips or lip-like parts or thickenedmargins.labidophorous a. [Gr. labis, forcepts; pherein, to carry] Havingpincer-like organs.labiella n.pl.; sing. labiellum [L. dim. labium, lip] 1. (ARTHRO:Chilopoda) A mouth part of a myriapod. 2. (ARTHRO: Insecta)The hypopharynx; the median mouthpart.labile a. [L. labilis, slipping] Readily changeable; unstable.labiostipes n.pl. [L. dim. labium, lip; stipes, stem] (ARTHRO:Insecta) A portion of the basal part of the labium.labis see sociilabium n.; pl. -bia [L. labium, lip] 1. A lip. 2. (ARTHRO: Chelicerata)In Araneae, the lower lip, forming the floor of themouth cavity. 3. (ARTHRO: Crustacea) The metastoma. 4.(ARTHRO: Insecta) One of the mouth-part structures, thelower lip, composed of fused second maxillae; has beenreferred to as the tongue at a certain phase of development.5. (MOLL) The inner lip of a univalve shell, the innerside of the aperture or columellar lip extending from theorigin at the lip of the labrum and resting on the columella.

502Maggenti and Gardnersee inner lip.labral a. [L. labrum, lip] 1. (ARTHRO: Insecta) Pertaining to theupper lip. 2. (MOLL: Gastropoda) Pertaining to the outer lipof a shell.labropalatum n. [L. labrum, lip; palatum, roof of mouth] (AR-THRO: Insecta) In Diptera, the oral surface of the labrum ofmosquitoes; a division of the palatum. see clypeopalatum.labrum n.; pl. -bra [L. labrum, lip] 1. A lip or edge. 2. (AR-THRO: Chelicerata) In Araneae, has been incorrectly usedfor the labium. 3. (ARTHRO: Crustacea) The unpaired outgrowtharising in front of the mouth and often covering it;upper lip. 4. (ARTHRO: Insecta) The upper lip located belowthe clypeus and in front of the other mouth parts. 5. (AR-THRO: Trilobita) The hypostoma of a trilobite fossil. 6.(ECHINOD: Echinoidea) A flap of the interambulacrum whichprojects over the ventral peristome.labrum-epipharynx (ARTHRO: Insecta) The mouth part representingthe labrum and epipharynx.lac n. [Skr. laksa] (ARTHRO: Insecta) A yellowish or reddishbrownresinous substance secreted by a homopterous scaleinsect in the family Kerridae (=Tachardiidae, Lacciferidae),important commercially as lac or shellac for varnishes, assealing wax, and as insulating material in electrical work,cultivated in India, Ceylon and Burma; also has a medicinaluse in Mexico.lacerated a. [L. lacer, torn] Having edges jagged or irregular.lacinia, lacinea n.; pl. laciniae [L. lacinia, flap] 1. (ARTHRO:Crustacea) The inner distal spiny lobe of the second segmentof the maxillula. 2. (ARTHRO: Insecta) a. In many, theinner lobe (elongate jaw-like structure) of the maxilla, locatedat the apex of the stipes. b. In Psocidae, representedby a hard elongate rod, slightly bifurcated at its free endand ensheathed by the galea, sometimes called the pick;similar modification to a stylet-like shape in Mallophaga.lacinia mandibulae see lacinia mobilislacinia mobilis 1. (ARTHRO: Crustacea) A small, generallytoothed process articulated with the incisor process of the

Online Dictionary of Invertebrate Zoology 503mandible. 2. (ARTHRO: Insecta) A small movable lobe-likeprocess near the extremity of the mandible; a prostheca.laciniate a. [L. lacer, torn] Slashed or cut into irregularly narrowlobes or deep segments.lacteous a. [L. lac, milk] Of white or milky color.lactescent a. [L. lactescere, to turn to milk] Like milk in appearance;yielding or secreting a milky fluid.lactic acid Organic acid formed in tissues of two molecules forevery molecule of glucose used where oxygen is in shortsupply.lacuna n.; pl. -ae [L. lacuna, cavity] 1. A space, gap, cavity orchannel. 2. (ACANTHO) Channels making up the lacunarsystem. 3. (ARTHRO: Insecta) In wing development, canalsthat contain nerves, tracheae, and hemolymph. 4.(BRACHIO:Articulata) The large open space surrounding thelophophore. 5. (BRYO) Open space between tubular porechambers.6. (MOLL: Bivalvia) Irregular, blood-filled spacesbetween various organs in the mantle and visceral mass.lacunar system (ACANTHO) The circulatory system.lacunose a. [L. lacuna, cavity] Marked by shallow, scattereddepressions; pitted.lacustrine a. [L. lacus, lake] Of or pertaining to living in ornear a lake.laeotorma n; pl. -ae [Gr. laios, left; torma, socket] (ARTHRO:Insecta) In beetle larvae, transverse sclerite extending inwardfrom the left hind angle of the epipharynx, usuallywith a projection.laeotropic a. [Gr. laios, left; tropos, turn] Of or pertaining tothe left; sinistral; opposed to dexiotropic.lagena n. [L. lagaena, flask] 1. Bottle-shaped; dilated belowand tapering to a narrow neck above; lageniform. 2. (AR-THRO: Insecta) In Lepidoptera, the smaller lobe of thespermatheca; may be fused into one organ. see utriculus.Lamarckism A theory espoused by Lamarck, that evolution isbrought about by volition or by environmental induction;Geoffroyism.lamella n.; pl. -ae [L. lamella, small plate] 1. A thin plate or

504Maggenti and Gardnerleaflike structure. 2. (ARTHRO: Chelicerata) A triangularplate on the promargin of the cheliceral fang furrow insome spiders. 3. (MOLL: Gastropoda) Flared axial projectionof the outer lip of the shell.lamellar ligament (MOLL: Bivalvia) That part of the ligamentsecreted by the mantle edge that is lamellar in structureand contains no calcium carbonate; elastic to both compressionand tension.lamellate a. [L. lamella, small plate] Composed of or coveredby thin scales, plates or layers.lamellate antennae (ARTHRO: Insecta) Antennae with anasymmetrical 3- to 7-segmented club of more or less flattenedsegments.Lamellibranchia see Class Bivalvia, Phylum Molluscalamellibranchiate a. [L. lamella, small plate; Gr. branchia,gills] (MOLL) With plate-like gills that are bilaterally symmetrical;bilaterally compressed, symmetrical body.lamellicorn a. [L. lamella, small plate; cornu, horn] Having thejoints of the antenna expanded into flattened plates.lamelliform a. [L. lamella, small plate; forma, shape] Havingthe form of scales, thin plates or layers.lamellocyte see plasmatocytelamello-fibrous (MOLL) Referring to shells with one portioncomposed of fibers and another of laminae.lamellose a. [L. lamella, small plate] Composed of lamella.lamina n.; pl. -nae, -nas [L. lamina, a plate] 1. A thin plate,scale or layer. 2. (ARTHRO) A distal synaptic region in theoptic lobes. 3. (NEMATA) The main body of the male spicule;the blade.lamina lingualis pl. laminae linguales (ARTHRO: Diplopoda)One of two median distal plates in the gnathochilarium.lamina of insertion see insertion platelamina phalli (ARTHRO: Insecta) In Caelifera, endophallicmembrane sclerotizations restricting the spermatophoresac.laminar a. [L. lamina, plate] Arranged in thin plates or layers;

Online Dictionary of Invertebrate Zoology 505laminiform.laminate a. [L. lamina, plate] Composed of leaf-like, overlappingplates or scales.laminiform a. [L. lamina, plate; forma, shape] Laminar.lampbrush chromosomes Very large chromosomes with finelateral projections; found in invertebrates and vertebrates.lanate a. [L. lana, wool] Covered with long, very fine or woolyhairlike filaments.lanceolate a. [L. lanceola, little lance] Tapering to a point atthe apex, or sometimes at both ends; lance-shaped.lancet n. [L. lancea, light spear] 1. Any piercing structure. 2.(ARTHRO: Insecta) a. In Hymentoptera, the first valvulae.b. The first gonapophyses of Apis. 3. [NEMATA] Small teethin the buccal cavity of some nematodes.lancinate v.t. [L. lancinare, to tear to pieces] To tear, lacerate,pierce or stab.Lang's vesicle (PLATY: Turbellaria) A blind extension of thefemale canal of certain Acotylea, proximal to where theoviducts join.lantern n. [L. lanterna, lantern] 1. (ARTHRO: Insecta) The lightorgans of fireflies and certain beetles. 2. (MOLL: Cephalopoda)The photophore. see Aristotle's lantern.lanuginous a. [L. lanugo, down] Covered with very fine softhair.lapidicolous a. [L. lapis, stone; colere, to inhabit] Living understones.lapidrous a. [L. lapis, stone] Of the nature of a stone.lappet n. [A.S. laeppa, a loose hanging part] 1. A fold, smallflap, lobe or loose hanging portion. 2. (ARTHRO: Crustacea)In Mysidacea, a ventrally projecting subdivision of thepleura. 3. (CNID: Scyphozoa) A flaplike projection on thebell margin. 4. (ECHINOD: Crinoidea) A movable plate onthe margin of an ambulacral groove. 5. (ECHI) In Bonellidae,the shortened arms of the proboscis. 6. (PLATY: Turbellaria)In Tricladida, earlike process on the head.larva n.; pl. -ae [L. larva, mask] The preadult stage in some

506Maggenti and Gardnerinvertebrates after hatching from the egg, lacking adultfeatures, usually active and feeding. larval a.larval-pupal apolysis (ARTHRO: Insecta) In Diptera, the interimbefore the cryptocephalic pupa. see pupal-adultapolysis.larval shell (MOLL: Gastropoda) The hard parts of a pelagiclarva before it settles down and undergoes metamorphosis.larval stages The period of growth between molts.larval stem nematogen (MESO: Rhombozoa) In Dicyemida, anearly stage in development.larvarium n. [L. larva, mask; -arium, place of a thing] A nestor case made by a larva as a shelter.larvate see pupa larvatalarviform a. [L. larva, mask; forma, shape] Shaped like alarva.larviparous a. [L. larva, mask; parere, to produce] Producingby bringing forth living larvae; viviparous. see oviparous.larvipositor n. [L. larva, mask; ponare, to place] (ARTHRO: Insecta)A modified ovipositor.larvivorous a. [L. larva, mask; vorare, to devour] Larvae eating.lasiopod n. [Gr. lasios, wooly; pous, foot] (ARTHRO: Crustacea)A cirral appendage of barnacles, with a transverse row ofsetae at each articulation. see acanthopod, ctenopod.lasso n. [L. laqueus, snare, noose] 1. (CNID) Fibrils, thought tobe contractile, extending down the stalk of a cnidoblast securingthe nematocyst. 2. (NEMATA) Circular traps; a threecelledring of predacious fungi that constrict around anematode, penetrating the cuticle and ramifying inside thetissue.lasso cell see coloblastlast whorl (MOLL: Gastropoda) In coiled shells, last-formedcomplete volution of a helicocone.latera pl. of latuslaterad adv. [L. latus, side; ad, toward] Toward the side, directedaway from the midline of the body.

Online Dictionary of Invertebrate Zoology 507lateral a. [L. latus, side] 1. Of or pertaining to the side; situatedat, coming from, or directed towards. 2. (ARTHRO:Crustacea) In Cirripedia, one of a pair of compartmentalplates, typically located between the carinolateral and rostrum;latus or median latus.lateral abdominal gills (ARTHRO: Insecta) In a few genera ofOdonata, filamentous (or true abdominal appendages) oneither side of the 2nd to 7th or 8th abdominal segments.lateral ala (NEMATA) Lateral longitudinal expansions or incisures.lateral apodeme see endopleuritelateral bar (ARTHRO: Crustacea) In Acrothoracica, one of a pairof external chitinous thickenings, extending from the aperturalthickenings medially down each side of the mantlesac.lateral carina (ARTHRO: Crustacea) In Conchostraca, a narrowridge on the side margin of the carapace.lateral cilia (MOLL: Polyplacophora) Cilia on the flat surfaces ofthe leaflets of the ctenidia.lateral comb (ARTHRO: Insecta) In Diptera, lateral spines orscales on the eighth abdominal segment of mosquito larvae.lateral commissures 1. (ANN) Commissural blood vessels. 2.(NEMATA) Dorso- or ventro-lateral nerves connecting gangliaand major dorsal or ventral nerves.lateral cups (ARTHRO: Crustacea) Paired elements of the naupliuseye; absent in malacostracans.lateral denticle (ARTHRO: Crustacea) In Stomatopoda, smallprojection at the base of each lateral tooth on the terminalabdominal segment.lateral facials (ARTHRO: Insecta) In Diptera, one or more bristleson each side of the face below and toward the eye.lateral field see lateral line, lateral ridgelateral filaments (ARTHRO: Insecta) Cerci on the margins ofthe abdomen in some aquatic larvae.lateral frontal organs (ARTHRO: Insecta) In most Apterygota,

508Maggenti and Gardnerseparate capsules containing the median neurosecretorycells on the dorsal side of the brain.lateral gonapophyses (ARTHRO: Insecta) In female Odonata,a pair of chitinous processes of the ovipositor on the 9thabdominal segment.lateral hearts see commissural vesselslateral hinge system (MOLL: Bivalvia) Hinges in some prodissoconchsboth anterior and posterior to the provinculum.lateralia n. [L. latus, side] 1. (ARTHRO: Crustacea) Lateralplates, variable in number, of lepadomorphs and balanomorphs.2. (GNATHO) Lateral paired sensory bristles on thehead.lateral line 1. (ANN: Oligochaeta) In aquatic forms, the lineformed by the nuclei of the fibers of the circular muscles.2. (ARTHRO: Insecta) In eruciform Trichoptera, finelyhaired, longitudinal cuticular fold on each side of the abdomen.see supraspiracular line. 3. (NEMATA) In somenematodes, lateral, longitudinal cuticular incisures beneathwhich the lateral nuclei of the hypodermis are found; lateralfield lines. see lateral ridge.lateral lips 1. (ARTHRO: Chelicerata) In Acari, lateroventralprotuberances anterior to the mouth; joined to the labrumusually, and the labium when present. 2. (NEMATA) Laterallobes of the hexaradiate labial region.lateral longitudinal carina (ARTHRO: Insecta) In ichneumonidHymenoptera, the longitudinal carina of the propodium oneach side laying between the median and pleural carinae.lateral mesentaries (CNID: Anthozoa) In Zoantharia, themesentaries, excluding directive or dorsal and ventralpairs.lateral ocelli see stemmalateral organs 1. (ANN: Polychaeta) Ciliated sensory structureslocated between the notopodium and neuropodium of eachparapodium. see dorsal organ. 2. (NEMATA) The amphids.lateral oviduct (ARTHRO: Insecta) Paired canals of the femalesystem, leading from ovaries, frequently mesodermal, andjoining the common (median) oviduct.

Online Dictionary of Invertebrate Zoology 509lateral penellipse (ARTHRO: Insecta) In lepidopterous larvae,an almost complete circle of crochets, open or incomplete,toward the meson. see penellipse.lateral ridge (NEMATA) The ridge formed by two contiguouslateral lines, when seen in cross-section or with SEM; lateralfield ridges.lateral skeletal projections (BRYO: Stenolaemata) Skeletalstructures in living chambers opposite the feeding organs;including hemisepta, hemiphragms, ring septa, muralspines, and skeletal cystiphragms.lateral teeth (MOLL: Bivalvia) Interlocking teeth, not functioningas a hinge, but serving to prevent valves from slidingupon each other when closed.laterigrade a. [L. latus, side; gradus, step] Walking sideways,as some spiders and crabs.lateris see pygidial fringelaterocranium n. [L. latus, side; LL. cranium, skull] (ARTHRO:Insecta) The region of the head comprised of the genaeand postgenae.laterofrontal a. [L. latus, side; frons, front] Situated on theside but towards the front.lateromarginal expansion (ARTHRO: Insecta) The medianpart of the marginal region of the phallobase of scarabaeoidbeetles, characterized by an expansion of the margininto the lateral membrane.lateropleural area (MOLL: Polyplacophora) The upper portionof the side slopes of an intermediate valve; denotingsculpture of a valve, lacking demarcation between the lateraland pleural areas.lateroproximal marginal region (ARTHRO: Insecta) A lateralmarginal region of the phallobase of scarabaeoid beetles,extending from the articulation with the tectum to wherethe margin and rugula intersect.laterosternite n. [L. latus, side; Gr. sternon, breast; -ites,part] (ARTHRO: Insecta) Lateral plates at the sides of theeusternum in Isoptera, Dermaptera, and Blattaria.laterotergite n. [L. latus, side; tergum, back; -ites, part] (AR-

510Maggenti and GardnerTHRO) A lateral or dorsolateral tergal sclerite.lateroventral a. [L. latus, side; venter, belly] To the side(away from the midline of the body) and below.lateroverted a. [L. latus, side; vertere, to turn] Displaced towardthe side of the body; laterally displaced.laticorn trumpet (ARTHRO: Insecta) In Diptera, a respiratorystructure of mosquito pupae bearing the longest axis transverseto the stem, frequently with a secondary cleft in thepinna opposite the meatal cleft, less wide-mouthed thanthe angusticorn type, but with an elaborate lobe (tragus)on the rim of the pinna. see angusticorn trumpet.laticostate a. [L. latus, broad; costatus, ribbed] Broad-ribbed.latigastric a. [L. latus, broad; Gr. gaster, stomach] (ARTHRO:Chelicerata) Pertaining to those of the subphylum that arebroadly joined between prosoma and opisthosoma. seecauligastric.latirostrate a. [L. latus, broad; rostrum, beak] Having a broadrostrum. see angustirostrate.latrodectism n. [ Latrodectus sp.; L. latro, brigand; Gr. dektes,biter; L. -ism, condition] (ARTHRO: Chelicerata) InArachnida, envenomation of humans by Latrodectus (blackwidow) spiders.latticed a. [Gr. latte, lath] To cross or interlace; cancellated.latus n.; pl. latera [L. latus, side] (ARTHRO) 1. The side of thebody. 2. (ARTHRO: Crustacea) In Cirripedia, any of thecapitular plates except paired scuta and terga and unpairedrostrum, carina, subrostrum and subcarina of certain Lepadomorpha.see carinal, inframedian, lower lateralplates, rostral and upper latus.Laurer's canal (PLATY: Trematoda) In Digenea, a tubular canalextending from the base of the seminal receptacle; sometimesopening dorsally to the exterior; Laurer-Stieda canal.leaflets n.pl. [A.S. dim. leaf] (MOLL: Bivalvia) A double row offlat, triangular, ciliated processes on the ctenidia of Protobranchiathat project into the mantle cavity for clearingparticulate matter from the gills.leberidocytes n.pl. [Gr. leberis, shed skin; kytos, container]

Online Dictionary of Invertebrate Zoology 511(ARTHRO: Chelicerata) In Arachnida, glycogen containingcells that develop from and back to leucocytes duringmolting.lecithin n. [Gr. lekithos, egg yolk; -in, ending for fats, etc.] Avery common, widely dispersed phospholipid, found inmany kinds of cells.lecithotrophic a. [Gr. lekithos, egg yolk; trophe, food] Obtainingnourishment from a large quantity of stored yolk, asin various invertebrates.lecithotrophic development (BRYO: Gymnolaemata) Productionof brooding larvae lacking a digestive tract.lectoallotype n. [Gr. lektos, choose; allos, other; typos, type]A subsequent specimen of the opposite sex of the lectotypechosen from the original material.lectotype n. [Gr. lektos, choose; typos, type] A specimen selectedfrom a syntypic series that, subsequent to the publicationof the original description, is selected and designatedthrough publication to serve as the type.left valve (MOLL: Bivalvia) While holding the bivalve shell withthe hinge up and the apex or umbo pointed away from thepallial sinus toward the holder, the left valve is to the left.lek n. [Sw. lika, to play] (ARTHRO: Insecta) A communal displayarea where males congregate for the purpose of attractingand courting females, and to which females come for mating;sometimes called an arena.lemniscate, lemniscata n. [Gr. lemniskos, ribbon] A clubshapedorgan.lemniscus n.; lemnisci pl. [Gr. lemniskos, ribbon] (ACANTHO)One of a pair of elongate structures attached to the neckregion and extending into the trunk cavity; may act as areservoir for the fluid of the neck region when the proboscisis invaginated.lemnoblast see Schwann celllength n. [A.S. lang, long] (MOLL: Bivalvia) Greatest dimensionby a projection of the shell extremities onto the cardinalaxis.lens n.; pl. lenses [L. lens, lentil] Transparent covering of the

512Maggenti and Gardnereye, serving to focus the rays of light.lentic, lenitic a. [L. lentus, slow, viscous] Living in still water;applied to organisms that inhabit swamps, ponds or lakes.see lotic.lenticular a. [L. lenticularis, lentil-shaped] Having the form ofa biconvex lens.lentigerous a. [L. lens, lentil; gerere, to bear] Having a lens.lepidopterism a. [Gr. lepis, scale; pteron, wing; -ismos, denotingcondition] (ARTHRO: Insecta) Any pathological conditioncaused by the Lepidoptera. see erucism, paraerucism,cryptotoxic, phanerotoxic, metaerucism, pseudoerucism.lepocyte n. [Gr. lepis, scale; kytos, container] A nucleated cellwith a cell wall. see gymnocyte.leprous a. [L. lepra, scaly] Having loose irregular scales; scalelike;covered with scales.leptiform see campodeiform larvaleptoblast n. [Gr. leptos, thin; blastos, bud] (BRYO) A floatoblastthat quickly germinates after release from the parentcolony.leptoderan a. [Gr. leptos, thin; deras, hide, leather] (NEMATA)With caudal alae restricted to two sides of the body and notsurrounding or meeting posterior to the tail tip. see peloderan.leptonema n. [Gr. leptos, thin; nema, thread] A chromatinthread or chromosome at leptotene stage of prophase I inmeiosis; sometimes used as a synonym of leptotene stage.see leptotene.leptopelagic a. [Gr. leptos, thin; pelagos, sea] Extremely fineliving or non-living material floating in sea water.leptophragmata n.pl. [Gr. leptos, thin; phragma, hedge,fence] (ARTHRO: Insecta) In cryptonephridial forms, specializedcells at points of attachment of Malpighian tubulesto the rectal peritrophic membranes.leptostraterate a. [Gr. leptos, thin; stratos, covered] (ECHI-NOD: Asteroidea) Having the ambulacral plates narrow andcrowded together.

Online Dictionary of Invertebrate Zoology 513leptotene n. [Gr. leptos, thin; tainia, ribbon] Early stage ofprophase I in meiosis with chromosomes appearing as finethreads, although made up of two chromatids which arenot apparent until the pachytene stage. see leptonema,pachynema.leptotrombicula n. [Gr. leptos, thin; It. tromba, trumpet](ARTHRO: Chelicerata) The slender larva of the thrombiculidmite that transmits Tsutsugamushi disease, also known asJapanese flood fever or scrub typhus.leptus n. [Gr. leptos, small] (ARTHRO: Chelicerata) In Acari,larval form of mites with 6 legs.lerp n. [Native name, lit., sweet] (ARTHRO: Insecta) In australianjumping plantlice, a scale or test on leaves or smalltwigs under which sedentary nymphs of Spondyliaspinaeshelter.lesion n. [L. laedere, to injure] In plants or animals, a woundor injury causing circumscribed pathological change in tissues,including a change or loss of function.lestobiosis n. [Gr. lestes, robber; biosis, manner of life] (AR-THRO: Insecta) In Hymenoptera, a type of symbiosis inwhich a group of 'thief ants' of small size nest in or nearthe chambers of termites and larger ants, eating theirstored food, larvae, and pupae unnoticed by their benefactors.see cleptobiosis.lethal factor see balanced lethalslethargy n.; pl. -gies [Gr. lethargios, drowsy] A state of inaction.letisimulation n. [L. lethum, death; similis, like] Feigningdeath; thanatosis.leucine n. [Gr. leukos, white] An amino acid, x-amino isocaproicacid found in tissues of various invertebrates.leucoblast n. [Gr. leukos, white; blastos, bud] The developingleucocyte; a precursor of a leucocyte; a proleucocyte; aprohemocyte; leukoblast.leucocyte see plasmatocyteleucon see leuconoid grade or typeleuconoid grade or type (PORIF) A grade of construction of

514Maggenti and Gardnersponges in which the choanocyte chambers are small, anddistributed through the interior tissues. see asconoidgrade, synconoid grade.leucopterine see pterine (pteridine) pigmentslevation n. [L. levare, to raise] The raising of the leg or a partof the leg; part of protraction.levator n. [L. levare, to raise] Any muscle serving to raise anorgan or part.levels of integration Levels of complexity in structures, patterns,or associations when new properties emerge thatcould not have been predicted from the properties of thecomponent parts.levigate a. [L. levigare, to make smooth] Smooth surfaced;polished.Leydig cells 1. Secretory cells of various glands. 2. (ARTHRO:Insecta) In Hymenoptera, produces an attractant pheronomein Apis; mandibular gland and Koshevnikov gland.3. (MOLL: Gastropoda) In Prosobranchia, cells in the mantle,foot and around the digestive tract.life cycle The complete series of successive forms throughwhich any particular kind of organism passes in the courseof its development to maturity.ligament n. [L. ligare, to bind] 1. A band or sheet of tough,fibrous tissue between parts or segments. 2. (BRYO) Musclefibers embedded in collagen with a tubular peritoneal envelope.3. (MOLL: Bivalvia) A horny, elastic band locatedabove the hinge, causing the valves to open when the adductormuscles relax.ligamental area (MOLL: Bivalvia) An area between the umboand ligament that shows the growth track of the ligament.ligament fulcrum see nymphaligament groove (MOLL: Bivalvia) A narrow depression in thecardinal area for attachment of ligament fibers.ligament pit (MOLL: Bivalvia) A broad depression in the cardinalarea for ligament attachment.ligament sac 1. (ACANTHO) Encloses the genital apparatus ofmale and female; separates immature eggs from mature in

Online Dictionary of Invertebrate Zoology 515females. 2. (MOLL) The sac housing the ligaments attachedto the base of the teeth.ligament strand (ACANTHO) The nucleated, syncytial band oftissue lying between the ligament sacs or along the ventralface of the single ligament sac.ligament suture Elongate space behind the umbones, apparentafter the ligament is gone.ligneous a. [L. lignum, wood] Of or like wood; woody.lignicolous a. [L. lignum, wood; cola, inhabitant] Living inwood.lignivorous a. [L. lignum, wood; vorare, to devour] Eatingwood or woody tissue.ligula n.; pl. -lae [L. ligula, little tongue] 1. (ANN: Polychaeta)Lobe of the parapodium. 2. (ARTHRO: Insecta) a. The terminallobe or lobes of the labium; the glossae and paraglossaecollectively. b. In adult dipteran mosquitoes, thesharp-pointed lobe on the midline of the labium betweenthe labella; ligular lobe. c. In male Odonata, the stronglycurved process over the stem of the prophallus. 3. (BRYO)A calcareous projection from the cross-bar of an avicularium.4. (MOLL: Cephalopoda) In octopods, a specializedterminal area of the hectocotylus.ligular lobe see ligulaligulate a. [L. ligula, little tongue] Strap shaped.ligule n. [L. ligula, little tongue] (ANN: Polychaeta) A parapodiallobe covering the anus dorsally.limacel n.; pl. -le [F., fr. L. limax, slug] (MOLL: Gastropoda)The concealed vestigial shell of slugs.limaciform a. [L. limax, slug; forma, shape] Shaped like aslug.limb n. [A.S. lim, limb] The leg or wing of an animal.limb n. [L. limbus, an edge] The border, rim or edge.limbate a. [L. limbus, an edge] 1. Having a margin or limb ofanother color. 2. (ANN) Term used to describe seta with aflattened margin to the blade.limbus n. [L. limbus, an edge] 1. (ARTHRO: Chelicerata) In

516Maggenti and GardnerAcari, the border of an element of the exoskeleton, such asa tectum. 2. (BRACHIO) The flattened inner margin of theinarticulate valve.limicolous a. [L. limus, mud; colus, dwelling in] Living in mudor shore dwelling.liminal a. [L. limen, threshold] Pertaining to threshold. seesubliminal.limited chromosome May be eliminated or diminished incleavage, thus producing clones of differing functionalkaryotypes.limiting factor Essential factor in the environment that is inshort supply; thus limiting growth, some life process orpopulation size.limivorous a. [L. limus, mud; vorare, to devour] (ANN) Mudeating to obtain the organic matter.limnic, limnetic a. [Gr. limne, marsh, lake, pool] 1. Living instanding fresh water. 2. Inhabiting the pelagic zone in abody of fresh water; limnicolous.limnium n. [Gr. limne, marsh, lake, pool] A lake community.limnobios n. [Gr. limne, marsh, lake, pool; bios, life] All life infresh water.limnology n. [Gr. limne, pond; logos, discourse] The study offresh waters, in physical, chemical, meteorological andbiological conditions.limophagous see limivorouslimpid a. [L. limpidus, clear] Characterized by being clear ortransparent.linea n.; pl. lineae [L. linea, line] Linear markings or structures.linear-ensate Somewhere between linear and ensiform inshape.lineate a. [L. linea, line] Marked longitudinally with depressedparallel lines or striae.lineola n. [L. dim. linea, line] Marked with minute lines.lineolate a.lingua n. [L. lingua, tongue] (ARTHRO: Insecta) The tongue;

Online Dictionary of Invertebrate Zoology 517maxillary appendages; the hypopharynx, or organ of;glossa.lingual a. [L. lingua, tongue] Of or pertaining to the tongue.lingual ribbon [L. lingua, tongue] (MOLL) The radula or odontophore.lingual sclerites (ARTHRO: Insecta) In Psocidae, two ovalsclerites, each connected to a median sitophore sclerite bya fine filament.linguiform a. [L. lingua, tongue; forma, shape] Tongueshaped;lingulate.lingula n. [L. dim. lingua, tongue] (ARTHRO: Insecta) In Aleyrodidae,a tongue or strap-shaped organ in the vasiformorifice with the anal opening at the base where honeydewaccumulates.lingulid larvae (BRACHIO) Free swimming bivalve larvae of theorder Lingula with elongate valves. see discinid.linkage n. [ME. linke] The association in heredity of genes locatedin the same chromosome; the more tightly they arelinked, the less likely they will be separated by crossingover.linkage group A group of gene loci placed in a linear order ona chromosome.linkage map A chromosome map.linker gene A small piece of synthetic DNA with a restrictionsite used to splice genes together.linneon n. [Linne, Swedish naturalist] A taxon distinguished onmorphological grounds, generally applies to one of thelarge species described by early naturalists.liocyte see chromophilelip n. [A.S. lippa, lip] Any liplike part or structure.lipase n. [Gr. lipos, fat; -ase, enzyme] An enzyme that hydrolysesfats.lip cap (NEMATA) A disc-like, anterior-most cuticular annulation,circumoral and usually thicker than adjacent head annuli.lip gland (SIPUN) A glandular organ with a ciliated groove run-

518Maggenti and Gardnerning from pore to tip of lip.lipids n.pl. [Gr. lipos, fat] Organic compounds soluble in variousorganic liquids and insoluable in water; including carbonand hydrogen with a small proportion of oxygen and/orother elements, i.e., fats, phospholipids, sterols, etc.lipin n. [Gr. lipos, fat] Complex lipids such as phospholipids,glycolipids, and cerebrocides.liplets [A.S. dim. lippa, lip] (NEMATA) Small, reduced lips restrictedto the apex of the head; pseudolips.Lipocephala see Bivalvia Class, Molluscalipochromes n. [Gr. lipos, fat; chroma, color] Fat soluble pigments.lipogastry n. [Gr. leipo, to be lacking; gaster, stomach] Temporaryobliteration of gastral cavity as occurs in spongesand some other organisms.lipoid a. [Gr. lipos, fat; eidos, like] Of fatty nature.lipoid membrane see fertilization membranelipolysis n. [Gr. lipos, fat; lysis, loosen] Decomposition of fatby lipase. lipolytic a.lipomerism n. [Gr. leipo, to be lacking; meros, part; ismos,denoting condition] Coalescence or suppression of segmentation.lipomicrons n. [Gr. lipos, fat; mikros, little] (ARTHRO: Insecta)Minute fat particles found in the blood.lipopalingenesis n. [Gr. leipo, to be lacking; palin, anew;genesis, beginning] The omission of a stage or series ofstages in phylogeny.lipopolysaccharide n. [Gr. lipos, fat; polys, many; sakcharon,sugar] Molecule with a lipid attached to a polysaccharide.lipoprotein n. [Gr. lipos, fat; proteios, primary] Molecule witha lipid joined to a protein.lipostomous a. [Gr. leipo, to be lacking; stoma, mouth] (PO-RIF) Having no apertures visible to the naked eye.lipotrophic n. [Gr. lipos, fat; trephein, to eat] A compoundwith an affinity for lipids; influencing fat metabolism.

Online Dictionary of Invertebrate Zoology 519lip ring (NEMATA) A ring at or near the oral aperture formed byfused, separate or subdivided cheilorhabdions.lira n., pl. lirae [L. lira, ridge] 1. Fine grooves or thread-likesculpture or ridge. 2. (MOLL: Gastropoda) Fine linear elevationon a shell surface or within outer lip. lirate a.list n. [A.S. liste, ridge] (ARTHRO: Crustacea) In Ostracoda, aridge inside the selvage on the sealing margin of the shell.listrium n. [Gr. listrion, small shovel] (BRACHIO:Inarticulata) Insome Discinidae, a plate closing the anterior end of thepedicle opening.lithistid n. [Gr. lithos, stone] (PORIF) A reticulated skeleton.lithite see statolithlithocyst see lithocytelithocyte n. [Gr. lithos, stone; kytos, container] Cell within astatocyst that contains the movable concretion or statolith;lithocyst.lithodesma n. [Gr. lithos, stone; desma, bond] (MOLL: Bivalvia)1. A calcareous reinforcement of the internal ligament.2. A small shelly plate; ossiculum.lithodomous a. [Gr. lithos, stone; domos, house] Living in orburrowing in rock.lithophagous a. [Gr. lithos, stone; phagein, to eat] Burrowingin rock.lithosere n. [Gr. lithos, stone; serere, to join] A sere originatingon exposed rock surfaces. see xerosere, hydrosere.lithostyle see rhopaliumlithotomous a. [Gr. lithos, stone; tomos, cut] Stone boring.littoral, litoral a. [L. litoralis, of the seashore] Of or pertainingto a shore, coastline, or region between high and low watermarks.lituate a. [L. lituus, augur's staff] Being forked with prongsoutwardly curving.litura, liturate An obscure color spot with pale margins; appearingdaubed or blotted.liver-pancreas Digestive gland in crustaceans and other in-

520Maggenti and Gardnervertebrates. see hepatopancreas.livid a. [L. lividus, to be black and blue] Pale purplish-brown;lead-colored; ashy-pale.living chamber (BRYO: Stenolaemata) Outer part of the zooidbody cavity that contains the major organs.lobar a. [Gr. lobos, lobe] Of or pertaining to a lobe or lobes.lobate a. [Gr. lobos, lobe] Provided with lobes; lobed.lobe n. [Gr. lobos, lobe] A generally rounded part or projectionof a part or organ.lobiform a. [Gr. lobos, lobe; L. forma, shape] Shaped like alobe or rounded process.lobopods n.pl. [Gr. lobos, lobe; pous, foot] (ONYCHO) Annulate,sacklike legs with internal musculature.lobula n. [Gr. dim. lobos, lobe] (ARTHRO: Insecta) The proximalsynaptic area in the optic lobes. see lobular complex.lobular complex (ARTHRO: Insecta) Lobula and lobular plate ofthe interior synaptic region of the optic lobes. see medullainterna, opticon.lobulate a. [Gr. dim. lobos, lobe] Divided into small lobes orlobules.lobulate glands (ARTHRO: Insecta) In Campodea, glands situatedin the head and the anterior part of the prothoraxcomposed of cells arranged around a system of ductsopening into the cephalic hemocoel; possibly functioning insecreting some form of growth hormone.lobule n. [F. dim. lobos, lobe] A small lobe.lobulus n.; pl. -li [F. dim. lobos, lobe] A lobe or lobule. seealula.local population see populationloci p. of locuslociation n. [L. locus, place] Local variations in the abundanceor proportion of dominant species in an association.lock and key theory Morphological theory of antibody-antigen,enzyme-substrate, and insect genitalia interactions;fitting exactly for the interactions to take place.

Online Dictionary of Invertebrate Zoology 521loco citato Place cited; abbr., l.c. and loc.cit.locomotor rods see ambulatory setae, adhesion tubeslocotype see topotypelocular a. [L. loculus, cell] Having or containing small cavitiesor chambers.loculus n.; pl. loculi [L. loculus, cell] 1. A cavity, compartmentor chamber. 2. (CNID) Cavities between septa at the baseof some polyps. 3. (PLATY: Turbellaria) Shallow, sucker-likedepressions in the adhesive organ.locus n.; pl. -ci [L. locus, place] The position of a gene in achromosome; may be occupied by any gene of a particularallelic series.lodix n. [L. lodix, blanket] (ARTHRO: Insecta) The ventral plateof the seventh (7th) abdominal segment that covers thegenital plate in Lepidoptera.logarithmic phase Geometric or exponential growth section ofthe logistic curve characteristic of unrestrained populationgrowth.logistic curve Growth of a population with time as describedby a sigmoid curve; begins slowly, increases rapidly, andgrows slowly or not at all as the population fills availablesites.logotype n. [Gr. logos, word; typos, type] A type species of agenus by subsequent designation, not originally describedas such.longicorn a. [L. longus, long; cornu, horn] Having long antennaeas in certain beetles.longipennate a. [L. longus, long; penna, wing] Having longwings.longirostral, longirostrate a. [L. longus, long; rostrum,beak] Having a long beak or rostrum.longitudinal a. [L. longus, long] 1. Lengthwise of the body oran appendage. 2. The length of a shell or direction of thelongest diameter.longitudinal canal see longitudinal tubelongitudinal muscle 1. (ECHI) Layer of longitudinal muscle of

522Maggenti and Gardnerthe body wall sometimes thickened into bundles. 2.(NEMATA) The somatic muscles of nematodes. 3. (SIPUN)Innermost layers of muscle that make up the body wall ofthe trunk.longitudinal rugae (NEMATA) The cuticular fold projecting anteriorlyfrom the stoma of diplogasterids supporting the circumoralmembrane.longitudinal section Section along or parallel to the longitudinalaxis.longitudinal septum (ARTHRO: Crustacea) An inner and outerlaminae partition of the compartmental plate in some balanomorphbarnacles, resulting in longitudinal tubes; parietaltubes.longitudinal tube (ARTHRO: Crustacea) In some Balanamorpha,a canal between longitudinal septa and inner andouter lamina in the compartmental plate; longitudinal canal;parietal tube; parietal pore.loop n. [ME. loupe, loop] (BRACHIO) A support for the lophophorecomposed of secondary shell and variously placed,usually ribbon-like with or without supporting septum fromfloor of the brachial valve.looper n. [Eng. looper, to crawl or slink] (ARTHRO: Insecta) 1.Caterpillars with two or more anterior prolegs reduced ormissing. 2. Crawl in a looping manner like the Geometridae(inch worm).lophobranchiate a. [Gr. lophos, crest; branchia, gills] Havingtufted gills.lophocaltrops n. [Gr. lophos, crest; A.S. coltraeppe, type ofthistle] (PORIF) A sponge spicule with branched or crestedrays.lophocytes n. [Gr. lophos, crest; kytos, container] (PORIF)Mobile collagen-secreting cells that trail attached collagenfibrils.lophophoral fold (BRYO) Part of the vesicle of the polypidefrom which the lophophore is formed.lophophore n. [Gr. lophos, crest; pherein, to carry] A crown oftentacles, found in Bryozoa, Brachiopoda and Phoronida.

Online Dictionary of Invertebrate Zoology 523lophophore neck (BRYO: Gymnolaemata) A long movable cylindricalstructure formed by the everted tentacle sheaththat allows extension of the tentacles beyond the orifice.lora pl. lorumloral arm (ARTHRO: Insecta) A laterally extending process fromthe middle of each suspensorium of the hypopharynx ofcertain primitive pterygote insects.lore see lorumlorica n.; pl. -ae [L. lorica, corselet] A hard shell or case onRotifera, Loricifera and Priapulida larvae. see cuirass.loricate a. [L. lorica, corselet] To cover with a protective coatingor crust.loricifera n. [L. lorica, corselet; fero, bear] A phylum of microscopicorganisms with a flexible, retractable tube mouth, agirdle of platelets and a crown of clawlike and club-shapedspines.lorum n.; pl. lora [L. lorum, strap] 1. (ARTHRO: Chelicerata) InArachnida, a protective dorsal plate on the pedicle. 2. (AR-THRO: Insecta) a. The cheek. b. A sclerite on both sides ofthe head of Homoptera and certain Hemiptera, and Hymenoptera.c. In Apis, the submentum. d. In Homoptera, anarrow lateral sclerite between the clypeus and the frontextending to the genae, that is an upward extension of thehypopharynx.lotic a. [L. lotus, washed] Living in rapidly flowing waters; appliedto organisms that inhabit these waters. see lentic.lower a. [ON. lagr, low] (MOLL) The abapical part of the shell.lower latus plate (ARTHRO: Crustacea) In Cirripedia, a valvenear the basis of the shell.loxometaneme n. [Gr. loxos, oblique; meta, behind; nema,thread] (NEMATA) Metaneme that is at an angle of 10-30 oto the longitudinal body line; found running diagonallyacross the lateral hypodermal cords.lozenge n. [OF. losenge, a square window pane] A parallelogramwith four equal sides having two acute and two obtuseangles; lozenge-shaped; a rhombus form; diamondshaped.

524Maggenti and Gardnerlucid a. [L. lucidus, clear] Luminous; translucent; pellucid;shining.luciferase n. [L. lux, light; ferre, to bring; -ase, enzyme] Anenzyme of luminescent organisms involved in the oxidationof luciferin and the production of light.luciferin n. [L. lux, light; ferre, to bring] A substance found inluminescent organisms that, in the presence of the enzymeluciferase, oxidizes and produces light.lucifugous a. [L. lux, light; fugere, to flee] Avoiding the light,or living in concealment. see photophobic, lucipetal.lucinoid teeth (MOLL: Bivalvia) Having 2 cardinal teeth in eachvalve; left valve anterior tooth is medial below the beak.lucipetal a. [L. lux, light; petere, to seek] Requiring light. seelucifugous.lumbar ganglia (NEMATA) Large paired ganglia in the anal regionwhich receive the lateral nerves and from which thelaterocaudal nerves pass posteriad in the tail.lumbriciform a. [L. lumbricus, earthworm; forma, shape] Likean earthworm in appearance; lumbricoid. see vermiform.lumbricine a. [L. lumbricus, earthworm] (ANN: Oligochaeta)Having 4 pairs of setae per segment as in earthworms ofthe family Lumbricidae. see perichaetine.lumen n. [L. lumen, light] Space within any tubular organ orvessel.lumenate a. [L. lumen, light] Having a lumen.luminescent a. [L. lumen, light; escens, beginning of] Producinglight. see bioluminescence.luminescent organ 1. Specialized light emitting organs ofvarious invertebrates. see bioluminescence. 2. (MOLL:Cephalopoda) Open ectodermal pockets filled with luminescentbacteria.lunate a. [L. luna, moon] Semicircular; falcate; crescentshaped.lunellarium see clausiliumlung books see book lunglunula n.; pl. lunulae [L. dim. luna, moon] 1. A small lunate

Online Dictionary of Invertebrate Zoology 525mark or crescent-shaped object. 2. (MOLL: Gastropoda) Acrescentic ridge on the selenizone, concave toward aperture.lunular a.lunule n. [L. dim. luna, moon] 1. A crescent-shaped part ormarking. 2. (ARTHRO: Crustacea) In Copepoda, small,sucker-like adhesion disc on the anterior margin. 3. (ECHI-NOD: Echinoidea) One of several perforations in the test ofsome sand dollars that may serve for passage of sand andwater while burrowing. 4. (MOLL: Bivalvia) Cordate shapeddepression anterior to the beaks.lurid a. [L. luridus, pale yellow] A dirty yellowish color; dismal;dingy.luteous a. [L. luteus, golden yellow] Yellow in hue, especiallyan orange or reddish yellow.lycophore n. [Gr. lykos, hook; pherein, to carry] (PLATY:Cestoda) Ten-hooked first larval stage of a tapeworm; adecacanth.lygophil n. [Gr. lygaios, gloomy; philos, fond of] Shade ordarkness dwellers.lymph gland 1. (ANN: Oligochaeta) Organs on the anteriorfaces of septa associated with the dorsal blood vessel, inthe intestinal regions of some earthworms, possibly functioningin production of phagocytes. 2. (ARTHRO: Insecta)Organs that release free mesodermal cells into the hemolymphnear pupation of Drosophila larvae.lymphocyte see plasmatocytelyocytosis n. [Gr. lyein, to loose; kytos, hollow] The process ofhistolysis by extracellular digestion.Lyonnet's glands (ARTHRO: Insecta) In Lepidoptera, pairedaccessory glands opening by a separate duct into the silkgland on its own side; Filippi's glands.lyra n. [L. lyra, lyre] (ARTHRO: Chelicerata) Stridulating organsof arachnids found on various places of the male body;they consist of a tooth (or teeth) that rubs against a seriesof ridges.lyrate a. [L. lyra, lyre] Lyre-shaped; spatulate and oblong withsmall lobes toward the base.

526Maggenti and Gardnerlyre n. [L. lyra, lyre] (ARTHRO: Insecta) In caterpillars, the borderor upper wall of the spinning tube.lyre-shaped Like a string musical instrument with two curvedarms and strings attached to a yolk between the curvedarms.lyrifissure n. [L. lyra, lyre; fissura, crack] (ARTHRO: Chelicerata)Small fissures or pores in the cuticle of the body orappendages; sometimes with an internal channel; thoughtto be stretch receptors.lyriform organs (ARTHRO: Chelicerata) In arachnids, a lyreshapedorgan on the joints of the legs and other appendages,sterna of the cephalothorax and abdomen and on thesting of Scorpiones; thought to be chemoreceptors; alsocalled slit sense organs.lyrule n. [L. dim. lyra, lyre] (BRYO) A median tooth on theproximal edge of the orifice.lyse a. [Gr. lysis, loosen] To undergo lysis.lysigenoma n. [Gr. lysis, loosen; gene, to produce; -oma, tumor](NEMATA) The name given a group of giant cells orsyncytia denoting their origin from lysis or dissolution ofwalls of normal cells, forming a tumor-like structure.lysin n. [Gr. lysis, loosen] Any of a number of substances capableof dissolving cells, bacteria, or tissues.lysis n. [Gr. lysis, loosen] 1. The decomposition of a substance.2. The digestion of cells or tissues by enzymatic action.lyssacine a. [Gr. lysis, loosen; akis, point] (PORIF: Hexactinellida)Skeletal framework formed by interlacing of the elongaterays of hexactines producing loose networks with irregularmeshes in siliceous sponges; may be considered anearlier stage of the dictyonine framework.lytic a. [Gr. lysis, loosen] Pertaining to lysis or to a lysin.

Mmacerate v. [L. macerare, to soften] To waste away; to softenor wear away.machopolyp, machozooid see dactylozooidmacraner n. [Gr. makros, large; aner, male] (ARTHRO: Insecta)A male ant of unusually large form.macrergate n. [Gr. makros, large; ergate, worker] (ARTHRO:Insecta) In Formicidae, an unusually large worker.macrobiota n. [Gr. makros, large; bios, life] Larger organismsin the soil, such as insects and earthworms. see mesobiota.macrocephalic female (ARTHRO: Insecta) In Hymenoptera, alarge female of Halictidae, that possesses a disproportionatelylarge head, usually the egg layers of the colony.macrocercous cercaria (PLATY: Trematoda) Cystophoroustype cercaria with a long, simple, cylindrical tail.macrochaetae n.pl. [Gr. makros, large; chaite, hair] Largebristles. see chaetotaxy.macrocilia n.pl.; sing. -ium [Gr. makros, large; L. cilium,eyelash] (CTENO) In Beroida, 2,500-3,500 giant ciliaryshafts interconnected and bound together on the mobilelips that function in food gathering.macrocnemes n.pl. [Gr. makros, large; kneme, lower leg](CNID: Anthozoa) In Actinaria, complete and filamentedmesenteries in the first one or two cycles of simple tentacles;maybe fertile or sterile and possess acontia andstrong retractors. see microcnemes.macrocyte see plasmatocytemacroesthetes see megalaesthetesmacroevolution n. [Gr. makros, large; L. evolvere, to unroll]Evolutionary processes that extend through geologic eras;large scale evolution of new species and genera due tomutations that result in marked changes in chromosomal

528Maggenti and Gardnerpatterns and reaction systems. see microevolution.macrofauna n. [Gr. makros, large; L. Faunus, diety of herdsand fields] 1. Widely distributed; from a macrohabitat. 2.Animals measured in centimeters rather than microscopicunits.macrogamete n. [Gr. makros, large; gamete, wife] A large,quiescent, female anisogamete. see microgamete.macrogametocyte n. [Gr. makros, large; gamein, to marry;kytos, container] The infected human red blood cell thatcontains the female form of the malarial parasite whichupon transfer to the Culicidae becomes a macrogamete.macrogamy see hologamymacrogenesis n. [Gr. makros, large; genesis, origin] The suddenorigin of new species by saltation.macrogyne n. [Gr. makros, large; gyne, woman] (ARTHRO: Insecta)In Formicidae, a female or queen of unusually largestature.macroic see meganephridiamacrolecithal a. [Gr. makros, large; lekethos, egg yolk] Witha large amount of yolk. see microlecithal.macromere n. [Gr. makros, large; meros, part] A distinctlylarge cell resulting from unequal cleavages during earlyembryology.macromesentery n. [Gr. makros, large; mesos, middle; enteron,gut] (CNID: Anthozoa) One of the larger completemesenteries.macromitosome n. [Gr. makros, large; mitos, thread; soma,body] (ARTHRO: Insecta) The paranucleus as seen in Lepidoptera.macromolecule n. [Gr. makros, large; L. moles, mass] Verylarge molecules such as protein, cellulose, starch, etc.macromutation n. [Gr. makros, large; mutare, to change]Theory of instantaneous evolution of new taxa by a mutationthat establishes reproductive isolation at once.macronotal a. [Gr. makros, large; notos, back] (ARTHRO: Insecta)Having a large thorax, as a queen ant.

Online Dictionary of Invertebrate Zoology 529macronucleocyte see prohemocytemacrophage n. [Gr. makros, large; phagein, to eat] A largephagocytic cell of the body.macrophagous a. [Gr. makros, large; phagein, to eat] Feedingon large objects. see microphagous.macrophthalmic a. [Gr. makros, large; ophthalmos, eye]Having large eyes; having eyes larger than normal.macroplankton n. [Gr. makros, large; planktos, wandering]Large organisms such as jellyfish that drift with the currents.macropore see megaloporemacropseudogyne see pseudogynemacropterous a. [Gr. makros, large; pteron, wing] (ARTHRO:Insecta) Having a long or large wing. see brachypterous.macrosclere see megascleremacroscopic, macroscopical a. [Gr. makros, large; skopein,to view] Capable of being studied with the unaided eye;megascopic. see microscopic.macroseptum n. [Gr. makros, large; L. septum, partition] 1.(CNID: Anthozoa) The variously functioning primary septum.2. (NEMER) In asexual reproduction, a partition acrossthe body marking the plane of subsequent fragmentation.macrosiphon n. [Gr. makros, large; siphon, tube] (MOLL:Cephalopoda) Internal siphon of certain cuttlefishes, and alloctopuses.macrosymbiont n. [Gr. makros, large; symbios, living together]The larger of two symbiotic organisms.macrotaxonomy n. [Gr. makros, large; taxis, arrangement]The classification of higher taxa.macrotrichia n.pl.; sing. -ium [Gr. makros, large; thrix, hair]1. The larger surface hairs. 2. (ARTHRO: Insecta) The largehairs on the wing membrane.macrotype n. [Gr. makros, large; typos, type] (CNID: Anthozoa)Modified arrangement of mesenteries consistingmainly of macromesenteries. see microtype.macrurous a. [Gr. makros, large; oura, tail] Long-tailed.

530Maggenti and Gardnermacula n.; pl. maculae [L. macula, spot] 1. A colored spot ofrather large size. 2. A spot level with surrounding surface.3. (BRYO: Stenolaemata) Prominences, and less commonlyflat or depressed areas on colony surfaces regularly spacedamong feeding zooids caused by clusters of a few polymorphs,and/or extrazooidal skeleton. see monticule. 4.(MOLL: Cephalopoda) An oval spot on the wall of a statocystto which a calcareous statolith is attached; gives informationon position relative to gravity.maculate a. [L. macula, spot] Splashed or spotted; blotched.madrepore n. [L. mater, mother; Gr. poros, friable stone](CNID) A stony, branched, reef building coral of the orderMadreporia.madreporic plate (ECHINOD: Asteroidea) An enlarged interradialplate on the disc, that connects the water vascularsystem to the sea.madreporite n. [L. mater, mother; porus, pore] (ECHINOD) Anoral or aboral perforated plate of the water-vascular systemconnecting with the stone canal; sieve plate.main bud (BRYO: phylactolaemata) The largest of three budprimordia which occurs on every mature zooid, and is thefirst to form a new polypide.major gene Controls production of qualitative phenotypic effectsin contrast to its modifiers.major worker (ARTHRO: Insecta) The largest worker subcastein social insects; in Formicidae, usually specialized for defenseand referred to as a soldier. see media worker, minorworker.mala n.; pl. malae [L. mala, cheek, jaw] 1. A lobe; ridge orgrinding surface. 2. (ARTHRO) a. Part of the maxilla of certaininsects. b. Mandible of some myriapods.malacoid a. [Gr. malakos, soft] Soft textured.malacology n. [Gr. malakos, soft; logos, discourse] Thebranch of zoology dealing with mollusks, the animal insidethe shell.malacophilous a. [Gr. malakos, soft; philios, loving] (MOLL:Gastropoda) Being pollinated by the action of gastropods.

Online Dictionary of Invertebrate Zoology 531malapophysis n.; pl. -ses [L. mala, cheek, jaw; Gr. apophysis,projection] (ARTHRO: Chelicerata) In Acari, the pairedanterior region of the infracapitulum.malar a. [L. mala, cheek] Of or about the cheek region.malar cavity (ARTHRO: Chelicerata) In Acari, interior of themalapophysis that connects to the pharynx.male n. [L. mas, a man] An individual that produces spermcells but not egg cells; designated by .male-cell receptacle (ARTHRO: Crustacea) In Rhizocephala, apocket or pair of pockets within the mantle cavity of thefemale where cells of male cyprid undergo spermatogenesis.male ducts, male gonoducts see sperm ductsmale funnel (ANN: Oligochaeta) A funnel or rosette-shapedenlargement of the ental end of the sperm duct for passageof sperm through the central aperture into lumen of theduct on their way to the exterior.malella n. [L. dim. mala, jaw] (ARTHRO: Symphyla) The distaltoothed process on the outer stipes of the deutomala ofsome myriapods.male tube (ECHI) A sexually maturing area in which developingmales are housed for one to two week inside the female.malleate mastax (ROTIF) Chewing apparatus; rami untoothedand unci are curved plates with prong type teeth.malleations n.pl. [L. dim. malleus, hammer] A hammered appearance.malleolus n.; pl. -li [L. dim. malleus, hammer] 1. (ARTHRO:Chelicerata) In Solpugida, 3 to 5 innervated appendages onthe coxae and trochanter of the fourth leg; function uncertain;racket-organs. 2. (ARTHRO: Insecta) see haltere.malleoramate mastax (ROTIF: Monogononta) Chewing apparatus,variant of the ramate type of mastax occurring in theorder Flosculariaceae.malleus n.; pl. malli [L. malleus, hammer] (ROTIF) Unci andmanubria of the mastax, collectively.Malpighian tubules (ARTHRO) Long, thin excretory tubules

532Maggenti and Gardnerextending into the body cavity from the posterior region ofthe gut in insects, arachnids and myriapods.maltha see mesogloeamamelon n. [F. mamelon, protuberance] 1. (ECHINOD: Echinoidea)Terminal knob on the boss that articulates with thespine on the test. 2. (NEMATA: Secernentea) Two or threeventral, serrated projections on the ventral surface of themale of the genus Syphacia; function unknown.mammillate a. [L. mamilla, small breast] Having roundedprotuberances or wart-like projections; mammiform;mammose.manca n. [L. mancus, imperfect] (ARTHRO: Crustacea) In Peracarida,a juvenile or postlarva that lack the last thoracopodwhen released from the marsupium.manchette n. [F. manchette, cuff] (NEMATA) Line of demarcationbetween the cheilostome and esophastome; nema'scollar; sleeve.mancoid stage (ARTHRO: Crustacea) Postlarval stage in Leptostraca,with rudimentary 4th pleopod.mandible n. [L. mandibula, jaw] 1. A jaw. 2. (ANN: Polychaeta)The ventral chitinous plates or rods, maybe dentate,against which the maxilla work. 3. (ARTHRO: Crustacea)One of the third pair of cephalic appendages. 4. (ARTHRO:Diplopoda) The first pair of jaws, consisting of cardo, stipesand gnathal lobe. 5. (ARTHRO: Insecta) One of the variouslymodified anterior pair of paired mouthpart structures. 6.(BRYO) A modified orificial wall of the avicularium. see operculum.mandibular fossa (ARTHRO: Insecta) The dorsal articulation ofthe mandible.mandibular gland (ARTHRO: Insecta) A sac-like reservoir usuallypaired, and partially or completely lined by secretorycells, opening in the mesal junction of the mandible withthe head; functioning as alarm pheromone, fungistaticagent, aggregation pheromone, sex pheromone, territorydefending secretion, location of food and/or the 'burning'secretion of the 'fire bees'; in larval Lepidoptera, large andsecrete saliva (with the normal salivary glands specialized

Online Dictionary of Invertebrate Zoology 533for silk production).mandibular palp 1. (ARTHRO: Crustacea) In Cirripedia, distallyarticulated part of the mandible functioning in feeding orcleaning; in Acrothoracica associated with the mandibulargnathobase; setose lobe on labrum. 2. (ARTHRO: Insecta)see prostheca.mandibular plates (ARTHRO: Insecta) In Hemiptera, platesbetween and attached to the mandibular stylets and theventral surface of the sucking pump.mandibular pouch (ARTHRO: Insecta) In Thysanoptera, aventrally oriented cone formed by the labrum and labiumcontaining maxillary stylets and a single (left) functionalmandible, emerging at the apex.mandibular ring (NEMATA: Adenophorea) In Enoplida, transverseextension of the mandibles in the buccal cavity.mandibular scar (ARTHRO: Insecta) In certain Coleoptera pupae,round or oval areas with raised margins that serve assupports for the deciduous provisional mandibles.mandibular sclerite (ARTHRO: Insecta) In some larval Diptera,mouth-hooks articulating basally with the intermediate(hypostomal) sclerites.Mandibulata n. [L. mandibula, jaw] Formerly a subphylum ofarthropods including Myriapoda, Crustacea and Insecta.mandibulate a. [L. mandibula, jaw] Having jaws fitted forchewing; mandibuliform.manducate v. [L. manducare, to chew] To bite; eat.manica n. [L. manica, sleeve] (ARTHRO: Insecta) In Lepidoptera,the inner layer of the anellus, that fastens around theaedeagus.maniform a. [L. manus, hand; forma, shape] Hand-shaped.manitruncus see prothoraxmanna n. [Gr. manna, morsel or honey dew] (ARTHRO: Insecta)Honeydew (90-95% sugar) produced by certain coccids,used as human food.manometabola see hemimetabolous metamorphosismantle n. [L. mantellum, cloak] 1. Something that enfolds,

534Maggenti and Gardnerenvelopes or covers. 2. (ARTHRO: Crustacea) In thoracicCirripedia, membranous covering of the body, oftenstrengthened by calcareous plates. 3. (BRACHIO) Prolongationof the body wall as fold of ectodermal epithelium. 4.(BRYO: Phylactolaemata) Ciliated fold of colony wall coveringone to four small, sexually produced colony progenitorpolypides. 5. (MOLL) A membranous covering that secretesthe shell; the marginal glands produce the periostracum;pallium.mantle canal (BRACHIO) One of several flattened, tube-likeextensions of the body cavity into each mantle lobe.mantle cavity Specialized cavity found in certain mollusks,brachiopods and crustaceans lined with epidermis and usuallyexposed to sea or fresh water, or air, due to habitat;may or may not contain part of the viscera; pallial chamberor cavity; mantle chamber.mantle cells (ARTHRO: Insecta) Corneagenous cells of the eyeenclosing the retina.mantle fold (MOLL: Bivalvia) In oysters, one of 3 small folds atthe edge of a mantle lobe.mantle groove (BRACHIO) Site of proliferation of the periostracumand bears the setae.mantle lobe 1. (BRACHIO) Lobe of the body wall that secretesand lines the valves; in some, cecae project into perforations(punctae) in the shell serving as food repositories ofglycoproteins and mucroproteins, inhibitors of boring organisms,and accessory respiratory structures. 2. (MOLL:Bivalvia) In oysters, one of 2 thin epithelial extensions ofthe mantle adjoining the valve.mantle papilla see caecummantle skirt (MOLL) Roof of the mantle cavity formed by theprojection of the mantle from the edge of the visceralmass.manubrium n. [L. manubrium, handle] 1. (ARTHRO: Crustacea)In fish parasitic Copepoda, the handle or distal part of theattachment organ. 2. (ARTHRO: Insecta) The basal part ofthe furcula of collembolan springtails; part of the sternumassociated with the cavity of the prothorax of Coleoptera.

Online Dictionary of Invertebrate Zoology 5353. (CNID: Hydrozoa) The extension between the stomachcavity and the mouth of a medusae or polyp; also calledgullet or esophagus. 4. (NEMATA) The proximal portion of aspicule; a capitulum. 5. (ROTIF) One of two paired trophi inthe mastax.manus n. [L. manus, hand] 1. The hand. 2. (ARTHRO: Crustacea)Broad proximal part of a propodal cheliped of a Decapoda.3. (ARTHRO: Insecta) Formerly applied to the anteriortarsus. 4. (MOLL: Cephalopoda) see tentacle.manuscript name An unpublished scientific name. see nomennudum.marble gall (ARTHRO: Insecta) The hard spherical gall ofCynipidae Adleria kollari , usually on oak that produce theagamic generation of that species.margaritaceous a. [Gr. margarites, a pearl] Pearly in texture;nacreous.margin n. [L. margo, border] 1. A border or an edge. 2. (AR-THRO: Insecta) The edge of a wing. 3. (CNID: Anthozoa)The junction of the oral disk and collum of a sea anemone.4. (MOLL) The edge of a shell. marginal a.marginal bodies (PLATY: Trematoda) In Aspidogastrea, sensorypits or short tentacles between marginal loculi of theopisthaptor.marginal bristles (ARTHRO: Insecta) In Diptera, abdominalbristles inserted dorsally on the margins of the segment.marginal cell (ARTHRO: Insecta) A cell in the distal part of thewing bordering the costal margin.marginalia n. [L. margo, border] (PORIF) Spicules protrudingupward around an oscule.marginal nuclei (NEMATA) Nuclei of marginal cells in thenematode esophagus; believed to lay down the fibers fromthe apex of the lateral arm to the basement membrane ofthe esophagus, or to secrete the cuticular lining of theesophagus, or both.marginal tubes (NEMATA) The distal cylindric endings of someesophageal radii, other forms have convergent terminals.marginal carina (MOLL: Bivalvia) A ridge running from umbo

536Maggenti and Gardnerto posteroventral angle of the shell delimiting the posteriorarea in Trigoniacea.marginal veins (ARTHRO: Insecta) A vein running along thefront margin of a wing that gives off a stigmal vein.marginate a. [L. margo, border] Having a distinct margin inappearance or structure.marine a. [L. mare, sea] Pertaining to or inhabiting the sea,ocean, or other salt waters.marita n. [L. maritus, conjugal] (PLATY: Trematoda) A sexuallymature fluke.marker gene Genetic marker; gene of known position andconspicuous in its action.marmorate a. [L. marmor, marble] Having color or veined likemarble.marsh n. [A.S. mersc, marsh] An area of wet soil.marsupium n. [L. marsupium, bag] 1. Brood pouch. 2. (AR-THRO: Crustacea) The oostegite in Peracarida, or broodchamber or pouch in others. 3. (ARTHRO: Insecta) In marsupialcoccids, a waxen ovisac, longer than the body, filledwith eggs that hatch while the insect is still mobile. 4.(BRYO) The ovicell. 5. (CNID: Hydrozoa) In some, the internalpouch borne by the blastostyle. 6. (ECHINOD) a. Insome, the cardiac stomach. b. In Viviparous Crinoidea, presenton the base of the pinnules adjacent to the gonad andhaving an external opening; a brood chamber.mask n. [Ar. maskhara, buffoon] (ARTHRO: Insecta) In dragonflynymphs, the prehensile labium that conceals the othermouthparts. masked a.masked pupa see pupa larvatamass communication (ARTHRO: Insecta) In Hymenoptera,transfer of information among large groups of individualswhich cannot be accounted for by one to one communication.mass provisioning (ARTHRO: Insecta) Social behavior of solitarybees and wasps by storing cells with sufficient food tosatisfy their developing offspring and closing them downbefore the eggs hatch. see progressive provisioning.

Online Dictionary of Invertebrate Zoology 537mastax n. [Gr. mastax, jaws] (ROTIF) A muscular rounded,trilobed, or elongate organ containing trophi; in suspensionfeeders adapted for grinding, in carnivores modified as forcepsthat can be projected from the mouth to seize prey;the pharynx.mastication n. [L. mastecare, to chew] The act of chewing; togrind or crush.masticatory process see gnathal lobemasticatory stomach see gastric millmasticomorphic a. [L. mastecare, to chew; Gr. morphos,form] Designed for chewing.mastidia n.pl.; sing. mastidion [Gr. mastos, breast] (ARTHRO:Chelicerata) Small, conical, nipple-like tubercles on thefront of the chelicerae of small spiders.mastigobranch, mastigobranchia n. [Gr. mastix, whip;branchos, gill] (ARTHRO: Crustacea) A slender respiratoryprocess at the base of the epipod.mastigophore n. [Gr. mastix, whip; pherein, to bear] (CNID:Anthozoa) A nematocyst with a cylindrical hempe and tubeextending beyond the hempe; microbasic with hempe notmore than 3 times the capsule length; macrobasic withhempe 4 or more times the capsule length.mastigopus larva (ARTHRO: Crustacea) Larva in the megalopastage found among some Decapoda.maternal inheritance Inheritance controlled by maternal extrachromosomal determinants.maternal zooid (BRYO: Gymnolaemata) An autozooid that extrudeseggs.mating plug (ARTHRO: Insecta) A plug formed from the accessorygland secretions of the male, deposited in the genitalchamber of the female, thought to prevent loss of sperm insome Culicidae and Lepidoptera; also called spermatophragma.see sphragis.mating spines (ARTHRO: Insecta) In female mayflies, compoundconical spines covering the lower surface of the eggvalve.matricidal hatching (NEMATA) Intrauterine larval development

538Maggenti and Gardnerleading to the destruction of the female by the larvae or juveniles;eclosion intrauterine.matrifilial a. [L. mater, mother; filia, daughter] (ARTHRO: Insecta)In Apis, having colonies made up of mothers anddaughters.matrix n.; pl. matrices [L. mater, mother] 1. That which givesform, origin or foundation to something enclosed or embeddedin it. 2. (NEMATA: Secernentea) The gelatinous substancesecreted by some female nematodes into whicheggs are deposited to form an egg mass. 3. (PLATY) InCestoda and Trematoda, a living interface of interactingphotoplasmic layer; part of the syncytium of the tegument.4. (PORIF) The non-cellular ground material of a sponge inwhich the cellular elements are dispersed.matrix glands (NEMATA: Secernentea) An excretory cell ormodified rectal glands that secrete the gelatinous matrixthrough the anus or excretory pore and into which eggsmaybe imbedded.matrix layer (NEMATA) Historically, a cuticular stratum ofspongy material between the fibrillar layer and the boundarylayer.matrone n. [L. mater, mother] (ARTHRO: Insecta) Macromolecularcomponents (proteins) contained in the seminalfluid of some male Culicidae that inhibits further inseminationof the female.maturation n. [L. maturus, ripe] The act or process pertainingto the developmental steps leading to reproducing adults.maturation divisions A series of nuclear divisions in the formationof the gametes in which the chromosome number,through meiosis is reduced from diploid to haploid.maturation feeding (ARTHRO: Insecta) Feeding required bysome insects before their gonads can mature to produceeggs.maturation zone In males of many invertebrates, that part ofthe genital follicle below the germarium in which eachspermatocyte undergoes the two meiotic divisions to producespermatids. see transformation zones.mature region see exozone

Online Dictionary of Invertebrate Zoology 539maxaponta n. [L. maxilla, jaw; pons, bridge] (ARTHRO: Insecta)A bridge formed by a midline fusion of the lowermaxillariae and the postgenae. maxapontal a.maxilla n.; pl. -llae [L. maxilla, jaw] 1. (ANN: Polychaeta) Thelarge, hook-shaped, dorsal chitinous jaw plate. 2. (ARTHRO)In most arthropods, one of the paired mouth-part structuresposterior to the mandibles or jaws; third pair of headappendages. 3. (ARTHRO: Diplopoda) One of the pairedsecond jaws to form the gnathochilarium.maxillary a. [L. maxilla, jaw] (ARTHRO) Of or pertaining to themaxilla.maxillary carrier (ANN: Polychaeta) A posterior supportstructure for the maxilla.maxillary glands (ARTHRO) Glands belonging to the maxillarysegment, possibly functioning in the lubrication of themouthparts.maxillary guides (ARTHRO: Insecta) In Anoplura, pairedstructures of wrinkled sucking lice arising from the maxillaryappendages that function as guides for the dorsalstylet.maxillary palp/palpus; pl. -pi (ARTHRO: Insecta) Small sensoryorgan arising from the maxilla, used to test quality offood. see labial palp.maxillary segment see maxillulaemaxillary stylets (ARTHRO: Insecta) In Hemiptera, the innerpair of stylets of the trophic sac.maxillary tentacle (ARTHRO: Insecta) In female TegeticulaLepidoptera, an inner elongate lobe of the maxilla, adaptedfor holding a large mass of pollen; perhaps palpifers.maxilliped, maxillipede, maxillipe a. [L. maxilla, jaw; pes,foot] (ARTHRO: Crustacea) The paired appendages on thoracicsomites 1-3 posterior to the maxillae, that usuallyfunction in feeding; sometimes adapted for other functionssuch as prehension in parasitic forms.maxillulae n.pl.; sing. -ula [L. dim. maxilla, jaw] 1. (ARTHRO:Crustacea) The first maxillae having more than one pair ofmaxillae; paragnath. 2. (ARTHRO: Insecta) In primitive

540Maggenti and Gardnerforms, the non-functional appendages between mandiblesand first maxillae. see superlinguae.maxim n. [L. maximus, greatest] (ARTHRO: Insecta) In Formicidae,a major worker or one of the soldier caste.mayrian furrow see notaulixmeatal cleft (ARTHRO: Insecta) A slit or line on the trumpet ofsome mosquito pupae extending into the meatus from thespiracular opening, facilitating enlargement of the openingat the surface of the water.meatus n. [L. metus, passage] A channel or duct.mechanical isolation Reproductive isolation due to mechanicalincompatibility of male and female genitalia.mechanoreceptor n. [Gr. mechane, contrivance; L. recipere,to receive] Specialized structures that perceive any mechanicaldistortion of the body, i.e., touch, vibrations, altitudeand gravity.meconida n.pl.; sing. -ium [Gr. mekon, poppy] 1. (ARTHRO:Insecta) Waste products of pupal metabolism that are dischargedshortly after adult emergence. 2. (CNID: Hydrozoa)Medusoid gonophores, sessile or pedicellate, which uponemergence from the gonangium act as external brood sacs.meconium n.media n. [L. medius, middle] 1. The middle structure. 2. (AR-THRO: Insecta) The longitudinal vein between the cubitusand the radius of the wing. medial a.mediad adv. [L. medius, middle; ad, toward] Toward the medianplane or line; mesad; admedial.medial cross vein (ARTHRO: Insecta) A cross vein connectingtwo branches of the media of the wing.medial-cubital cross vein (ARTHRO: Insecta) A cross vein ofan insect wing between the posterior medial vein and theanterior cubital vein.median a. [L. medius, middle] In the middle; along the midlineof the body; middle variate when variates are arranged inorder of magnitude.median bulb see metacorpus

Online Dictionary of Invertebrate Zoology 541median caudal nerve (NEMATA) A nerve extending from thedorsorectal ganglion to the tail.median cercus see urogomphusmedian cord (ARTHRO: Insecta) An embryonic chain of cellsderived from the ectoderm lining the neural groove.median dorsal plate (ARTHRO: Crustacea) In some Peracardia,an elongate plate separating carapace valves posterodorsally.median esophageal bulb see metacorpusmedian eye see nauplius eyemedian lamina see median wallmedian latus (ARTHRO: Crustacea) In Lepadomorpha, a platebetween the rostral and carinal latera in forms with pairedlatera in one whorl. see lateral.median ligament (ARTHRO: Insecta) A common thread formedby the ovarioles of opposite sides that help maintain theovaries in position and is attached to the body-wall, thefat-body or the pericardial diaphragm.median oviduct see common oviductmedian segment (ARTHRO: Insecta) The basal segment of theabdomen when it is fused with the metathorax during thechange from larva to pupa. see propodeum, epinotum.median tubuli (BRYO: Stenolaemata) Aligned pustules or murallacunae in a laminated skeleton.median valve see intermediate valvemedian wall (BRYO: Stenolaemata) Erect colony wall parallelto the growth direction from which zooids bud to form abifoliate colony.mediator n. [L. medius, middle] Association, internuncial,neuron; chemical such as a hormone that controls or modifiesa metabolic process.media worker (ARTHRO: Insecta) In Formicidae, an individualbelonging to the medium-size subcaste in a polymorphicseries of three or more worker subcastes. see minorworker, major worker.medio-cubital cross vein see medial-cubital cross vein

542Maggenti and Gardnermediolateral nerve cord (NEMATA) Several nerves extendingfrom the median and posterior externolateral ganglia andthe posterior internolateral ganglia to the lumbar ganglia.mediotergite n. [L. medius, middle; tergum, back] (ARTHRO:Insecta) In Diptera, the median region of the mesopostnotum.medioventral a. [L. medius, middle; venter, belly] In the middleventral line.mediproboscis see haustellummedulla n. [L. medulla, marrow, pith] 1. Central portion of anorgan. 2. (ARTHRO) Apical lobes of the brain; the centralsynaptic region; epiopticon; medulla externa; external medullarymass.medulla externa see medullamedulla interna (ARTHRO: Insecta) The lobular complex.medulla X-organ, medulla terminalis ganglionic X-organ,MTGX (ARTHRO: Crustacea) A group of neurosecretory cellsin the medulla terminalis; the main source of eyestalkhormones.medusa n.; pl. -sae [L. Medusa, a gorgon of mythology](CNID) The free swimming umbrella-like forms.megabenthos see abyssobenthosmegacephalic a. [Gr. megas, large; kephale, head] Having anabnormally large head. see microcephalic, mesocephalic.megaclad n. [Gr. megas, large; klados, branch] (PORIF) Inmegascleres, a relatively large smooth desma; megaclone.megaclone see megacladmegadrile n. [Gr. megas, large; drilos, worm] (ANN: Oligochaeta)Terrestrial forms; not used systematically, althoughrecognized as a general term. see microdrile.megalaesthetes n.pl. [Gr. megas, large; aisthesis, sensation](MOLL: Polyplacophora) Large sensory organs terminatingin the tegmentum in the forms of eyes with cornea, lens,pigment layers, iris and retina. see micraesthetes.megalolecithal see macrolecithal

Online Dictionary of Invertebrate Zoology 543megalopa stage (ARTHRO: Crustacea) 1. Larvae of Malacostracawith functional pleopods; also referred to as glaucothoe.2. First postlarval stage in development of Eucarida,not present in other crustaceans. 3. Originally appliedto Brachyura larvae with large stalked eyes and functionalpleopods.megalopore, megapore n. [Gr. megas, large; poros, pore](MOLL: Polyplacophora) Large pore in the dorsal plate; associatedwith aesthete.megalops see megalopa stagemegamere see macromeremegameric a. [Gr. megas, large; meros, part] With relativelylarge parts; autosomes with large heterochromatic segments.meganephridia n.pl.; sing. -ium [Gr. megas, large; dim.nephros, kidney] (ANN: Oligochaeta) A pair of largenephridia in each segment of the body except, for first andlast segments; holonephridia; holoic; macroic. seenephridium, micronephridia.megaplankton see macroplanktonmegasclere n. [Gr. megas, large; skleros, hard] (PORIF) Alarge structural spicule. see microsclere.megascolecin n. [Gr. megas, large; skolex, worm] (ANN: Oligochaeta)The single pair of prostates, tubular or racemose,opened to the exterior, along side of or togetherwith the sperm ducts.megascopic see macroscopicmegetic a. [Gr. megas, large] Pertaining to size variations inpolymorphic forms. see epimegetic, eumegetic, hypomegetic.Mehlis' glands (PLATY: Trematoda) Unicellular mucous andserous glands surrounding the ootype in the reproductivesystem.meiocyte n. [Gr. meion, smaller; kytos, container] Primary oocytesand spermatocytes.meiofauna n. [Gr. meion, smaller; L. Faunus, diety of herdsand fields] Microscopic and small macroscopic fauna on the

544Maggenti and Gardnersea bottom.meiolecithal a. [Gr. meion, smaller; lekithos, egg yolk] Havinglittle yolk.meiomery n. [Gr. meion, smaller; meros, part] The conditionof possessing fewer than the normal number of parts.meiosis n.; pl. meioses [Gr. meiosis, to make smaller] Twosuccessive cell divisions in the developing germ cells characterizedby the pairing and segregation of homologouschromosomes, resulting in reduction from a diploid numberto a haploid one. meiotic a.meiotic drive A meiotic mechanism of cell division resulting intwo kinds of gametes produced by a heterozygote with unequalrecovery.meiotrichy n. [Gr. meion, smaller; thrix, hair] Loss of setae inontogenetic development or of homologous setae in naturalgroups.melania n. [Gr. melas, black] Blackness.melanin n. [Gr. melas, black] A term for a group of chemicallyill-defined pigments, often found associated with protein,produced by insects and marine animals responsible forcolors from brown to black. melanoid a.melanism n. [Gr. melas, black; ismos, denoting condition] 1.An excessive darkening of color owing to increasedamounts of black pigment. 2. A certain percentage of individualsin a population that give rise to polymorphism. seeindustrial melanism, albinism.melanoid a. [Gr. melas, black; eidos, like] Looking black ordark.meliphagous a. [Gr. meli, honey; phagein, to eat] Honeyeating;melivourous.melittology n. [Gr. melitta, honeybee; logus, discourse] Thestudy of bees.melittophily n. [Gr. melitta, honeybee; philos, love] (ARTHRO:Insecta) 1. A symbiont of social bees. 2. Any organism thatmust spend a portion of its life cycle in a bee colony.melivorous see meliphagous

Online Dictionary of Invertebrate Zoology 545mellifera n. [L. mel, honey; ferre, to bear] (ARTHRO: Insecta)Honey-makers; bees as a whole.melliferous a. [L. mel, honey; ferre, to bear] Honey producing.mellisugent a. [L. mel, honey; sugere, to suck] Honey-sucking.member n. [L. membrum, part] A limb or organ.membrane n. [L. membrana, skin] A thin film of tissue.membranization n. [L. membrana, skin] Changed into amembrane.membranous a. [L. membrana, skin] Consisting of membranes;soft and pliable; membranaceous.membranous sac (BRYO: Stenolaemata) Membrane surroundingdigestive and reproductive systems of zooid; the entosaccaland exosaccal cavity.membranule, membranula n. [L. dim. membrana, skin] (AR-THRO: Insecta) A small semi-opaque membrane on thebase of the hind wing of certain Odonata.Mendelian character Character formed under the control ofchromosomal genes.Mendelian inheritance Mode of inheritance from chromosomalgenes.Mendelian mutation True gene mutation and recombination.Mendelian population A population with unrestricted interbreedingof organisms sharing a common gene pool.Mendelism n. [Gregor Mendel] Particulate inheritance ofchromosomal genes.Mendel's laws of inheritance Genetic principles proposed byMendel; law of segregation and law of independent assortment.meniscoidal a. [Gr. meniskos, a crescent] 1. Crescent-shapedlens; concavo-convex lens; one side convex and the otherconcave. 2. With one side concave, crescent shape of waterin a tube, or convex, crescent-shaped as with mercury in atube.menognath n. [Gr. menein, to remain; gnathos, jaw] (AR-

546Maggenti and GardnerTHRO: Insecta) Having biting mandibles in both larval andadult stages. menognathous a. see Menorhyncha, metagnath.Menorhyncha n.pl. [Gr. menein, to remain; rhynchos, snout](ARTHRO: Insecta) A former division of insects composed ofthose who ingest by suction in both larval and adult stages.see menognath and metagnath.menotaxis n. [Gr. menein, to remain; taxis, arrangement]Orientation in a fixed direction with respect to the stimulus.mental a. [L. mentum, chin] Of or pertaining to the mentum.mental plate (ARTHRO: Insecta) In Lepidoptera, representingthe basal sclerites of the labium. see labial plate.mental setae (ARTHRO: Insecta) Setae located on the mentum.mental suture (ARTHRO: Insecta) A distinct sclerite defined bya suture intervening between the mentum and the gula.mentasuture see mental suturementigerous a. [L. mentum, chin; gerere, to bear] (ARTHRO:Insecta) Having a mentum.mentum n. [L. mentum, chin] 1. (ARTHRO: Diplopoda) A median,slightly triangular sclerite in the gnathochilarium. 2.(ARTHRO: Insecta) a. The distal sclerite of a typical insectlabium, bearing the palps and the ligula. b. In bees, thesecond joint bearing the palps, paraglossa and ligula.meraspis larva (ARTHRO: Trilobita) The second larval stagewith the pygidium located behind the cephalon; the thoracicregion will appear during succeeding molts. see holaspislarva.merdivorous see scatophagousmereopodite see merusmeridional canal (CTENO) One of the eight canals extending inan oral-aboral direction under the external surface; part ofthe gastrovascular system; in Pleurobranchia it emits agreenish-blue luminescence.meristal annuli (ARTHRO: Insecta) In Orthoptera and Odonata,annuli derived from, and adjacent to, the meriston that di-

Online Dictionary of Invertebrate Zoology 547vides.meriston n. [L. merizein, to divide] (ARTHRO: Insecta) Themost basal annulus of the antennal flagellum.meritrichy a. [Gr. meros, part; trichos, hair] (ARTHRO: Chelicerata)In Acari, chaetotaxy characterized by a reduction innumber and size of setae from the holotrichous form.mermithaner n. [Gr. mermis, cord; aner, male] (ARTHRO: Insecta)Male Formicidae parasitized by the nematode Mermis;a mermithophore.mermithergate n. [Gr. mermis, cord; ergates, worker] (AR-THRO: Insecta) In Formicidae, a worker parasitized by thenematode Mermis; a mermithophore.mermithized a. [Gr. mermis, cord] (NEMATA) Pertaining toparasitism by nematodes of the genus Mermis.mermithodinergate see mermithostratiotemermithogyne n. [Gr. mermis, cord; gyne, woman] (ARTHRO:Insecta) A female Formicidae parasitized by the nematodeMermis; a mermithophore.mermithophore n. [Gr. mermis, cord; pherein, to carry](NEMATA) An anomalous form resulting from parasitism bythe nematode Mermis; a mermithaner, mermithergate,mermithogyne, mermithostratiote.mermithostratiote n. [Gr. mermis, cord; stratiotes, soldier](ARTHRO: Insecta) Soldier Formicidae parasitized by thenematode Mermis; a mermithophore.mermitoid esophagus see stichosomemeroandry n. [Gr. meros, part; aner, male] The condition ofpossessing less than the normal number of testes.meroandric a. see holandry.meroblastic cleavage Cleavage of a heavily yolked egg inwhich only the egg cell divides, leaving the yolk undivided.merocerite n. [Gr. meros, part; keras, horn] (ARTHRO: Crustacea)The 4th segment of an antenna.merocrine a. [Gr. meros, part; krinein, to separate] Thepassing of a secretion by a gland in which the nucleus remainsintact and thereby can recover. see holocrine.

548Maggenti and Gardnermerognathite see merusmeroic a. [Gr. meros, part] (ANN: Oligochaeta) Pertaining tothe excretory system with nephridial tubules formed bylongitudinal or transverse fragmentation of the original singlepair of embryonic rudiments of each segment.meroistic ovariole (ARTHRO: Insecta) An ovariole in whichnurse cells, or trophocytes are present; telotrophic (acrotrophic)and polytrophic types; panoistic; meroistic eggtube.meromyarian a. [Gr. meros, part; mys, muscle] (NEMATA)Muscle arrangement with only a few, frequently only two,flat muscle cells seen in each quadrant of a cross section ofthe animal.meron n. [Gr. meros, upper thigh] (ARTHRO: Insecta) Theposterior part of the basicoxite; in higher Diptera, separatedfrom the coxa and forms part of the thoracic wall(mesomeron, metameron).meronephridium see micronephridiameropleuron n.; pl. -ura [Gr. meros, part; pleuron, side] (AR-THRO: Insecta) A sclerite composed of the meron of thecoxa and the lower region of the epimeron.meropodite n. [Gr. meros, part; pous foot] (ARTHRO) 1. Thefourth segment of a generalized limb. 2. The femur in Chelicerataand Insecta. 3. For Crustacea see merus.merosome n. [Gr. meros, part; soma, body] A body segment;a somite or metamere.merospermy n. [Gr. meros, part; sperma, seed] Fusion of anegg cell with a sperm that has lost its nucleus; therefore, itcannot take part in karyogamy with the egg nucleus.merus n. [Gr. meros, part] (ARTHRO: Crustacea) The fourthsegment of the mouth part, articulating with the ischiumanteriorly and carpus posteriorly; a meropodite.mesad, mesiad adv. [Gr. mesos, middle; ad, toward] Towardthe midline of the body.mesadenia n.pl.; sing. mesadene [Gr. mesos, middle; aden,gland] (ARTHRO: Insecta) 1. Mesodermal accessory glandsof male genitalia. 2. In some male Heteroptera, paired,

Online Dictionary of Invertebrate Zoology 549highly coiled tubules that run side by side to enter anteriorlythe bulbus ejaculatorius or closely associated with theshort vasa deferentia.mesal, mesial a. [Gr. mesos, middle] At or near the midline ofthe body.mesal penellipse (ARTHRO: Insecta) In larvae, a series of crochetscovering at least the mesal half of the proleg, incompletelaterally. see penellipse.mesanapleural suture (ARTHRO: Insecta) In Diptera, a suturebetween the mesanepisternum and the meskatepisternum.mesanepisternum n. [Gr. mesos, middle; ana, up; epi, on;sternon, chest] (ARTHRO: Insecta) 1. In Diptera, the upperarea of the mesepisternum separated from themeskatepisternum by the mesanapleural suture; sometimesdivided into anterior and posterior by anepisternalcleft; the anepisternum. 2. In Odonata, the anepisternum.mesaxon n. [Gr. mesos, middle; axon, axel] (ARTHRO: Insecta)The spiral arrangement of a Schwann cell around an axon;suspensory fold.mesenchymatous cell see hemocytemesenchyme, mesenchyma n. [Gr. mesos, middle; enchyma,infusion] Embryonic connective tissue derived primarilyfrom mesoderm and consisting of a diffuse networkof loosely connected or scattered cells not segregated intolayers or blocks.mesenteron n. [Gr. mesos, middle; enteron, gut] The midgutor midportion of the alimentary tract, endodermal in origin;ventriculus; midintestine.mesenteron rudiments (ARTHRO: Insecta) Groups of embryologicendodermal cells that regenerate the midgut(stomach) including the anterior and posterior; becomesthe epithelium of the adult mesenteron.mesentery n. [Gr. mesos, middle; enteron, gut] A supportingmembrane or one that forms a partition.mesepimeral scale or seta (ARTHRO: Insecta) Any scale orseta borne on the mesepimeron.mesepimeral suture see mesopleural suture

550Maggenti and Gardnermesepimeron n.; pl. -mera [Gr. mesos, middle; epi, on;meros, part] (ARTHRO: Insecta) 1. The area of the mesopleuronposterior to the mesopleural suture; the epimeronof the mesothorax. 2. In Odonata, the area between thehumeral and first lateral suture.mesepisternum n.; pl. -sterna [Gr. meros, middle; epi, on;sternum, chest] (ARTHRO: Insecta) 1. The area of themesopleuron anterior to the mesopleural suture; sometimesdivided into an upper mesanepisternum and a lowermeskatepisternum; the episternum of the mesothorax. 2.In Diptera, horizontally divided into a large mesanepimeronbut with a minute meskatepimeron below. 3. In HymenopteraIchneumonidae, usually termed mesopleurum.mesiad see mesadmesial see mesalmesial sclerite see labellar mesial scleritemesic a. [Gr. mesos, middle] Climate characterized by a moderateamount of water.mesinfraepisternum n. [Gr. mesos, middle; L. infra, below;Gr. epi, on; sternon, chest] (ARTHRO: Insecta) A ventralsubdivision of the mesepisternum.meskatepimeron n. [Gr. mesos, middle; kata, inferior; epi,on; meros, part] (ARTHRO: Insecta) The lower division ofthe mesepimeron.meskatepisternum n. [Gr. mesos, middle; kata, inferior; epi,on; sternon, chest] (ARTHRO: Insecta) In Diptera, the lowerarea of the mesepisternum.mesobasisternum n. [Gr. mesos, middle; basis, bottom; sternon,chest] (ARTHRO: Insecta) 1. The basisternum of themesothorax. 2. In Diptera, maybe separated from themesofurcasternum by a secondary line of inflection. seefurcasternum.mesobiota n. [Gr. mesos, middle; bios, life] Organisms in thesoil ranging in size from nematodes to microannelids, microarthropodsand mites; mesofauna.mesoblast n. [Gr. mesos, middle; blastos, bud] Embryonicmesoderm; the middle germ layer. mesoblastic a.

Online Dictionary of Invertebrate Zoology 551mesoblastic somites Segmental divisions of embryonicmesoderm.mesobranchial lobe or area (ARTHRO: Crustacea) In Decapoda,an intermediate part of the branchial region of thecarapace.mesocardiac ossicle (ARTHRO: Crustacea) In Decapoda, a triangularor oblong plate, the apex pointing forward maybemore or less truncated; forming the keystone of the anteriorarch of the gastric mill.mesocephalic a. [Gr. mesos, middle; kephale, head] Having amedium size head.mesocephalic pillars (ARTHRO: Insecta) In bees, two obliquechitinous bars forming a brace between the anterior andposterior walls of the head.mesocercaria n. [Gr. mesos, middle; kerkos, tail] (PLATY:Trematoda) A juvenile stage occurring in digenetic trematodes,an unencysted stage between the cercaria and themetacercaria.mesocerebrum n. [Gr. mesos, middle; L. cerebrum, brain](ARTHRO: Crustacea) Ganglion of antennular somite; deuterocerebrum.mesocoel n. [Gr. mesos, middle; koilos, hollow] 1. The bodycavity of the second division of the deuterostome body. 2.(BRYO) Assumed to be the cavity within and at the base ofthe tentacles. 3. (MOLL) Second or middle division of thecoelom.mesocole a. [Gr. mesos, middle; L. colere, to inhabit] Livingconditions with neither too much nor too little water.mesoconch n. [Gr. mesos, middle; konche, shell] (MOLL: Bivalvia)An intermediate stage in formation of the dissoconch;separated from other stages by pronounced discontinuities.mesocuticle n. [Gr. mesos, middle; L. cutis, skin] A layer withdistinctive staining properties between the exocuticle andendocuticle.mesoderm n. [Gr. mesos, middle; derma, skin] The cell layerbetween ectoderm and endoderm in the embryonic cells of

552Maggenti and Gardnerall animals above the Cnidaria.mesodermal tube The dorsal blood vessel; heart.mesodont a. [Gr. mesos, middle; odous, tooth] (ARTHRO: Insecta)Pertaining to male Lucanidae bearing mandibles intermediatein size; amphiodont. see teleodont, priodont.meso-epinotal suture (ARTHRO: Insecta) In Formicidae, thetransverse seam separating the mesonotum from the epinotum.mesoepisternum see mesepisternummesofacial plate see facemesofauna see mesobiotamesofurca see furcamesogastric lobe/area (ARTHRO: Crustacea) In Decapoda,the medial division of the gastric region of the carapace;usually five-sided in outline with a long narrow forwardprojection.mesogloea n. [Gr. mesos, middle; gloios, glutinous] A thin tovery thick, acellular to rather cellular, gelatinous connectivetissue between the inner and the outer layers of a two-layeredanimal.mesohyl n. [Gr. mesos, middle; hyle, matter] (PORIF) Thespace lying between the pinacoderm and the choanoderm.mesolamella n. [Gr. mesos, middle; L. dim. lamina, layer] Athin mesogloeal layer between epidermis and gastrodermisin Cnidaria and Porifera.mesolecithal egg Eggs with moderate yolk content. see centrolecithalegg.mesology see ecologymesomere n. [Gr. mesos, middle; meros, part] 1. A blastomereof medium size. 2. A mesoblastic somite. 3. Centralzone of coelomic pouches in an embryo. 4. (ARTHRO: Insecta)The inner divisions of the phallic lobes that unite toform the aedeagus (the intromittent organ).mesomerites n.pl. [Gr. mesos, middle; meros, part; -ites,having nature of] (ARTHRO: Diplopoda) Modified 9 pair oflimbs; together with 8 pair (promerites) of limbs function-

Online Dictionary of Invertebrate Zoology 553ing as pincers to pull out female vulvae.mesomeron n. [Gr. mesos, middle; meros, thigh] (ARTHRO:Insecta) In Diptera, the meron of the mesothorax behindthe midcoxa below the mesepimeron. see metameron,meron.meson n. [Gr. mesos, middle] The central plane; the midline ofthe body; an imaginary plane dividing the body into rightand left halves; the saggital plane.mesonephridium n. [Gr. mesos, middle; nephros, kidney]Nephridium of mesodermal origin.mesonotum n. [Gr. mesos, middle; notos, back] (ARTHRO: Insecta)The back or upper side of the mesothorax.mesopelagic a. [Gr. mesos, middle; pelagos, sea] Pertainingto the pelagic zone of intermediate depth of 200-1000 m;between the epipelagic and bathypelagic zones.mesopeltidium see schizopeltidmesophragma n. [Gr. mesos, middle; phragma, fence] (AR-THRO: Insecta) A chitinous piece that descends into the interiorof an insect body with the postscutellum as the base.mesoplankton n. [Gr. mesos, middle; plankton, wandering]Floating life below euphotic zone; plankton organisms retainedby a plankton net.mesoplax n. [Gr. mesos, middle; plax, plate] (MOLL: Bivalvia)A calcareous transverse plate straddling the two valves ontheir dorsal margins. see protoplax, metaplax.mesopleural bristles (ARTHRO: Insecta) In Diptera, a row ofbristles on the posterior margin of the mesopleura.mesopleural fovea (ARTHRO: Insecta) In Hymenoptera Ichneumonidae,a pit or short horizontal groove on the mesopleurum,anterior to the mesopleural suture and below thespeculum.mesopleural ridge (ARTHRO: Insecta) In Diptera, the pleuralridge marked externally by the mesopleural suture, betweenpleural apophyseal pit above the midcoxal articulationto the base of the wing.mesopleural sulcus (ARTHRO: Insecta) In Diptera, passingdownwards from the wing base to the middle coxa.

554Maggenti and Gardnermesopleural suture (ARTHRO: Insecta) The external groove ofthe mesopleural ridge, between the base of the wing to themidcoxal articulation.mesopleuron n.; pl. -ra [Gr. mesos, middle; pleuron, side](ARTHRO: Insecta) 1. The pleuron of the mesothorax; inwinged insects, composed of basalare, subalare, mesepisternum,mesepimeron and mesotrochantin. 2. In Diptera,the dorsal part of the mesepisternum; area in front of theroot of the wing between the noto- and sternopleural sutures.mesopleurosternal ridge (ARTHRO: Insecta) In Diptera, alarge, posteriorly curved invagination of the mesopleurosternalsuture.mesopleurosternal suture (ARTHRO: Insecta) In Diptera, theexternal groove between the meskatepisternum and themesobasisternum, or mesosternum when the mesobasisternumis not distinguishable; the pleurosternal suture.mesopleurum n. [Gr. mesos, middle; pleuron, side] (ARTHRO:Insecta) In Hymenoptera Ichneumonidae, the mesepisternum.mesopostnotum n. [Gr. mesos, middle; L. post, after; Gr.notos, back] (ARTHRO: Insecta) The postnotum of themesothorax. see metapostnotum.mesopostscutellum n. [Gr. mesos, middle; L. post, after;scutellum, small shield] (ARTHRO: Insecta) The postscutellumof an insect's mesothorax.mesopraescutum n. [Gr. mesos, middle; L. prae, before;scutum, shield] (ARTHRO: Insecta) The praescutum of themesothorax. see prescutum.mesopsammic a. [Gr. mesos, middle; psammos, sand] Pertainingto organisms living interstitially in sand or a materialin the form of rounded grains; psammous. mesopsammonn. see sabulous.mesopseudogyne see pseudogynemesorhabdions n.pl. [Gr. mesos, middle; dim. rhabdos, rod](NEMATA) The walls of the mesostome. see rhabdion.mesoscutellum n. [Gr. mesos, middle; L. scutellum, little

Online Dictionary of Invertebrate Zoology 555shield] (ARTHRO: Insecta) The scutellum of the mesothorax,usually referred to as scutellum.mesoscutum n. [Gr. mesos, middle; L. scutum, shield] (AR-THRO: Insecta) The scutum of the mesothorax.mesoseries n. [Gr. mesos, middle; L. series, row] (ARTHRO:Insecta) In larva, a band of crochets or hooks extendinglongitudinally on the mesal side of a proleg; when curved,varying from a quadrant to slightly more than a semicirclein extent, seldom exceeding two-thirds of a circle.mesosoma n. [Gr. mesos, middle; soma, body] 1. The middlepart of an invertebrate's body. 2. (ARTHRO: Chelicerata) InArachnida, the anterior portion of the abdomen, oftenclearly set off from the metasoma. 3. (ARTHRO: Insecta)For Hymenoptera, see alitrunk. 4. (POGON) The shortfrenular region of the body.mesosome n. [Gr. mesos, middle; soma, body] (ARTHRO:Crustacea) A collective term for all free thoracic somitesbehind the head.mesospermalege n. [Gr. mesos, middle; sperma, seed; L.legere, to gather] (ARTHRO: Insecta) A special pouch incertain females for reception of sperm; Ribaga's or Berlese'sorgan.mesosternal cavity (ARTHRO: Insecta) In Elateridae, theopening into which the prosternal process catches.mesosternellum n. [Gr. mesos, middle; L. dim. sternum,breast bone] (ARTHRO: Insecta) A small rod-like plate thatarticulates posteriorly with the mesosternum.mesosternum n. [Gr. mesos, middle; sternon, breast] 1. (AR-THRO: Crustacea) In some Decapoda Brachyura, the medianplate of the sternum. 2. (ARTHRO: Insecta) In Hymenoptera,the ventral part of the mesothorax; between thefore and mid-coxae.mesostome, mesostom n. [Gr. mesos, middle; stoma,mouth] (NEMATA) A division of the protostome precededanteriorly by the prostome and posteriorly by the metastome.see prostome.mesostracum n. [Gr. mesos, middle; ostrakon, shell] (MOLL:Polyplacorphora) A calcareous shell layer between the teg-

556Maggenti and Gardnermentum and the articulamentum in certain more highly developedliving species.mesotarsal ring see basitarsal ringmesotarsus n. [Gr. mesos, middle; tarsos, sole of foot] (AR-THRO: Insecta) The tarsus of the middle leg.mesotergum see mesonotummesothoracotheca n. [Gr. mesos, middle; thorax, chest;theke, case) (ARTHRO: Insecta) In pupal forms, the coveringof the mesothorax.mesothorax n. [Gr. mesos, middle; thorax, chest] (ARTHRO:Insecta) The middle of the thoracic divisions.mesothyridid n. [Gr. mesos, middle; thyridos, a window](BRACHIO) Pedicle opening partly in the ventral umbo andpartly in the delthyrium, with beak ridges appearing to bisectthe opening.mesotriaene n. [Gr. mesos, middle; triaina, trident] (PORIF) Amegasclere triaene with a rhabd projecting on both sides ofa cladome.mesotroch n. [Gr. mesos, middle; trochos, wheel] (ANN: Polychaeta)A ciliated band around the midbody of a marineannelid.Mesozoa, mesozoans n.; n.pl. [Gr. mesos, middle; zoon,animal] Ciliated, multicellular organisms, endoparasitic in avariety of marine invertebrates; two layered, having noskeletal, muscular, nervous, digestive, respiratory, or excretoryelements.mesozona n. [Gr. mesos, middle; zone, belt] (ARTHRO: Insecta)The middle portion of the pronotum. see prozona.metabiosis n. [Gr. meta, between; bios, life] A condition of lifewhere an organism precedes and prepares the environmentfor another organism, inducing an exchange of growthfactors beneficial among species.metablastic see ectodermmetabola n. [Gr. metabole, change] (ARTHRO: Insecta) Specieshaving distinct external changes during the stages of theirlife history. see paurometabola, hemimetabola,holometabola.

Online Dictionary of Invertebrate Zoology 557metabolic activities Any forms of activity that have to do withmetabolism.metabolic water Water produced in the cells as a by-productof metabolism.metabolism n. [Gr. metabole, change; ismos, denoting condition]The sum total of chemical reactions occurring in livingmatter. metabolic a. see catabolism, anabolism.metabolite n. [Gr. metabole, change; ites, like] Any by-productof a living organism; a metabolized substance.metabranchial lobe or area (ARTHRO: Crustacean) In Decapoda,the posterior branchial region of the carapace.metacentric a. [Gr. meta, after; kentron, center of circle]Having the centromere situated along the chromosome,except at or near the tip, e.g., J- or V-shaped in metaphase.see telocentric, acrocentric.metacephalon n. [Gr. meta, after; kephale, head] (ARTHRO:Insecta) In Diptera, the area behind the mouth extendingup toward the neck.metacercaria n. [Gr. meta, after; keros, tail] (PLATY: Trematoda)The stage succeeding the cercarial, following loss oftail; it may invade the definitive host (blood flukes) or maybecome encysted and await passive transfer to that host.metacerebrum n. [Gr. meta, after; L. cerebrum, brain] (AR-THRO: Crustacea) Ganglion of antennal somite; tritocerebrum.metacestode n. [Gr. meta, after; kestos, girdle; eidos, form](PLATY: Cestoda) The developmental stage of the plerocestoidwhere proglottids are evident but generative organsare not fully mature.metachemogenesis n. [Gr. meta, change of; chemeia, infusion;genesis, beginning] (ARTHRO: Insecta) In holometabolousforms, post-emergence biochemical maturation;does not include sexual maturation.metachromasia, metachromasis, metachromasy n. [Gr.meta, change of; chroma, color] Staining of tissue componentsin different colors by a single dye.metacnemes n.pl. [Gr. meta, after; kneme, leg] (CNID: Antho-

558Maggenti and Gardnerzoa) Secondary mesentaries between the primary cycle.metacoel n. [Gr. meta, after; koilos, hollow] 1. The body cavityof the third division of the deuterostome body. 2.(BRYO) Believed to be the main body cavity.metacorporal valve (NEMATA) An expanded, strongly cuticularizedportion of the triradiate lumen at the center of themetacorpus that functions as a pump during feeding.metacorpus n. [Gr. meta, after; L. corpus, body] (NEMATA)The median esophageal bulb; the middle bulb; the medianbulb.metacoxal plate (ARTHRO: Insecta) In Coccinellidae, a portionof the first ventral segment included above the ventrallines, visible on the metathorax.metacyclic a. [Gr. meta, after; kyklos, circle] Pertaining to astage in the life cycle of a parasite that is infective to itsdefinitive host.metacyst n. [Gr. meta, after; kystis, bladder] A cystic stage ofa parasite in a host.metaepisternum see metepisternummetaerucism n. [Gr. meta, after; L. eruca, caterpillar] (AR-THRO: Insecta) Poisoning by larval setae on cocoons, etc.see lepidopterism.metafemale n. [Gr. meta, after; L. femella, little woman] (AR-THRO: Insecta) In Diptera, an individual with 3 X-chromosomesand 2 sets of autosomes; found in Drosophila.metagastric lobe or area (ARTHRO: Crustacea) In Decapoda,the posterior division of the gastric region of the carapace;sometimes ill-defined.metagenesis n. [Gr. meta, after; genesis, beginning] Alternationof sexual and asexual reproduction in the life cycle ofcertain animals; alternation of generations. see heterogenesis.metagnath n. [Gr. meta, change of; gnathos, jaw] (ARTHRO:Insecta) Those insects with biting mandibles when youngand sucking mouth parts as adults. see menognath, Menorhyncha.metagonia n. [Gr. meta, after; gonia, angle] (ARTHRO: In-

Online Dictionary of Invertebrate Zoology 559secta) The anal angle of a wing.metagynous a. [Gr. meta, after; gyne, female] (ANN: Oligochaeta)Having the ovaries only in segment xiii or a homoeoticsegment.metagyny see protandrymetakinesis n. [Gr. meta, after; kinesis, movement] Separationof chromatids during anaphase.metamale n. [Gr. meta, change of; L. mas, male] (ARTHRO:Insecta) A male Drosophila with three (3) sets of autosomesand one X-chromosome.metamere n. [Gr. meta, after; meros, part] One or more of aseries of homologous parts of many animals; a merosome;a somite. metameric a.metameric sac see osmeteriummetamerism n. [Gr. meta, after; meros, part] Segmentalrepetition of homologous body parts; metameres; metasomes.metameron n. [Gr. meta, after; meros, upper thigh] (ARTHRO:Insecta) In Diptera, the meron of the metathorax; a verticalsclerite above the hindcoxa. see mesomeron, meron.metameros n. [Gr. meta, after; meros, part] (ARTHRO: Insecta)In Lepidoptera, the combined sixth to eighth abdominalsegments.metamorphosis n.; pl. -ses [Gr. meta, change of; morphe,form] A marked change in form or structure an animal undergoesfrom one growth stage to another; also applies tothe actual process of changing from larval to adult form.see anamorphosis, epimorphosis, hypermetamorphosis.metanauplius n. [Gr. meta, after; nauplios, shellfish] (AR-THRO: Crustacea) One to several larval stages subsequentto the first (nauplius) larva; characterized by increasingsize and the appearance of additional appendages.metandry n. [Gr. meta, after; aner, male] (ANN) Possessingonly the posterior pair of testes; in earthworms, testes restrictedto segment xi. metandric a. see proandry,holandry.

560Maggenti and Gardnermetaneme n. [Gr. meta, after; nema, thread] (NEMATA) Filamentousorgans in or near the lateral epidermal cords thatusually have anterior and sometimes posterior filamentsand a central scapulus; thought to be stretch receptors.see orthometaneme, propriocepter.metanephridium n.; pl. -ia [Gr. meta, after; nephros, kidney]Paired osmoregulatory or excretory tubules in some phyla;tubules that open into the body cavity and are found incoelomate animals.metanephromixium n. [Gr. meta, after; nephros, kidney;mixis, mingling] (ANN: Polychaeta) Nephromixium in whichthe coelomostome and nephrostome are combined into agenital and/or excretory duct. see mixonephridium.metanotal gland (ARTHRO: Insecta) In male Oecanthus (Orthoptera)and some blattids, special glands on the dorsumof the thorax that produces a secretion attractive to females.metanotal slopes (ARTHRO: Insecta) In Diptera, the pleurotergites.metanotum n.; pl. -nota [Gr. meta, after; notos, back] (AR-THRO: Insecta) The dorsal sclerite of the metathorax.metanotal a.metaparapteron n. [Gr. meta, after; para, beside; pteron,wing] (ARTHRO: Insecta) In Formicidae, the postscutellum.metapeltidium see schizopeltidmetaphase n. [Gr. meta, after; phasis, to appear] The stageof mitosis when the chromosomes line up in the equatorialplane of the spindle.metaplasis n. [Gr. meta, after; plasis, molding] The matureperiod in an individuals life.metaplasm n. [Gr. meta, after; plasma, formed or molded]Non-living protoplasmic inclusions. metaplastic a.metaplax n. [Gr. meta, after; plax, plate] (MOLL: Bivalvia) Along narrow posteriorly pointed, rounded or forked accessoryplate covering the gape between the two valves on thedorsal margins posterior to the umbo. see protoplax,mesoplax.

Online Dictionary of Invertebrate Zoology 561metapleural bristles (ARTHRO: Insecta) In Diptera, a bristle orbristles on the metapleura.metapleural gland (ARTHRO: Insecta) In most Formicidae, agland with an external bulla and a small orifice, opening oneach side of the metathorax at its lower posterior corners;thought to function as a protection against microorganismsin the nest chamber due to fungistatic and bacteriostaticactivity.metapleuron n.; pl. -ura [Gr. meta, after; pleuron, side] (AR-THRO: Insecta) 1. The lateral sclerites of the metathorax. 2.In Diptera, the pleuron of the metathorax. metapleural a.metapleurum n. [Gr. meta, after; pleuron, side] (ARTHRO: Insecta)In Hymenoptera Ichneumonidae, ordinarily dividedinto two parts, the lower is largest and generally referredto; the lower part an oval or subtriangular area on the sideof the thorax, between middle and hind coxae to the propodeum;the upper area lies behind the upper half of themesepimeron and below and behind the base of the hindwing, separated from the propodeum by a suture.metapneustic a. [Gr. meta, after; pneustikos, of breathing](ARTHRO: Insecta) Said of aquatic insect larvae having onlythe posterior pair of spiracles open and functioning. seeoligopneustic.metapodeon n. [Gr. meta, after; podeon, neck] (ARTHRO: Insecta)That part of an abdomen behind the podeon or petiole.metapodium n. [Gr. meta, after; pous, foot] (MOLL) The posteriorportion of the foot.metapodosoma n. [Gr. meta, after; pous, foot; soma, body](ARTHRO: Chelicerata) In ticks or mites, that portion of thepodosoma that bears the third and fourth pair of legs.metapolar cells (MESO) The posterior tier of cells in the calotte.metapon n. [Gr. metopon, forehead] (ARTHRO: Crustacea) InDecapoda, the entire preoral area, including part of themandibular somite.metapostnotum n. [Gr. meta, after; L. post, after; Gr. notos,back] (ARTHRO: Insecta) The postnotum of the metathorax.

562Maggenti and Gardnersee mesopostnotum.metapostscutellum see postscutellummetapraescutum, metaprescutum n. [Gr. meta, after; L.prae, before; scutum, shield] The prescutum of themetathorax.metapygidium n. [Gr. meta, after; pyge, rump] (ARTHRO: Insecta)1. In Dermaptera, the posterior ventral segment ofthe supra-anal plate. 2. In Coleoptera, the penultimate tergitewhen the elytra are shorter than the abdomen.metarhabdions n.pl. [Gr. meta, after; rhabdos, rod] (NEMATA)The cuticularized walls of the metastome. see rhabdion.metascolex n. [Gr. meta, after; scolex, worm] (PLATY:Cestoda) The posterior portion of a transversely dividedscolex.metascutellum n. [Gr. meta, after; L. scutellum, dim. scutum,shield] (ARTHRO: Insecta) The scutellum of the metathorax.metasoma n. [Gr. meta, after; soma, body] 1. The posteriorregion of many invertebrates. 2. (ACANTHO) The posteriorpart of the body or trunk. 3. (ARTHRO) The abdomen orurosome. 4. (ARTHRO: Chelicerata) In Arachnida, the abdominalbody segments and telson; posterior part of opisthosoma.5. (ARTHRO: Crustacea) see metasome. 6.(PHORON) The long gonadal region following themesosoma, and bearing external papillae and chitinous attachmentstructures. see opisthosoma.metasome n. [Gr. meta, after; soma, body] (ARTHRO: Crustacea)In Copepoda, a portion of the prosome, consisting offree thoracic somites anterior to the major point of bodyflexion; or first three abdominal somites; metasoma.metastasis n.; pl. -ses [Gr. meta, after; stasis, standing] Thetransfer of pathogenic microorganisms to parts of the bodyremote from the origin of infection.metasternal glands (ARTHRO: Insecta) In Formicidae, pairedorgans in the posterior area of the thorax, opening to theoutside near the pleural-sternal margins of the metathorax.metasternal orifice (ARTHRO: Insecta) In Formicidae, theopening of the metasternal gland.

Online Dictionary of Invertebrate Zoology 563metasternum n. [Gr. meta, after; sternon, chest] (ARTHRO:Insecta) 1. The sternum or ventral sclerite of themetathorax. 2. For Diptera, see mesepimeron.metastigmata n.pl. [Gr. meta, after; stigma, point] (ARTHRO:Insecta) The posterior spiracles of the synthorax.metastome, metastom n. [Gr. meta, after; stoma, mouth](NEMATA) The posterior subdivision of a prostome.metastoma n.; pl. -mata [Gr. meta, after; stoma, mouth] 1.(ARTHRO: Crustacea) The lower lip posterior to the mandibles,usually cleft into paragnaths; hypostoma; hypostome;hypopharynx; labium. 2. (ARTHRO: Insecta) In Orthropera,the hypopharynx.metasyndesis see acrosyndesismetatarsus n.; pl. -si [Gr. meta, after; tarsos, flat of the foot](ARTHRO) The basal segment of a tarsus; next to the tibia;the basitarsis.metatentorium n.; pl. -ia [Gr. meta, after; L. tentorium, tent](ARTHRO: Insecta) A posterior arm of the tentorium.metatergum see metanotummetathetely n. [Gr. meta, after; theein, to run; telos, end](ARTHRO) 1. A neotenous adult arthropod after undergoingnormal or more than normal numbers of molts. 2. In Insecta,often resulting in failure to develop wings, or formingbrachypterous adults.metathoracotheca n. [Gr. meta, after; thorax, chest; theke,case] (ARTHRO: Insecta) The pupal covering of themetathorax.metathorax n. [Gr. meta, after; thorax, chest] (ARTHRO: Insecta)The third or posterior segment of the thorax, bearingthe hind legs and the hind wings.metatroch n. [Gr. meta, after; trochos, wheel] (ANN) In Polychaeta,trochophore larvae, as well as some other groups,the postoral girdle of cilia. see prototroch, telotroch.metatrochophore n. [Gr. meta, after; trochos, wheel;phorein, to bear] (ANN: Polychaeta) A ciliated trochophorelarva developing trunk segments.metaxyphus n. [Gr. meta, after; xiphos, sword] (ARTHRO: In-

564Maggenti and Gardnersecta) In Hemiptera, spinose or triangular process of themetasternum.Metazoa, metazoans n.; n.pl. [Gr. meta, after; zoon, animal]1. A small phylum of endoparasitic, ciliated, multicellularorganisms composed of two layers, lacking skeletal, muscular,nervous, digestive, respiratory or excretory elements.2. Often regarded as degenerate flatworms appendedto phylum Platyhelminthes. metazoic a.metazoea n. [Gr. meta, after; zoe, life] (ARTHRO: Crustacea) Alate zoeal stage in Anomura and Brachyura with simpleuniramous limbs on posterior thoracomeres, budding pleopods1-5 at the same time, and having stalked eyes.metazona n. [Gr. meta, after; zone, belt] (ARTHRO: Insecta)The posterior part of the pronotum. see prozona.metazonite n. [Gr. meta, after; zone, belt] (ARTHRO: Diplopoda)Theposterior portion of a diplosomite, divided by atransverse groove. see prozonite.metecdysis n. [Gr. meta, after; ekdysis, molt] (ARTHRO) Theperiod following a molt before the new cuticle hardens, especiallyin Decapoda (Crustacea).metelattosis n. [Gr. meta, after; elatton, smaller] (ARTHRO:Chelicerata) Regression of postembryonic development,initiated after the beginning stasis.metenchium n. [L. meta, conical column; Gr. enchos, spear](NEMATA: Secernentea) Conus of the stylet in plant parasitesin the order Tylenchida. see telenchium.metenteron n. [Gr. meta, after; enteron, intestine] (CNID) Theradial digestive chamber. see mesenteron.metepimeron n.; pl. -mera [Gr. meta, after; epi, on; meros,part] (ARTHRO: Insecta) The epimeron of the metathorax.metepisternum n.; pl. -sterna [Gr. meta, after; epi, on; sternon,breast] (ARTHRO: Insecta) 1. The episternum of themetathorax. 2. In Culicidae, behind and below themetathoracic spiracle.meter n. [Gr. metron, a measure] A measure of length in themetric system; 39.37 inches. see centimeter, millimeter.metinfraepisternum n. [Gr. meta, after; L. infra, underneath;

Online Dictionary of Invertebrate Zoology 565Gr. epi, on; sternon, breast] (ARTHRO: Insecta) In Odonata,a ventral subdivision of the metepisternum.metochy see symphily, synechthrymetoecious parasite A parasite that is not host-specific. seeheteroecious.metope n. [Gr. metopon, forehead] The middle frontal portionof a head. see metapon.metopic suture see coronal suture or branchmetopidium n. [Gr. metopidios, of the forehead] (ARTHRO: Insecta)In Membracidae, the anterior downward slopingsurface of the prothorax.metraterm n. [Gr. metra, womb; terma, end] (PLATY: Trematoda)In Digenea, the muscular, terminal portion of theuterus.metric system A decimal system of measures and weights.metrocyte n. [Gr. metros, mother; kytos, container] A cellhaving given rise to other cells by division; mother cell;precursory cell.micelle n.; pl. -ae [L. micarius, crumbs] A supermolecularcolloid particle, often an orderly packet of chain moleculesin parallel arrangement.micraesthetes n.pl. [Gr. mikros, small; aisthetes, one whoperceives] (MOLL: Polyplacophora) One or more small sensoryorgans, in the form of eyes, sometimes accompanyingthe megaesthetes. see aesthete.micraner n. [Gr. mikros, small; aner, male] (ARTHRO: Insecta)In Formicidae, a dwarf male. see microgyne.micrergate n. [Gr. mikros, small; ergate, worker] (ARTHRO:Insecta) In Formicidae, a dwarf worker, a microergate.microbe n. [Gr. mikros, small; bios, life] A microscopic organism.microbiota n. [Gr. mikros, small; bios, life] 1. The combinedor singularly considered microflora and microfauna of anorganism. 2. Microscopic soil organisms.microbivorous a. [Gr. mikros, small; bios, life; L. vorare, todevour] Microbe eating; microbiotrophic.

566Maggenti and Gardnermicrobody n. [Gr. mikros, small; Eng. body] Spherical orovoid bodies that are rich in enzymes of peroxide metabolism.microbotroph n. [Gr. mikros, small; bios, life; trophein, tofeed] Microscopic faunal forms that obtain nourishmentfrom digesting living microorganisms; microbivorous.microcalthrop, microcaltrop n. [Gr. mikros, small; ML. calcitrapa,a four-pointed weapon] (PORIF) A microscleretetraxon spicule with four rays, one elongated and threeshort; a euaster with 4 persistent rays.microcentrum see centrosomemicrocephalic a. [Gr. mikros, small; kephale, head] Having anabnormally small head. see megacephalic, mesocephalic.microcercous cercaria (PLATY: Trematoda) Small cercariawith a very short tail and a stylet in the oral sucker. seexiphidiocercaria.microchaetae n.pl. [Gr. mikros, small; chaeta, mane] Smallbristles. see chaeta, macrochaetae.microclimate n. [Gr. mikros, small; klima, slope] The climateof the habitat in which the individual lives.microcnemes n.pl. [Gr. mikros, small; knemis, leg] (CNID:Anthozoa) In Actinaria, younger, narrow mesentaries lackingfilaments. see macrocnemes.microcotylate cercaria (PLATY: Trematoda) A group of smallxiphidiocercariae with a postequatorial ventral sucker, andfinless tail equal to the body length.microdrile n. [Gr. mikros, small; drilos, worm] (ANN: Oligochaeta)A general term for the aquatic forms. seemegadrile.microelectrode n. [Gr. mikros, small; elektron, amber] Smallelectrode for sensing electrical activity in a neuron.microergate see micrergatemicroevolution n. [Gr. mikros, small; L. evolutus, unrolling]All processes of species formation and differentiationbrought about by the combined action of various evolutionaryfactors. see macroevolution.

Online Dictionary of Invertebrate Zoology 567microfauna n. [Gr. mikros, small; L. Faunus, diety of herdsand fields] Very small animals; animals less than 200 m.microfibril n. [Gr. mikros, small; L. dim. fibra, fiber] Microscopicor submicroscopic fiber.microfilaria n. [Gr. mikros, small; L. filum, thread] (NEMATA)The uncoiled mobile embryo of a filaria, that either escapesfrom the egg shell (unsheathed) or causes stretching of theshell into an elongated sac accommodated to the uncoiledembryo (sheathed).microgamete n. [Gr. micros, small; gametes, husband] 1. Aslender, active, male anisogamete. 2. Derived from the microgametocyteof the malarial protozoan. see macrogamete.microgametocyte n. [Gr. mikros, small; gamete, husband;kytos, container] The male gametocyte that gives rise tomicrogametes.microgeographic race A local race, restricted to a small area.microgram n. [Gr. mikros, small; gramma, small weight] Onethousandth of a gram.microgranular cells (PORIF) Cells with cytoplasm charged withsmall dense granules.microgyne n. [Gr. mikros, small; gyne, woman] (ARTHRO: Insecta)In Formicidae, a dwarf female. see micraner.microhabitat n. [Gr. mikros; small; L. habitare, to dwell] Asmall or restricted habitat. see niche.microhexactine n. [Gr. mikros, small; hex, six; aktis, ray](PORIF) A small hexactine spicule.microic a. [Gr. mikros, small; eidos, like] (ANN: Oligochaeta)Smaller than macroic, a substitute for micronephridial, oftenapplied to nephridia as large as or larger than meganephridia.microlecithal a. [Gr. mikros, small; lekithos, egg yolk] Containinglittle yolk.microleucocyte n. [Gr. mikros, small; leukos, white; kytos,container] A small amoebocyte.micromere n. [Gr. mikros, small; meros, part] Small cells of

568Maggenti and Gardnerthe animal pole in eggs with abundant yolk.micromesentary n. [Gr. mikros, small; mesos, middle; enteron,gut] (CNID: Anthozoa) In Zoantharia, an incompletesecondary mesentary.micrometer n. [Gr. mikros, small; metron, a measure] A unitof microscopic measure, designated by the Greek lettersm; one-thousandth of a millimeter.micromillimeter see nanometermicromutation see point mutationmicron see micrometermicronekton n. [Gr. mikron, small; nektos, swimming] Small,swimming organisms in the ocean.micronephridia see microic, nephridiummicroniscus, micronicus see epicaridummicronucleocytes see plasmatocytesmicroorganism n. [Gr. mikros, small; organon, instrument] Amicroscopic organism such as most nematodes, rotifers,etc.micropaleontology n. [Gr. mikros, small; palaios, ancient;logos, discourse] The study of microscopic fossils.microphagous a. [Gr. mikros, small; phagein, to eat] Feedingon small objects. see macrophagous.microphthalmy n. [Gr. mikros, small; ophthalmos, eye] Anabnormally small antenna. microphthalmic a.microplankton n. [Gr. mikros, small; plankton, wandering]Small organisms floating in water.microplasmatocyte n. [Gr. mikros, small; plasmatos, image;kytos, container] (ARTHRO: Insecta) A small plasmatocytehaving a small amount of vacuolar cytoplasm. see eoplasmatocyte.micropore n. [Gr. mikros, small; poros, pore] (MOLL: Polyplacophora)A small pore in the dorsal plates; associated withan aesthete.micropredator n. [Gr. mikros, small; L. praedator, plunderer]A temporary parasite.

Online Dictionary of Invertebrate Zoology 569micropseudogyne see pseudogynemicropterism, microptery n. [Gr. mikros, small; pteron,wing] Small wings.micropterogyne n. [Gr. mikros, small; pteron, wing; gyne,woman] (ARTHRO: Insecta) A female with small wings.micropterous a. [Gr. mikros, small; pteron, wing] Havingsmall or vestigial wings.micropyle n. [Gr. mikros, small; pyle, entrance] A pore in theinvesting membrane of an egg through which a spermatozoanenters for fertilization. micropylar a.micropyle apparatus (ARTHRO: Insecta) Raised structuresaround the micropyle of an egg.micropyrenic a. [Gr. mikros, small; pyren, kernel] Having nucleismaller than average for a particular cell type of an individualor species.microsclere n. [Gr. mikros, small; skleros, hard] (PORIF) Apacking or reinforcing spicule, usually of a size, and ornateshape that occur strewn throughout the mesenchyme. seemegasclere.microscolecin, microscolecine n. [Gr. mikros, small; skolex,worm] (ANN: Oligochaeta) Provided with a pair of tubularprostates opening to the exterior in segment xvii along sideof, or together with, the sperm ducts.microscopic a. [Gr. mikros, small; skopein, to view] Being invisiblewith the naked eye, usually requiring the aid of amicroscope for elucidation of structure or recognition ofwhatever characters are involved. see macroscopic.microsensillum n. [Gr. mikros, small; L. sensillus, sensitive]Small sensillum or sensory puncture.microseptum n. [Gr. mikros, small; L. septum, partition](CNID: Anthozoa) A Zoantharia with incomplete or imperfectmesentary.microsomes n. [Gr. mikros, small; soma, body] Formerly anysmall granules in the cytoplasm; fragments of endoplasmicreticulum.microsomia n. [Gr. mikros, small; soma, body] Dwarfishness;nanism.

570Maggenti and Gardnermicrosomites n.pl. [Gr. mikros, small; soma, body] (ARTHRO:Insecta) In embryology, small secondary rings or somitesof the macrosomites later to become body segments.microspecies n.pl. [Gr. mikros, small; L. species, a kind] Asmall local species population that shows little variability;jordanon.microspines n.pl. [Gr. mikros, small; L. spina, thorn] (AR-THRO: Insecta) In some larvae, minute spines on the exteriorbody wall.microstome n. [Gr. mikros, small; stoma, mouth] A smallopening or orifice.microsymbiote n. [Gr. mikros, small; symbiosis, life together]A term designating the smaller organism, or microorganism,of a symbiotic association.microthorax n. [Gr. mikros, small; thorax, chest] (ARTHRO:Insecta) The neck or cervix, when the cervix is a reducedbody segment.microthrix n.; pl. microtrices [Gr. mikros, small; thrix, hair](PLATY: Cestoda) One of the minute folds of the tegumentthat aid in absorption of nutrients.microtome n. [Gr. mikros, small; temnein, to cut] Instrumentfor cutting thin sections of tissues for microscopic examination.microtomy n. [Gr. mikros, small; temnein, to cut] The scienceof cutting and staining of thin sections of tissues for microscopicexamination.microtrichia n.pl.; sing. -ium [Gr. mikros, small; thrix, hair]1. (ARTHRO: Insecta) Minute, abundant, non-articulate hairsfound on the wings (aculeae). see macrotrichia. 2.(PLATY: Cestoda) see microthrix.microtubules n.pl. [Gr. mikros, small; L. tubulus, small waterpipe] Minute tubules in cells that are often cross-linked;found in cilia, spindle fibers, and in the cytoplasm wherethey form the cytoskeleton.microtype n. [Gr. mikros, small; typos, type] (CNID: Anthozoa)A normal mesentery arrangement. see macrotype.microvillus n.; pl. -villi [Gr. mikros, small; L. villus, shaggy

Online Dictionary of Invertebrate Zoology 571hair] Minute processes on the inner surface of epithelialcells. see brush border.microxea n. [Gr. mikros, small; oxys, sharp] (PORIF) A microscleresimilar to an oxea, but very small.microzoon n. [Gr. mikros, small; zoon, animal] A microscopicanimal.mictic egg Eggs that have undergone meiosis and are thereforehaploid; when unfertilized they produce haploid males.see amictic egg.micton n. [Gr. mictos, mixed] Widely distributed species producedby interspecific hybridization which are fully fertilewith parent species.mid-axis n. (MOLL: Bivalvia) Straight line in commissural planeat a right angle to the hinge axis and beginning at the midpointof the ventral margin of the resilifer.midbody n. [A.S. middel, middle; bodig, body] The equatorialregion of the body.middle bulb see metacorpusmiddle cuticular layer (NEMATA) Formerly used for the matrixlayer of the cuticle.middle field see discoidal areamiddle plate (ARTHRO: Insecta) In embryology, that area betweenthe mesodermal rudiment and the lateral ectodermalplates.middorsal a. [A.S. middel, middle; L. dorsum, back] Pertainingto the true dorsal line of an individual; dorsomedian.midgut n. [A.S. middel, middle; gut] The mesenteron; themiddle portion of the alimentary tract.midgut gland (MOLL) A lobed or unlobed gland, of a compoundtubular or acinous nature, opening into the gut in one ormore places; sometimes called liver.midintestine see midgutmidventral a. [A.S. middel, middle; L. venter, belly] Pertainingto the true ventral line; ventromedian.midventral glands see supplementary organs

572Maggenti and Gardnermigrante n. [L. migrator, wanderer] (ARTHRO: Insecta) Inaphids, the winged, parthenogenetic, viviparous femalesthat develop on the primary host, then fly to the secondaryhost. see alienicola, fundatrix.migration n. [L. migratus, change habitat] The act or instanceof any form of invertebrate that moves from the place ofbirth for food or other purposes. migrational a.milk gland (ARTHRO: Insecta) Specialized accessory gland ofGlossina and the Pupipara that produces a milk containinglipids, proteins and amino acids.millepunctatus a. [L. mille, a thousand; punctum, prick] Coveredor studded with many dots, points, or minute depressions.millimeter n. [L. mille, a thousand; Gr. metron, a measure]One-thousandth of a meter, or 0.03937 of an inch; mm.millimicron see nanometermimesis see mimicrymimetic a. [Gr. mimikos, initative] Characterized by mimicry.mimetic polymorphism Polymorphism in which the variousmorphs resemble other species distasteful or dangerous toa predator; often restricted to females.mimic n. [Gr. mimos, actor] 1. An organism that resemblesanother in color, habit or structure for the purpose of protection.2. Nonallelic genes with similar phenotypic effects.mimicry n. [Gr. mimikos, imitative] The resemblance in coloror structure to other species that are distasteful or poisonousto a predator. see Batesian and Mullerian mimicry.mines n. [Celtic origin] (ARTHRO: Insecta) Larval galleries orburrows on the inside of leaf tissue.minim n. [L. minimus, least] 1. A very small object. 2. 1/60 ofa fluid dram or 0.06 ml. 3. (ARTHRO: Insecta) In Formicidae,a minor worker.minor worker (ARTHRO: Insecta) An individual belonging tothe smallest worker subcaste, esp. in Formicidae; a minim.see media worker, major worker.minute a. [L. minutus, small] 1. Very small. 2. (ARTHRO: In-

Online Dictionary of Invertebrate Zoology 573secta) A few millimeters in length or less.miolecithal a. [Gr. meion, less; lekithos, egg yolk] Referring toeggs containing little yolk.miracidium n.; pl. -dia [Gr. dim. meirakion, young girl](PLATY: Trematoda) In Digenea, the first larval stage; aciliated, free-swimming form.mirror n. [L. miror, to look at] (ARTHRO: Insecta) In HemipteraCicadidae, clear cuticular membrane located near thestridulatory apparatus; specular membrane.missense mutation Gene mutation in which one amino acid ischanged; the altered proteins may show some activity.mitochondria n.pl.; sing. mitochondrion [Gr. mitos, thread;chondros, grain] Sausage-shaped structures in the cytoplasmof animal and plant cells.mitogen n. [Gr. mitos, thread; genos, birth] An agent thatstimulates a cell to undergo mitosis.mitosis n.; pl. -ses [Gr. mitos, thread] The division and separationof chromosomes during cell division, involving thelongitudinal splitting of each chromosome resulting in twoequal sets of daughter chromosomes. mitotic a.mitosome n. [Gr. mitos, thread; soma, body] A body arisingfrom the spindle fibers of the preceding mitosis; spindleremnant.mitraria larva (ANN: Polychaeta) Post-trochophore larva ofOwenia with three hypertrophied setae for defense or floatation.mixed nerve A nerve with both motor and sensory fibers.mixed nest (ARTHRO: Insecta) A nest inhabited by two or morespecies of social insects with intermingling between adultsand broods. see compound nest.mixocoel n. [Gr. mixis, mingling; koilos, hollow] (ARTHRO) Theadult body cavity (not a true coelom) derived from a blastocoeland secondary body cavities that functions as ahemocoel.mixonephridium n. [Gr. mixis, mingling; nephros, kidney](ANN: Polychaeta) A type of nephromixium in which thenephridium and coelomoduct are combined into a single

574Maggenti and Gardnerorgan having both excretory and genital functions.mixoploidy n. [Gr. mixis, mingling; aploos, onefold; eidos,like] Having cells with different chromosome numbers incell populations.mnemotaxis n. [Gr. mneme, memory; taxis, arrangement]Movements in which memory plays a part.mode n. [L. modus, measure] The most frequent value of anymeasurable characteristic in a population.modifer genes Genes that affect the phenotypic expression ofgenes at other loci.modification n. [L. modus, measure; facare, to make] Anyvariation caused by non-genetic factors.modioliform a. [L. modiolus, a small measure or drinking vessel;forma, form] 1. In the form of a nave or hub of awheel; more or less globular with truncated ends. 2. (MOLL:Bivalvia) Beaks are not terminal and anteroventral regionforms a slight bulge; shell shaped like the genus modiolus .modulation n. [L. modulare, to measure] 1. Alteration in cellsby environment without change in their basic character. 2.Interactive modification of cells during development.moiety n.; pl. -ties [L. medius, the middle] 1. One of twoequal parts. 2. An indefinite portion.mola n. [L. mola, mill] (ARTHRO: Insecta) In Coleoptera, thethickened and enlarged basal part of the internal ridge ofthe mandible used for grinding. see molar lobe.molar a. [L. mola, mill] 1. Adapted for grinding. 2. (ARTHRO:Crustacea) Pertaining to the grinding surface on the inneredge of the mandibles or jaws.molar lobe (ARTHRO: Insecta) The proximal lobe of the mandiblesused for chewing or grinding. see mola.molar process (ARTHRO: Crustacea) The grinding portion ofthe gnathal lobe of the mandible; pars molaris.molecular biology The study of biological phenomena interms of the physiochemical properties of molecules in acell.molecular genetics The study of genetics at the level of mole-

Online Dictionary of Invertebrate Zoology 575cules.molecules n.pl. [L. dim. moles, mass] The small particles intowhich any substance can be divided without chemicalchange.Mollusca n.; pl. mollusks, molluscs [L. molluscus, soft] Aphylum of invertebrates with a soft unsegmented body andusually covered with a double or single shell, or having aninternal shell; includes snails, chitons, tusk shells, bivalves,limpets, squids, octopi, etc.molluscicide n. [L. molluscus, soft; caedere, to kill] An agentthat kills snails.molt, moult n. [L. mutare, to change] The periodic process ofloosening and discarding the cuticle, accompanied by theformation of a new cuticla in the process of growth; may bedivided into two distinct processes: apolysis and ecdysis.see pharate.molting fluid 1. Often undetermined fluid that causes theloosening of the old cuticle. 2. (ARTHRO: Insecta) A fluidcontaining chitinase and proteinase that digests theunsclerotised cuticle (except the ecdysial membrane).molting hormone see ecdysonemoltinism n. [L. mutare, to change] Polymorphs of differingstrains or biotypes that undergo a different number of larvalmolts.molula n. [L. dim. mola, mill] (ARTHRO) The dicondylic joint bywhich the tibia articulates with the femur.monacanthid a. [Gr. monos, one; acantha, thorn] (ECHINOD:Asteroidea) Having one row of ambulacral spines.monactinal a. [Gr. monos, one; aktis, ray] (PORIF) Spicule developmentoriginating from a fixed point in one directiononly.monaene a. [Gr. monos, one; triaina, trident] (PORIF) A modifiedtetraxon with only one clad.monarsenous a. [Gr. monos, one; arsen, masculine] Polygamous;having one male to numerous females.monaster n. [Gr. monos, one; aster, star] A unipolar spindlethat results in a nucleus with an unreduced chromosome

576Maggenti and Gardnernumber instead of two nuclei.monaulic a. [Gr. monos, one; aulos, pipe] (MOLL: Gastropoda)Male and female portions with a common gonopore. seediaulic, triaulic.monaxon n. [Gr. monos, one; axon, axis] (PORIF) Spiculesformed by growth in one or both directions along a singleaxis. monaxonid a.monecious see monoeciousmonila n. [L. monile, necklace] (BRYO) Concentric thickening ofthe zooecial wall causing a beadlike appearance.monilicorn see moniliformmoniliform a. [L. monile, necklace; forma, shape] Beadlike;resembling a string of beads; contracted or jointed atregular intervals.moniliform glands (NEMATA) Beadlike cells around the uvetteof the demanian system, usually forming a rosette.monoallelic a. [Gr. monos, one; allelon, one another] Referringto a polyploid in which all alleles at a locus are identical.monobasic a. [Gr. monos, one; basis, step] Describing generaoriginally based on one species only.monocentric a. [Gr. monos, one; kentron, point] Pertaining toa chromosome with one centromere.monochromatic a. [Gr. monos, one; chromos, color] Of onecolor only; unicolored.monocondylar see monocondylicmonocondylic a. [Gr. monos, one; kondylos, knuckle] Havingone condyle.monocondylic joint A joint with a single point of articulationbetween segments.monocrepid a. [Gr. monos, one; krepis, base] (PORIF) Pertainingto a desma formed on a monaxon.monocule n. [Gr. monos, single; L. oculus, eye] (ARTHRO) Aone-eyed animal, as certain crustaceans and insects.monocyclic a. [Gr. monos, one; kyklos, circle] (ECHINOD: Cri-

Online Dictionary of Invertebrate Zoology 577noidea) Refers to calyx plates of primitive stalked crinoidshaving an aboral cycle of 5 plates (basal) and 5 plates (radial)oral to the basal plates.monodactyl, monodactyle, monodactylous a. [Gr. monos,one; dactylos, finger] (ARTHRO) Pertaining to an appendage,ambulacrum or claw with only one unguis. seebidactyl.monodelphic a. [Gr. monos, one; delphys, womb] (NEMATA)Having one uterus.monodesmatic a. [Gr. monos, one; desmos, tendon] (AR-THRO: Chelicerata) Pertaining to an articulation betweentwo segments of an appendage with one tendon inserted atthe base of the distal segment.monodisk, monodisc n. [Gr. monos, one; diskos, disc] (CNID:Scyphozoa) One ephyra developed and released at a timebefore another forms by transverse fission. see polydisk,strobilization.monodomous a. [Gr. monos, one; doma, house] (ARTHRO: Insecta)Having one nest per colony. see polydomous.monoecious a. [Gr. monos, one; oikos, house] Having twokinds of gametes produced by the same individual; hermaphrodite;ambisexual. monoecism n. see dioecious.monoembryony n. [Gr. monos, one; embryon, fetus] Theproduction of only one embryo from a fertilized ovum oregg.monogamy n. [Gr. monos, one; gamos, marriage] The conditionof having only one mate. monogamous a. see polygamy.monogenesis n. [Gr. monos, one; genesis, beginning] 1. Thedevelopment of life from a single entity or cell. 2. Asexualreproduction. 3. Direct development without metamorphosis.monogenetic a. [Gr. monos, one; genesis, beginning] 1. Pertainingto monogenesis. 2. Designates parasites with asimple direct life cycle that is completed in one host. 3.Producing offspring of one sex by arrhenogenesis or thelygenesis.

578Maggenti and Gardnermonogenic a. [Gr. monos, one; genesis, beginning] 1. Monogenetic.2. Reproducing in only one way. 3. Determined bythe alleles of a single gene. see polygenic. 4. Monomeric.monogeny n. [Gr. monos, one; genos, offspring] The productionof offspring of one sex by arrhenogenesis or thelygenesis.monogonoporus a. [Gr. monos, single; gonos, offspring; poros,channel] Having both male and female gonads openingthrough a common orifice.monogony n. [Gr. monos, one; gonos, offspring] Asexual reproduction.monograph n. [Gr. monos, one; graphos, a writing] An accountor description of one subject or class of subjects; atreatise discussing a single subject in detail.monogyny n. [Gr. monos, one; gyne, woman] (ARTHRO: Insecta)The existence of only one functional queen in a nest.see polygyny.monohybrid n. [Gr. monos, one; L. hybrida, mongrel] The offspringof parents differing in one character.monolayer n. [Gr. monos, one; Eng. layer] A single layer ofcells growing on a substrate.monomers n.pl. [Gr. monos, one; meros, part] Simple compoundsfrom which polymers are synthesized.monomeri n.pl., sing. -us [Gr. monos, one; meros, part] (AR-THRO: Insecta) Insects with one-jointed tarsi.monomeric a. [Gr. monos, one; meros, part] 1. Pertaining toa single segment. 2. Derived from one part. 3. Monogenic.monomerosomatous a. [Gr. monos, one; meros, part; soma,body] Having all body segments fused.monomerous a. [Gr. monos, one; meros, part] Having onlyone joint or part.monometrosis see haplometrosismonomial a. [Gr. monos, one; L. nomen, name] Having onename or designation consisting of one term only; uninomial.see binomial.monomorphic colony (BRYO) A colony in which only one kind

Online Dictionary of Invertebrate Zoology 579of zooid occurs in the zone of asexual reproduction.monomorphic polypides (BRYO: Phylactolaemata) One morphologictype of organ system in an asexual budding zone.monomorphic zooids (BRYO: Gymnolaemata) Zooids of onemorphologic type in the zone of astrogenetic repetition.monomorphism n. [Gr. monos, one; morphe, form] 1. Apopulation that exhibits a single form. see polymorphism.2. Species that contain only the female sex. see dimorphism.3. (ARTHRO: Insecta) In social insects, havingwithin a species or colony only a single worker subcaste.monomorphic a.monomyarian a. [Gr. monos, one; mys, muscle] 1. Havingonly one muscle. 2. (MOLL: Bivalvia) In oysters and scallops,pertaining to the anterior adductor muscle that hascompletely disappeared, and the posterior adductor shiftedto a more central location between the valves; monomyariancondition. see anisomyarian.mononchoid a. [ Mononchus; Gr. eidos, like] (NEMATA: Adenophorea)Having the characteristics of the predaciousnematode genus Mononchus.mononychous a. [Gr. monos, single; onyx, claw] Pertains toorganisms having a single or uncleft claw.monoparental a. [Gr. monos, one; L. parens, progenitor] Withfemales only.monophagous a. [Gr. monos, one; phagein, to eat] Adaptedto subsist on a single kind of food; specialized on a singlehost species; monotrophic. see polyphagous, oligophagous.monophyletic a. [Gr. monos, single; phyle, tribe] 1. With asingle common ancestry. 2. Any group whose most recentcommon ancestor is cladistically a member of that group.see polyphyletic, oligophyletic.monophyly see monophyleticmonoplacid a. [Gr. monos, one; plax, flat plate] Having onlyone plate.Monoplacophora, monoplacophorans n., n.pl. [Gr. monos,one; plax, flat plate; pherein, to carry] A class of Mollusca

580Maggenti and Gardnermostly extinct, with a limpet-like, cap-shaped, cone-shapedor spoon-shaped shell with serially paired muscle scars.monoploid a. [Gr. monoploos, onefold] 1. Any somatic cell orindividual with one set of chromosomes. 2. Having the basicnumber of chromosomes in a polyploid series. seeeuploid, aneuploid.monoplont see haplontmonorchic a. [Gr. monos, one; orchis, testicle] Having onetestis. see diorchic.monosiphonous a. [Gr. monos, one; siphon, tube] (CNID: Hydrozoa)Having a single central tube as in the hydrocaulus.monosome n. [Gr. monos, one; soma, body] 1. A chromosomelacking an allele. see polysome. 2. A single ribosomebound to messenger RNA.monosomic a. [Gr. monos, one; soma, body] Lacking onechromosome of a normal complement (somatic number is2N-l).monospermy n. [Gr. monos, one; sperma, seed] One spermfertilizing an ovum; normal fertilization of an ovum.monostich n. [Gr. monos, one; stichos, row] 1. Cells arrangedin a row along one side of an axis. 2. (NEMATA: Adenophorea)Esophagi in Stichosomida (=Trichocephalida; Mermithida)in which the cells are external to the esophagusand along one side. monostichous a. see distich.monostigmatous a. [Gr. monos, single; stigma, mark] Havingone stigma only.monostome n. [Gr. monos, one; stoma, mouth] (PLATY: Trematoda)A fluke lacking a ventral sucker.monostome cercaria (PLATY: Trematoda) A cercaria with amuscular oral sucker anteriorly and no ventral sucker; encystson objects in water.monothalamous a. [Gr. monos, one; thalamos, chamber]Unilocular; single chambered. see monothecal.monothecal a. [Gr. monos, one; theke, case] 1. Having onechamber or loculus. see monothalamous. 2. (ANN: Polychaeta)Having only one spermatheca. see polythecal.

Online Dictionary of Invertebrate Zoology 581monothely n. [Gr. monos, one; thelys, woman] Polyandry,with one female being fertilized by many males. monotheliousa.monothetic a. [Gr. monos, one; tithenai, to place] Pertainingto taxa based on only one or a few characters. see polythetic.monotrochous a. [Gr. monos, one; trochous, wheel] (ARTHRO)Having the trochanter composed of a single piece.monotrophic see monophagousmonotropic a. [Gr. monos, one; tropikos, a turning] 1. Turningin one direction. 2. (ARTHRO: Insecta) Visiting only onekind of flower for nectar. see polytropic.monotype n. [Gr. monos, one; typos, type] A holotype of aspecies based on a single specimen.monotypic a. [Gr. monos, one; typos, type] Pertains to ataxon containing only one immediate subordinate taxon, asa genus containing only one species, or a species containingonly one subspecies.monovalent articulation Articulation permitting movement inone mode only; forward and backward, but not up anddown, etc.monovarial a. [Gr. monos, one; L. ovum, egg; arium, producingorgan] Having one ovary.monovoltine see univoltinemonoxenic a. [Gr. monos, one; xenos, guest] Pertaining tothe rearing of an organism with only one know species as afood source. see axenic.monoxenous a. [Gr. monos, one; xenos, guest] Living withina single host during a parasite's life cycle. see dixenous.monozoic a. [Gr. monos, one; zoon, animal] (PLATY: Cestoda)Non-strobilated cestodes.monozonian a. [Gr. monos, one; zone, girdle] (ARTHRO: Diplopoda)Having a cylindrical sclerite composed of fused tergites,pleurites and sternites.montane a. [L. mons, mountain] Pertaining to mountains andconiferous forests of mountains.

582Maggenti and Gardnermonticolous a. [L. mons, mountain; colare, to inhabit] Livingin mountains.monticule n. [L. dim. mons, mountain] (BRYO: Stenolaemata)A prominence on the colony surface made by a cluster ofpolymorphs. see macula.morgan n. [named for T. H. Morgan] A chromosome map unit;expresses the relative distance between genes on a chromosome,as determined by crossing-over phenomena.moribund a. [L. mors, death] Dying; near death.morph n. [Gr. morphe, form] Any of the individual variants ofa polymorphic population.morpha n. [Gr. morphe, form] (ARTHRO: Insecta) A word endingrecently incorporated in Hemiptera indicating majorgroups; Nepomorpha (=Hydrocorisae).morphallaxis n. [Gr. morphe, form; allaxis, exchange] A regenerativeprocess in which the new parts are reorganizedfrom the old, instead of being formed anterior or posteriorto the level of amputation.morphism see polymorphismmorphogenesis n. [Gr. morphe, form; genesis, beginning]The development of the characteristic form and structure ofa cell or an organism.morphology n. [Gr. morphe, form; logos, discourse] The scienceof structural characteristics, particularly those on thesurface of the body. morphological a.morphometrics n. [Gr. morphe, form; metron, measurement]Body measurements.morphometry n. [Gr. morphe, form; metron, measurement]Measurement of external form.morphopathology n. [Gr. morphe, form; pathos, suffering;logos, discourse] The branch of pathology dealing with themorbid changes occurring in the structure of tissues, cellsand organs.morphosis n. [Gr. morphosis, a shaping] Nonadaptive and unstablevariation in an individual's morphogenesis associatedwith environmental changes.

Online Dictionary of Invertebrate Zoology 583morphospecies n.pl. [Gr. morphe, form; L. species, kind] Atypological species based on morphological differences. seephenon.morphotype n. [Gr. morphe, form; L. typos, type] The typespecimen of one of the forms of a dimorphic species.morula n. [L. dim. morus, mulberry] In embryology, consistingof a cluster of cleaving blastomeres; stage preceding blastula.morular cell (BRYO) A cell filled with refringent spheres in theperitoneal membrane and funicular strand.morular organ see columellamorulation n. [L. dim. morus, mulberry] Formation of themorula during holoblastic egg cleavage.morulit see nucleolusmosaic n. [Gr. Mousaios, of the Muses] 1. An organism composedof two or more cell lines of different genetic orchromosomal constitution, both cell lines being derivedfrom the same zygote; genetic mosaic. see chimera. 2. Anindividual displaying characteristics of more than one sexor polymorphic form; phenotypic mosaic.mosaic evolution Evolution that involves differential rates fordifferent structures, organs, or other components of thephenotype.mosaic theory (ARTHRO) The theory explaining the function ofthe compound eye, with the numerous ommatidia receivinga portion of the image and then combining them into a totalimage in the brain.moschate a. [L. moschus, musk] Having an odor similar tomusk.mother cell A precursory cell or metrocyte.mother genus An original genus from which others have derivedby nomenclatorial division.motile a. [L. movere, to move] Capable of spontaneousmovement.motor nerve see motor neuronmotor nervous system A part of the nervous system lying

584Maggenti and Gardnerentirely within the body that transmits stimuli from thecentral nervous system to the motor elements of the body.motor neurocyte The neurocyte of a motor neuron.motor neuron A neuron that transmits excitation directly to aneffector; motor nerve.mottled a. [F. mattele, curdled] Spotted with different colors;maculated; blotched.moult see moltmound nest (ARTHRO) Nest or part of one built above groundof soil or carton material.mouse unit (MOLL: Bivalvia) A unit of measurement employedas a gradient of shellfish poisoning.mouth n. [A.S. muth, mouth] The oral aperture.mouth-anus axis (MOLL: Bivalvia) In oysters, a line throughthe mouth and anus.mouth capsule see buccal cavitymouth cirri (ARTHRO: Crustacea) In Cirripedia, the first pair ofmodified cirri.mouth cone (ARTHRO: Insecta) The rostrum; proboscis,prostomium.mouth fork see laciniamouth hooks (ARTHRO: Insecta) In Cyclorrhapha 2nd instars,cuticular claw-like structures, one on each side of the atrialopening, thought to articulate with a small ventral scleritethat may represent the maxillary cardo; mandibularsclerites.mouth spear see stomatostyle, odontostylemovable finger (ARTHRO: Crustacea) The dactyl of the chela.movable hook (ARTHRO: Insecta) In Odonata, a small tooth onthe inner border of the lateral lobe slightly external to theend-hook.mucid a. [L. mucidus, mucus-like] Mouldy; slimy.mucific a. [L. mucus, mucus; facere, to make] Pertains to mucus-secreting.mucigen n. [L. mucus, mucus; genos, to produce] A substance

Online Dictionary of Invertebrate Zoology 585from which mucin is derived in mucin secreting cells.mucilaginous a. [L. mucus, mucus] Pertaining to gum-like ormucilage.mucin n. [L. mucus, mucus] A glycoprotein secreted by variouscells or glands.mucivorous a. [L. mucus, mucus; vorare, to devour] Feedingon the juices of plants. mucivore n.mucoid a. [L. mucus, mucus; Gr. eidos, like] Glycoproteinsthat are found in cartilage, cuticle, etc.mucolytic a. [L. mucus, mucus; lysis, loosen] The breakingdown or dissolving of mucus.mucopolysaccharides n.pl. [L. mucus, mucus; Gr. polys,many; sakcharon, sugar] Polysaccharides with aminosugarand uronic acid; a constituent of glycoproteins.mucoprotein a. [L. mucus, mucus; Gr. protos, first; eidos,form] A glucoprotein containing more than 4% hexosamine.see glucoprotein, glycoprotein.mucoreous a. [L. mucor, mould] Pertaining to or appearingmouldy; surface covered with small fringe-like processes.mucosa n. [L. mucus, mucus] Mucus membrane; lining of internalpassageways.mucous a. [L. mucus, mucus] Secreting mucus or a similarsticky substance by various cells, glands, or membranes.mucous membrane see mucosamucro n.; pl. mucrones [L. mucro, sharp point] A smallpointed projection, or spine-like ending on a terminus.mucronate a.mucron see mucromucronate valve see beakmucus n. [L. mucus, mucus] A slimy fluid secreted by glandcells present in many epithelia known as mucous membranes.mulberry corpuscle see spherule cellMullerian association A group of species showing Mullerianmimicry.

586Maggenti and GardnerMullerian mimicry Similarity (usually consisting of coloration)of several species that are distasteful, poisonous, or otherwiseharmful to a predator. see Batesian mimicry.Muller's larva (PLATY: Turbellaria) In Polycladida, larva possessingeight posteriorly directed postoral lobes. seecephalotrocha larva.Muller's organ (ARTHRO: Insecta) A group of numerousscolopophores forming a swelling; in Acridoidea, applied tothe inner surface of each tympanum and connected by theauditory nerve to the metathoracic ganglion.Muller's thread see ovarial ligamentmultiangular, multiangulate a. [L. multus, many; angulus,angle] Having many angles.multiarticulate a. [L. multus, many; articulus, joint] Manyjointed;polyarthric.multicamerate a. [L. multus, many; camera, chamber] Havingmultiple chambers. see multilocular.multicarinate a. [L. multus, many; carina, keel] Having manyridges or carinae.multicellular a. [L. multus, many; cella, cell] Comprised oftwo or more cells; many-celled.multicolonial n. [L. multus, many; colonia, colony] (ARTHRO:Insecta) Population of social insects divided into independentcolonies or nests.multifactorial a. [L. multus, many; facere, to do] Controlledby several gene loci.multifarious a. [L. multifarius, manifold] Arranged in severalrows. see polystichous.multifid a. [L. multus, many; findere, to cleave] Having manydivisions or clefts.multiforous a. [L. multus, many; foris, gate] (ARTHRO: Insecta)A spiracle with three or more secondary openings inor near the peritreme.multilocular a. [L. multus, many; loculus, little place] Manycelled or chambered; having many divisions or compartments;plurilocular. see multicamerate.

Online Dictionary of Invertebrate Zoology 587multilocular hydatid cyst see alveolar hydatid cystmultinucleate a. [L. multus, many; nucleus, kernel] Pertainingto cells with many nuclei; a coenocyte; polykaric.multiordinal crochets (ARTHRO: Insecta) Crochets of larvaewhen they arise from a single row, but with many alternatinglengths. see ordinal.multiovulate a. [L. multus, many; dim. ovum, egg] Withmany ovules.multiparasitism n. [L. multus, many; Gr. para, near; sitos,food] The coincident parasitism of an organism by two ormore parasites of different species.multiparous a. [L. multus, many; parere, to beget] Bearingmany offspring.multipartite a. [L. multus, many; partitis, divided] Dividedinto many parts.multiple allele A series of three or more alternative forms of agene at a single locus in a chromosome.multiplicate a. [L. multus, many; plicare, to fold] Havingmany folds or plicae.multipolar cell Cells with more than two nerves precedingfrom it.multiporous septulum (BRYO: Gymnolaemata) A membraneor plate with many holes; a rosette-plate.multiramous a. [L. multus, many; ramus, branch] Manybranched.multiramous plasmatocyte A plasmatocyte with three spindleends.multiramous vermiform cell A vermiform cell with threespindle ends.multiserial a. [L. multus, many; series, a row] Having manyseries or rows.multiserial bands (ARTHRO: Insecta) In Lepidoptera, caterpillarswith crochets absent from the mesial and lateral partsof the circle.multiserial circle (ARTHRO: Insecta) In Lepidoptera, caterpillarcrochets arranged in three or more concentric circles.

588Maggenti and Gardnermultiserial crochets (ARTHRO: Insecta) In Lepidoptera, crochetsarranged in several rows.multisetiferous a. [L. multus, many; seta, bristle; ferre, tobear] With many setae.multispinose a. [L. multus, many; spina, spine] With manyspines.multispiral a. [L. multus, many; spira, a coil] With numerouswhorls.multistriate a. [L. multus, many; stria, furrow] With manystriations; numerous thread-like lines, grooves orscratches.multivalent a. [L. multus, many; valens, strong] Pertaining toseveral chromosomes being attached together.multivalved a. [L. multus, many; valva, leaf of a folding door](MOLL: Polyplacophora) Having more than two sections.multivincular a. [L. multus, many; vinculum, to bind] (MOLL:Bivalvia) Having a ligament with many bonds of union.multivoltine a. [L. multus, many; It. volta, time] Having twoor more generations or broods in a year or season. seebivoltine.multizooidal bud see giant budmumia n. [ML. mumia, mummy] (ARTHRO: Insecta) A pupa.mumia pseudonympha (ARTHRO: Insecta) A pupa with somedegree of locomotion.munite a. [L. munitus, fortify] Provided with armature.mural lacuna see pustulamural plate see compartmental platemural spine (BRYO: Stenolaemata) A small skeletal spine extendinginto the zooidal chamber.mural tooth (NEMATA) A tooth attached to, or derived from thestomatal wall.muricate a. [L. murex, a pointed stone] Formed with sharpelevated points; covered with sharp points.muscidiform larva (ARTHRO: Insecta) Like a Diptera larva;sub-cylindrical larva with the cephalic-end pointed and the

Online Dictionary of Invertebrate Zoology 589caudal-end broad.muscle n. [L. musculus, muscle] Tissue made up of specializedcells for the production of motion by contraction; a sheet,bundle, or mass of such tissue.muscle fibers see fibroplasmmuscle layer(s) 1. One or more layers of muscle below theepithelium. 2. (BRYO: Phylactolaemata) Both longitudinaland circular muscles between epithelial and peritoneal layersof the colony wall.muscle scar A mark on the interior of valve or carapace inCrustacea, Mollusca and Brachiopoda representing the positionof muscle attachment, recognizable by surface texture,elevation, depression or a delimiting narrow groove; amuscle imprint.muscle segment A myomere.muscularis n. [L. musculus, muscle] (ARTHRO: Insecta) Amuscular sheath surrounding the alimentary canal.muscular pad (ECHI) A muscular tissue pad or pads associatedwith the ventral setae.muscular sheath (ARTHRO: Insecta) In Culicidae, a sheath enclosinga coelomic section of each of the ventral setae.musculature n. [L. musculus, muscle] The system or arrangementof muscular structure of an organism.musculus bursae basalis (NEMATA: Secernentea) Bursal musclethat arises from the ventral side of the bursa and extendsdorsally to the root of the dorsal ray.musculus costae dorsalis (NEMATA: Secernentea) A manybranched bursal muscle that arises mediodorsally in thedorsal ray, and extending anteriorly to become trifurcate,then the median arm splits into four parts.musculus costae lateralis externus anterior (NEMATA: Secernentea)Bursal muscles that arise anterior to the musculuscostae lateralis externus posterior, extending posteriorlyto the base of the ventral rays; possibly functioning toextend the bursa.musculus costae lateralis externus posterior (NEMATA: Secernentea)A bursal muscle that arises anteriorly dorsad of

590Maggenti and Gardnerthe lateral cords, extending posteriorly and becoming trifurcateat the base of the lateral rays; possibly functioningto extend the bursa.musculus costerum lateralium internis (NEMATA: Secernentea)Bursa muscle that arises as paired submedianmuscles at the body wall anterior to the intestino-rectalvalve; each laterally extended branch entering the root ofthe lateral ray; possibly functioning to bend the bursa inwards.mushroom bodies (ARTHRO: Insecta) The two stalked nervestructures of the protocerebrum, that are connected withthe optic lobes. see corpora pedunculata.mushroom gland (ARTHRO: Insecta) Large mushroom-shapedseminal vesicles.mutafacient n. [L. mutatus, change; facere, to make] Gene orgenetic element that causes or increases the chance ofmutation at another site.mutagen n. [L. mutare, to change; Gr. gennaein, to produce]Any physical or chemical agent that increases mutationalevents.mutant n. [L. mutare, to change] An organism that undergoesmutation.mutation n. [L. mutare, to change] A structural change in agene, consisting of a replacement, duplication, or deletionof one or several pairs in the DNA.mutation frequency The frequency of mutants in a population.mutationism see De Vriesianismmutation rate Frequency with which a mutation occurs persite per generation.mutation theory A theory of the origin of new characteristicsin organisms as a result of changes in the genes. see saltation.mutator genes Any gene that causes an increase in mutationrates in other genes. see mutafacient.mutein n. [L. mutatus, change; Eng. protein] A mutationallyaltered protein analogous to the normal type.

Online Dictionary of Invertebrate Zoology 591mutic, mutilous a. [L. muticus; shortened] Unarmed; lackingdefensive processes that usually occur.mutilate v.t. [L. mutilus, cut-off] To deprive of one or moreessential part(s); to amputate.muton n. [L. mutare, to change] The smallest element in thearray of mutation sites, that when altered, may give rise toa mutant.mutualism n. [L. mutuus, reciprocal] A type of symbiosis inwhich both host and symbiont benefit from the association.muzzle n. [OF. musel, snout] Snout.myarian a. [Gr. mys, muscle] 1. Referring to muscle, as inmeromyarian. 2. (MOLL: Bivalvia) Used in classification asto number and position of the adductor muscles.mycelium n. [Gr. mykes, fungus] In fungi, the network offilaments that form the vegetative part.mycetangium n. [Gr. mykes, fungus; angeion, vessel] (AR-THRO: Insecta) The fungus-storing organs of Platypodinae,a sac-like invagination of the epidermis at the posteriorpart of the prothorax.mycetocyte n. [Gr. mykes, fungus; kytos, container] A large,polyploid cell containing intracellular mutualistic and commensalisticmicrosymbiotes; one of many cells that makeup the mycetome. see symbiosis.mycetome n. [Gr. mykes, fungus; -oma, mass] A specializedstructure or organ that houses symbiotes.mycetometochy n. [Gr. mykes, fungus; metochos, sharing](ARTHRO: Insecta) Symbiosis between fungi and the dwellersof compound nests.mycetophagous a. [Gr. mykes, fungus; phagein, to eat]Feeding on fungi; mycophagous; fungivorous.mycohelminths n.pl. [Gr. mykes, fungus; helmins, worm]Fungivorous nematodes.mycophagous a. [Gr. mykes, fungus; phagein, to eat] Feedingon fungi; mycetophagous; fungivorous.mycosis n. [Gr. mykes, fungus; -sis, process of] Any diseasecaused by the invasion of fungi.

592Maggenti and Gardnermycotoxin n. [Gr. mykes, fungus; toxikon, poison] A low molecularweight metabolite of fungi which is poisonous toanimals.myelin sheath A fatty material surrounding a nerve fiber.myiasis n. [Gr. myia, fly; -iasis, morbid condition] A conditionderiving from invasion by dipterous larvae.myoblast n. [Gr. mys, muscle; blastos, bud] A cell that producesmuscular fiber.myochordotonal organ (ARTHRO: Crustacea) In Decapoda, aproprioceptor at the proximal end of the meropodite, a flatmembrane lying between the skeleton and sheath of theaccessory flexor muscle of the carpus, with distal bipolarsensory cells passing through the membrane and attachedto the skeleton; having scolopidia similar to the insectchordotonal organs.myocytes n.pl. [Gr. mys, muscle; kytos, container] (PORIF)Cells that cause contraction.myoepithelial n. [Gr. mys, muscle; epi, upon; thele, nipple] 1.(BRYO) A contractile ectodermal cell with intracellular striatedmuscles. 2. (CNID) Epithelium with a longitudinal contractilefiber at the base; epitheliomuscular.myofibrillae, myofibrils n.pl; sing. -a [Gr. mys, muscle; dim.fibra, fiber] Longitudinal fibrils of muscle cells.myogenic a. [Gr. mys, muscle; gennaein, to produce] Pertainsto a muscle contraction initiated by nerve impulse. seeneurogenic.myoglobin n. [Gr. mys, muscle; L. globus, ball] A type of hemoglobinoccurring in muscle cells concerned with oxygentransport and storage; also called myohemoglobin.myohematin, myohaematin n. [Gr. mys, muscle; haima,blood] An iron pigment said to occur in muscles; thought tobe a cytochrome.myoid a. [Gr. mys, muscle; eidos, like] Composed of musclefibers.myology n. [Gr. mys, muscle; logos, discourse] That branch ofanatomy dealing with the arrangement of muscles.myomere n. [Gr. mys, muscle; meros, part] A muscular seg-

Online Dictionary of Invertebrate Zoology 593ment.myoneural junction Point of junction between a motor nerveand the muscle which it activates.myoneure n. [Gr. mys, muscle; neuron, nerve] A motor neuron.myonicity n. [Gr. mys, muscle] The contracting power of muscletissue.myophore n. [Gr. mys, muscle; pherein, to bear] (MOLL: Bivalvia)A spoon- or sickle-shaped structure beneath thebeak on the interior of the shell; functioning as a place ofattachment for certain muscles.myoplasm n. [Gr. mys, muscle; plasma, formed or molded]The contractile portion of a muscle cell.myosin n. [Gr. mys, muscle] Muscle protein that combineswith actin to form actomyosin in muscle contraction.myostracum n. [Gr. mys, muscle; ostrakon, shell] (MOLL: Bivalvia)That part of the shell wall secreted at the attachmentof the adductor muscles.myotasis n. [Gr. mys, muscle; tasis, tension] Muscular tonicityor tension.myotome n. [Gr. mys, muscle; tome, to cut] A muscle segment,somite or myomere.myrmecobiosis n. [Gr. myrmex, ant; biosis, life] A symbioticrelationship between ants; consociation.myrmecochory n. [Gr. myrmex, ant; chorein, to spread] Activedispersion of seeds by ants.myrmecoclepty n. [Gr. myrmex, ant; kleptes, thief] (ARTHRO:Insecta) A form of symbiosis in which the guest ant stealsfood from the host ant.myrmecodomatium n.; pl. -ia [Gr. myrmex, ant; domos,house] A plant tissue cavity inhabited by ants.myrmecole n. [Gr. myrmex, ant; L. colere, to inhabit] An organismthat lives in ants' nests, but does not otherwise interactwith them. see myrmecophilous.myrmecology n. [Gr. myrmex, ant; logos, discourse] The divisionof entomology that studies ants.

594Maggenti and Gardnermyrmecophagous a. [Gr. myrmex, ant; phagein, to eat]Feeding on ants.myrmecophile n. [Gr. myrmex, ant; philos, love] A symbiontof ants.myrmecophilous a. [Gr. myrmex, ant; philos, love] Fondnessof, or benefited by an association with ants. see myrmecole.myrmecophily n. [Gr. myrmex, ant; philos, love] (ARTHRO:Insecta) The utilization by other insects, mainly beetles, ofant colonies as domiciles and sources of food; ant symbiosis.myrmecophilous a.myrmecophobic a. [Gr. myrmex, ant; phobeisthai, to flee]Having the ability to repel ants.myrmecophyte n. [Gr. myrmex, ant; phyton, plant] A myrmecophilousplant that has an obligatory, mutualistic relationshipwith ants.myrmecoxenes n.pl. [Gr. myrmex, ant; xenos, guest] Trueguests of ants. see symphile.mysis stage (ARTHRO: Crustacea) In Decapoda, a larval stagein which only the thoracopods are used in swimming andthe compound eye is stalked; schizopod larva. see zoea.mystacine a. [Gr. mystax, moustache] Bearded; having tactilehairs or vibrissae.mystax n. [Gr. mystax, moustache] (ARTHRO: Insecta) A clusterof hairs or bristles above the mouth; beard.mytiliform a. [L. mytilus, sea mussel; forma, shape] 1. (AR-THRO: Insecta) In aquatic Hemiptera, the shell-shapedswimming feet. 2. (MOLL: Bivalvia) Having the form of amussel shell; mytiloid; shell shaped like the genus Mytilus.myzesis n. [Gr. myzein, to suck] Suction or sucking.myzorhynchus n. [Gr. myzein, to suck; rhynchos, snout](PLATY: Cestoda) In some Tetraphyllidea, an apical stalked,sucker-like organ on the scolex.

Nnacre n. [F. nacre, mother-of-pearl] (MOLL) The pearly or iridescentsubstance that lines the interior of shells, especiallygastropods and pelecypods; mother-of-pearl; nacreousa.naiad n. [Gr. Naias, water nymph] (ARTHRO: Insecta) InHemimetabola, the aquatic, gill-breathing nymph.nail n. [A.S. naegel, nail] (ARTHRO) A tarsal claw; unguis.naked a. [A.S. nacod, nude] Lacking the usual covering.nanism n. [Gr. nanos, dwarf] Dwarfishness. nanoid a.nanitic worker (ARTHRO: Insecta) In Formicidae, dwarf workersproduced in first broods or later starved broods.nanometer n. [Gr. nanos, dwarf; metron, a measure] Unit ofmeasurement equal to one billionth of a meter; also calledmillimicron, micromillimeter and bicron.nanoplankton n. [Gr. nanos, dwarf; plankton, wandering] Microscopicfloating animal and plant organisms.nanozooid n. [Gr. nanos, dwarf; zoon, animal; eidos, like](BRYO: Stenolaemata) In Tubuliporidae, a polymorph with asingle tentacle and reduced alimentary sac.narcosis n. [Gr. narke, numbness, torpor] Stupor or unconsciousnesscaused by a drug or carbon dioxide build up inthe blood.nasale n. [L. nasus, nose] (ARTHRO: Insecta) Anterio-medianprojection from the frons formed by fusion of frons, clypeusand labrum, or by frons and clypeus alone, especially someColeoptera larvae.nascent a. [L. nascens, arising, beginning] Beginning to exist,grow, or develop; the act of being born.naso n. [L. nasus, nose] (ARTHRO: Chelicerata) In Acari, anacronal protuberance at the anterior of the body overhangingthe chelicerae.Nassanoff's gland see Nassanov's gland

596Maggenti and GardnerNassanov's gland (ARTHRO: Insecta) In Apis, a gland openingto the exterior beneath abdominal tergites six and seven,that function in pheromone production; well developed inworkers, but absent in drones and maybe queens.nasus n. [L. nasus, nose] (ARTHRO: Insecta) 1. The clypeal region;the drawn-out foreward part of the face. 2. In Isoptera,the snout-like frontal projection that functions to ejectpoisonous or sticky fluids at intruders.nasute n. [L. nasus, nose] (ARTHRO: Insecta) A type of soldiertermite that bears a frontal snout-like projection or hornthrough which it ejects a defensive toxin; some possesslarge hooked mandibles, while in others the mandibles aregreatly reduced.natal a. [L. natalis, of birth] Of or pertaining to birth.natality rate Birth rate; the number of births per populationunit during a given period of time.natant a. [L. natare, to swim] Adapted for swimming; floating;swimming at the surface of the water.natatory a. [L. natare, to swim] Characterized by swimming;adapted for swimming.natatory lamellae (ARTHRO: Insecta) In Orthoptera Gryllotalpidae,long slender plates of the hind tibiae.nates n.pl. [L. natis, rump] The umbones of bivalves.naticid a. [LL. naticae, buttocks] (MOLL: Gastropoda) Pertainingto Natica , a genus of carnivorous sea snail.naticiform a. [LL. naticae, buttocks; forma, shape] (MOLL:Gastropoda) Having globose last whorl and small spire, likethe shell of Natica.native a. [L. nativus, inherent, conferred by birth] Animals andplants originating and living in a particular area; not imported.natural classification In biology, a classification of groups oforganisms or objects to show their characteristics andevolutionary relationships with each other. see artificialclassification.natural decrease The rate of population decrease measuredby subtracting the natality rate from the mortality rate. see

Online Dictionary of Invertebrate Zoology 597natural increase.natural group A group of organisms having a common ancestor.natural increase The rate of population increase measured bysubtracting mortality rate from natality rate.natural requeening see supersedurenatural selection The process of elimination of the least fittedindividuals, and hence species, by the natural conditions oftheir habitat.naupliar eye see nauplius eyenaupliiform a. [L. nauplis, shellfish; forma, shape] (ARTHRO:Crustacea) Pertaining to the nauplius larva.nauplius eye (ARTHRO: Crustacea) In nauplii and many adults,an unpaired median eye consisting of 1 to few light-sensitivecells; median eye; naupliar eye.nauplius larva (ARTHRO: Crustacea) The earliest larvalstage(s), usually with one central eye, and characterized byhaving only three pairs of appendages: antennules, antennae,and mandibles, all primarily of locomotive function.nautilicone a. [Gr. nautilos, nautilus shell; L. conus, cone](MOLL: Cephalopoda) Spirally coiled in a single plane.nautiliform see nautiloidnautiloid a. [Gr. nautilos, nautilus shell; eidos, form] (MOLL:Cephalopoda) Any nautilid shell coiled in a symmetrical involutespiral; nautiliform.navicular a. [L. dim. navis, ship] Boatshaped; cymbiform;scaphoid.neala n. [L. ne, not; ala, wing] (ARTHRO: Insecta) 1. Thejugum or jugal region of a wing. 2. Vannusneallotype n. [Gr. neos, new; allos, other; typos, type] An allotypeof the opposite sex from that described in the publicationof a neotype.neanic a. [Gr. neanikos, fresh] 1. Being youthful or immature;a stage of development between the brephic and mature.2. (ARTHRO: Insecta) The pupal stage. 3. (BRACHIO) Ayouthful stage when generic characters are beginning to

598Maggenti and Gardnerbecome apparent. 4. (BRYO) Zooids laid down in the phaseof astogenic change.neap a. [ME. neep, neap] A series of tides exhibiting a smalltidal range; occurring midway between spring tides.Nearctic a. [Gr. neos, new; arkticos, bear] Pertaining to orbelonging to a terrestrial division comprised of Greenlandand North America, and including northern Mexico.neascus larva (PLATY: Trematoda) In Strigeidae and Diplostomatidae,a type of metacercaria with a cup-shapedforebody and a well developed hindbody.nebulous a. [L. nebula, cloud] Clouded; marked with manyscattered dilated colors or spots; indistinct.neck n. [A.S. hnecca, neck] 1. (ARTHRO: Insecta) The slenderconnecting structure between head and thorax where thehead is free. 2. (MOLL) Distal part of the base of a siphonostomatousshell, starting where outline of left sidechanges from convex to concave. 4. (PLATY: Cestoda) Theunsegmented area between the scolex and strobilae. 3.(NEMATA) The slender, anterior portion of the body containingthe esophagus.neck organ see nuchal organnecrobiosis n. [Gr. nekros, corpse; bios, life] A series of tissuechanges occurring after the death of an individual cell.necrocytosis n. [Gr. nekros, corpse; kytos, container] Deathof a cell.necrophagous a. [Gr. nekros, corpse; phagein, to eat] Feedingupon decaying flesh.necrophoresis, necrophoric behavior (ARTHRO: Insecta)Carrying dead colony members away from the nest.necrosis n. [Gr. nekros, corpse; izein, cause to be] The deathof cells or tissues.necrotize v.t. [Gr. nekros, corpse] To kill cells and tissues in aliving organism.nectar n. [Gr. nektar, drink of the gods] A sweet substancesecreted by flowers and certain leaves; the food of manyinsects.

Online Dictionary of Invertebrate Zoology 599nectobenthic a. [Gr. nektes, swimmer; benthos, depths of thesea] Organisms swimming freely on or near the bottom ofthe sea.nectocalyx see nectophorenectochaeta larva (ANN: Polychaeta) A free swimming planktogeniclarva of some aquatic forms that bear rings of ciliaand 3 pairs of parapodia.necton see nektonnectophore n. [Gr. nektos, swimming; phorein, to carry](CNID: Hydrozoa) In Siphonophora, the muscular swimmingbell that propels the colony; nectocalyx; nectozooid. seepneumatophore.nectopod n. [Gr. nektos, swimming; pous, foot] An appendageadapted for swimming.nectosome n. [Gr. nektos, swimming; soma, body] (CNID: Hydrozoa)In Siphonophora, the part that bears the swimmingbells.nectozooid see nectophoreNeedham's sac/organ (MOLL: Cephalopoda) In males, a specializationof the sperm duct for formation and storage ofspermatophores; spermatophoric sac.negative geotropism Movement directed away from theearth's gravitational force.negative phototropism The tendency to retreat from light.negative tropism The tendency to retreat from stimuli.nekton n. [Gr. nektes, swimmer] Organisms that swim in theopen water, i.e., jellyfish, squid, fishes, turtles, seals andwhales; necton. see seston.nema n. [Gr. nema, thread] (NEMATA) Any individual of thephylum Nemata; a nematode.nema curds see nema woolnemaposit v.i. [Gr. nema, thread; L. ponere, to place] (AR-THRO: Insecta) Mock oviposition by insects parasitized bynematodes; the insect deposits nematodes instead of theirown eggs.Nemata, nematodes n.; n.pl. [Gr. nema, thread] A phylum

600Maggenti and Gardnercontaining a large, diverse group of free-living, plant andanimal parasitic roundworms, covered by cuticle and havingwell developed nervous, reproductive and digestivesystems, but lack true segmentation, a true coelom andjointed appendages; formerly called Nematoda and Nematoidea.Nemathelminthes n. [Gr. nema, thread; helmins, worm] Aformer name for the phylum that included the phylaNemata, Nematomorpha and Acanthocephala collectively.nematicide see nematocidenematize v.i. [Gr. nema, thread] (NEMATA) To populate or infestwith nematodes. nematization n.nematoblast n. [Gr. nema, thread; blastos, bud] (CNID) A cellthat forms a nematocyst; cnidoblast.nematocide n. [Gr. nema, thread; L. caedare, to kill] Anyagent lethal to nematodes.nematocyst, cnida n. [Gr. nema, thread; kystis, bladder](CNID) Intracellular organelles that function in defense andcapture of prey by injecting a toxin; in hydras, they functionin adhesion to the bottom; also called stinging cells,nettle cells, or thread capsule or cell. see spirocyst.nematocyte see plasmatocytes, cnidocystNematoda see Nematanematode n. [Gr. nema, thread; eidos, form] A member of thephylum Nematanematode wool see nema woolnematogen n. [Gr. nema, thread; genos, offspring] (MESO:Rhombozoa) The vermiform adult that reproduces vermiformembryos. see rhombogen.nematoid a. [Gr. nema, thread; eidos, form] Thread-like.Nematoidea see Nematanematology n. [Gr. nema, thread; logos, discourse] Thatbranch of zoology dealing with nematodes.Nematomorpha, nematomorphs n.; n.pl. [Gr. nema, thread;morphos, form] A phylum of worm-like animals that arefree-living as adults and parasitic in arthropods as juve-

Online Dictionary of Invertebrate Zoology 601niles; horsehair worms; gordian worms.nematophagous a. [Gr. nema, thread; phagein, to eat] Feedingon nematodes.nematophore n. [Gr. nema, thread; phorein, to carry] (CNID:Hydrozoa) A club-like or capitate ended structure in a hydroidcolony containing nematocysts or adhesive cells; sarcostyle.nematopore n. [Gr. nema, thread; poros, pore] (BRYO:Stenolaemata) A slender tubular kenozooecium that openson the backside of the zoarium with tubules directed distally.nematosis n. [Gr. nema, thread; osis, denotes morbid condition](NEMATA) A morbid state due to parasitism by nematodes.nematosphere n. [Gr. nema, thread; sphaira, ball] (CNID:Anthozoa) In Actinaria, a club-like tentacle tip.nematostat n. [Gr. nema, thread; stasis, stand] (NEMATA) 1.Any phenomenon that holds a population in equilibrium. 2.A chemical that does not kill nematodes, but paralyzesthem.nematotheca n. [Gr. nema, thread; theke, case] (CNID: Hydrozoa)In Leptomedusae, small stemmed structures fromwhich nematophores develop; one-chambered, single andimmovable; two-chambered, shaped like a wineglass, withupper chamber capable of limited movement on its stem.nematozooid n. [Gr. nema, thread; zoon, animal; eidos, form](CNID: Hydrozoa) A defense polyp; machozooid; dactylozooid.nema wool (NEMATA) Masses of cryptobiotic nematodes adheringto certain plant tissues (bulbs).Nemertea, nemerteans, nemertines or rhynchocoels n.;n.pl. [Gr. Nemertes, a nereid, sea nymph] A phylum of unsegmented,bilaterally symmetrical acoelomate worms,commonly called ribbon worms, that are predatory carnivoresor scavengers that frequently use their eversible proboscisto catch prey.Nemertini see Nemertea

602Maggenti and Gardnernemic a. [Gr. nema, thread] Of or pertaining to nematodes.nemin n. [Gr. nema, thread] (NEMATA) An unknown or unidentifiedendogenous substance in nematodes that causes trapformation by predacious fungi.nemoricolous, nemoricole a. [L. nemus, woodland; colere, todwell] Living in open woodland areas.neobiogenesis n. [Gr. neos, new; bios, life; genesis, beginning]The theory that life may have been evolved severaltimes; recurring biopoiesis. see biogenesis.neoblast n. [Gr. neos, new; blastos, bud] Undifferentiated cellsthat migrate to wounds and participate in repair and regeneration.Neo-Darwinism 1. The theory of evolution stressing the continuityof germ plasm and non-transmission of acquiredcharacters (Weismannism). 2. Any evolutionary theoryfeaturing natural selection.neogallicolae-gallicolae (ARTHRO: Insecta) In Phylloxeridae,dimorph fundatrigeniae that will become gallicolae (leaf gallformers).neogallicolae-radicolae (ARTHRO: Insecta) In Phylloxeridae,dimorph fundatrigeniae that will become radicolae (rootgall formers).neogea see neotropical regionneogeic a. [Gr. neos, new; ge, earth] Belonging to the WesternHemisphere or New World. see gerontogeous.neonatal a. [Gr. neos, new; L. natus, bborn] Recently born orhatched.neontology n. [Gr. neos, new; on, being; logos, discourse]The study of recent organisms.neophorans n.pl. [Gr. neos, new; pherein, to carry] (PLATY:Turbellaria) 1. Individuals in which the yolk and oocytes areproduced by a separate gland, or are produced in separateparts of an ovovitellarium; ectolecithal eggs. see archoophorans.2. A former division of Turbellaria; a superorder.neoplasm n.; pl. neoplasia [Gr. neos, new; plasma, formedor molded] An abnormal mass of tissue.

Online Dictionary of Invertebrate Zoology 603neosistens n. [Gr. neos, new; L. sistere, to stop] (ARTHRO: Insecta)In Hemiptera Adelgidae, the overwintering nymph ofthe sistens.neosome n. [Gr. neos, new; soma, body] The entire organismaltered by neosomy.neosomule n. [Gr. neos, new; dim. soma, body] The newstructure that results from the neosomic process.neosomy n. [Gr. neos, new; soma, body] External transformation,during the formation of new cuticle, in an activestadium of a group normally metamorphosing by molts,i.e., certain insects, acarines, crustaceans and nematodes.neosomic a.neostigma n. [Gr. neos, new; stigma, point] (ARTHRO: Chelicerata)In Prostigmata Acariformes, a secondary spiraclenear the base or farther forward of the chelicera.neotaxy n. [Gr. neos, new; taxis, arrangement] A secondarychange of characters during phylogeny.neoteinia see neotenyneote(i)nic a. or n. [Gr. neos, new; teinein, to extend] (AR-THRO: Insecta) In Isoptera, a supplementary reproductivein a colony that may retain some juvenile characters; theword is used both as a noun and adjective (a neoteinic orneoteinic reproductive). Now spelled neotenicneotenic see neotenyneotenic plerocercoid (PLATY: Cestoda) All adult Caryophyllidea,whose adult developmental forms are thought to beextinct; exception: Archigetes. see neotenic procercoid.neotenic procercoid (PLATY: Cestoda) In Caryophyllidea, adultArchigetes that reaches sexual maturity complete with cercomer.neotenic reproduction see neotenyneotenin n. [Gr. neos, young; teinein, to extend] One of thejuvenile harmones.neoteny, enoteinia, neoteiny n. [Gr. neos, young; teinein, toextend] 1. A term referring to the condition in which thegonad completes its development prematurely before thenormal differentiation of imaginal structures are completed.

604Maggenti and Gardnersee hysterotely. 2. (ARTHRO) Further classified into twocategories: prothetely and metathetely. neotenic a.neotrichy n. [Gr. neos, new; trichos, hair] (ARTHRO: Chelicerata)In Acari, secondary formation of setae by multiplicationof primary setae in a given area.neotropical region A zoogeographical region extending southfrom the Mexican Plateau throughout Central America, theCaribbean and South America.neotype n. [Gr. neos, new; typos, type] A single specimen selectedas the type specimen from as near to the original localeas practicle in cases where the original types areknown to be destroyed or are lost.neozoology see neontologynephridial papilla (ANN) The projection marking the openingof the excretory organ.nephridioblast n. [Gr. nephros, kidney; blastos, bud] An ectodermalcell that is precursor to a nephridium.nephridiopore n. [Gr. nephros, kidney; poros, pore] 1. Theexterior opening of an excretory organ (nephridium). 2.(ARTHRO: Crustacea) see nephropore.nephridiostome see nephrostomenephridium n.; pl. -ia [Gr. dim. nephros, kidney; L. ium, natureof] 1. In various invertebrates, simple or branched,tubular structures that function in excretion, opening to theoutside through a nephridiopore. see protonephridium,metanephridium. 2. (ANN: Oligochaeta) A segment essentiallycomposed of excretory tubules that may dischargedirectly onto the body surface, or lead to a sinus dischargingto the exterior through pores by the setal ring. 3.(ECHI) One to many organs used for the temporary storageof eggs and sperm.nephroblast see nephridioblastnephrocytes n.pl. [Gr. nephros, kidney; kytos, container] Cellsthat occur singly or in groups in various parts in an invertebratebody and function to transform original waste materialinto a form with which the metabolic pathways candeal.

Online Dictionary of Invertebrate Zoology 605nephrodinic a. [Gr. nephros, kidney; odis, labor] Having asingle duct serving both excretory and genital purposes.nephrogonoduct n. [Gr. nephros, kidney; gonos, progeny; L.ductus, leading] Combined genital and excretory ducts.nephromixium n.; pl. -ia [Gr. nephros, kidney; mixis, mingling]An organ with flame cells and coelomic funnel servingas both excretory and genital duct; a nephrogonoduct.see protonephromixium, metanephromixium, mixonephridium.nephropore n. [Gr. nephros, kidney; poros, pore] (ARTHRO:Crustacea) The elevated opening of the antennal gland onthe ventral surface of the coxa of the antenna.nephrostomal lips (ECHI) The lip-like tissue surrounding thenephrostome; may be inconspicuous, expanded, or leaflike,or extended into long threads that may be spirallycoiled.nephrostome n. [Gr. nephros, kidney; stoma, mouth] Thecoelomic opening of a nephridium.nepioconch n. [Gr. nepios, infant; konch, shell] (MOLL: Bivalvia)The first part of the dissoconch, when separated by adiscontinuity.nepionic a. [Gr. nepios, infant] Pertaining to very young;postembronic larva; stage of development succeeding theembryonic.nepionic constriction (MOLL: Cephalopoda] In a nautiloidshell, a definite growth discontinuity of the shell micro-ornamentationthought to correspond to eclosion from theegg.nepionotype n. [Gr. nepios, infant; typos, type] The typelarva of a species.NEPO virus Referring to NEmatode-transmitted, POlyhedralshapedviruses. see NETU virus.neritic zone The region of shallow water over the continentalshelf that is subdivided into supratidal (wave splash area),intertidal (littoral), and subtidal regions.nerve n. [L. nervus, nerve] 1. A single fiber or group of fibersof the peripheral nervous system. 2. (ARTHRO: Insecta) A

606Maggenti and Gardnertubular wing vein.nerve cell see neuronnerve ending The terminal arborization of a neuron.nerve fiber The dendrite or collateral branch of a neurocyte.nerve net A network of nerve cells connecting sensory andmuscular elements in certain cnidarians, ctenophores,bryozoans, and some other invertebrates.nerve pentagon (ECHINOD) The nerve ring around the mouth.nerve ring Any ring of nerve fibers, may be around the mouth,esophagus, anus, bell margin, etc. see circumesophagealcommissure.nerve root That part of the nerve close to its origin from aganglion, cord or brain; may be just inside or outside of theganglion, etc.nervicole, nervicolous a. [L. nervus, nerve; colere, to inhabit]Living on or in leaf veins.nervous a. [L. nervus, nerve] Pertaining to nerves; restless orimpulsive behavior as in nervous movements.nervous system A system of nerves with which an organismadapts to its environment.nervulation see venationnervules see nervuresnervures n. [L. dim. nervus, nerve] (ARTHRO: Insecta) 1. Thetubular wing veins. 2. Branches of the tracheal system.nesium n.; pl. nesia [Gr. nesion, an islet] (ARTHRO: Insecta)In scarab beetle larvae, one or two sclerotized projectingmarks between the inner end of the dexiotorma and crepis;when two are present, termed nesium externum and nesiuminternum; chitinous plate of Hayes.nest n. [A.S. nest] (ARTHRO: Insecta) A dwelling of social insectsin which young are raised and reproductive femaleslay eggs; may be a burrow or hollow in soil, log, etc., or beconstructed of materials brought to the site, or materialselaborated by the individuals in the colony.nestlers n.pl. [A.S. nestlian, to build a nest] (MOLL: Bivalvia)Clams nestling in cavities or concealment in clay or among

Online Dictionary of Invertebrate Zoology 607dead shells that occasionally produce variations in shellshape.nest odor (ARTHRO: Insecta) In social insects, the distinctiveodor of a nest that enables its inhabitants to distinguish thenest from those belonging to other colonies or the surroundingenvironment; hive aura/odor. see colony odor.nest parasitism (ARTHRO: Insecta) In Isoptera, one species oftermite that lives on the carton walls of the nest of the hostspecies.nest robbing see cleptobiosisNETU virus Referring to NEmatode-transmitted, TUbularshapedviruses. see NEPO virus.nettle cells see nematocystsneuraforamen n. [Gr. neuron, nerve; L. foramen, hole] (AR-THRO: Insecta) The foramen through which the nerve cordpasses when it is separated from the occipital foramen.neural a. [Gr. neuron, nerve] Pertaining to the nerves or nervoussystem of an organism.neural arc Simple receptor-effector nerve circuit.neural canal (ARTHRO: Insecta) The incomplete canal on thefloor of the meso- and metathorax, formed by fusion ofapodemes; functioning in the reception and protection ofthe ventral nerve cord and for attachment of muscles.neural groove (ARTHRO: Insecta) The median ventral groove,extending the entire length of the embryo, between theneural ridges.neural lamella The noncellular outer covering of the centralnervous system consisting of mucopolysaccharides andmucoproteins with collagen-type fibrils in the outer part ofthis layer.neural ridges (ARTHRO: Insecta) In embryology, the two longitudinalventral ridges that contain the lateral cords of theneuroblasts.neuration see venationneurilemma see Schwann cell

608Maggenti and Gardnerneurite see axonneurobiotaxis n. [Gr. neuron, nerve; bios, life; taxis, arrangement]1. The hypothetical migration of nerve cellsand ganglia toward regions of maximum stimulation duringphylogeny. 2. In embryology, tendency of nerve cells tomigrate toward the source of their stimuli.neuroblast n. [Gr. neuron, nerve; blastos, bud] (ARTHRO: Insecta)In embryology, the inner layer of ectodermal cellsthat forms the nervous tissue. see dermatoblasts.neurocirrus n.; pl. -ri [Gr. neuron, nerve; L. cirrus, curl](ANN: Polychaeta) Cirrus normally on the lower edge of theneuropodium.neurocyte n. [Gr. neuron, nerve; kytos, container] The cellbody of a neuron; the nerve cell; cyton.neurofibrils n.pl. [Gr. neuron, nerve; L. dim. fibre, thread]Fine fibers running longitudinally in axons and dendritesand through the body of the neuron.neurogenic a. [Gr. neuron, nerve; gennaein, to produce] 1.Forming nervous tissue. 2. Stimulating nervous energy forcertain muscular or glandular reactions. see myogenic.neuroglia n.pl. [Gr. neuron, nerve; glia, glue] Nonnerve cellsin the brain or ganglia; glia; glial cells; gliacytes.neurohemal organs (ARTHRO: Insecta) Organs involved withthe release of products of neurosecretory cells into thehemolymph; corpora cardiaca best developed though lessconspicuous ones make up the perisympathetic system associatedwith the ventral nerve cord.neurohormone n. [Gr. neuron, nerve; hormaein, to excite] Ahormone produced by neurosecretory cells.neurohumor see neurotransmitterneuroid transmission Arousal activity by cells other thannerve cells.neurolemma see Schwann cellneuromere n. [Gr. neuron, nerve; meros, part] (ARTHRO: Insecta)Any of the transitory segmental elevations in thewall of a developing embryo.

Online Dictionary of Invertebrate Zoology 609neuron n. [Gr. neuron, nerve] A nerve cell.neurone see neuronneuropile n. [Gr. neuron, nerve; pilos, felt] The central part,or mass of different axons within a ganglion; neurospongium.neuroplasm n. [Gr. neuron, nerve; plasma, formed or molded]Cytoplasm of neurons.neuropodium n. [Gr. neuron, nerve; pous, foot] (ANN: Polychaeta)The ventral division of the parapodium, supportedinternally by one or more chitinous rods or aciculae.neuropore see trichoporeNeuropteroidea see Holometabolaneuropterous a. [Gr. neuron, nerve; pteron, wing] (ARTHRO:Insecta) Pertaining to the order Neuroptera.neurosecretory cells (ARTHRO: Insecta) Cells found in theganglia of the central nervous system that secrete hormoneswhich act directly on effector organs or on other endocrineorgans.neurospongium see neuropileneurosynapse see synapseneurotransmitter n. [Gr. neuron, nerve; L. trans, across;mittere, to send] A chemical secreted at nerve endings totransmit a nervous impulse across a synapse; neurohumor.neurotropic a. [Gr. neuron, nerve; tropos, turn] Having anaffinity for nervous tissue.neurotubules n. [Gr. neuron, nerve; L. dim. tubus, tube]Microtubules in nervous tissue.neuston n. [Gr. neustos, able to swim] Small organisms thatfloat or swim in or on the surface film of water. seeseston.neuter n. [L. ne, not; uter, either] 1. Sexless. 2. A sterile organism.3. A non-fertile mature female.neutralism n. [L. ne, not; uter, either; ismus, denoting a condition]Organisms living together with no mutual harm orbenefit; hamabiosis.

610Maggenti and Gardnerneutral synoekete (ARTHRO: Insecta) An insect living on therefuse of a host colony but providing little in return.new name A replacement name for an available name; nomennovum.niche n. [L. nidus, nest] A position or occupation filled by anorganism in the food-web of a community.nictation see negative geotropismnictitant a. [L. nictare, to wink] An ocellus bearing a lunatespot.nidamental gland Any of various structures that secrete acapsule or covering material for an egg or egg masses.nidicole a. [L. nidus, nest; colere, to dwell] Pertaining to anorganism that spends much of its life in the nest of its host.nidificant a. [L. nidus, nest; facere, to make] Building a nest.nidifugous a. [L. nidus, nest; fugere, to flee] Departing thenest soon after birth.nidus n.; pl. nidi [L. nidus, nest] 1. A group of regenerativecells; a cell-group. 2. A location for the natural deposit ofeggs; a hatching place. 3. The specific locality of a disease,resulting from a combination of ecological factors that favorthe disease organism. 4. (ARTHRO: Insecta) Regenerativecells that replace the midintestinal cells used up duringholocrine secretion.niger n. [L. niger, black] Black; glossy black.nigerrima a. [L. niger, black; -rimus, superlative ending] Veryblack.nigrescent a. [L. nigrescens, to grow black] Turning black;blackish.nisto n. (ARTHRO: Crustacea) In Decapoda, the postlarval stageof Scyllaridae and Palinuridae; pseudibacus; puerulus.nitid, nitidus a. [L. nitidus, shining] Glossy; shining; brilliant;lustrous.nitrate n. [Gr. nitron, native soda] A salt or ester of nitric acid(HNO 3 ).nitrite n. [Gr. nitron, native soda] A salt or ester of nitrousacid (HNO 2 ).

Online Dictionary of Invertebrate Zoology 611nitrogen n. [Gr. nitron, native soda; gennaein, to produce] Acolorless, odorless gas that constitutes about four-fifths ofthe atmosphere.nitrogen cycle Inorganic nitrogen incorporated into organicnitrogen in living organisms and returned to inorganic nitrogenby breakdown of the organic molecules on death ofthe living organisms.nitrogenous a. [Gr. nitron, native soda; gennaein, to produce]Pertaining to, or containing nitrogen.nits n.pl. [A.S. hnitu, egg of louse] (ARTHRO: Insecta) In Siphunculata,the eggs; particularly when cemented to hair.niveous a. [L. niveus, snow] Resembling the color of snow.nocturnal a. [L. nocturnus, of the night] Occurring or performedat night. see diurnal, crepuscular.nocturnal eyes (ARTHRO: Chelicerata) The pearly white eyes ofArachnida.nodal furrow (ARTHRO: Insecta) In Odonata, a transverse sutureof the wing, beginning at the costal margin correspondingto the nodus and extending toward the innermargin; costal hinge.node n. [L. nodus, knob] 1. A knob or swelling. 2. (BRYO) Aplace of articulation in a colony.nodicorn a. [L. nodus, knob; cornu, horn] (ARTHRO: Insecta)Having antennae with joints swollen at the apex.nodiferous a. [L. nodus, knob; fero, bear] Having or bearingnodes.nodiform a. [L. nodus, knob; forma, shape] In the form of aknob or knot.nodose a. [L. nodus, knob] With small knotlike protuberances.nodular a. [L. dim. nodus, knob] Having small knobs or nodule-likeprojections.nodular sclerite see epaulettnodule n. [L. dim. nodus, knob] A swollen knob-like structure.nodulus n. [L. dim. nodus, knob] (ANN) An enlarged region ona crotchet chaeta at about midlength.

612Maggenti and Gardnernodus n. [L. nodus, knob] (ARTHRO: Insecta) 1. In HymenopteraIchneumonidae, a dorsal prominence on the tip of theovipositor, shortly before the apex. 2. In Odonata, a strongcross vein near the middle of the costal border of the wing.nomadism n. [Gr. nomas, roaming] (ARTHRO: Insecta) Frequentmovement by a colony from one site to another.nomenclator n. [L. nomen, name; calare, to call] A nomenclaturalbook containing a list of scientific names, not fortaxonomic purposes.nomenclature n. [L. nomen, name; calare, to call] In biology,a system of names for biological units.nomen conservandum A name preserved by action of theInternational Commission on Zoological Nomenclature andplaced on the appropriate official list.nomen dubium The name of a nominal species that lacksavailable evidence so as to permit recognition of the zoologicalspecies to which it was applied.nomen inquirendum The scientific name is subject to investigation.nomen novum see new namenomen nudum A published binominal without an adequate description,definition or illustration to permit its officialadoption.nomen oblitum No longer in effect in ICZN after 1973; aname that has not been used in the primary zoological literaturefor 50 years; a forgotten name.nomen taxon Any named taxon, objectively defined by itstype, whether valid or invalid.nominalism n. [L. nomen, name; ismus, denoting a condition]Doctrine of nominalists denying the existence of universals,and emphasizing the importance of man-given names forthe grouping of individuals.nominate a. [L. nomen, name] Pertaining to a subordinatetaxon that contains the type of the subdivided higher taxonand bears the same name as the original parent taxon.noncelliferous side of colony (BRYO: Stenolaemata) The reverseor back side of the colony.

Online Dictionary of Invertebrate Zoology 613noncellular outgrowth A cuticular prominence of the bodywall.noncoelomate see acoelomatenon-congression n. [L. non, not; congressus, meeting] Chromosomesnot pairing on the spindle equator.non-conjunction n. [L. non, not; cum, with; junctus, joined]Absence of meiotic chromosome pairing.nondimensional species The concept of a species characterizedby the noninterbreeding of two coexisting demes, uncomplicatedby space and time.nondisjunction n. [L. non, not; disjunctus, unyolked] The failureto separate of paired chromosomes during meiosis.non-essential amino acids Amino acids that can be synthesizedby animals and not required in their diet.nonincubatory oysters (MOLL: Bivalvia) Oysters that do notincubate their larvae.non-medullated nerve A nerve fiber lacking a myelin sheath;non-myelinated.nonsense codon see nonsense mutationnonsense mutation A mutation that changes a coding tripletinto a triplet that codes for no amino acid and terminatesthe polypeptide chain.normalizing selection The removal of all alleles that producedeviations from the normal (average) phenotype of apopulation by selection against all deviant individuals.nosogenic a. [Gr. nosos, disease; gennaein, to produce]Causing disease; pathogenic.nosography n. [Gr. nosos, disease; graphos, writing] A branchof pathology dealing with the description of diseases.nota pl. of notumnotacoria n. [Gr. notos, back; L. corium, leather] (ARTHRO:Insecta) A membranous area separating the pleuron andnotum in the thorax; sometimes reduced to a suture.notal comb see genal combnotate a. [L. nota, mark] Marked by spots or depressed marks.

614Maggenti and Gardnernotation n. [L. nota, mark] The method of identifying charactersby a system of numbers, letters or ratios.notaulix n.; pl. -lices, [Gr. notos, back; L. aulix, furrow] (AR-THRO: Insecta) One of a pair of grooves on the mesoscutum,from the front margin to one side of the midline andextending backward; divides the mesoscutum into 3 parts:a median lobe between the notaulices and a lateral lobe oneach side (parapsides).notch n. [ME. nock, a notch] (MOLL: Gastropoda) A break orirregularity in the peristome, denoting the position of thesiphon.notched a. [ME. nock, a notch] Nicked or indented; usually ofa margin.notocephalon n. [Gr. notos, back; kephale, head] (ARTHRO:Insecta) 1. In Notonectidae, the dorsal view of the head. 2.(ARTHRO: Chelicerata) In Arachnida, the dorsal shield of theprosoma.notocirrus n. [Gr. noton, back; L. cirrus, curl] (ANN:Polyuchaeta) Cirrus of the notopodium.notodeltidium see chilidiumnotodont a. [Gr. notos, back; odous, tooth] (ARTHRO: Insecta)Pertaining to larval Notodontidae with a variously humpeddorsal surface.Notogaea n. [Gr. notos, back; ge, earth] The zoogeographicalarea including Australia, New Zealand and Pacific OceanIslands regions.notogaster n. [Gr. noton, back; gaster, belly] (ARTHRO: Chelicerata)The posterior dorsal opisthosomatal shield.notonectal a. [Gr. notos, back; nektos, swimming] Swimmingon the back.notopleura n.pl.; sing. notopleuron [Gr. notos, back; pleuron,side] (ARTHRO: Insecta) In Diptera, a sometimessunken, triangular area on the thoracic dorsum, at the lateralend of the transverse suture, behind the humerus.notopleural a.notopleural bristles (ARTHRO: Insecta) In Diptera, bristles locatedin a small triangular area, one on each corner of the

Online Dictionary of Invertebrate Zoology 615notum just above the anepisternum or mesopleura; betweenthe humeral callus and wing base.notopleural suture (ARTHRO: Insecta) A suture between thenotum and the pleural sclerites.notopodium n. [Gr. notos, back; pous, foot] (ANN: Polychaeta)The dorsal or upper division of the parapodium, supportedinternally by one or more chitinous rods, or aciculae.notopterale n. [Gr. notos, back; pteron, wing] (ARTHRO: Insecta)The first axillary sclerite of a wing.notoseta n. [Gr. notos, back; L. seta, bristle] (ANN) Seta originatingon the notopodium.nototheca n. [Gr. notos, back; theke, case] (ARTHRO: Insecta)That region of a pupa covering the dorsal surface of theabdomen.notothyrium n. [Gr. notos, back; thyrion, door] (BRACHIO) Thetriangular notch in the dorsal valve, when present, open tothe hinge line facilitating pedicle exit, usually closed offfrom the hinge plate by the chilidium. see delthyrium.notum n. [Gr. notos, back] 1. (ARTHRO: Crustacea) Theshrimplike decapod posterior part of the dorsal carapace. 2.(ARTHRO: Insecta) The dorsal surface of a body segment,particularly of the thoracic segment. notal a.nucha n. [ML. nucha, neck] The upper surface of the neck connectingthe head and thorax. nuchal a.nuchal caruncle (ANN) A sensory organ on the prostomium, orextending posteriorly in the form of a ciliated ridge orgroove.nuchal cavity (MOLL: Gastropoda) In Patellacea, the enlargedportion of the pallial cavity above the head.nuchal cirrus see cirrusnuchal constriction (MOLL: Cephalopoda) In most Sepiidaeand Teuthoidea and a few Octopodidae, the separation orconstriction between the head and body or neck.nuchal organ(s) 1. (ANN: Polychaeta) A pair of ciliated sensorypits or slits in the head region. 2. (ARTHRO: Crustacea) InBranchiopoda, a sensory organ on the upper side of thecephalon. 3. (SIPUN) Ciliated epidermal cells at the mid-

616Maggenti and Gardnerdorsal edge of the oral disc; believed to be sensory.nuchal papilla (ANN: Polychaeta) Small sensory papilla at thebase of the prostomium; cirrus.nuchal tentacles (PLATY: Turbellaria) In Polycladida, tentacleswell set back from the anterior part of the body.nuclear envelope Double layered membrane separating thenucleoplasm from the cytoplasm; nuclear membrane.nuclear plate A metaphase or equitorial plate.nuclear sap see nucleoplasmnuclear whorls (MOLL: Gastropoda) The whorls of the protoconchthat emerges from the egg.nucleate a. [L. nucleus, kernel] Having a nucleus.nucleic acids Polymers of nucleotides that are active in inheritanceas genes, plasmids, etc.nuclei of Semper (ARTHRO: Insecta) The nuceli of the crystallinecone cells.nucleolar chromosome Any chromosome with a nucleolar organizer.nucleolar organizer Chromosome region that is active in nucleolusformation.nucleolinus n. [L. dim. nucleus, kernel] A small granule withinthe nucleolus.nucleolonema n. [L. dim. nucleus, kernel; Gr. nema, thread]Filamentous structures within the nucleolus of all cells.nucleolus n. [L. dim. nucleus, kernel] Small, dense, more orless spherical bodies in the nucleus of cells associated withthe nucleolar organizer.nucleoplasm n. [L. dim. nucleus, kernel; Gr. plasma, formedor molded] The protoplasmic fluid contained in the nucleus.nucleoplasmic index The ratio of nuclear volume to cytoplasmicvolume; seems to trigger cell division; nucleoplasmicratio.nucleoprotein n. [L. dim. nucleus, kernel; Gr. proteios, primary]A compound of nucleic acid and protein.nucleoside n. [L. dim. nucleus, kernel] Compounds derived by

Online Dictionary of Invertebrate Zoology 617hydrolysis of nucleic acids or nucleotides consisting of apurine or pyrimidine base linked to ribose or deoxyribose.nucleotide n. [L. dim. nucleus, kernel] Unit of the DNA andRNA molecules, including phosphoric acid, a purine orpyrimidine base, and a ribose.nucleus n.; pl. -lei [L. nucleus, kernel] 1. A spheroidal structurepresent in a cell containing the chromatin. 2. (MOLL:Gastropoda) The earliest-formed part of the shell, or operculum,of a protoconch.nudibranchiate a. [L. nudus, naked; branchiae, gills](BRACHIO) Having the gills uncovered and not protected bya shell or membrane in the brachial chamber.nudum n. [L. nudus, naked] (ARTHRO: Insecta) A small bare,sensitive portion of a butterfly antenna.nulliplex a. [L. nollus, none; plectare, to weave] A polyploidhaving all genes for a particular recessive character.numerical phenetics The hypothesis that relationship betweenorganisms can be determined by a calculation of anoverall, unweighted similarity value.numerical taxonomy Numerical evaluation of similarity betweentaxonomic units and grouping of these units intohigher taxa on the basis of their affinities; taxometrics. seetaxonomy.nuptial flight (ARTHRO: Insecta) In Hymenoptera, the matingflight of winged males and females.nurse cells 1. Cells of developing oocytes that provide materialfor further growth; trophocytes. 2. (ARTHRO: Insecta) Insome species, the nurse cells synthesize nucleic acids andpossibly protein and supply them to the oocyte via intercytoplasmicconnections. 3. (NEMATA) A specialized plantresponse to feeding sessile forms, characterized by specialfeeding cells around the nemas' head that are not subjectto necrosis; giant cells. 4. (PORIF) The archaeocytes.nutant a. [L. nutare, to nod] Nodding; drooping; having a tipbent horizontally.nutricial castration, castration nutriciale (ARTHRO: Insecta)In Hymenoptera, the condition of undeveloped gonads in

618Maggenti and Gardneryoung adult females due to devoting itself to nursing larvalforms instead of herself taking on the nutrition necessaryfor the reproductive form. see alimentary castration.nutricism n. [L. nutrix, nurse] A symbiotic relationship inwhich one partner obtains all the benefits.nutrition n. [L. nutrire, to feed] The ingestion, digestion andassimilation of food substances that includes their distributionwithin the organism, as well as the metabolism andelimination of waste products.nyctipelagic a. [Gr. nyktos, night; pelagos, sea] Coming tothe water surface only at night.nymph n. [Gr. nymphe, bride] 1. (ARTHRO: Chelicerata) Theimmature stage of Acari and Ixodoidea with a full complementof legs; an instar. 2. (ARTHRO: Insecta) An immaturestage that does not have a pupal stage. 3. (MOLL: Bivalvia)see nympha.nympha n.; pl. -phae [Gr. nymphe, bride] 1. (ARTHRO: Chelicerata)In Acari, sclerites beneath the epigynium. 2. (MOLL:Bivalvia) The immersed area behind the beak thatstrengthens the margin to which the ligament is attached,or reinforcement for the normal hinge structure; ligamentfulcrum; sometimes nymph.nymphal phase (ARTHRO: Chelicerata) The second or thirdphase of postembryonic development; in Acari with six stases,the third phase comprised of proto-, deuto- and tritonymphs.nymphipara a. [Gr. nymphe, bride; L. parere, to beget] (AR-THRO: Insecta) Bearing live young in an advanced stage ofdevelopment. see pupipara.nymphochrysalis n. [Gr. nymphe, bride; chrysallis, gold coloredpupa] (ARTHRO: Chelicerata) In chigger mites, a nonfeeding,prenymph; a calyptostasic protonymph.nymphoid a. [Gr. nymphe, bride; eidos, form] (ARTHRO: Chelicerata)Nymphal phase instars that cannot be homologizedwith nymphal instars of other species.nymphoid reproductive (ARTHRO: Insecta) A neoteinic reproductivewith wing buds; a second-form reproductive; secondaryreproductive; a brachypterous neoteinic.

Online Dictionary of Invertebrate Zoology 619nymphosis n. [Gr. nymphe, bride] The process of transforminginto a nymph or a pupa.

Oobconical a. [L. ob, inverse; conic, cone] Inversely conical; inthe form of a reversed cone.obcordate a. [L. ob, inverse; cor, heart] Inversely heartshaped.obese a. [L. obesus, fat] Distended; enlarged; corpulent.obimbricate a. [L. ob, inverse; imbrex, tile] Having regularlyoverlapping scales. see obsite.objective synonym One of two or more names based on thesame type.oblanceolate a. [L. ob, inverse; lanceolatus, spear-like] Inverselylanceolateoblate a. [L. oblatus, spread out] Flattened; pertaining to aspheroid of which the diameter is shortened at two oppositeends; flattened at the poles.obligate a. [L. obligare, to be required] Pertaining to the inabilityto live in a different environment. see facultative.obligate parasite A parasite that cannot exist without a hostduring all or some portion of the life cycle. see facultativeparasite.obligate symbiont An organism that is physiologically dependentupon a symbiotic relationship with another. seefacultative symbiont.oblique a. [L. ob, inverse; liquis, awry] Slanting; deviatingfrom the perpendicular, or a particular horizontal direction,but not perpendicular to it.oblique muscles 1. (ECHI) Innermost muscle layer of bodywall; may form oblique or nearly transverse fascicles betweenbands of the longitudinal muscles. 2. (SIPUN) A thinlayer of diagonally placed muscle between the circular andlongitudinal muscles.oblique vein (ARTHRO: Insecta) A slanting cross wing vein.obliterate a. [L. obliteratus, erased] Indistinct.

Online Dictionary of Invertebrate Zoology 621oblong a. [L. oblongus, rather long] Elliptical; elongated;longer than broad.oblong plates (ARTHRO: Insecta) In aculeate Hymenoptera,the innermost or posterior pair of plates immovably fixedon each side of the bulb and stylet of the sting.oblongum n. [L. oblongus, rather long] (ARTHRO: Insecta) InColeoptera wings, a special oblong cell formed when M 1 isconnected with M 2 by means of one or two cross veins.obovate a. [L. ob, inverse; ovate, egg-shaped] Inversely eggshapedwith narrower end downward.obpyriform a. [L. ob, inverse; pyrum, pear; forma, shape] Inverselypear-shaped.obscure a. [L. obscurus, covered] 1. Dark; dark of color; dim.2. Remote; hidden. 3. Not well defined.obsite a. [L. obsitus, barred] Refers to a surface covered withequal scales or other objects. see obimbricate.obsolescence n. [L. obsoletus, to wear out] 1. The process ofgradual reduction or disappearance of a taxon. 2. A gradualcessation of a physiological process.obsolete a. [L. obsoletus, to wear out] Obscure; not distinct;atrophied; imperfectly developed.obtect, obtected a. [L. obtectus, covered over] Covered; enclosedwithin a hard covering.obtect pupa (ARTHRO: Insecta) A pupa in which the appendagesare glued down to the body by a secretion producedat the larval/pupal molt. see exarate pupa.obturaculum n. [L. dim. obturare, to plug or close] (ARTHRO:Insecta) In Anoplura, a connective-like tissue structure thatdivides the hemocoel of the head from the thoracic hemocoel;continuous posteriorly with a heavy coat surroundingthe thoracic ganglia; neck-plug.obturator n. [L. obturare, to plug or close] Any structure thatcloses off a cavity.obtuse a. [L. obtusus, blunt] Blunt or rounded at the extremity;not pointed. see acute.obtusilingues n.pl. [L. obtusus, blunt; lingua, tongue] (AR-

622Maggenti and GardnerTHRO: Insecta) In a former classification, those bees withshort tongues having an obtuse or bifid tip. see acutilingues.obumbrate a. [L. obumbrare, to over-shadow] Overhanging,or partially concealing.obverse a. [L. obvertere, to face] 1. Looking head on. 2. Havingthe base narrower than apex. 3. Being a counterpart.obverse side of colony (BRYO) The frontal side of the colony.obvolvent a. [L. obvolvere, to wrap around] Bending downwardand inward.occasional species A species sometimes found in a particulararea, but not habitually.occipital a. [L. occiput, back of the head] Pertaining to the occiputor the back part of the head.occipital arch (ARTHRO: Insecta) The area of the cranium betweenthe occipital and postoccipital sutures.occipital carina (ARTHRO: Insecta) In Ichneumonidae Hymenoptera,a subcircular carina on the hind aspect of the head,between the vertex and hind margin of the compound eyesand the foramen magnum.occipital cilia see ocular setaoccipital condyles (ARTHRO: Insecta) A projection on eitherlateral margin of the postocciput with which the cephaligerof a cervical sclerite articulates; cervical condyle.occipital foramen (ARTHRO: Insecta) The posterior opening ofthe head into the cervix; neck foramen. see foramenmagnum.occipital ganglion (ARTHRO: Insecta) A single or paired postcerebralganglion.occipitalia n.pl. [L. occiput, back of the head] (GNATHO) Anunpaired row of dorsal cilia on the head.occipital margin (ARTHRO: Insecta) In Mallophaga, the posteriormargin of the head.occipital notch (ARTHRO: Crustacea) In Conchostraca, theangulated indentation at the ear of the cephalon.occipital suture (ARTHRO: Insecta) A transverse suture some-

Online Dictionary of Invertebrate Zoology 623times present on the back of the head that separates thevertex from the occiput dorsally and the genae from thepostgenae laterally.occipital tentacle see cirrusocciput n. [L. occiput, back of the head] (ARTHRO: Insecta) 1.The dorsal posterior part of the cranium, between the occipitaland postoccipital sutures; in many the boundarieswith the vertex and postgenae are not delimited. 2. InFormicidae, the short region between the vertex and theneck. occipital a.occludent margin (ARTHRO: Crustacea) In Cirripedia, themargin of the scutum and tergum bordering the orifice.occludent teeth (ARTHRO: Crustacea) In Cirripedia, smallprojections on the occludent scutal margin interdigitatingwith the teeth on the margin of the opposed scutum.occlusion plate (ARTHRO: Insecta) In Heteroptera larvae, asemicircularly shaped plate located below the lateral porein the ostiole; functioning in scent ejection in any horizontaldirection.occlusor a. [L. occludare, to close] An organ or muscle thatcloses an opening.occult a. [L. occulere, to hide] Hidden from sight.oceanic zone The open sea beyond the edge of the continentalshelf.ocellara (-ae) see ocellusocellar basin (ARTHRO: Insecta) In Hymenoptera, a concavearea, varying in form and size, occupying the median portionof the frontal area.ocellar bristles (ARTHRO: Insecta) In Diptera, bristles arisingclose to the ocelli; in the ocellar triangle.ocellar bulb see tentacular bulbocellar centers (ARTHRO: Insecta) The brain centers of theocelli, found in the outer part of the ocellar pedicels.ocellar group (ARTHRO: Insecta) In Lepidoptera larvae, sixocelli on the lateral area of the larval head, dorsal fourforming the quadrant of a circle, ventral two farther apart.

624Maggenti and Gardnerocellar pair see ocellar bristlesocellar pedicels (ARTHRO: Insecta) Long slender nerve stalksconnecting the facial ocelli with the protocerebrum.ocellar plate see ocellar triangleocellar triangle (ARTHRO: Insecta) In Diptera, the triangularregion bearing the ocelli and often bounded by grooves ordepressions.ocellata see apharyngeate cercariaocellate a. [L. dim. oculus, eye] Eye-like; spotted; havingocelli or eye-like spots.ocellus n.; pl. ocelli [L. dim. oculus, eye] 1. The simple eyesor eyespots, occurring singly or in small groups, found inmany invertebrates. 2. (ARTHRO: Crustacea) see naupliuseye. 3. (ARTHRO: Insecta) see stemma, ommata. 4.(MOLL: Polyplacophora) see aesthete.ochraceous a. [Gr. ochros, yellow brown] Pale yellow;brownish-yellow.ochroleucous a. [Gr. ochros, yellow brown; leukos, white]Yellowish; whitish yellow; buff.octactine a. [Gr. okto, eight; aktis, ray] (PORIF) A modifiedhexactine spicule with 8 rays.octamerous a. [Gr. okto, eight; meros, part] (CNID: Anthozoa)Organs or parts of organs arranged in series of 8.octoploid a. [Gr. okto, eight; aploos, onefold] Cells having 8chromosome sets in the nucleus (8n).octopod a. [Gr. okto, eight; pous, foot] Bearing 8 tentacles,feet or arms. octopody n.octoprostatic a. [Gr. okto, eight; prostates, one who standsbefore] (ANN: Oligochaeta) Having 8 prostates.octothecal a. [Gr. okto, eight; theke, case] (ANN: Oligochaeta)Having 8 spermathecae.ocular a. [L. oculus, eye] Of or pertaining to the eyes.ocular bulla (ARTHRO: Crustacea) A knob on the inner surfaceof the carapace joining the lower and upper orbital marginswith the basal segment of the antenna; functioning to protectthe eye.

Online Dictionary of Invertebrate Zoology 625ocular emargination (ARTHRO: Insecta) In Mallophaga, a lateralemargination of the head in front of the eyes.ocular fleck (ARTHRO: Insecta) In Mallophaga, a black spot inthe eyes.ocular fringe (ARTHRO: Insecta) In Mallophaga, small hairs onthe posterior half of the ocular emargination, may extendon the temporal margin.ocularium n.; pl. -ia [L. oculus, eye] (ARTHRO: Insecta) 1. Thearea around the simple eye or eyes of larvae. 2. In Hymenopterasawflies, the pigmented area.ocular lobe (ARTHRO: Insecta) On some Coleoptera, a projectingthoracic lobe.ocular papilla (ARTHRO: Crustacea) In some Malacostraca, theanterior projection on the eyestalk.ocular peduncle (ARTHRO: Crustacea) A movable peduncle(eyestalk) with a compound eye at the distal end, sometimeswith two or three segments, sometimes retractable.ocular plates (ECHINOD: Echinoidea) Plates at the terminal endof the ambulacral areas.ocular sclerites (ARTHRO: Insecta) 1. In some Pseudococcidae,well developed sclerites extending completely aroundeach side, each bearing a row of 7 simple eyes near anteriormargin, plus a single lateral ocellus on each side behindthe mid-lateral member of the anterior row. 2. An annularsclerite surrounding the compound eyes.ocular seta (ARTHRO: Insecta) In Diptera, one of several setaeoccurring in a line near the posterior margin of each compoundeye.ocular sinus (MOLL: Cephalopoda) In the Nautilus , an openingon the lateral shell margin accommodating the normal arcof vision of the eyes.ocular suture (ARTHRO: Insecta) An annular inflection surroundingthe compound eyes.ocular tube (SIPUN) A tubular depression in the brain containingthe pigment of the eyespots or eyes.ocular tubercles (ARTHRO: Insecta) In Hemiptera, supplementaryeyes with prominent facets on the posterior area,

626Maggenti and Gardnerin addition to the compound eyes.oculiferous a. [L. oculus, eye; fero, bear] Bearing eyes.oculomotor a. [L. oculus, eye; movere, to move] The nervecenter of muscle that moves the eye.oculus n.; pl. oculi [L. oculus, eye] The eye; a spot shapedlike an eye.odona a. [Gr. odous, tooth] Having teeth.odonate a. [Gr. odous, tooth] (ARTHRO: Insecta) Of or pertainingto the Odonata.odontium n. [Gr. odous, tooth] (NEMATA) The stomatal armaturegenerally in the form of a tooth or teeth originatingfrom the anterior stoma (cheilostome). see onchium.odontoblast n. [Gr. odous, tooth; blastos, bud] (MOLL: Gastropoda)Cells in the radular sac that secrete the radularteeth.odontoidea see occipital condylesodontophore n. [Gr. odous, tooth; phoreus, bearer] 1. (MOLL:Gastropoda) The cartilaginous supporting organ of theradula, tongue or lingual ribbon possessing a complicatedseries of lingual teeth; Huxley included the radula. seebuccal mass. 2. (NEMATA) A rigid section of the anterioralimentary tract from the base of the odontostyle to thebeginning of the esophageal musculature, often withflanges or knobs for muscle attachment.odontostyle, odontostylet n. [Gr. odous, tooth; stylos, column](NEMATA: Adenophorea) A stylet derived from anodontium terminating with a dorsally oblique aperture, andoriginating in the esophageal wall.odoriferous glands see scent glandsodor trail (ARTHRO: Insecta) A chemical trace laid down by oneinsect to be followed by other insects of the same speciesor nest; the substance is called trail pheromone or trailsubstance.oecium, ooecium n. [Gr. oion, egg; oikos, house] (BRYO) Anovicell or brood pouch.oeco- see eco-

Online Dictionary of Invertebrate Zoology 627oedaeagus, oedeagus, oedoeagus see aedeagusoenocytes n.pl. [Gr. oinos, wine; kytos, container] (ARTHRO:Insecta) Large cells in a group on either side of each abdominalsegment, between the bases of the epidermal cellsand basement membrane, or form clusters in the bodycavity or dispersed and embedded in the body fat; in immatures,associated with molting, and maybe production oflipids in cuticle or synthesis of ecdysone.oenocytoid n. [Gr. oinos, wine; kytos, container; eidos, form](ARTHRO: Insecta) Round or oval cells, with darkly stainingnucleus and clear, uniform, weakly acidophil cytoplasm.oeruginous, oeruginus see aeruginousoesophagus see esophagusoestrus see estrusofficial index A list of names or works suppressed or declaredinvalid by the ICZN.official list A list of names or works declared to be valid by theICZN.ogival a. [F. ogive, pointed arch] Bearing the shape of an arch.ogive n.oikosite n. [Gr. oikos, house; sitos, food] An attached or stationarycommensal or parasite.olfactory a. [L. olfacere, to smell] Pertaining to the sense ofsmell; among invertebrates, the organs are variouslyplaced: antennae of insects and other arthropods, tips ofthe palpi and legs of spiders, pits on the heads of variousworms, or osphradia of mollusks. olfactibon n.olfactory cone see sensillum basiconicumolfactory hair see aesthetascolfactory lobes (ARTHRO) In the midbrain or deutocerebrum.olfactory papilla (MOLL: Cephalopoda) Papilla found onTeuthoidea, Sepiidae and Vampyromorpha on either side ofthe head near the neck.olfactory pits (MOLL: Cephalopoda) In Octopodidae, olfactorypits on either side of the head near the neck.olfactory pores see sensillum campaniformium

628Maggenti and Gardneroligogene n. [Gr. oligos, few; genos, descent] A gene determininga pronounced phenotypic effect. see polygenes.oligogyny n. [Gr. oligos, few; gyne, female] (ARTHRO: Insecta)Several functional queens in a colony.oligogyral see paucispiraloligolecithal egg An egg with a small amount of yolk;isolecithal. see centrolecithal egg, telolecithal egg.oligolectic a. [Gr. oligos, few; lektos, chosen] (ARTHRO: Insecta)Selecting only a few, as bees collecting pollen fromonly a few kinds of flowers; oligotropic.oligomerous a. [Gr. oligos, few; meros, part] Having fewerparts or organs than other related forms. oligomery n.oligonephria a. [Gr. oligos, few; nephros, kidney] Having fewexcretory tubules.oligoneura a. [Gr. oligos, few; neuron, nerve] (ARTHRO: Insecta)Having very few wing veins.Oligoneuroptera, Oligoneoptera see Endopterygotaoligophagous a. [Gr. oligos, few; phagein, to eat] Feeding ononly a few species of food plants. see monophagous.oligophyletic a. [Gr. oligos, few; phyle, tribe] Derived from afew ancestral forms. see monophyletic.oligopneustic a. [Gr. oligos, few; pneustikos, of breathing](ARTHRO: Insecta) Having one or two functional spiracleson each side, including the amphipneustic, metapneusticand propneustic.oligopod n. [Gr. oligos, few; pous, foot] 1. Bearing few legs. 2.Having fully developed thoracic legs. see polypod, protopod.oligopod larva see campodeiform larvaoligopyrene a. [Gr. oligos, few; pyren, stone of a fruit] Withreduced number of functional spermatozoa. see apyrene,eupyrene.oligosaprobic a. [Gr. oligos, few; sapros, putrid] Describing abody of water with slow organic matter decomposition andhigh oxygen content.oligotaxy n. [Gr. oligos, few; taxis, arrangement] Weak devel-

Online Dictionary of Invertebrate Zoology 629opment of secondarily formed organs (usually not numerous).oligothermic a. [Gr. oligos, few; thermos, heat] Having a tolerancefor low temperatures.oligotokous a. [Gr. oligos, few; tokos, offspring] Having asmall number of young.oligotrichy n. [Gr. oligos, few; trichos, hair] Few, weakly developedsetae.oligotrophic a. [Gr. oligos, few; trophe, food] Pertaining tofreshwater bodies poor in plant nutrients and unproductive.oligotropic a. [Gr. oligos, few; tropikos, turning] (ARTHRO: Insecta)Visiting only a few kinds of flowers for nectar; oligolectic.see monotropic, polytropic.oligoxenous a. [Gr. oligos, few; xenos, host] Said of certainparasites adjusted to live in a limited number of hosts. oligoxenyn.oligozoic a. [Gr. oligos, few; zoon, animal] Having a few speciesor numbers of animals in a particular habitat.olivaceous a. [L. oliva, olive] Resembling or having the colorof olive green.oliviform a. [L. oliva, olive; forma, shape] Oval; resembling anolive in shape.olynthus n. [Gr. olynthus, unripening fig] (PORIF) In calcareousforms, a post-settlement stage; in asconoid forms, remainsas adult form.omega-ramule (ECHINOD: Crinoidea) A branchlet issuing fromthe terminal axial of the main-axil.ommata see ommatidiumommateum n. [Gr. ommation, little eye] (ARTHRO: Insecta) Acompound eye.ommatidium n.; pl. -ia [Gr. ommation, little eye; idion, dim.](ARTHRO) One of the component units of a compound eye,consisting essentially of an optical (light gathering) partand a sensory part (perceiving and transforming into electricalenergy); a facet.ommatochrome see ommochrome

630Maggenti and Gardnerommatoid n. [Gr. omma, eye; eidos, form] (ARTHRO: Chelicerata)In some Arachnida, a light colored spot on the posteriorbody segment.ommatophore n. [Gr. omma, eye; pherein, to bear] (MOLL:Gastropoda) A movable process bearing an eye, as insnails; may be fused with the tentacles.ommochrome, ommatochrome n. [Gr. omma, eye; chroma,color] A group of pigments, products of tryptophane metabolism,found in eyes and epidermis of certain invertebrates;it is apparently not involved in the visual process.omnivorous a. [L. omnis, all; vorare, to devour] Capable ofobtaining nourishment from both animal and plant tissue.omphalian a. [Gr. omphalos, the navel] (ARTHRO: Insecta)Referring to the orifice (excluding ostiole) of the metathoracicscent gland of Heteroptera as median and unpaired.omphalium n. see diastomian.omphalous a. [Gr. omphalos, the navel] (MOLL: Gastropoda)Having a shell with an umbilicus.onchial plate (NEMATA: Adenophorea) In Enoplida, the basalplate of the onchium.onchiophore see odontophoreonchiostyle see odontostyleonchium n.; pl. onchia [Gr. onkinos, hook] (NEMATA)Stomatal armature, generally in the form of a tooth orteeth originating from the posterior stoma (esophastome).see odontium, esophastome.onchomiracidium n. [Gr. onkinos, hook; merakidion, youth](PLATY: Trematoda) 1. A term for an embryo in the egg. 2.The ciliated larva of a monogenetic trematode.onchosphere, oncosphere n. [Gr. onkinos, hook; sphaira,ball] (PLATY: Cestoda) The shelled embryo; a hexacanth;the first larval stage.oncogenic a. [Gr. onkos, swelling; gennaein, to produce] Tumorcausing.oncophysis n. [Gr. onkos, swelling; physis, growth] (ARTHRO:Chelicerata) Any extension of an arthrodial membrane,usually in the form of a more or less hyaline intumescence.

Online Dictionary of Invertebrate Zoology 631see Tragardh's organ.onisciform larva see platyform larvaonomatophore n. [Gr. onoma, name; pherein, to carry] Aname-bearer; a type.ontogeny n. [Gr. on, being; genesis, beginning] The developmentor course of development of an individual organismfrom zygote to maturity; as distinguished from that of aspecies. ontogenetic a. see phylogeny.onychaetes n.pl. [Gr. onyx, claw; chaite, hair] (PORIF) Microsclereswith long, thin oxeote spicules, roughened withspines.onyches see tarsal clawsonychii see pulvillionychium n.; pl. -ia [Gr. onyx, claw] (ARTHRO: Insecta) Ageneral term for a pad between the tarsal claws.Onychophora, onychophorans n.; n.pl. [Gr. onyx, claw;phorein, to carry] A phylum of terrestrial animals comprisedof a single class or order of the same name, frequentlyreferred to as Peripatus ; once considered to be themissing link between annelids and arthropods, but nowconsidered to be the sister group of the arthropod complexof Crustacea, Tracheata, and Chelicerata.ooblast n. [Gr. oion, egg; blastos, bud] A cell from which anovum develops.ooblastema n. [Gr. oion, egg; blastos, bud] A fertilized egg;an oosperm.oocapt n. [Gr. oion, egg; L. captus, capture] (PLATY: Cestoda)A controlling spincter of the oviduct that allows mature oocytesto enter the proximal oviduct.oocyst n. [Gr. oion, egg; kystis, pouch] The cystic form in theparasitic protozoans (Apicomplexa), resulting from sporogony;may be hard covered, with a resistant membrane(Eimera) or be naked (Plasmodium).oocytes n.pl. [Gr. oion, egg; kytos, container] An immaturefemale gamete that undergoes meiosis, giving rise to ovaor eggs.

632Maggenti and Gardnerooecia n.pl.; sing. -ium [Gr. oion, egg; oikos, house] (BRYO:Gymnolaemata) In Cheilostomata, the outer protective partof an ovicell; sometimes thought to be zooid morphs; abrood pouch.ooecial vesicle (BRYO: Gymnolaemata) In Cheilostomata, aninner membrane of an ooecium.ooeciostome n. [Gr. oion, egg; oikos, house; stoma, mouth](BRYO: Stenolaemata) The gonozooidal orifice, may or maynot have peristome surrounding the aperture of ovicell.oogamy n. [Gr. oion, egg; gamos, marriage] The union duringfertilization of a nonmotile female gamete and a motilemale gamete. oogamous a. see anisogamy, isogamy.oogenesis n. [Gr. oion, egg; genesis, beginning] The developmentof the female egg cell or ovum that takes place inthe gonad.oogenotop n. [Gr. oion, egg; genesis, beginning; topos, place](PLATY: Cestoda) A small cellular complex following the oviductwithin the female reproductive system where shellmembranes form, enclosing the zygote and several vitellinecells. see columella.oogone see oogoniumoogonium n.; pl. oogonia [Gr. oion, egg; gonos, offspring] Agerm cell that gives rise to the oocytes by mitotic division.ookinete n. [Gr. oion, egg; kinetos, move] (ARTHRO: Insecta)A motile, elongate zygote of a Plasmodium that encysts inthe stomach wall of a Culicidae.oolemma see vitelline membraneoophagy n. [Gr. oion, egg; phagein, to eat] 1. The eating ofeggs; egg cannibalism. 2. (ARTHRO: Insecta) In social insects,eating its own or nestmate's eggs.oophore n. [Gr. oion, egg; phoreus, carrier] (ANN: Oligochaeta)The egg case or capsule.ooplasm n. [Gr. oion, egg; plasma, formed or molded] Thecytoplasm of an egg.oopod n. [Gr. oion, egg; pous, foot] (ARTHRO: Insecta) A componentpart of a sting or ovipositor.

Online Dictionary of Invertebrate Zoology 633oosperm n. [Gr. oion, egg; sperma, seed] A fertilized ovum; azygote; an ooblastema.oosphere n. [Gr. oion, egg; sphaira, ball] An unfertilized egg.oostegite n. [Gr. oion, egg; stege, roof] (ARTHRO: Crustacea)In female Peracarida, modified thoracic lamella arising fromthe coxa of the pereopod that forms a pouch (marsupium)for brooding embryos.oostegopod n. [Gr. oion, egg; stege, roof; pous, foot] (AR-THRO: Crustacea) 1. Thoracic limb bearing an oostegite. 2.An appendage of the genital somite that forms a broodpouch in some Branchiopoda.ootheca n.; pl. -cae [Gr. oion, egg; theke, case] (ARTHRO: Insecta)The covering or case over an egg or egg mass.ootid n. [Gr. oion, egg; eidos, form] One of the four meioticproducts arising in oogenesis.ootocous a. [Gr. oion, egg; tokos, delivery] Egg laying.ootype n. [Gr. oion, egg; typos, type] (PLATY: Trematoda) Asmall chamber of the female duct, surrounded by Mehlis'glands, where ducts from a seminal receptacle and vitellinereservoir join.oozooid n. [Gr. oion, egg; zoon, animal; eidos, form] Any individualdeveloped from an egg, not fragmented or budded.see blastozooid.opaline a. [L. opalus, opal] Opalescent; bluish or milky whitewith iridescent luster.opaque a. [L. opacus, shady] Not transparent or translucent.open cell (ARTHRO: Insecta) A wing cell that extends to thewing margin.open coxal cavity (ARTHRO: Insecta) In Coleoptera, when thecoxal cavity is only bridged over by the membrane.open population A population freely exposed to gene flow.opercular membrane (ARTHRO: Crustacea) In Balanomorpha,a thin, flexible membrane attaching the opercular valves tothe sheath; in Verrucomorpha, a membranous hinge.opercular plug or spot (NEMATA) An escape zone or plug bywhich a larva leaves the egg membrane.

634Maggenti and Gardneropercular scar (BRYO: Gymnolaemata) In Cheilostomata, atrace of a cuticular operculum in the frontal closure of theautozooid.opercular valves (ARTHRO: Crustacea) In sessile Cirripedia,movable plates (2 or 4) occluding the aperture.operculate a. [L. operculum, lid] Having a lid or operculum.operculiform a. [L. operculum, lid; forma, shape] Having theshape of a lid or cover.operculigenous a. [L. operculum, lid; Gr. gennaein, to produce]Producing an operculum.operculigerous a. [L. operculum, lid; gero, bear] Having anoperculum.operculum n.; pl. opercula [L. operculum, lid] 1. A lid or flaplikecover. 2. (ANN: Polychaeta) In certain sedentary forms,a modified tentacle that closes the tube; in some Spirorbidae( Pileolaria and Janua ) enlarges and serves as abrood pouch. 3. (ARTHRO) a. In Chelicerata, a plate coveringthe opening of the book-lungs of spiders. b. In Crustacea,scuta and terga and sometimes associated membraneforming the apparatus occluding an aperture. c. In Diplopoda,a plate-like anterior sclerite of the vulva. d. In Insecta,various plates, flaps and specialized structures of thegenital segments. 4. (BRYO) A generally uncalcified membrane,hinged on its posterior lip that closes the zooidialorifice. see mandible. 5. (CNID: Hydrozoa) A cover sealingthe hydrotheca or gonotheca, may be up to four sections;the lid on the distal end of a nematocyst. 6. (MOLL) A corneousor calcareous structure borne by the foot serving forclosure of the aperture. 7. (PLATY) The lid-like opening ofan egg-shell.opere citato L. Work cited; op. cit.; op. c.operon n. [L. opera, work] Adjacent series of nucleiotides thatcodes for messenger RNA molecules.opesiule n. [Gr. dim. ope, hole] (BRYO: Gymnolaemata) One ofthe small notches or pores in a cryptocyst through whichthe frontal membrane depressor muscles pass.opesium n.; pl. -ia [Gr. dim. ope, hole] (BRYO: Gymnolaemata)In Anasca, a large opening below the frontal mem-

Online Dictionary of Invertebrate Zoology 635brane bordered by the cryptocyst; functioning as a passagewayfor the lophophore in some species.ophiopluteus n. [Gr. ophis, serpent; pluteus, shed] (ECHINOD:Ophiuroidea) Brood larva of Phrynophiurida, with armsedged with cilia, that metamorphose into adults after escapefrom the bursa through the bursal slits or rupture ofthe aboral disk.ophirhabd n. [Gr. ophis, serpent; rhabdos, rod] (PORIF) Amegasclere with oxea curved in several places. see eulerhabd.ophiurida n. [Gr. ophis, serpent; oura, tail] (ECHINOD: Ophiuroidea)Simple arms with usually lateral, not verticle movement.Ophiuroidea, ophiuroids n.; n.pl. [Gr. ophis, serpent; oura,tail; eidos, form] A Class of Echinodermata, with narrow,gradually tapered arms, sharply offset from the centraldisk, generally 6 or 7 radiate; also called brittle stars, basketstars and snake stars.ophthalmic a. [Gr. ophthalmos, eye] Pertaining to the eye.ophthalmic somite see acronophthalmocercaria n. [Gr. ophthalmos, eye; kerkos, tail](PLATY: Trematoda) A cercaria with eyespots.ophthalmopod n. [Gr. ophthalmos, eye; pous, foot] (ARTHRO:Crustacea) In Malacostraca, an eye-stalk; a movable pedunclewith a terminal eye.ophthalmotheca n. [Gr. ophthalmos, eye; theke, case] (AR-THRO: Insecta) That part of the pupal case that covers theeyes.opisthaptor n. [Gr. opisthen, behind; haptein, to fasten](PLATY: Trematoda) In Monogenea, the posterior attachmentorgan (sucker or disc). see Baer's disc.opisthocline a. [Gr. opisthen, behind; clinein, to lean] 1.Leaning backward. 2. (MOLL: Gastropoda) The growth directionof a helicocone shell; commonly referring to growthlines.opisthocyrt a. [Gr. opisthen, behind; kyrtos, curved] 1.Arched backward. 2. (MOLL: Bivalvia) Referring to sloping in

636Maggenti and Gardnera direction posterior from the hinge axis; used to describehinge teeth or the slope of the shell. 3. (MOLL: Gastropoda)The growth direction of a helicocone shell; commonly referringto growth lines.opisthodelphic a. [Gr. opisthen, behind; delphys, womb](NEMATA) Having uteri parallel and posteriorly directed. seeamphidelphic, monodelphic, prodelphic, didelphic.opisthodetic a. [Gr. opisthen, behind; detos, bind] (MOLL: Bivalvia)Said of the ligament that extends posterior to theumbo (beak). see amphidetic, parivincular.opisthogenesis n. [Gr. opisthen, behind; genesis, beginning]Development from posterior end of the body forward.opisthognathous a. [Gr. opisthen, behind; gnathos, jaw]Having mouth parts directed posteriorly.opisthogoneate a. [Gr. opisthen, behind; gonos, seed] Havingthe genital opening situated terminally, at the posterior endof the body. see progoneate.opisthogonia n. [Gr. opisthen, behind; gonia, corner] (AR-THRO: Insecta) The anal angle of the hind wings.opisthogyrate a. [Gr. opisthen, behind; L. gyratus, revolve] 1.Curving backwards. 2. (MOLL: Bivalvia) Having the beakpointing posteriorly.opisthohapter see opisthaptoropisthomeres n.pl. [Gr. opisthen, behind; meros, part] (AR-THRO: Insecta) In Dermaptera, the transversely dividedepiproct; the so-called pygidium, metapygidium and telson.opisthomerite n. [Gr. opisthen, behind; meros, part] (AR-THRO: Diplopoda) The gonopods of Julida; the posteriorpart of the modified 9th pair of legs in the male.opisthoparamere n. [Gr. opisthen, behind; para, beside;meros, part] (ARTHRO: Insecta) In Diptera (Cyclorrhaphra),especially Calyptrata, one of two parameral processes. seeproparamere.opisthosoma n. [Gr. opisthen, behind; soma, body] 1. (AR-THRO: Chelicerata) In Acari or Ixodida, that portion of thebody posterior to the legs. 2. (POGON) A terminal septateregion. see protosoma, metasoma, mesosoma.

Online Dictionary of Invertebrate Zoology 637opisthosomatic appendages (ARTHRO: Chelicerata) Vestigialappendages present on the ventral regions of segmentsVII-XIII, such as genital papillae or valves.opisthosomatic scissure (ARTHRO: Chelicerata) In Acari, anarrow band of skin between sclerotized plates; oftentransverse on the opisthosoma.opsiblastic a. [Gr. opsios, late; blastos, bud] A delay in cleavage,and therefore a prolonged period before hatching;winter egg. see tachyblastic.optic a. [Gr. optikos, pertaining to sight] Pertaining to the eyeor sense of sight.optical isomerism Compounds that are mirror images anddiffer in turning the plane of polarized light left (L-form) orright (D-form).optic lobes Lateral extensions of the protocerebrum or nervoussystem for innervation of an eye.opticon n. [Gr. opsis, sight] (ARTHRO: Insecta) The inner zoneof the optic lobes.optimum a. [L. optimus, best] The most suitable condition forthe growth and development of an organism.orad adv. [L. os, mouth; ad, toward] Toward the mouth.oral a. [L. os, mouth] Pertaining to or near the mouth.oral arms (CNID: Scyphozoa) In medusae, 4 or 8 often frillyoral arms, bearing cnidocytes and aid in the capture andingestion of prey.oral cavity The mouth; the buccal cavity.oral cone (CNID: Hydrozoa) In polyps, a conical projectionsurrounded by tentacles with the mouth in the center.oral disk (CNID: Anthozoa) In polyps, a flattened area fromwhich, usually 8 or multiples of 6, tentacles arise thatcommunicate with the coelenteron.oral hooks see mandibular scleritesoral lappet (MOLL) Basal expansion of labial tentacles; labialveil.oral lobe (CTENO) A muscular lobe on either side of the mouthin Lobata.

638Maggenti and Gardneroral plate (ARTHRO: Insecta) The hypopharyngeal floor of thecibarial pump.oral segment A ring or segment bearing the mouth.oral spear see stomatostyle, odontostyleoral styles (KINOR) Spines arranged in a series around themouth cone.oral surface (ECHINOD: Asteroidea) The entire undersurface ofthe disc and arms.oral tentacles (MOLL) Tentacle-like outgrowths of the lip.oral valve (ECHINOD: Crinoidea) One of 5 low triangular flapsseparating the ambulacral grooves.oral vibrissae (ARTHRO: Insecta) In certain Diptera, a pair ofstout bristles or hairs on each side of the face, near orabove the oral margin; larger than those on the vibrissalridge.orb n. [L. orbis, circle] A circle or globe. orbicular a.orbit n. [L. orbis, circle] 1. (ARTHRO) The part of the headsurrounding an eye; orbital fossa. 2. (ARTHRO: Crustacea)In Decapoda, an opening in the anterior face of the carapacesupporting the ocular peduncle.orbital bristles see facio-orbitaorbital carina (ARTHRO: Crustacea) In Decapoda, the narrowregion on the margin of the orbit.orbital fossa see orbitorbital hiatus (ARTHRO: Crustacea) Gap or slit in the orbitalmargin.orbital plate see genovertical plateorbital region (ARTHRO: Crustacea) That part posterior to theeyes bordered by the frontal and antennal regions.orbital tooth (ARTHRO: Crustacea) A tooth on the orbital margin.orchitic a. [Gr. orchis, testis] Of or pertaining to testicles.order n. [L. ordin, methodical arrangement] A taxonomicgroup; a subdivision of a class or subclass, containing agroup of naturally related superfamilies or families.

Online Dictionary of Invertebrate Zoology 639ordinal a. [L. ordin, methodical arrangement] 1. Belonging orpertaining to an order. 2. (ARTHRO: Insecta) Crochets oflarvae, describing the length or arrangements at the tip.see uniordinal crochets, biordinal crochets, triordinalcrochets, multiordinal crochets.ordinate a. [L. ordin, methodical arrangement] Arranged inrows, such as ornamentations or punctures.oreillets n.pl. [F. dim. oreille, projection] (ARTHRO: Insecta)Lateral, spinose processes of male Anisoptera and someZygoptera on the second abdominal tergite, presumed toact as copulatory aids; auricles.organelle n.; pl. -es, -ae [Gr. dim. organon, instrument] Anystructure having a specialized function in the cytoplasm ofthe cell, such as mitochondria, nucleus, plastids, etc.orange rouge (ARTHRO: Insecta) Cells with intracellular tracheoles.organism n. [Gr. organon, instrument] Any individual livingthing.organization center see organizerorganizer n. [Gr. organon, instrument] The region of an embryoseeming to control the differentiation and developmentof other cells; organization center; inductor; evocator.organ of Bellonci (ARTHRO: Crustacea) Receptors innervatedfrom the medullae terminales of the brain, consisting ofciliated sensory neurons associated with supporting cells,such as glial, bordering and perilemmal cells; has also beencalled frontal organ, x-organ, rod-shaped organ. seefrontal eye complex.organ of Berlese see mesospermalegeorgan of Bojanus (MOLL: Bivalvia) A kidney, especially inoysters.organ of Hicks see sensillum campaniformiumorgan of Hoyle see Hoyle's organorgan of Johnston see Johnston's organorgan of Kolliker see Kolliker's organ

640Maggenti and Gardnerorgan of Ribaga see mesospermalegeorganogenesis n. [Gr. organon, instrument; genesis, beginning]Formation and development of organs in the embryo.organogenetic a.organogeny see organogenesisorganoid n. [Gr. organon, instrument; eidos, kind] The bodyforming part of the cytoplasm.organoleptic a. [Gr. organon, instrument; lambanein, to takehold of] Capable of receiving a sensory stimulus.organotroph see heterotrophorgans of Tomosvary (ARTHRO) A pair of sensory organs presenton the head at the base of the antennae in Lithobiomorpha,Scutigeromorpha and some Insecta, consisting ofa disc with a central pore into which the endings of subcuticularsensory cells converge; temporal organs.organs of Valenciennes (MOLL: Cephalopoda) Paired lamellatedorgans in female nautiloids.orichalceous a. [L. aurum, gold; Gr. chalkos, copper] A coloror luster between gold and brass.Oriental Realm A zoogeographical region including Asia eastof the Indus River, south of the Himalayas and the Yangtse-kiangwatershed, Ceylon, Sumatra, Java and the Philippines.orientation n. [L. oriens, the rising sun] Sense of direction; achange in position.orifice n. [L. os, mouth; facere, to make] 1. An opening into acavity; a mouth-like opening. 2. (ARTHRO: Crustacea) Insessile Cirripedia, the opening in the wall occupied by theoperculum. see aperture. 3. (BRYO) The opening on themargin of the orificial wall through which the lophophorepasses.orificial wall (BRYO) 1. In Gymnolaemata, an exterior zooidalwall that bears or defines the orifice through which the lophophorepasses. 2. In Stenolaemata, an orifice throughwhich the tentacles protrude.original description A statement of characters along with theproposal of a name for a new taxon.

Online Dictionary of Invertebrate Zoology 641orismology n. [Gr. horos, boundary; logos, discourse] The scienceof defining technical or scientific words of a particularsubject or field of study.ornamentation n. [L. ornare, to adorn] Sculpturing on thebody of an animal or shell.ornate cercaria (PLATY: Trematoda) A larval form in theXiphidiocercaria group, with a tail fin fold; cercariae ornatae.orphan nest (ARTHRO: Insecta) In social insects, a nest containingoffspring without adults.orthocerous condition (ARTHRO: Insecta) In some adult Coleoptera,antennae showing no sign of geniculation, thescape being longer than succeeding segments, and the clubloose and three-segmented. see gonatocerous condition.orthochromatic a. [Gr. orthos, straight; chromos, color] Withnormal staining characteristics.orthochromatin n. [Gr. orthos, straight; chromos, color] Stablechromatin.orthocline a. [Gr. orthos, straight; clinein, to lean] (MOLL) Atright angles to the growth direction of the helicocone, especiallyin oysters; growth lines.orthodont hinge (MOLL: Bivalvia) A hinge in which the teethapproximate the direction of the cardinal margin.orthodromic a. [Gr. orthos, straight; dromos, running] Movingin a normal direction. see antidromic.orthogenesis n. [Gr. orthos, straight; genesis, beginning]Evolution following a predetermined rectilinear pathway,independent of natural selection.orthognathous a. [Gr. orthos, straight; gnathos, jaw] Havingstraight mouth parts; not projecting.orthogyral, orthogyrate a. [Gr. orthos, straight; gyrate, revolve](MOLL: Bivalvia) Having the beak point at right anglesto the hinge axis, especially oysters.orthokinesis n. [Gr. orthos, straight; kinesis, movement] Anon-directional response in which the speed or frequency ofactivity depends on the intensity of stimulation. see klinokinesis.

642Maggenti and Gardnerorthometaneme n. [Gr. orthos, straight; meta, after; nema,thread] (NEMATA) A metaneme parallel to the longitudinalbody line; found at the dorsal or ventral border of the lateralepidermal cords.Orthonectida, orthonectids n.; n.pl. [Gr. orthos, straight;nekton, swimming] A class of Mesozoa with an asexualparasitic plasmodial generation in many marine invertebratesand a sexual free-swimming generation.orthoneury n. [Gr. orthos, straight; neuron, nerve] (MOLL:Gastropoda) In forms with bilateral zygoneury, the conditionof the visceral loop ganglia and crossed connectivesindicating earlier streptoneury are still evident thoughsometimes reduced. see detorsion.orthoploid see euploidorthoselection n. [Gr. orthos, straight; L. selectus, select]Natural selection continuously acting in one direction over along period of time.orthosomatic a. [Gr. orthos, straight; soma, body] Having abody in a straight line.orthostasy n. [Gr. orthos, straight; stasis, standing] (ARTHRO:Chelicerata) Stage in acarology life-cycle evolution showingonly stases and no stasoids.orthostrophic a. [Gr. orthos, straight; strophe, to turn] (MOLL:Gastropoda) Coiled in a normal manner, as opposed to hyperstrophic.orthotaxy n. [Gr. orthos, straight; taxis, arrangement] Thearrangement of similar organs that have ancestral characters,and have preserved their normal position.orthotriaenes a.pl. [Gr. orthos, straight; triaina, trident] (PO-RIF) In tetraxons, having clads in the angular form of about90° with the axis of the rhabdome.orthotrichy n. [Gr. orthos, straight; trichos, hair] (ARTHRO:Chelicerata) In acarology, all setae that have not disappearedhave maintained their ancestral position.os n.; pl. ora [L. os, oris, mouth] The mouth.oscillation n. [L. oscillare, to swing] A single swing from oneextreme limit to the other of a sine wave.

Online Dictionary of Invertebrate Zoology 643osculant a. [L. osculare, to kiss] 1. Adhering closely. 2. A connectinglink between two groups; having intermediatecharacters, as in genera and species.oscular chimney see osculumosculum, oscule n.; pl. -la [L. dim. os, mouth] 1. (PORIF) Acomparatively large exhalant aperture; an oscular chimney.see apopore. 2. (PLATY: Cestoda) A sucker.osmeterium n.; pl. osmeteria [Gr. osme, odor] (ARTHRO: Insecta)A fleshy, tubular, eversible pouch usually V or Y-shaped, sometimes arising from cephalo- dorso-meson ofthe prothorax of Papilionidae caterpillars, that produce apenetrating odor; also appearing elsewhere in the bodies ofother forms.osmiophilic, osmophilic a. [Gr. osme, smell; philein, to love]Staining readily with osmic acid.osmium see osmosiumosmoconformer n. [Gr. osmos, pushing; cum, with; forma,shape] An organism having the salt content of the blooddetermined by that of the surrounding sea water.osmomorphosis n. [Gr. osmos, pushing; morphos, form]Change in shape due to osmotic (salt) changes in the environment.osmoreceptors n.pl. [Gr. osmos, pushing; recipere, to receive]Receptors that sense changes in osmotic pressure.osmoregulation n. [Gr. osmos, pushing; L. regulatus, regulated]Maintaining the osmotic pressure in the body byregulating the amount of water and salts, effected by theremoval of salts, excretory products or water by the excretoryorgans.osmosis n. [Gr. osmos, pushing] Passage of water through asemi-permeable membrane from a solution of lower concentrationto one of higher concentration until the solutionsare equal in concentration.osmosium n. [Gr. osmos, pushing] (NEMATA) A structure ofmodified intestinal tissue that protrudes into the tissue ofthe Demanian organ that is of gonadal origin.osmotaxis n. [Gr. osmos, pushing; taxis, arrangement] A re-

644Maggenti and Gardnersponse to osmotic pressure change.osmotic see osmosisosmotic pressure Pressure required to prevent the flow ofsolvent through a membrane that has different concentrationsof salt on either side.osphradium n.; pl. -dia [Gr. osphradion, strong smell] (MOLL)1. In Gastropoda, a small sensory organ on the posteriormargin of each afferent gill membrane that functions as achemoreceptor and also determines the amount of sedimentin the inhalant current. 2. In Bivalvia, located in theexhalant chamber, doubtfully homologous to Gastropods.osseous a. [L. os, ossis, bone] Composed of or resemblingbone.ossicle n. [L. dim. os, ossis, bone] 1. A small nodule of chitinthat resembles bone. 2. (ARTHRO: Crustacea) Teeth andtooth-like process in the gastric mill. 3. (ARTHRO: Insecta)For Diptera, see axillary sclerites. 4. (ECHINOD) Plates,spicules and rods that make up the structure of the endoskeleton.ossiculum n. [L. dim. os, ossis, bone] 1. An ossicle. 2. (MOLL:Bivalvia) A small calcareous plate reinforcing an internalligament; a lithodesma.ostia see ostiumostiolar peritreme (ARTHRO: Insecta) The ridged, cuticularprojections surrounding the ostiole, cresting and beingsubdivided into several smaller projections with ridges runningparallel to the line from each ostiole to the correspondingevaporative cuticle.ostiole, ostiola n. [L. ostiolum, little door] 1. Any small opening.2. (ARTHRO: Insecta) In Heteroptera, one of paireddorsal abdominal scent gland openings; in adults, locatednear the coxa.ostium n.; pl. ostia [L. ostium, door] 1. Any opening to a passage,usually associated with a valve or circular muscle. 2.(ARTHRO) The paired slitlike openings in the heart. 3. (AR-THRO: Insecta) In male Lepidoptera, the opening or areathrough which the internal pouch is everted during copulation.4. (MOLL: Bivalvia) One of many tiny holes in the gill

Online Dictionary of Invertebrate Zoology 645walls allowing currents of water through the gills. 5. (PO-RIF) Pore openings entering the interior cavity (the spongocoelor atrium) of sponges; incurrent pores; inhalent pores.ostial a. see ostium bursae.ostium bursae (ARTHRO: Insecta) The copulatory entrance ofthe bursa copulatrix in female Lepidoptera, correspondingto the vulva of other female insects with the genital openingon the 8th abdominal segment.ostium oviductus (ARTHRO: Insecta) In female Lepidoptera,the primary opening of the genitalia through which theeggs are laid, situated near the 9th abdominal segment.ostracum n. [Gr. ostrakon, shell] (MOLL: Bivalvia) 1. The entirecalcareous part of the shell. 2. The outer part of the shellsecreted at the mantle edge.otidium see statocystotocrypt n. [Gr. ous, ear; kryptos, hidden] (MOLL) An open invaginationof the integument of the foot in certain mollusks.otocyst see statocystotolith see statolithotoporpae n.pl. [Gr. ous, ear; porpe, pin] 1. (CNID: Hydrozoa)Lines of cnidoblasts on the exumbrella. 2. (CNID: Scyphozoa)Internal tissue tracts on the bell surface above thesensory organs at the margin of the jellyfish bell.outer coelomic space (BRYO: Stenolaemata) In free-walledforms, the coelomic space between the outer skeletal walland the exterior membranous wall.outer face (MOLL: Gastropoda) In a shell whorl, the surfacebetween the shoulder and the abapical suture or margin ofbase; same as side of whorl.outer leaf crown see corona radiataouter ligament see lamellar ligamentouter lip (MOLL: Gastropoda) Labrum; the outer edge of theaperture of a univalve shell extending from the suture tothe foot of the columella.outer pigment cells see accessory pigment cells

646Maggenti and Gardnerouter plate see quadrate platesouter squama see alulaouter vertical bristles (ARTHRO: Insecta) In Diptera, the morelaterally located of the large bristles on the vertex, andrather behind the upper inner corner of the eye.ova pl. of ovumoval a. [L. ovum, egg] Egg-shaped.ovarial ligament (ARTHRO: Insecta) A ligamentous strand attachingthe terminal filaments of an ovary to the dorsaldiaphram or body wall, or may be from the opposite sideby way of a median ligament to the ventral wall of the dorsalblood vessel; functioning in suspending the developingovaries in the hemocoel.ovarian balls (ACANTHO) In females, a central mass found inthe dorsal ligament sac or free in the pseudocoelom fromwhich oogonia are differentiated; free floating ovaries.ovarian tube (ARTHRO: Insecta) The tubular part of an ovariolecontaining the germ cells, oocytes, nurse cells, and folliclecells.ovariole n. [L. dim. ovum, egg] (ARTHRO: Insecta) The tubulardivision of a female ovary where the oocytes develop.ovariotestis see ovotestisovarium see ovaryovary n. [L. ovum, egg] The female gonad of animals in whichthe egg cells are developed. ovarial, ovarian a.ovate a. (L. ovum, egg] Egg-shaped; oval.ovately-conic Formed like an egg with a somewhat conicapex.ovate-oblong Between oval and oblong.ovate-subquadrate Rounded, but somewhat four-sided.ovejector see ovijectoroverdispersion An ecological term referring to nonrandomdispersion of individuals in a habitat; as, when a minorityof individual hosts bear the majority of parasites.ovicapt n. [L. ovum, egg; captus, capture] (PLATY: Cestoda) A

Online Dictionary of Invertebrate Zoology 647sphincter on the oviduct.ovicell n. [L. ovum, egg; cella, cell] (BRYO) 1. In Gymnolaemata,marine Cheilostomata with a modified zooeciumserving as a brood pouch. 2. In Stenolaemata, a gonozooid;an ooecium.oviducal gland (MOLL: Cephalopoda) A glandular complex oneach oviduct involved in egg coat formation; in some octopods,a sperm storage area.oviduct n. [L. ovum, egg; ducere, to lead] Ducts or passagescarrying female gametes from the ovary toward the exterior;a gonoduct. oviducal a.oviferous see ovigerousoviform a. [L. ovum, egg; forma, shape] Egg-like in shape.oviger n. [L. ovum, egg; gerere, to bear] (ARTHRO: Chelicerata)In some Pycnogonida, specialized egg carrying appendages,as well as functioning in cleaning the long legsand trunk surface.ovigerous a. [L. ovum, egg; gerere, to bear] Carrying eggs;oviferous.ovigerous frena (ARTHRO: Crustacea) In Lepadomorpha Cirripedia,a fleshy ridge or lap on the inner surface of themantle anchoring the egg masses.ovigerous lamella (ARTHRO: Crustacea) In LepadomorphaCirripedia, the egg masses forming one or more lamellaewithin the cavity. see ovigerous frena.ovijector n. [L. ovum, egg; jacere, to throw] (NEMATA) A musculardevelopment of the vagina uterina that aids in thepassage of eggs.oviparous a. [L. ovum, egg; parere, to bring forth] Egg-laying.oviporus n. [L. ovum, egg; porus, passage] (ARTHRO: Insecta)In Lepidoptera, the reproductive opening on segment 9that serves for the discharge of eggs.oviposit v. [L. ovum, egg; ponere, to place] To lay or depositeggs.oviposition n. [L. ovum, egg; ponere, to place] The act of depositingeggs.

648Maggenti and Gardnerovipositor n. [L. ovum, egg; ponere, to place] Structure on afemale animal modified for deposition of eggs.ovisac n. [L. ovum, egg; saccus, bag] 1. An egg capsule, broodpouch, or receptacle. 2. (ARTHRO: Crustacea) In female Copepoda,the external sac attached to the somite that bearsthe openings of the gonoducts. 3. (ARTHRO: Insecta) Incoccids, the envelope in which eggs are laid; the ovarialcavity in which the eggs are stored.oviscapt, oviscapte n. [L. ovum, egg; captare, to conduct] Anovipositor.ovivalvula n. [L. ovum, egg; dim. valva, leaf of a folding door](ARTHRO: Insecta) In female Heteroptera and Ephemeroptera,a subgenital plate.ovocyte see oocytesovogonium see oogoniumovoid a. [L. ovum, egg; Gr. eidos, form] Egg-shaped; ovate.ovotestis n.; pl. -testes [L. ovum, egg; testis, testicle] Hermaphroditicreproductive gland; an organ that producesboth spermatozoa and ova at the same or at different periodsof the life cycle; a syngonic gonad.ovovitellarium n. [L. ovum, egg; vitellus, yolk] (PLATY:Cestoda) A combined mass of ova and vitelline cells.ovoviviparous a. [L. ovum, egg; vivus, alive; parere, to bringforth] Producing eggs that are incubated and hatchedwithin the female's body. see oviparous, viviparous.ovum n.; pl. ova [L. ovum, egg] The egg cell.oxea n. [Gr. oxys, sharp] (PORIF) A smooth spicule tapering totwo similarly pointed ends; amphioxea.oxyaster n. [Gr. oxys, sharp; aster, star] (PORIF) A starshapedspicule with a small center and pointed rays.oxydiact a. [Gr. oxys, sharp; di-, two; aktis, ray] (PORIF)Having three rays with two fully developed.oxygnathous a. [Gr. oxys, sharp; gnathos, jaw] Having sharpjaws.oxyphil, oxyphile see oxyphilicoxyphilic, oxyphilous a. [Gr. oxys, sharp; philein, to love] 1.

Online Dictionary of Invertebrate Zoology 649Tolerant of acid. 2. Staining readily in an acid stain.oxyphobe, oxyphobic a. [Gr. oxys, sharp; phobos, fright] Nottolerant of acid soils; acidophobic.oxytylote n. [Gr. oxys, sharp; tylos, knob] (PORIF) A slenderstraight sponge spicule, sharp at one end and knobbed atthe other.ozadene n. [Gr. ozein, to smell; aden, gland] (ARTHRO: Diplopoda)A defense gland, secreting a repugnant or poisonouschemical.ozopore n. [Gr. ozein, to smell; L. porus, pore] (ARTHRO: Diplopoda)The opening of the ozadene.

PP 1 In Mendel's laws, the first parental generation; parents of agiven individual of the F 1 generation.pachynema n. [Gr. pachys, thick; nema, thread] Thickened,paired chromosomes of meiosis prophase I, third stage;sometimes used as a synonym of pachytene.pachyodont a. [Gr. pachys, thick; odous, tooth] (MOLL: Bivalvia)With heavy, blunt, amorphous teeth.pachytene n. [Gr. pachys, thick; tainia, ribbon] A prophase Istage in meiosis in which the chromosomes are thickenedand paired and crossing over occurs. see pachynema.pad n. [origin uncertain] (MOLL: Bivalvia) In oysters, a thinaragonite layer on which the adductor muscle is inserted.paedogenesis n. [Gr. pais, child; gennaein, to produce] 1.(ARTHRO: Insecta) Parthenogenetic reproduction by insectlarvae structurally unable to copulate. 2. Progenesis. seeneoteny.paedomorphosis n. [Gr. pais, child; morphosis, shaping]Evolutionary change in which ancestrally immature structuresare retained.paedoparthenogenesis see paedogenesispagina n. [L. pagina, leaf] (ARTHRO: Insecta) The surface of awing; inferior= lower surface; superior= upper surface.pagiopodous a. [Gr. pagios, solid; pous, foot] (ARTHRO: Insecta)In aquatic Hemiptera, refers to the posterior coxaehaving the articulation in the form of a hinge joint. see trochalopodous.paired see didymouspairing a. [L. par, equal] Chromosome pairing, highly specificassociation (side by side) of homologous chromosomes.pala n.; pl. palae [L. pala, shovel] (ARTHRO: Insecta) In corixidHemiptera, the tarsus modified as a hair-fringed scoop forparticle feeding.

Online Dictionary of Invertebrate Zoology 651palaeartic region A zoogeographical region encompassingEurope and northern Asia including Japan, the Middle andNear East and areas along the southern coast of the MediterraneanSea.palatal a. [L. palatum, palate] 1. Belonging to the outer lip. 2.(MOLL: Gastropoda) Referring to folds and lamellae of theshell.palatal setae (ARTHRO: Insecta) In Culicidae, four small peglikecibarial setae located on the anterior hard palate.palate n. [L. palatum, roof of the mouth] 1. (ARTHRO: Diplopoda)The endostome. 2. (ARTHRO: Insecta) The epipharynx.3. (BRYO: Gymnolaemata) In Cheilostomata, the mandibularpart of the avicularium.palatum n. [L. palatum, roof of the mouth] (ARTHRO: Insecta)In Culicidae, the oral surfaces of the labrum and clypeus;divided into labropalatum and clypeopalatum.palea n.; pl. paleae [L. palea, chaff] (ANN:broad flattened seta used for burrowing.Polychaeta) Apaleospecies n. [Gr. palaios, ancient; L. species, form] Fossilsthat are placed in a species because of similar appearance.paleotropical n. [Gr. palaios, ancient; tropos, turn] Of or pertainingto the tropical or subtropical regions of the oldworld.palette n. [L. pala, spade] (ARTHRO: Insecta) In males of Coleoptera,the modified cupule-bearing tarsus of an anteriorleg.pali n.pl.; sing. palus [L. palus, stake] 1. (ARTHRO: Insecta) Astraight or pointed spine. 2. (CNID: Anthozoa) Small ridgesbetween the columella and septa of scleractinian corals.palidium n.; pl. -ia [L. dim palus, stake] (ARTHRO: Insecta) Inscarabaeoid larvae, a paired group of spines placed eitherbefore the anus or from the ends of the anal slit; the paliare recumbent and may occur in one to many rows.paliform lobe (CNID) A palus detached from the inner edge ofa septum.palingenesis n. [Gr. palin, back; genesis, descent] 1. Characteristicsof an individual that repeats the phylogenetic de-

652Maggenti and Gardnervelopment of its taxon. 2. The regeneration or restorationof a lost part. 3. Abrupt metamorphosis. see cenogenesis,recapitulation theory.palintrope n. [Gr. palin, back; tropos, turn] (BRACHIO) The recurvedpart of the ventral valve that fills the gap betweenthe beak and hinge line in the dorsal valve of some shells.palisade n. [L. palus, stake] (ARTHRO: Insecta) The clear regionformed around the rhabdom in a light-adapted euconeapposition eye when exposed to darkness.pallets n.pl. [L. dim. pala, spade] (MOLL: Bivalvia) Two variouslyshaped calcareous structures at the siphonal tip ofsome woodboring forms; abrading tools.pallial a. [L. pallium, mantle] (MOLL) Of or pertaining to themantle.pallial artery (MOLL) An artery that supplies blood to the mantle.pallial chamber or cavity (MOLL) The mantle cavity.pallial complex (MOLL) All of the organs of the mantle cavitycombined (ctenidia, osphradia, anus, renal and genitalopenings and glands).pallial curtain (MOLL: Bivalvia) The inner fold of the mantleedge of oysters, with a row of tentacles, supplied withmuscles and blood sinuses.pallial duct (MOLL: Gastropoda) Region of the genital duct thathas undergone elaboration or differentiation to provide forsperm storage and egg membrane formation.pallial groove (MOLL: Polyplacophora) Ventral groove markingthe separation between the foot and mantle.pallial line (MOLL: Bivalvia) A fine, single-lined impression nearthe periphery of each valve, produced by the edge of themantle and indicating the internal line of attachment of themantle to the shell.pallial markings see vascular markingspallial nerves (MOLL) The pair of large dorsal nerves that innervatethe mantle.pallial region (MOLL: Bivalvia) Marginal region inside the shell

Online Dictionary of Invertebrate Zoology 653next to the pallial line.pallial retractor muscles Muscles that withdraw the edge ofthe pallium into the shell.pallial sinus 1. (BRACHIO) see mantle canal. 2. (MOLL: Bivalvia)A notch or recess in the pallial line.palliobranchial fusion (MOLL: Bivalvia) Having the ctenidiaouter tips fused to the mantle margin.palliolum n. [L. dim. pallium, mantle] (ARTHRO: Insecta) InSiphonaptera, the outer (external) wall of the aedeagus.palliopedal a. [L. pallium, mantle; pedis, foot] (MOLL) Pertainsto the mantle and foot.pallioperitoneal a. [L. pallium, mantle; Gr. periteinein, tostretch around] (MOLL) Pertaining to a complex that includesheart, renal organs, gonads and ctenidia.pallium n. [L. pallium, mantle] 1. The mantle of a bivalve Molluscaor a Brachiopoda. 2. (ARTHRO: Insecta) In certainOrthoptera (Caelifera), a membrane from the free marginof the subgenital plate covering the retracted phallus.palm see manuspalmaria, palmars see tertibrachpalmate a. [L. palma, hand] 1. Digitate; parts arising from acommon center; flat and wide with projections like fingers,as certain corals. 2. (PORIF) Megasclere with chela havingsheetlike or winglike elaborations.Palmen's organ (ARTHRO: Insecta) In Ephemeroptera, a cuticularnodule at the junction of four tracheae mid-dorsallybehind the eyes of the adult and larva; may function as astatocyst.palmula see pulvilluspalp see palpus/palppalpation n. [L. palpus, feeler] (ARTHRO: Insecta) The act oftouching with labial or maxillary palps; serves as sensoryprobe or tactile signal to another insect.palp foramen (ARTHRO: Crustacea) A small opening in themandibular body.palpifer n. [L. palpus, feeler; ferre, to carry] (ARTHRO: Insecta)

654Maggenti and GardnerA small lobe of the maxillary stipes to which the maxillarypalpus (palp) articulates. palpiferous a. see palpiger.palpiform a. [L. palpus, feeler; forma, shape] Shaped like apalpus.palpiger n. [L. palpus, feeler; gerere, to carry] (ARTHRO: Insecta)A lobe of the mentum of the labium that bears thepalpus. see palpifer.palpimacula n. [L. palpus, feeler; macula, spot] (ARTHRO: Insecta)A sensory area on the labial palps of certain insects.palpon see dactylozooidpalp proboscis/proboscide (MOLL: Bivalvia) A tentaculiformoutgrowth on each outer labial palp that can extend into oron the substrate, where ciliated and glandular surfaces pickup particles of food.palpus/palp n.; pl. -pi [L. palpus, feeler] 1. (ANN) a. In Oligochaeta,one of a pair of elongate projections on the analsegment. b. In Polychaeta, one of a pair of projections onthe sides of the head. 2. (ARTHRO: Chelicerata) a. InArachnida, the segmented appendage of the pedipalp, excludingcoxa and endite; simple in female, a reproductiveorgan in males. b. In Acari, paired appendage of segment2, sensory in function; maybe up to 6 segments long. 3.(ARTHRO: Crustacea) In Cirripedia, oval, setose mandibularendopod attached to the mandible or to the lateral marginof the labium. 4. (ARTHRO: Insecta) A telopodite of thegnathal appendage. see maxillary palpus; labialpalp/palpus.paludicole a. [L. paludis, marsh; colere, to inhabit] Living in orfrequenting marshes.palule n. [L. palus, stake] (CNID) A detached calcareous processof corals.palus n.; pl. -li [L. palus, stake] 1. A stake-like structure. 2.(CNID) A verticle column along the inner edge of somesepta.pandemic a. [Gr. pan, all; demos, people] A widespread epidemic.see eumenical, cosmopolitan, endemic.panduriform a. [L. pandura, musical instrument; forma,

Online Dictionary of Invertebrate Zoology 655shape] Violin-shaped, oblong at the two extremities andcontracted in the middle; pandurate.Pangaea n. [Gr. pan, all; gaia, earth] The theory of an ancientcontinent from which the present continents split off bycontinental drift.pangamy see panmixiapangenesis n. [Gr. pan, all; genesis, origin] Darwin's pregenetichypothesis that somatic cells contain particles influencedby the environment that can move to the sex cellsand influence heredity.panmixia, panmixy n. [Gr. pan, all; mixis, a mixing] Randominterbreeding in a population; nonselective breeding. panmictica.panoistic ovariole Ovarioles that have no specialized nursecells and are of a primitive type; germ cells occurring withoutinterruption from one end to the other; panoistic eggtube. see meroistic.panthalassic a. [Gr. pan, all; thalassa, sea] Living in coastaland offshore waters.pantherine n. [L. pantherinus, panther-like] Spotted like apanther; similar in color to cervinus.pantropical a. [Gr. pan, all; tropikos, turning] Denoting athorough distribution in the tropics.panzootic a. [Gr. pan, all; zoon, animal] Referring to a widespreaddisease of animals in a region; extensively epizootic.papilioform a. [L. papilio, butterfly; forma, shape] Resemblinga butterfly wing.papilla n., pl. -lae [L. papilla, nipple] 1. A nipplelike elevation,generally sensory in function. 2. (ANN: Hirudinoidea) Inleeches, a small to large protrusible sensory organ;metamerically arranged or scattered on the dorsal surface;large papillae are called tubercules. 3. (ARTHRO: Crustacea)Small steep-sided prominences on the valve surface of Ostracods.4. (ARTHRO: Insecta) A minute soft projection, amodified ligula of silk-spinning caterpillars. 5. (BRACHIO)Fine spines either solid or hollow on the inside of the shell;

656Maggenti and Gardnerendospines. 6. (ECHINOD) In holothurians and ophiuroids,tube foot with sensory function. 7. (ECHI) Wart-like orrounded tubercles on the surface of the body, maybe uniformover the surface, and are often associated with glandularcells. 8. (NEMATA) Pimple-like, simple sensory organs.9. (PLATY: Trematoda) An accessory adhesive organ bearinga retractile tip. 10. (SIPUN) Variously shaped elevationsof the surface of the trunk or introvert, usually associatedwith glandular cells.papillae anales (ARTHRO: Insecta) In female Lepidoptera, apair of soft hairy lobes that flank the genital opening,sometimes modified and heavily sclerotized for the insertionof the eggs into plant tissue or into crevices.papilla genitalis (ARTHRO: Insecta) An outgrowth containingthe genital opening.papillary a. [L. papilla, nipple] A small nipple-like process;minute nodes or bumps.papillary sac (MOLL) The left nephridium with two nephridia;usually filled with projecting papillae.papillate a. [L. papilla, nipple] Having surface elevations;papillose; verrucose.papilliform a. [L. papilla, nipple; forma, shape] Shaped like apapilla.pappus n. [L. papus, down] Down.papula n.; pl. -lae [L. papula, pimple] 1. An isolated pimple orsmall bump. 2. (ECHINOD: Asteroidea) Small finger-likeprojections arising between the body wall spines, mainly onthe upper surface, that function in gas exchange and excretion.papulous a. [L. papula, pimple] 1. Covered with small bumpsor pimples. 2. (MOLL: Gastropoda) The operculum of someNeritidae.parabiosis n. [Gr. para, beside; biosis, manner of life] A formof symbiosis where animals of two or more species live togetheramicably, but keep their broods separate.parabranchial groove (ARTHRO: Crustacea) In Nephropidae, acarapace groove below, behind and almost parallel to the

Online Dictionary of Invertebrate Zoology 657branchiocardiac and postcervical grooves and joining thepostcervical in the lower part.paracardo n. [Gr. para, beside; L. cardo, hinge] (ARTHRO: Insecta)A part of the basal sclerite of the cardo of the maxilla.paraclypeus see mandibular plateparacme n. [Gr. parakme, decadence] The state of decline of agroup of organisms after the highest stage of development(acme). see phylogerontic.paracopulatory organ (ARTHRO: Crustacea) In Isopoda, aspecialized endopod of the pleopod utilized in copulation.paracymbium n. [Gr. para, beside; kymbion, small boat] (AR-THRO: Chelicerata) In mature male Arachnida, a genital appendagearising from the base of the cymbium in manygroups.parademe n. [Gr. para, beside; demas, body] A secondaryapodeme arising from the edge of a sclerite.paraderm see pronymphal membraneparadigm n. [Gr. para, beside; deigma, example] An example,pattern, or model.paraerucism n. [Gr. para, beside; L. eruca, caterpillar] (AR-THRO: Insecta) Poisoning by hairless caterpillars with secretionsby specialized glands. see lepidopterism.parafaciala n.pl. [Gr. para, beside; L. facies, face] (ARTHRO:Insecta) In Diptera, that portion of the face between thefacial ridges and the eyes. see gena.parafrontals see genovertical plateparagaster see spongocoelparagastrula n. [Gr. para, beside; dim. gaster, stomach] (PO-RIF) The gastrula formed by invagination of the flagellatecells of a amphiblastula.parageneon n. [Gr. para, beside; genos, descent] A littlechangingspecies that embraces some aberrant genotypes.paragenetic a. [Gr. para, beside; genesis, descent] A chromosomechange that influences the expression of a gene butnot structure.

658Maggenti and Gardnerparaglossa n.; pl. -ae [Gr. para, beside; glossa, tongue] (AR-THRO: Insecta) One of a pair of terminal lingular lobes ofthe labium that arise distal to the postmentum.paragnath n.; pl. -naths [Gr. para, beside; gnathos, jaw] 1.Any part or structure that lies alongside a jaw or palp. 2.(ANN: Polychaeta) One of a pair of chitinous jaws. 3. (AR-THRO: Crustacea) One of a pair of metastomal lobes. seeendognath. 4. (ARTHRO: Insecta) see superlinguae.paragula n. [Gr. para, beside; gula, throat] (ARTHRO: Insecta)In some Coleoptera larvae, a paired, elongate sclerite oneither side of the gula.parahemizonid n. [Gr. para, beside; hemisys, half; L. zona,girdle] (NEMATA: Secernentea) A hemizonion or other similarstructure.paralabial areas (ARTHRO: Insecta) In aquatic Diptera larvaethat possess a labial plate, a pair of areas lateral to thebase of the labial plate.paralectotype n. [Gr. para, beside; lektos, choose; typos,type] Any of the remaining syntypes after the selection of alectotype.paralimnion n. [Gr. para, beside; limne, pond] The shore areaof lakes.parallel mandibles (ARTHRO: Insecta) In Diptera larva, parallelmouth-hooks that move dorsoventrally.paramentum n. [Gr. para, beside; L. mentum, chin] (ARTHRO:Insecta) In Coleoptera, paired, usually elongate, sclerite oneither side of the mentum.paramera see parameresparameral lobes (ARTHRO: Insecta) In scarabaeoid beetles,lobe-shaped expansions at the distal end of a paramere.parameres n.pl. [Gr. para, beside; meros, part] 1. The right orleft halves of a bilaterally symmetrical animal. 2. (ARTHRO:Insecta) The outer pair of phallomeres that develop intomale copulatory appendages; sometimes synonymized withgonopophyses. 3. (ECHINOD) The perradius with half of interradiuson either side.paranal a. [Gr. para, beside; L. anus, anus] To the side of or

Online Dictionary of Invertebrate Zoology 659next to an anal structure.paranal lobes see paraproctsparaneural muscle (SIPUN) Paired longitudinal muscles oneach side of the anterior portion of the nerve cord.paranota n.pl.; sing. paranotum [Gr. para, beside; notos,back] (ARTHRO) Lateral extension of the tergite or pleurotergitein Diplopoda and Insecta; paranotal expansions orlobes; generally accepted as the origin of wings.paranuclear body see centrosomeparapatric speciation Populations in geographical ranges thatcome in contact and genetic interchange is possible evenwithout sympatry. see dichopatry.parapet see collarparapharynx see hypopharynxparaphyletic a. [Gr. para, beside; phyletes, tribesman] A monophyleticgroup that does not contain all of the descendantsof the most recent common ancestor of that group.paraphysis n.; pl. -yses [Gr. para, beside; physis, growth](ARTHRO: Insecta) In Coccoidea, the chitinized thickenings,lateral ingrowths, or projections near the base of the pygidium.parapleurolophocercous cercaria see pleurolophocercouscercariaparapleuron n.; pl. -ura [Gr. para, beside; pleuron, side] (AR-THRO: Insecta) In Coleoptera, the undivided pleura of thethorax.paraplicate folding (BRACHIO) A fold on either side of the dorsalsulcus on the brachial valve.parapod, parapodium n.; pl. -dia [Gr. para, beside; pous,foot] 1. (ANN: Polychaeta) Paired lateral, fleshy, paddle-likeappendages that bear one or more cirri; usually consistingof two main divisions, the notopodium and the neuropodium.2. (MOLL: Gastropoda) a. In Opisthobranchia, a lobelikeextension of the creeping sole; a fin. b. In Apysiidae,arising from the middle of the body. c. In Pteropoda, locatedanteriorly; functioning as oars.

660Maggenti and Gardnerparapolar cells (MESO) Cells making up the ciliated somatodermbehind the calotte.paraproct n. [Gr. para, beside; proktos, anus] (ARTHRO) Oneof a pair of plates, valves or lobes bordering the anuslateroventrally in some Insecta, Chelicerata, and Diplopoda;synonyms vary with species and authors. paraproctala.parapsidal see parapsisparapsidal furrow (ARTHRO: Insecta) The longitudinal grooveon each side of the mesonotum, lying near to the lateralmargin and separating the parapsides from the mainmesonotal plate.parapsidal grooves see parapsidal furrowparapsidal suture (ARTHRO: Insecta) A longitudinal suture ofthe mesonotum separating the median area from the lateralarea.parapsis n.; pl. -sides [Gr. para, beside; hapsis, arch] (AR-THRO: Insecta) In Hymenoptera, side pieces of the scutellumseparated from the median area by the parapsidalfurrow or suture; scapula.paraptera see tegulaeparasagittal a. [Gr. para, beside; sagitta, arrow] A plane parallelto the sagittal plane.parascolus n. [Gr. para, beside; skolos, thorn] (ARTHRO: Insecta)In Coleoptera ladybird beetle larvae, a modificationof the scolus in which the projection is 2-3 times as long aswide.parascutal area see alar areaparasematic a. [Gr. para, beside; sema, sign] Pertaining tocolors, structures or behavior that deceive preditors. seeantiaposematic, sematic.parasexual a. [Gr. para, beside; LL. sexualis, sexual] Refers toall non-meiotic reproductive processes.parasigmoidal a. [Gr. para, beside; sigma, the 16th letter;eidos, form] Curved like a reversed letter "S."parasite n. [Gr. para, beside; sitos, food] An organism that

Online Dictionary of Invertebrate Zoology 661lives part or all of its life in or on the body of another livingorganism (host), obtaining nutriment from the latter, orexerting other harmful influence upon it. parasitic a. seeparasitoid.parasitic castration Pertaining to the suppression or destructionof gonads by parasites; first used regarding Crustacea;individual parasitic castration. see social parasitic castration.parasiticide a. [Gr. para, beside; sitos, food; L. caedare, tokill] Distructive to parasites; parasiticidal.parasitism n. [Gr. para, beside; sitos, food] A form of symbiosisin which the symbiont benefits from the association andcauses detriment to the host.parasitization n. [Gr. para, beside; sitos, food] The act of anorganism taking food from the body of another organism(host) for the completion of its life cycle; usually detrimentalto the host.parasitoid n. [Gr. para, beside; sitos, food; eidos, form] 1.Any organism that is typically parasitic in its development,but kills the host during or at the completion of its development.2. Also used as an adjective to describe this modeof life. 3. Alternately free-living and parasitic.parasitology n. [Gr. para, beside; sitos, food; logos, discourse]The study of parasites.parasitophorous vacuole A vacuole within a host cell containinga parasite.parasocial a. [Gr. para, beside; socius, companion] (ARTHRO:Insecta) Referring to forms that show one or more of thefollowing traits: cooperation in care of the young, reproductivedivision of labor, and overlapping of life stages thatcontribute to colony labor. see presocial.parastipes see subgaleaparasulcate folding (BRACHIO) With a sulcus on either side ofthe median fold of the brachial valve.parasymbiosis see neutralismparasyndesis n. [Gr. para, beside; syndesis, binding together]Parasynapsis; union of chromosomes side-to-side in the

662Maggenti and Gardnerprocess of meiosis. see acrosyndesis.paratenic host A host harboring a parasite that does not undergofurther development and is generally of ecologic advantagein the disease cycle.paratergite see laterotergiteparathyridium n.; pl. -dia [Gr. para, beside; dim. thyris, window](BRACHIO) Deep indentation of both valves on eitherside of the beak; most pronounced in the dorsal valve.paratomy n. [Gr. para, beside; tomos, cut] (ANN) Designatingthe reproduction by fission with regeneration following preparatoryinternal tissue reorganization. see architomy.paratopotype n. [Gr. para, beside; topos, place; typos, type]A paratype recovered from the same locality as the holotype.paratroch see telotrochparatrophic a. [Gr. para, beside; trophe, food] Deriving foodparasitically.paratype n. [Gr. para, beside; typos, shape] A specimen collectedat the same time as the holotype and was so designatedor indicated by the original author.parauterine organ see paruterine organparaxial a. [Gr. para, beside; L. axis, axle] 1. To move parallelto the body axis. 2. par-axial (ARTHRO: Chelicerata) In spiders,pertaining to chelicerae with the paturon projectingforward with the fangs moving in a downward direction.see di-axial.paraxial organs (ARTHRO: Chelicerata) Special gland pocketsthat produce the spermatophores of male Scorpions.paraxon n. [Gr. para, beside; axon, axle] The collateral branchof an axon.Parazoa n. [Gr. para, beside; zoon, animal] A subkingdomcontaining Porifera; the sponges.parazoeal a. [Gr. para, beside; zoe, life] (ARTHRO: Crustacea)In Bathynellacea, postembryological development (larval)phase, quite often completed in the egg.parcidentate a. [L. parcus, sparing; dens, tooth] Having few

Online Dictionary of Invertebrate Zoology 663teeth.parecium n. [Gr. para, beside; oikos, house] (ARTHRO: Insecta)Air space surrounding a fungus garden in the nest ofIsoptera.parenchyma n. [Gr. para, beside; NL. enchyma, type of celltissue] Undifferentiated tissue between organs in variousinvertebrates. parenchymatous a.parenchymalia n.pl. [Gr. para, beside; NL. enchyma, type ofcell tissue] (PORIF: Hexactinellida) Spicules scatteredthroughout the parenchyma, consisting of hexactines, diactines,various hexasters and sometimes amphidisks.parenchymula, parenchymella n. [Gr. para, beside; NL. enchyma,type of cell tissue] (PORIF) A solid, ciliated larva; astereogastrula.paria n.; pl. -ae [Gr. pareion, cheek] (ARTHRO: Insecta) Inscarabaeoid larvae, the lateral paired region of theepipharynx from the clithrum, or epizygum and haptomerumto the dexiotorma or laetorma.paries n.; pl. parietes [L. paries, wall] 1. A wall; any wall of apart, cavity or hollow organ. 2. (ARTHRO: Crustacea) Themedian part of every compartmental plate of sessile Cirripedia.parietal a. [L. paries, wall] 1. (ARTHRO: Crustacea) Of or pertainingto paries. 2. (ARTHRO: Insecta) Referring to the dorsalsclerites of the cranium, between the frontal and occipitalareas; the adfrontal area or plate. 3. (MOLL: Gastropoda)Pertaining to the inside wall of a univalve within theaperture, the broader upper part of the inner lip.parietal callus (MOLL: Gastropoda) A thickening of the innerlip.parietal fold (MOLL: Gastropoda) A spiral ridge on the parietalregion projecting into the interior of the shell.parietal lip (MOLL: Gastropoda) A part of the inner lip on theparietal region.parietal muscles (BRYO) Generally multiple, bilaterally pairedmuscles that insert on the front wall or floor of the ascus;usually functioning in the hydrostatic system.

664Maggenti and Gardnerparietal pore 1. (ARTHRO: Crustacea) see longitudinal tube.2. (BRYO: Gymnolaemata) A hole in the distal wall of thezooecium allowing communicating fibers betweenpolypides.parietal region (MOLL: Gastropoda) The basal surface of thehelical spiral shell located within and without the aperture.parietal ridge (MOLL: Gastropoda) The prominence on the parietallip near the adapical corner of the aperture.parietal septum see longitudinal septumparietal tube see longitudinal tubeparietal wall see parietal regionparieto-basilar muscles (CNID: Anthozoa) Muscles on thecolumn of Actinaria that run obliquely from the outer endsof the mesenteries near the base on to the central parts ofthe pedal disk; functioning to aid in fastening the animal tothe substratum.parivincular a. [L. par, equal; vinculum, bond] (MOLL: Bivalvia)Having a ligament similar to a cylinder split on oneside, attached by several edges (nymphae), with one edgeto each valve. see opisthodetic, amphidetic.parocciput n. [Gr. para, beside; L. occiput, back of head] (AR-THRO: Insecta) A thickening of the occiput for articulation ofthe cervical sclerites.paronychium n.; pl. -ia [Gr. para, beside; onykos, claw] (AR-THRO: Insecta) A bristle-like appendage on the pulvillusbetween the tarsal claw.pars n.; pl. partes [L. pars, part] A part of an organ.pars ampullaris (ARTHRO: Crustacea) In Malacostraca (Hoplocaridaand Anaspidacea), a bottle-shaped structure at theentrance of the digestive glands into the pyloric chamber ofthe stomach.pars basalis see cardopars bothrialis (PLATY: Cestoda) In Trypanorhyncha, a divisionof the scolex from the anterior end to the hind margin ofthe bothridia.pars bulbosa (PLATY: Cestoda) In Trypanorhyncha, a division

Online Dictionary of Invertebrate Zoology 665of a scolex extending the length of the bulbs at the tentaclebase.parsimony n. [L. parsimonia, frugality] Economizing in assumptionof reasoning.pars incisiva see incisor processpars intercerebralis (ARTHRO: Insecta) A group of neurosecretorycells near the midline on each side of the brainfrom which secretions promote the functioning of the prothoracicglands, stimulate protein synthesis and arethought to control water loss, oocyte development and activity.pars molaris see molar processpars postbulbosa (PLATY: Cestoda) In Trypanorhyncha, a divisionof the scolex from the hind margin of the tentacularbulb to the posterior end of the scolex.pars prostatica (PLATY: Cestoda) Dilation of the ejaculatoryduct encircled by unicellular prostate cells.pars stipitalis labii see prementumpars stridulans see strigilpars vaginalis (PLATY: Cestoda) In Trypanorhyncha, a divisionof the scolex from the anterior end to the anterior end ofthe tentacular bulbs.parthenapogamy n. [Gr. parthenos, virgin; apo-, separate;gamein, to marry] Diploid parthenogenesis.parthenita n.; pl. -ae [Gr. parthenos, virgin] (PLATY: Trematoda)The unisexual stage in an intermediate host.parthenogenesis n. [Gr. parthenos, virgin; genesis, origin]The development of an individual from an unfertilized egg.parthenogenetic a. see arrenotoky, thelyotoky.parthenogenone n. [Gr. parthenos, virgin; genesis, origin;on, being] A parthenogenetic organism; parthenogone. seeparthenote.parthenote n. [Gr. parthenos, virgin] A haploid organism producedparthenogenetically.partial coverage see valve coverageparticulate inheritance Mendel's theory that inheritance in an

666Maggenti and Gardnerindividual has distinct genetic factors from paternal andmaternal forebearers.partite a. [L. partitus, divided] Divided; separated; parted.parturition n. [L. parturire, to bring forth] The act of givingbirth.paruterine organ (PLATY: Cestoda) In Paruterininae, fibromuscularappendage that receives and stores the eggs, replacingthe uterus.parva stage (ARTHRO: Crustacea) In Decapoda Caridea, thefirst postlarval stage.parviconoid a. [L. parvus, small; conus, cone] Resembling asmall cone.pastinum n. [L. pastinum, two pronged tool] (ARTHRO: Crustacea)In male Ostracoda, chitinized skeletal rods (cauduallyfork-shaped) that support the entire copulatory complex.patabionts see cryptozoapatagium n.; pl. patagia [L. patagium, border] (ARTHRO: Insecta)1. In Lepidoptera, a pair of articulated, thin, lobelikeerectile expansions (overlapping plates) of the prothorax.2. For Culicidae, see antepronotum.patella n.; pl. -lae [L. patella, small pan] 1. The knee cap. 2.(ARTHRO: Chelicerata) a. In Arachnida, a leg segment betweenthe femur and tibia (the 4th segment). b. For Acari,see genu. patelliform a.patellar a. [L. patella, small pan] 1. Pertaining to the patella; asmall pan; a kneepan. 2. (MOLL: Cephalopoda) The saucershape,typical of Patellacea.patent a. [L. patens, lying open] Open; diverging; expanded;spreading apart. see prepatent period.pathogen n. [Gr. pathos, suffering; gennaein, to produce] 1. Adisease causing microorganism. 2. A parasite causing injuryto a host.pathogenesis n. [Gr. pathos, suffering; genesis, origin] Theorigination and development of disease. pathogenic a.pathognomonic a. [Gr. pathos, suffering; gnom, sign] A diagnosticsymptom by which a disease may be recognized.

Online Dictionary of Invertebrate Zoology 667pathology n. [Gr. pathos, suffering; logos, discourse] Thestudy of diseases. pathological a.patocoles n.pl. [Gr. patos, bottom; L. colere, to dwell] Animalsthat spend part of their time dwelling in the cryptospherebut emerge to hunt and mate.patronymic a. [Gr. pater, father; onyma, name] In nomenclature,a name based on that of a person.patulous a. [L. patulus, standing open] Spreading; expanded;distended; having a wide aperture.paturon n. [Gr. patein, to trample on; oura, after part] (AR-THRO: Chelicerata) In Acarina, a structure on the chelicerabearing numerous toothlike projections; rastellum.paucispiral a. [L. paucus, few; spira, coil] With relatively fewwhorls; oligogyral.paunch see cropPaurometabola n. [Gr. pauros, little; metabole, change] (AR-THRO: Insecta) A division of the Heterometabola.paurometabolous a. [Gr. pauros, little; metabole, change](ARTHRO: Insecta) Having slight metamorphosis, the youngand adults living in the same habitat, and the adults havewings. see holometabolous.Pauropoda n. [Gr. pauros, little; pous, foot] (ARTHRO) Blindmyriapoda, having 9-11 leg-bearing trunk segments, belongingin the phylum Arthropoda.paurostyle n. [Gr. pauros, little; stylos, pillar] (BRYO: Stenolaemata)A type of stylet of cryptostomates with an irregularrod of nonlaminated material, with laminae weakly deflectedtoward the zoarial surface; usually smaller thanacanthostyles.Pavan's gland (ARTHRO: Insecta) A gland of many Dolichoderine,associated with a conspicuous palisade epitheliumon the 7th sternum that functions to secrete a pheromonetrail; a sternal gland.Pawlowsky's glands (ARTHRO: Insecta) In Siphunculata, apair of glands that open into the stylet sac and possiblyfunction to lubricate the stylets.paxilla n.; pl. -lae [L. paxillus, a peg] 1. A small spine or peg.

668Maggenti and Gardner2. (ECHINOD: Asteroidea) A raised ossicle on the aboralsurface, crowned with small movable spines or granules.paxilliform a.Pearman's organ (ARTHRO: Insecta) A rugose area adjacentto a membranous tympanum on the inner side of the hindcoxae of Psocids, thought to be a stridulatory organ.pecilonymy see poecilonymypecking order see hierarchypecten n.; pl. pectines [L. pecten, comb] 1. Any comb- orrake-like structure. 2. (ARTHRO: Chelicerata) In Scorpiones,one of a pair of appendages on the somite immediately behindthe genital somite. 3. (ARTHRO: Insecta) a. In Culicidae,a Culicinae larvae, bearing a comblike row of spiculeson the basal part of the siphon; in Anophelinae and Dixidaelarvae, borne on the posterior margin of the pecten plate.b. In Apidae, the pollen rake. c. In genitalia, distally pointingrows of comblike teeth lining the articular membrane ofthe gonopophyses. d. In Diaspidinae, see gland spines.pectina n.; pl. -ae [L. pecten, comb] (ARTHRO: Insecta) One ofthe broad fringed plates on the pygidium of coccids.pectinate a. [L. pecten, comb] 1. Having branches or processeslike a comb. 2. Of claws; having teeth.pectinate chaeta (ANN: Oligochaeta) Crochet seta with twolateral teeth with several fine teeth between.pectinations n.pl. [L. pecten, comb] (MOLL: Polyplacorphora)Small sharp teeth on the outer edges of the insertionplates.pectunculate a. [L. pecten, comb; -unculus, little] Having arow of minute appendages; pectunculoid.pectus n. [L. pectus, breast] (ARTHRO) A sclerite composed ofpleuron fused with the sternum.pedal a. [L. pedis, foot] Pertaining to a footlike appendage.pedal disc (CNID: Anthozoa) In Actinaria, the base or foot.pedal elevator muscle (MOLL: Bivalvia) Muscle fibers attachedin the umbonal cavity that raise the foot.pedal gape (MOLL: Bivalvia) Opening between shell valves that

Online Dictionary of Invertebrate Zoology 669allows extension of the foot.pedal glands (ROTIF: Bdelloidea) Glands in the retractile foot,opening through the toes, that secrete an adhesive to attachthe animal to the substrate while feeding.pedal groove (MOLL: Solenogastres) A longitudinal fold or foldswith ciliated and secretory cells in the median ventral position.pedalium n.; pl. -alia [Gr. pedalion, rudder] (CNID) Bladelikeexpansions at each corner of the umbrella that bear a motileand contractile hollow tentacle or group of tentacles.pedal levator muscle see pedal retractor musclepedal lobe (ARTHRO: Insecta) A fleshy, bump-like, non-segmentedrudimentary leg of a larva.pedal pit (MOLL: Solengastres) A ciliated pit containing secretorycells at the anterior end of the pedal groove.pedal protractor muscle (MOLL: Bivalvia) The muscle thatextends the foot.pedal retractor muscle (MOLL: Bivalvia) The muscle attachedto the shell that withdraws the foot; pedal levator muscle.pedal stridulating organ (ARTHRO: Insecta) In male HemipterousCorixidae, the spinose area on the inside of eachfront femur when drawn over the edge of the clypeus.pedamina n.pl.; sing. -um [L. pes, foot; mina, projectingpoint] (ARTHRO: Insecta) In Lepidoptera, the aborted forelegsof a nymph.peddler n. [ME. pedlere, fr. ped, basket] (ARTHRO: Insecta) Alarva of Cassidinae Coleoptera, having a forked caudalprocess supporting excrement and exuviae.pedicel n. [L. pediculus, little foot] 1. Any small or short stalkor stem supporting an organ or other structure. 2. (AR-THRO: Chelicerata) In Arachnida, the attenuated first abdominalsegment, joining the abdomen to the cephalothorax.3. (ARTHRO: Insecta) a. The second segment of theantenna. b. An ovariole stalk, or short duct connecting theegg tubes with the later oviduct. c. In Formicidae, the stemof the abdomen, between the thorax and gaster.pedicellariae n.pl. [L. pediculus, little foot] (ECHINOD) In

670Maggenti and GardnerEchinoidea and Asteroidea, stalked pincer-like structures,usually armed with teeth, used for removal of foreign particlesand prevention of larvae of sessile organisms fromsettling on the animal; sessile pedicellariae are composedof two or more short, movable spines on the same or adjacentossicles.pedicellate a. [L. pediculus, little foot] Supported by a pedicelor petiole.pedicellus spines (ARTHRO: Insecta) In Hymenoptera andDiptera, sensory spines at the bases of the antennae thatplay a role in the perception of gravity and possibly currentstimuli.pedicle n. [L. pediculus, little foot] (BRACHIO) A variously developed,tough flexible stalk protruding from the bivalveshell; functioning as a tether, a pivot around which theshell may be moved, or as a locomotory organ.pedicle collar (BRACHIO) The two deltidial plates curvedaround the pedicle base, may or may not be fused.pedicle foramen (BRACHIO) Ring-like perforation of a shellthrough which the pedicle passes.pedicle groove (BRACHIO) When present, subtriangular groovedividing the ventral pseudointerarea medially and allowingpassage for pedicle.pedicle muscles (BRACHIO) 1. In Articulata, adjuster musclesexternal to the pedicle and longitudinal fibrils in the connectivetissue of the pedicle. 2. In Inarticulata, muscles inthe wall and coelom of the pedicle.pedicle plate (BRACHIO) A tongue-like shell deposit inside thedorsal edge of the labiate foramen.pedicle sheath (BRACHIO) A tube projecting posteroventrallyfrom the ventral umbo; probably enclosing the pedicle inthe young stages of shell development with a supra-apicalpedicle foramen.pedicle tube (BRACHIO) A tube of secondary shell enclosingthe proximal part of the pedicle.pedicle valve (BRACHIO) The valve from which the pedicleusually emerges, generally larger than the brachial valve;

Online Dictionary of Invertebrate Zoology 671ventral valve.pedigerous a. [L. pes, foot; gerare, to carry] Bearing footlikeappendages.pedipalp, pedipalpus n.; pl. -pi [L. pes, foot; palpare, totouch] (ARTHRO: Chelicerata) The second pair of cephalothoracicappendages, variously modified as a pincerlikeclaw, or simple leg-like in different groups.pedisulcus n. [L. pes, foot; sulcus, furrow] (ARTHRO: Insecta)In Diptera, an indentation near the base of the second hindtarsal segment of some Simuliidae.pedium n.; pl. -dia [Gr. pedion, open plain] (ARTHRO: Insecta)In scarabaeoid larvae, the central part of the epipharynx,bare and soft-skinned, between the haptomerum and haptolachus;crossed on the left side by the epitorma.pedofossae n.pl. [L. pes, foot; fossa, ditch] (ARTHRO: Chelicerata)In Acari, concavities in the podosoma into whichlegs II, III and IV can be tucked.pedogenesis see paedogenesispedothecae n.pl. [Gr. pedon, ground; theke, case] (ARTHRO:Insecta) In Diptera pupae, the adhering sheaths of thelegs.peduncle n. [L. pedunculus, small foot] A stem, stalk or petiolesupporting an organ or other structure. pedunculate a.pedunculate bodies see corpora pedunculatapedunculate papillae (NEMATA) A modified, stalked, genitalpapillae of males.pelagic a. [Gr. pelagos, open sea] Pertaining to the open sea;ocean-dwelling.pelagosphera n. [Gr. pelagos, open sea; sphaira, ball] (SIPUN)The second larval stage, characterized by a terminal organfor temporary attachment to the substratum, a band ofmetatrochal swimming cilia, and a retractable anteriorbody.Pelecypoda see Bivalviapellicle n. [L. pellis, skin] A thin skin, film or layer.pellions see rosettes

672Maggenti and Gardnerpellucid a. [L. per, through; lucere, to shine] Transparent orclear; not colored.pelma n. [Gr. pelma, sole] (ECHINOD: Crinoidea) The stalk andholdfast beneath the crown.peloderan a. [Gr. pella, cup, bowl; deros, skin] (NEMATA) Pertainingto caudal alae that meet at the male tail tip. seeleptoderan.pelopsiform a. [Gr. pelops, genus of orbatid mites; L. forma,shape] (ARTHRO: Chelicerata) In Acari, having the form ofthe genus Pelops.peltate a. [Gr. pelte, shield] Shield-shaped; escutcheon. peltationn.peltidium n. [Gr. pelte, shield] (ARTHRO: Chelicerata) In acari,the prodorsal shield. see schizopeltid.peltogonopod n. [Gr. pelte, shield; gone, seed; pous, foot](ARTHRO: Diplopoda) Accessory gonopods; often plate-likeshields of the gonopods.pen n. [L. penna, feather] (MOLL: Cephalopoda) In Teuthoidea,an internal shell that may be slender, thin, delicate, hornyor lanceolate. see gladius.pencil n. [L. dim. penis, tail] 1. A brush of hair or bristles. seebrushes. 2. (ARTHRO: Insecta) In Diptera, sensory hair onthe distal part of the antenna.pendent a. [L. pendere, to hang] Hanging; suspended fromabove. pendulous a.penellipse n. [L. paene, almost; Gr. elleipsis, leaving out] (AR-THRO: Insecta) In larvae, a series of crochets usually morethan a semicircle and less than a complete circle. see lateralpenellipse, mesal penellipse.penetrant see stenotelepenial chaeta/seta (ANN: Oligochaeta) One of the extra setanear the male pore that facilitate the passage of spermduring copulation; usually long, sculptured, and in pairedbundles.penicilla n.; pl. -ae [L. penicillum, painter's brush] (ARTHRO:Crustacea) In certain Anaspidacea, dentate setae on themandible.

Online Dictionary of Invertebrate Zoology 673penicilliform a. [L. penicillum, painter's brush] Having theform of a brush or pencil; tipped with fine hairs or fibers.penicillum, penicillus n.; pl. -li [L. penicillum, painter'sbrush] A pencil or brush of setae or hair.peniferum n. [L. penis, male copulatory organ; ferum, bear](ARTHRO: Crustacea) In Ostracoda, the varied, sclerotizedmale copulatory apparatus that bears the penis and hingeon which the apparatus may turn around the zygum.penis n.; pl. -es [L. penis, male copulatory organ] A malecopulatory organ or paired organs for conveying sperm tothe genital tract of a female. see phallus, aedeagus.penis funnel see anelluspenis valves (ARTHRO: Insecta) In Hymenoptera, genitalclasper organs.pennaceous a. [L. penna, feather] Resembling a feather, as amarking; penniform.pentacrinoid a. [Gr. pente, five; krinon, lily] (ECHINOD: Crinoidea)A larval stage following the cystidean stage thatattaches to the substrate or adult crinoid and develops acrown of arms and cirri.pentactula larva (ECHINOD: Holothuroidea) A young larva with5 primary tentacles and one or two podia that eventuallysettle to the bottom and assume the adult mode of existence.pentaglossate a. [Gr. pente, five; glossa, tongue] (MOLL)Having no central tooth and teeth of the same shape thatincrease in size toward the edge of the radula.pentagonal a. [Gr. pente, five; gonia, angle] Five-sided; having5 angles.pentamerous a. [Gr. pente, five; meros, part] Composed of 5similar parts; having 5-jointed tarsi.pentaradiate a. [Gr. pente, five; L. radius, ray] Arranged in 5rays.pentazonian segment (ARTHRO: Diplopoda) A segmentformed of 5 separate sclerites; the tergum, 2 lateral pleuritesand 2 sternites.

674Maggenti and Gardnerpenultimate a. [L. paene, almost; ultimus, last] Next to thelast; the whorl preceding the last.peptonephridia n.pl. [Gr. pepton, digested; nephros, kidney](ANN: Oligochaeta) Organs opening into the buccal cavity ofpharynx (supposedly modified nephridia).peraeon see pereonperaeonite see pereoniteperaeopod see pereopodpercurrent a. [L. per, through; currere, to run] Extendingthrough the entire length; continuous.percutaneous a. [L. per, through; cutis, skin] Penetrationthrough the skin.peregrine see allochthonous, anthropochorouspereionite see pereonitepereiopod see pereopodpereon, pereion, peraeon n. [Gr. peraioun, to convey] 1.(ARTHRO: Crustacea) A thoracic region of Isopoda; anteriorportion of the trunk bearing thoracopods, except for maxillipedalsomites and appendages. 2. pereion (ARTHRO: Insecta)see prothorax. pereonal a.pereonite n. [Gr. peraioun, to convey; -ites, joined to] (AR-THRO: Crustacea) Somite of the pereon; peraeonite,pereionite.pereopod, peraeopod, pereiopod n. [Gr. peraioun, to convey;pous, foot] (ARTHRO: Crustacea) Thoracic appendageused in locomotion and for seizing and handling food; ambulatoryleg; walking leg; trunk legs.perfect mesentaries (CNID: Anthozoa) Mesenteries spanningthe gastrovascular space and inserting on the body walland actino-pharynx. see imperfect mesentaries.perfoliate a. [L. per, through; folium, leaf] With terminal jointsleaflike and surrounding the stalk connecting them.perforate a. [L. per, through; forare, to bore] Pierced; havingpores or small openings.pergameneous a. [L. pergamena, parchment] Of the natureor texture of parchment.

Online Dictionary of Invertebrate Zoology 675perianal a. [Gr. peri, around; L. anus] Situated or occurringaround the anus.periaxial a. [Gr. peri, around; L. axis] To surround an axis.peribuccal a. [Gr. peri, around; L. bucca, mouth cavity] Encirclingthe buccal cavity.pericardial cavity see dorsal sinuspericardial cells (ARTHRO: Insecta) Nephrocytes present onthe surface of the heart, or lying on the pericardial septumor the alary muscles.pericardial gland 1. (ARTHRO: Insecta) see prothoracic gland.2. (MOLL: Gastropoda) Marginal cells of the pericardium inProsobranchia; filled with yellow-green granules.pericardial sinus see dorsal sinuspericardium n. [Gr. peri, around; kardia, heart] The cavity enclosingthe heart as well as membranes lining the cavityand covering the heart. pericardial a.pericaryon see perikaryonpericentric inversion An inversion that includes the centromere.perichaetine a. [Gr. peri, around; chaite, mane] (ANN: Oligochaeta)Referring to setal location, when there is morethan 8 per segment, encircling a segment; perichaetal condition.perideltidium n.; pl. -ia [Gr. peri, around; dim. delta, ](BRACHIO) One of a pair of raised triangular areas on eitherside of the pseudodeltidium with both striae and growthlines. perideltidial a.periderm n. [Gr. peri, around; derma, skin] (CNID: Hydrozoa)A hydroid perisarc.perienteric a. [Gr. peri, around; enteron, gut] Surrounding thealimentary tract.periflagellar membrane (PORIF) A membrane between choanocytecollar tentacles and the apical flagellum.perigastric a. [Gr. peri, around; gaster, stomach] Surroundingthe visera.perignathic girdle (ECHINOD: Echinoidea) A calcareous ridge

676Maggenti and Gardneron the inner side of the peristomal edge of the test thatserves as the attachment for the muscles of the masticatoryapparatus.perihemal a. [Gr. peri, around; haima, blood] (ECHINOD) Varioustubular coelomic sinuses that form channels of the hemalsystem.perikaryon, pericaryon n.; pl. -karya [Gr. peri, around;karyon, nucleus] The portion of the cell that contains thenucleus.perilemma n.; pl. -ae [Gr. peri, around; lemma, bark] (AR-THRO) A layer of glial cells beneath the fibrous neurilemmaglanglia.perilymph n. [Gr. peri, around; L. lympha, water] (MOLL:Cephalopoda) In Octopodidae, the liquid that fills the outersac of the statocyst.perimetrical attachment organ (BRYO: Stenolaemata) Collarlikemembrane attached to the tentacle sheath and toboth the outer end of the membranous sac and skeletalbody wall.perinaeum see perineumperinductura n. [Gr. peri, around; L. inductura, a covering](MOLL: Gastropoda) A continuous outer shell layer formedby the edge of the mantle reflected back over the outer lip.perineum n. [Gr. peri, around; enein, to empty out] (ARTHRO:Insecta) The area between the posterior of the anus andthe anterior part of the external genitalia, especially in females.perineal a.perineural a. [Gr. peri, around; neuron, nerve] Surrounding anerve or nerve cord.perineurium n. [Gr. peri, around; neuron, nerve] (ARTHRO:Insecta) A layer of cells beneath the neural lamella in thenerve sheath.perinotum see girdleperiodicity a. [Gr. peri, around; hodos, way] Functions thatoccur at regular intervals or times; rhythm.periodomorphosis n. [Gr. peri, around; hodos, way; morphosis,shaping] (ARTHRO: Diplopoda) In some male Julida, re-

Online Dictionary of Invertebrate Zoology 677gression from a copulatory stage to a noncopulatory stagein consecutive molts; subsequent molting leads to a copulatorystage again.periopticon see laminaperioral disc see labial discperiostracal glands (MOLL: Bivalvia) Glands of the mantleedge that secrete the base layer of the periostracum.periostracal groove (MOLL: Bivalvia) The groove between thetentacular fold and the shell fold that houses the periostracalglands.periostracum n. [Gr. peri, around; ostrakon, shell] A thin skinor horny covering on the exterior of the shells of mostMollusca and Brachiopoda. periostracal a.periparturient period That period before, during and aftergiving birth.periphallic organs (ARTHRO: Insecta) Genital processes on theposterior ventral surface of segment 9.peripharyngeal ganglion (BRYO) Prolongation of the cerebralganglion around the oral opening.peripheral a. [Gr. peri, around; pherein, to carry] To or towardthe surface; distant from the center.peripheral nerve net (NEMATA: Adenophorea) A subcuticularneural meshwork that connects the setae and papillae onthe whole body surface of some marine forms.peripheral nervous system Contains all sensory cell bodies(exceptions rare), plus local plexuses in the body wall orviscera, local ganglia of either sensory or motor-and-internuncialcomposition, plus the pheripheral axons making upthe nerves.periplasm n. [Gr. peri, around; plassein, to mold] (ARTHRO:Insecta) A bounding layer formed by cytoplasm in the eggthat lies just beneath the vitelline membrane and completelysurrounds the egg.peripneustic a. [Gr. peri, around; pneustikos, of breathing](ARTHRO: Insecta) Having 9 pairs of functional spiracles;usually a prothoracic pair and 8 abdominal pairs. seepolypneustic.

678Maggenti and Gardnerperipodial cavities (ARTHRO: Insecta) A cavity formed duringmetamorphosis when the imaginal disc becomes invaginatedbeneath the larval epidermis.peripodial membrane (ARTHRO: Insecta) The cell layer or wallsurrounding the peripodal cavity and at pupation, comes toform part of the epidermis of the general body wall.peripodial sac (ARTHRO: Insecta) In metamorphosis, themembrane enclosing the imaginal disc (bud).periproct n. [Gr. peri, around; proktos, the anus] 1. The distalpiece or segment of the body containing the anus. 2. (ANN:Oligochaeta) The pygomere or pygidium. 3. (ARTHRO) seetelson. 4. (ECHINOD) The circular membrane containing theanus, surrounded by a varying number of embeddedplates.perisarc n. [Gr. peri, around; sarx, flesh] (CNID: Hydrozoa) Ayellowish or brown chitinous covering of a colony that issecreted by the epidermis; the periderm.perisomatic plates (ECHINOD: Crinoidea) Tegminal plates:interradials, interambulacrals, or radianal plates.perispicular spongin (PORIF) Spongin surrounding spicules.peristalsis n. [Gr. peri, around; stalsis, constriction] Rhythmicmovement of the wall of the enteron or other tubular organs,traveling in successive contractions in one direction.peristethium see mesosternumperistigmatic glands (ARTHRO: Insecta) Glands that secrete ahydrophobic material preventing wetting of the spiracles.peristome n. [Gr. peri, around; stoma, mouth] 1. The regionsurrounding the mouth. 2. (ANN) Segment modified to formpart of the head and surround the mouth; buccal segments.see prostomium. 3. (ARTHRO: Insecta) Membranoustissue around the base of the mouth. 4. (BRYO) Modificationsof the area around the orifice. 5. (ECHINOD: Ophiuroidea)Membranous area surrounding the mouth; on theaboral surface of the jaw. 6. (MOLL: Gastropoda) Thickenedrim or lip around the mouth; the margin of the aperture.peristomium n. [Gr. peri, around; stoma, mouth] (ANN: Oligochaeta)The lateral and ventral margins of the mouth,

Online Dictionary of Invertebrate Zoology 679behind the prostomium.perisympathetic system (ARTHRO: Insecta) Neurohemal organsconnected to the transverse nerves of the ventralsympathetic nervous system, that release the products ofthe neurosecretory cells in the ventral ganglia.peritoneal membrane see peritoneumperitoneal sheath (ARTHRO: Insecta) A network of anastomosingmuscle fibers that holds together the ovarioles ofthe ovary.peritoneum n. [Gr. peri, around; tonos, strain; eous, composedof] A thin serous membrane lining the body cavity;covering and supporting the organs. peritoneal a.peritreme n. [Gr. peri, around; trema, hold] 1. (ARTHRO: Chelicerata)In Acari, a concave plate surrounding a stigma(=spiracle). 2. (ARTHRO: Insecta) An annular sclerite surroundinga spiracle. 3. (MOLL: Gastropoda) see peristome.peritrophic membrane (ARTHRO) An extracellular sheath inwhich chitin is present, separating the apical surface of themid-gut that protects the gut cells from mechanical damagecaused by abrasive food particles; usually looseningfrom the mid-gut and remaining around the food, passingwith the feces.perivisceral a. [Gr. peri, around; L. viscus, entrail] Surroundingthe viscera.permanent haplometrosis (ARTHRO: Insecta) A colony that isfounded by a single female whose initial offspring are sterilefemales, then later towards the end of the annual cyclereproductives are produced. see temporary haplometrosis,functional haplometrosis.permanent hybrid Hybrid that maintains its heterozygosity bybalanced lethal factors in its genotype.permanent parasite A parasite living its entire adult lifewithin or on a host.permanent pleometrosis (ARTHRO: Insecta) In social Hymenoptera,the foundation of colonies through swarming. seeprimary pleometrosis.permesothyridid foramen (BRACHIO) A pedicle opening found

680Maggenti and Gardnermostly within the ventral umbo.peronium n.; pl. -ia [Gr. perona, fibula] (CNID: Hydrozoa)Thick epidermal tract from the base of the tentacle on tothe bell.peroral a. [L. per, through; os, mouth] By way of, or throughthe mouth.perradius n.; pl. -ia [L. per, through; radius, ray] In Echinodermataand Cnidaria, body parts and organs located alonga limited number of radial planes; primary or 1st order radius.pervious a. [L. per, through; via, way] Perforate or open.petaloid a. [Gr. petalon, leaf] Resembling petals.petasma n. [Gr. petasma, something spread out] (ARTHRO:Crustacea) Complex male copulatory organs with couplinghooks on the first pair of pleopods.petiole n. [L. petiolus, little foot] 1. A stock or stem. 2. (AR-THRO: Insecta) a. In Hymenoptera Apocrita, the narrowconstricted zone at the base of the gaster. b. In Formicidae,a one or two segmented pedicel. petiolate a., petioliforma.petraliiform colony (BRYO: Gymnolaemata) In Cheilostomata,encrusting unilaminate colony loosely attached by the protrudingbasal walls of zooids or by basally budded kenozooids.petricolous a. [L. petra, rock; colere, to inhabit] Dwellingwithin stones, crevices or in hard clay.pH A symbol of a scale measuring the acidity or alkalinity of amedium, with a value of 7.0 indicating neutral, lower valuesindicating acidity, and higher values indicating increasedvalues of alkalinity.phacella n.pl.; sing. -um [Gr. phakellos, bundle] (CNID: Scyphozoa)Tentacle-like gastric filaments covered with gastrodermis,nematocysts and gland cells.phaeno- see phenophage n. [Gr. phagein, to eat] A bacterial virus.phagocytes n.pl. [Gr. phagein, to eat; kytos, container] Cells

Online Dictionary of Invertebrate Zoology 681in a body, fixed or moving, capable of active ingestion anddigestion. see plasmatocytes.phagocytosis n. [Gr. phagein, to eat; kytos, container] Theingestion of solid particles by a cell. phagocytic a.phagosome n. [Gr. phagein, to eat; soma, body] A membrane-boundvesicle in the cytoplasm of a cell resultingfrom phagocytosis.phagotroph n. [Gr. phagein, to eat; trophon, food] An organismthat ingests food by phagocytosis.phallic gland (ARTHRO: Insecta) In some Orthoptera, a glandthat lies on the posterior part of the accessory gland tubulemass to the left of the ejaculatory duct and opens on thedistal part of the left phallomere; conglobate gland.phallic organ (ARTHRO: Insecta) Median intromittent apparatusof males located on segment 9 and consisting of phallusor phallomeres and lobes from the phallobase; penis.phallobase n. [Gr. phallos, penis; basis, bottom] (ARTHRO: Insecta)Proximal part of the phallus of males, a large basalstructure supporting the aedeagus; a thecal fold or sheatharound the aedeagus; basal phallic sclerites in the wall ofthe genital chamber.phallocrypt n. [Gr. phallos, penis; kryptos, hidden] (ARTHRO:Insecta) In males, a pocket of the phallobase or wall of thegenital chamber containing the base of the aedeagus.phallomeres n.pl. [Gr. phallos, penis; meros, part] (ARTHRO:Insecta) Genital phalic lobes formed at the sides of thegonopore of males, that form an inner pair of mesomersthat unite to form the aedeagus, the intromittent organ,and outer parameres that develop into claspers of variableform.phallosome n. [Gr. phallos, penis; soma, body] (ARTHRO: Insecta)Complex structure ssurrounding the gonopore betweenthe proctiger, gonocoxite and sternum IX in malemosquitoes.phallotheca n.; pl. -thecae [Gr. phallos, penis; theke, case](ARTHRO: Insecta) In males, a fold or tubular extension ofthe phallobase partly or completely enclosing theaedeagus.

682Maggenti and Gardnerphallotreme, phallotrema n. [Gr. phallos, penis; trema, hole](ARTHRO: Insecta) In males, the opening of the duct at thetip of the aedeagus.phallus n. [Gr. phallos, penis] (ARTHRO: Insecta) The malecopulatory organ; the parameres together with theaedeagus; the aedeagus; the penis. phallic a.phanere n. [Gr. phaneros, visible] Any prominent tegumentaryformation, i.e., setae or seta-like processes.phanerocephalic pupa (ARTHRO: Insecta) In Diptera, the pupalstage between the cryptocephalic pupa and the pharateadult.phanerocodonic a. [Gr. phaneros, visible; kodon, bell] (CNID:Hydrozoa) Of or pertaining to detached and free-swimmingmedusa of a hydroid colony.phaneromphalous a. [Gr. phaneros, visible; omphalos, thenavel] (MOLL: Gastropoda) A shell with a completely openumbilicus; may be wide, narrow, or very minute. seeanomphalous.phanerotaxy n. [Gr. phaneros, visible; taxis, arrangement](ARTHRO: Chelicerata) The number and arrangements ofphaneres. phanerotactic a.phanerotoxic a. [Gr. phaneros, visible; toxikos, poison] (AR-THRO: Insecta) Erucism caused by toxic setae of lepidopterouscaterpillars. see lepidopterism.phaosome n. [Gr. phaos, light; soma, body] A light-sensitiveepidermal organelle; eyespot.pharate a. [Gr. pharos, garment] (ARTHRO: Insecta) 1. A stagein metamorphosis that does not usually represent a distinctmorphological stage. 2. Any stage of development that remainswithin the cuticle of the preceding stage. 3. Pertainingto the last larval instar forming the puparium and fromwhich an adult emerges.pharyngeal canal (CTENO) The stomodeal canal.pharyngeal ganglion see corpora cardiacapharyngeal glands 1. (ARTHRO: Insecta) In Hymenoptera: a.Lateral : a long coiled chain of follicles in the antero-dorsalregion of the head of worker Apoidea; the source of royal

Online Dictionary of Invertebrate Zoology 683jelly. b. Ventral : a transverse row of cells opening into thefloor of the pharynx between the ducts of the lateral pharyngealglands. 2. (NEMATA) see esophageal glands.pharyngeal skeleton see cephalopharyngeal skeletonpharyngeal tube (ARTHRO: Insecta) In Siphunculata, the entranceto the cibarial pump. see sac tube, trophic sac.pharyngeate, nonocellate cercariae (PLATY: Trematoda)Furcocercous cercariae that develop in sporocysts or rediaeand penetrate into a vertebrate to encyst.pharyngo-intestinal valve see cardiapharynx n.; pl. pharynges, pharynxes [Gr. pharynx, gullet]1. In insects, annelids, arachnids and platyhelminths theanterior part of the foregut, between the mouth and theesophagus. 2. (NEMATA) a. The posterior portion of thestoma (esophastome); anterior stomal region of theesophagus proper. b. Sometimes used as a synonym ofesophagus.pharynx of Leisblein see esophageal bulbphasic castration Pertaining to individuals in which the gonadsare inhibited in development due to seasonal or ontogeneticconditions. see alimentary castration, nutricialcastration.phasic muscle (MOLL: Bivalvia) In oysters, the fast muscle;adductor muscle that reacts quickly but does not endure.phasma n.; pl. -ata [Gr. phasma, apparition] (NEMATA: Adenophorea)Phasmid-like areas on the tails of some Desmoscolecida;tiny canals lead away from these structures, butno phasmidial gland has been found.phasmid n. [Gr. phasma, apparition; edios, like] (NEMATA) Oneof a pair of lateral caudal pores (sensilla) connecting with aglandular pouch that alledgedly functions as a chemoreceptor.see scutellum.Phasmidia see Secernenteaphena pl. of phenonphene n. [Gr. phainein, to appear] A genetically controlledphenotypic character.

684Maggenti and Gardnerphenetic classification A classification based on phenotypesrather than evolution from a common ancestor.pheneticist see numerical pheneticsphenetic ranking Ranking into categories according to degreeof overall similarity.phengophil a. [Gr. phengos, light; philos, loving] Preferringlight.phengophobe a. [Gr. phengos, light; phobos, fear] Shunninglight.phenogram n. [Gr. phainein, to appear; gramme, mark] Adiagram showing degree of similarity among taxa.phenology n. [Gr. phainein, to appear; logos, discourse] Abranch of science concerned with periodic biotic eventssuch as flowering, breeding and migration.phenome n. [Gr. phainein, to appear] The phenotypic charactersof an organism.phenomenology see phenologyphenon n. [Gr. phainein, to appear] A group of phenotypicallysimilar organisms.phenotype n. [Gr. phainein, to appear; typos, type] Thephysical appearance of an individual as a result of interactionbetween genotype and environment.pheromone n. [Gr. phero, bear; hormao, to instigate] Achemical substance secreted by an animal on the substratum,on the bodies or possibly in the air, that influencesthe behavior of other individuals of the same or differentspecies, such as trail-marking or following, alarm, dispersants,territorality, synchronization, aggregation and sexattractants.phialiform, phialaeform a. [L. phiala, shallow cup; forma,shape] Cup-shaped; saucer-shaped.philopatry n. [Gr. philos, loving; patrios, fatherland] The tendencyof an individual to either stay in or return to itshome or adopted locality.phlebedesis, phleboedesis n. [Gr. phleps, vein; desis, abinding together] Suppression of the true coelom by a

Online Dictionary of Invertebrate Zoology 685hemocoel.phoba n.; pl. -ae [Gr. phobe, tuft] (ARTHRO: Insecta) In manyscarabaeoid larvae, a dense hair-like set of projections,often forked, at the posterior inner edge of the paria.phobotaxis see klinokinesisphonation n. [Gr. phone, sound] The production of sounds.phonoreceptor n. [Gr. phone, sound; L. receptor, receiver] Asense organ responsive to sound.phoresis n. [Gr. phoreus, carrier] A form of symbiotic relationshipwhen the symbiont, the phoront, is mechanically carriedabout by its host; neither being physiologically dependenton the other. see phoretic host, transport host.phoresy see phoresisphoretic host One partner in a phoretic relationship; an organismthat transports another microorganism to which itis nonsusceptible; a transport host; a mechanical vector.phoretomorph n. [Gr. phoretos, carried; morphe, form] (AR-THRO: Chelicerata) In mites, forms adapted especially forphoretic transport.Phoronida, phoronids n.; n.pl. [L. Phoronis, surname of Io]Phylum or class of the phylum Lophophorata; marine, enterocoeliccoelomates, free-living in secreted chitinous, cylindricaltubes.phoront n. [Gr. phoretos, carry] Any organism mechanicallyconveyed by another organism. see phoresis.phospholipids n.pl. [Gr. phosphoros, light bringer; lipos, fat]Lipids containing phosphorus and nitrogen, found in allcells.phosphorescent see bioluminescencephotic zone Surface waters penetrated by light. see aphoticzone.photochemical a. [Gr. phos, light; chemeia, infusion] Pertainingto any chemical reaction produced by exposure tolight.photogenic a. [Gr. phos, light; genes, born] Light producing;luminescent.

686Maggenti and Gardnerphotokinesis n. [Gr. phos, light; kinesis, movement] A kinesisin response to stimulation by visual cognizance.photophil n. [Gr. phos, light; philos, loving] Light-loving. seephengophil.photophobic, photophobe a. [Gr. phos, light; phobos, fear]Shunning or avoiding light. see lucifugous, lucipetal,phengophobe.photophobotaxis n. [Gr. phos, light; phobos, fear; taxis, arrangement]Movement involved in the avoidance of light;negative tropism.photophore n. [Gr. phos, light; pherein, to bear] A light producingorgan of certain marine Hydrozoa, Crustacea andCephalopoda.photopic see apposition eyephotoreactivation reaction Partial reversal of damage tobiological systems by ultraviolet light by longer wave lengthlight.photoreceptor n. [Gr. phos, light; L. receptor, receiver] Asense organ responsive to light.photosynthesis n. [Gr. phos, light; synthesis, place together]The formation of carbohydrates from carbon dioxide andwater by the absorption of light by chlorophyll.phototaxis n. [Gr. phos, light; taxis, arrangement] Themovement in response to the stimulus of light. see heliotaxis.phototelotaxis n. [Gr. phos, light; telos, end; taxis, arrangement]The direct movement of an animal toward shade.phototonus n. [Gr. phos, light; tonos, tension] 1. Sensitivenessto light. 2. Muscle tonus stimulated by light.phototropism n. [Gr. phos, light; tropos, turn] Movement determinedby the direction of incident light. photropic a.phragma n.; pl. -mata [Gr. phragmos, fence] 1. An inwardlyextending process. 2. (ARTHRO: Insecta) In winged forms,an internal plate or invagination of the dorsal wall for theattachment of muscles. phragmatal a. see prephragma,postphragma.

Online Dictionary of Invertebrate Zoology 687phragmocone n. [Gr. phragmos, fence; konos, cone] (MOLL:Cephalopoda) A thin, conical internally chambered shell.phragmocyttarous a. [Gr. phragmos, fence; kyttaros, partition](ARTHRO: Insecta) Pertaining to nests, especially ofsocial wasps, in which brood combs are attached laterallyto the inner surface of the sack-like envelope.phragmosis n. [Gr. phragmos, fence] (ARTHRO: Insecta) Amethod used by Formicidae and Termitidae in which thehead or tip of the abdomen is used as a plug for the nestentrance.phthiriasis n. [Gr. phtheir, louse; -iasis, disease] A skin conditioncaused by an infestation of certain Siphunculata.phthisaner n. [Gr. phthisis, decline; aner, male] (ARTHRO: Insecta)A pupal male Formicidae in which the wings aresuppressed and the legs, head, thorax and antennae remainabortive due to the extraction of the juices of the latelarval or semi-pupal stage by the larval ant chalcid wasp ofthe family Eucharitidae. see phthisogyne.phthisergate n. [Gr. phthisis, decline; ergates, worker] (AR-THRO: Insecta) In Formicidae, an emaciated pharate adultworker due to parasitic feeding in the larval, prepupal orpharate adult stage by the larval ant chalcid wasp of thefamily Eucharitidae; an infra-ergatoid form.phthisodinergate n. [Gr. phthisis, decline; deinos, terrible;ergate, worker] (ARTHRO: Insecta) In Formicidae, pupatedsoldier denied adulthood due to parasitism.phthisogyne n. [Gr. phthisis, decline; gyne, woman] (ARTHRO:Insecta) In Formicidae, a form resulting from a femalelarva under the same parasitism as a phthisaner.phylacobiosis n. [Gr. phylax, guard; biosis, manner of life](ARTHRO: Insecta) A form of symbiosis in which a species ofFormicidae lives in the hills of Termitidae supposedly actingas a guard or protector.phylactocarps n.pl. [Gr. phylax, guard; karpos, fruit] (CNID:Hydrozoa) Protective modifications for the gonangia of Hydroida.see corbula.Phylactolaemata, phylactolaemates n.; n.pl. [Gr. phylax,guard; laimos, throat] A small, basically cylindrical, mono-

688Maggenti and Gardnermorphis, freshwater class of Bryozoa, with a crescentic lophophoreand an epistome.phylacum n. [Gr. phylax, guard] (ARTHRO: Diplopoda) InJulida, the outer leaf-like flange of the solenomerite.phyletic a. [Gr. phyle, tribe] Pertaining to a line of descent.see phylogeny.phyletic correlation The occurrence of characters that arephenotypic manifestations of a well-integrated ancestralgene complex.phyletic evolution Genetic changes that occur within an evolutionaryline.phyllidium n. [Gr. phyllon, leaf] (PLATY: Cestoda) Leaf-shapedoutgrowth on the side of the scolex; bothridium.phylliform a. [Gr. phyllon, leaf; L. forma, shape] Leaf-shaped.phyllobombycin n. [Gr. phyllon, leaf; L. bombyx, silkworm](ARTHRO: Insecta) In Lepidoptera, a crystalline derivative ofchlorophyll found in the feces of silkworms.phyllobranch, phyllobranchia a. [Gr. phyllon, leaf; branchia,gills] (ARTHRO: Crustacea) A gill with paired lamellarbranches (leaflike filaments) arising from the branchialaxis. phyllobranchiate a.phyllode n. [Gr. phyllon, leaf] (ECHINOD: Echinoidea) Petal-likearrangement of ambulacra around the peristome.phyllophagous a. [Gr. phyllon, leaf; phagein, to eat] Feedingupon leaf tissue.phyllopod(ium) n.; pl. -dia [Gr. phyllon, leaf; pous, foot](ARTHRO: Crustacea) Leaflike thoracic appendages.phyllosoma n. [Gr. phyllon, leaf; soma, body] (ARTHRO:Crustacea) In Decapoda, a larval stage in the developmentof Palinuridae, characterized by a flattened leaf-shapedplanktonic form; equivalent to zoea stage of other crustaceanlarvae.phyllotriaene n. [Gr. phyllon, leaf; triaina, trident] (PORIF)Tetractinal spicule with three rays of flattened discs and thefourth ray short and pointed.phyllozooid n. [Gr. phyllon, leaf; zoon, animal] (CNID: Hydro-

Online Dictionary of Invertebrate Zoology 689zoa) In Siphonophora, a thick, gelatinous leaf-like or helmet-shapedmedusoid containing a simple or branchedgastrovascular canal, protective in function; a hydrophyllium;a bract.phylogeny n. [Gr. phyle, tribe; genesis, beginning] The studyof the history of the lines of evolution of a species or highergroup of organisms; distinguished from ontogeny. seeclassification. phylogenetic a.phylogerontic a. [Gr. phyle, tribe; gerontos, old man] Inphylogeny, referring to the decadence of the old age stage.see paracme, typolysis.phylogram n. [Gr. phyle, tribe; gramme, mark] A tree-likediagram indicating degree of relationship among taxa.phyloneanic a. [Gr. phyle, tribe; neanikos, youthful] Adolescentstage in phylogeny. see neanic.phylum n.; pl. phyla [Gr. phyle, tribe] One of the higher taxonomiccategories of the animal kingdom.physa n. [Gr. physa, bladder] (CNID: Anthozoa) The bulbousbase of burrowing Actinaria.physergate n. [Gr. physa, bladder; ergate, worker] (ARTHRO:Insecta) In Hymenoptera Formicidae, large workers capableof egg production, but mainly utilized for honey storage.physiogenesis n. [Gr. physis, nature; genesis, beginning]Differentiation of the embryo leading to distinctive differencesbetween and within regions. see histogenesis.physiology n. [Gr. physis, nature; logos, discourse] The studyof cell and tissue function and activities of living organisms.physogastry n. [Gr. physa, bladder; gaster, belly] (ARTHRO:Insecta) Swelling of the abdomen due to hypertrophy of fatbodies, ovaries, or both.phytoalexins n. [Gr. phyton, plant; alexein, to protect] Agroup of protective substances synthesized by plants as aresult of infection, thought to aid in resistance to nematodes,bacteria and environmental accidents.phytobiotic a. [Gr. phyton, plant; bios, life] Living withinplants.

690Maggenti and Gardnerphytoparasite n. [Gr. phyton, plant; para, beside; sitos, food]A plant parasite. phytoparasitic a.phytophaga n.pl. [Gr. phyton, plant; phagein, to eat] A memberof a vegetable-eating group of animals.phytophagous a. [Gr. phyton, plant; phagein, to eat] Feedingon plants; herbivorous.phytophilous a. [Gr. phyton, plant; philos, loving] Pertainingto species that live or feed on plants.piceous a. [L. piceus, pitchy] Pitch-black, brownish or reddishblack.pick n. [A.S. pic, pike] (ARTHRO: Insecta) In Psocoptera, a detachedstyliform process of the lacinia.pictured a. [L. pictura, picture] (ARTHRO: Insecta) Pertaining tospots or bands on wings.pigment n. [L. pignere, to paint] Coloring matter of plants andanimals.pigmenta cercaria (PLATY: Trematoda) Amphistome cercariawith stellate melanophores. see diplocotylea cercaria.pigment cell A chromatophore; a chromocyte.pileus n.; pl. pilei [L. pileus, cap] (CNID: Scyphozoa) The umbrella-shapedstructure of a jellyfish.pilidium n. [L. dim. pileus, cap] (NEMER) A helmet-shapedfree-swimming larva.pilifer n. [L. pilus, hair; ferre, to carry] (ARTHRO: Insecta) InLepidoptera, one of a pair of lateral projections on the labrum.piliferous a. [L. pilus, hair, ferre, to carry] Bearing hair.pillar n. [L. pila, pillar] 1. (MOLL: Bivalvia) An inwardly projectingouter shell layer along the length of the lower valve.2. See columellapillared eye see turbinate eyepilose a. [L. pilus, hair] Hairy; with fine, soft hair.pilus n.; pl. pili [L. pilus, hair] A hair or hair-like structure.pinacocyte n. [Gr. pinax, tablet; kytos, container] (PORIF) Thelarge flat polygonal cells that line all surfaces, except those

Online Dictionary of Invertebrate Zoology 691of the choanocyte chambers. see exopinacocyte,endopinacocyte, basopinacocyte.pinacoderm, pinnacoderm n. [Gr. pinax, tablet; derma, skin](PORIF) The outer delimiting membrane layers of pinacocytes;ectosome.pinaculum n. [Gr. pinax, tablet] (ARTHRO: Insecta) Small, flator slightly raised chitinized area with one to four setae.pincers n.pl. [OF. pincier, to pinch] Any structure that resemblesthe grasping end of pincers.pinna n.; pl. pinnae [L. feather] 1. A wing or fin. 2. (ARTHRO:Insecta) The part of the trumpet of Culicidae pupae fromthe apex to an imaginary line drawn approximately perpendicularto the longitudinal axis at the proximal marginof the spiracular opening.pinnafid n. [L. pinna, feather; findare, to split] (ARTHRO: Insecta)Wings that are deeply divided, as in Thysanoptera.pinnate a. [L. pinnatus, feathered] 1. Feather or fern-like inappearance. 2. Having hairs, thorny or lateral processes onopposite sides.pinnules n.pl. [L. dim. pinna, feather] 1. (ANN: Polychaeta)The lessened lateral paddle-like parapodia. 2. (ECHINOD:Crinoidea) Short tapering, flexible lateral projections orbranches on either side of the arms.pinocytosis n. [Gr. pino, drink; kytos, container] Ingestion orabsorption of surrounding fluids by a cell, that forms avesicle by incupping of the surface membrane.pinosome n. [Gr. pino, drink; soma, body] Intracellular vesiclecontaining material taken up by pinocytosis.pinule, pinulus n. [L. dim. pinna, feather] (PORIF) A spiculeresembling a fir tree because of small spines developing onone ray, usually 5 rayed spicules.pioneer community Organisms that establish a new communityon bare ground.piping n. [L. pipare, to chirp] (ARTHRO: Insecta) In Apis, soundmade by young queens after their emergence.piptoblast n. [Gr. piptein, to fall; blastos, bud] (BRYO) An encapsulatedbud not released from parent colony.

692Maggenti and Gardnerpiriform a. [L. pirum, pear; forma, shape] Pear-shaped; pyriform.piscicolous a. [L. piscis, fish; colere, to inhabit] Living in fish.pisciform n. [L. piscis, fish; forma, shape] Fish-shaped.pisiform a. [L. pisum, a pea; forma, shape] Pertaining to peashaped;a small globular body.pit gland (ROTIF: Monogononta) A secretion gland in the formof a cuplike pit on the corona.pith n. [A.S. pitha, marrow, pith] (PORIF) A central region ofmore diffuse collagen found within a spongin fiber.pivotal axis (MOLL: Bivalvia) An axis at the ligament aboutwhich the valves rotate.pivotal bar (BRYO) In Cheilostomata avicularia, a completeskeletal rim on which the fixed end of the mandible ishinged.placids n.pl. [Gr. plax, plate] (KINOR) Large plates located onthe 3rd zonite (neck) with retractable necks; nonretractableare located on the 2nd zonite and sometimes referredto as a closing apparatus.placoid a. [Gr. plax, plate] Plate-like.placoid sensilla see sensillum placodeumplaga a.; pl. plagae [L. plaga, stripe] A stripe or streak ofcolor. plagate a.plagiosere n. [Gr. plagios, oblique; serere, to join] The successionof plant diversion into a new course by biotic factoror factors. see prisere.plagiotriaene a. [Gr. plagios, oblique; triaina, trident] (PORIF)In tetraxons, having clads directed forward and making anangle of about 45° with the produced axis of the rhabdome.plagula n. [L. plagula, veil] (ARTHRO: Chelicerata) In Arachnida,a ventral plate protecting the pedicle.plait n. [L. plicare, to fold] 1. Longitudinally folded or laid inpleats. 2. (MOLL: Gastropoda) Applied to folds on the columellaor pillar.planaea n. [L. planus, flat] A conjectured organism in the form

Online Dictionary of Invertebrate Zoology 693of a ciliated planula, purported to be a stage in the evolutionof higher animals.plane a. [L. planus, flat] 1. A smooth flat surface, devoid ofmarkings or configurations. 2. A plasmagene or plasmid.plane of symmetry The median plane dividing a bilaterallysymmetrical animal into two halves that are mirror imagesof each other.planidium n.; pl. -idia [Gr. dim. plane, wanderer] (ARTHRO:Insecta) The free-living, active, first-instar larva of someparasitic hypermetamorphic Neuroptera, Coleoptera (triungulin),all Strepsiptera (triungulinid), Diptera, Lepidopteraand Hymenoptera.planipennate a. [L. planus, flat; penna, wing] Flat-winged.planispiral a. [L. planus, flat; spira, coil] (MOLL: Gastropoda)Shells coiled in a single plane like a flat spiral with symmetricalsides; loosely used for shells whorled in a discoidform with asymmetrical sides. see isostrophic.plankton n. [Gr. plankton, wandering] 1. Pelagic animals collectively,distinguished from coast or bottom forms. 2. Ageneral name for animals (zooplankton) or plants (phytoplankton)living at or near the surface of the water. seeseston.planktotrophic larva (BRYO: Gymnolaemata) Free-living, ciliatedlarvae with a long motile life before metamorphosis.planoblast (CNID: Hydrozoa) The free-swimming medusa form.planorboid a. [L. planus, flat; orbis, a circle] Flat and orb-like.planta n.; pl. plantae [L. planta, sole of foot] (ARTHRO: Insecta)In some larval forms, an apical area of the legbearing a row or circle of outwardly curved hooks or crochetsthat aid in gripping.plantar a. [L. planta, sole of foot] (ARTHRO: Insecta) Of orpertaining to the planta or sole of the foot.plantella see empodiumplantula n.; pl. -lae [L. plantula, small sole] (ARTHRO: Insecta)A pad-like sole on the underside of the tarsal segment. seepulvillus.

694Maggenti and Gardnerplanula n.; pl. -lae [L. planus, flat] (CNID) A free-swimmingciliated larva, cylindrical to ovoid with two cell layers (ectodermand endoderm).plaques n. [F. plaque, plate] 1. (NEMATA) Cuticular "warts". 2.(POGON) Small scales of cuticle on the trunk papillae.plasma n. [Gr. plasma, formed or molded] The fluid portion ofblood or lymph.plasmagene n. [Gr. plasma, formed or molded; gennaein, toproduce] A genetic factor located in the cytoplasm, ratherthan in the nucleus; a plasmid; a plane.plasmalemma see plasma membraneplasma membrane A unit membrane surrounding the cell'sprotoplasm; cell membrane; plasmalemma.plasmatocytes n.pl. [Gr. plasma, formed or molded; kytos,container] Small to large polymorphic hemocytes with around to elongate nucleus and with either homogeneous orfinely granular or finely vacuolated cytoplasm.plasmid n. [Gr. plasma, formed or molded; eidos, like] DNAmolecules that are not attached to a chromosome but areinherited regularly.plasmon n. [Gr. plasma, formed or molded] All extrachromosomalhereditary determinents; plasmotype.plasmosome see nucleolusplasmotype see plasmonplastic a. [Gr. plasma, a thing molded] Formative.plastids n.pl. [Gr. plastos, formed; dim. -idion] A generalizedterm for cell organelles.plastosomes see mitochondriaplastron n. [F. plastron, breast plate] 1. The chorion of someeggs. 2. (ARTHRO: Insecta) A permanent film of air retainedby hairs on the outside of an aquatic insect body allowingan air water interface for gaseous exchange. 3. ECHINOD:Echinoidea) In Spatangoida, a ventral interambulacral areabetween the labrum and periproct, sometimes with specialspination.plate organ see sensillum placodeum

Online Dictionary of Invertebrate Zoology 695plates n.pl. [L. plattus, flat] (ARTHRO: Insecta) In Diaspidinae,gland spines of the pygidium that are multiple branched,with or without a duct.platyform larva (ARTHRO: Insecta) An extremely flattenedlarva; an onisciform larva.Platyhelminthes n.pl. [Gr. platys, flat; helminthos, of worms]A phylum of acoelomate animals commonly called flatworms,including the flukes, tapeworms and turbellarians.platymyarian a. [Gr. platys, flat; mys, muscle] (NEMATA)Having fibers of the muscle cells adjacent and perpendicularto the hypodermis. see coelomyarian.plectanes n. [Gr. plektos, twisted] (NEMATA) Cuticular platesthat function as supports for the male genital papillae.plectolophe n. [Gr. plektos, twisted; lophos, crest] (BRACHIO)A lophophore where each branchium has a U-shaped sidearm with a double row of paired filamental appendages,terminating distally in a medial plano-spire normal tocommissural plane with a single row of paired appendages.plectolophous a.plectrum n. [L. plectrum, a tool for plucking a stringed instrument](ARTHRO: Insecta) In Coleoptera, a single scraperused against a roughened file (strigil) that causes a membraneto vibrate and therefore produce sound.plegma n.; pl. plegmata [Gr. plegma, plaited] (ARTHRO: Insecta)In scarabaeoid larvae, a single fold. see plegmatium,proplegmatium.plegmatium n.; pl. -tia [Gr. plegma, plaited] (ARTHRO: Insecta)In scarabaeoid larvae, a lateral paired area with aplicate, sclerotized surface, bordered by marginal plegmatedspines with acanthoparia.pleiomorphic, pleomorphic a. [Gr. pleion, more; morphe,form] Having the ability to change shape; polymorphic, ora type of polymorphism.pleiomorphism, pleomorphism n. [Gr. pleion, more; morphe,form] 1. Polymorphism. 2. A type of polymorphismexhibited as several different stages in a life cycle.pleiotrophy, pleiotropism n. [Gr. pleion, more; tropein, to

696Maggenti and Gardnerturn] Multiple phenotypic effects of a single gene.pleomere see abdominal somitepleometrosis n. [Gr. pleion, more; metros, mother] (ARTHRO:Insecta) A colony containing two or more fertilized egglayingfemales (queens); social colony foundation; monometrosis;polygyny. pleometrotic a. see primary/periodicalpleometrosis, permanent pleometrosis,temporary pleometrosis, secondary pleometrosis,haplometrosis.pleomorphic see pleiomorphicpleomorphism see pleiomorphismpleon, pleonites see abdomenpleonic hinges (ARTHRO: Crustacea) In Decapoda, mid-lateralhinges that lock together the pleural somites.pleophyletic see polyphyleticpleopod n. [Gr. plein, to swim; pous, foot] (ARTHRO: Crustacea)In Malacostraca, paired appendages of any of the first5-6 somites, adapted for swimming; swimmeret.pleotelson n. [Gr. plein, to swim; telson, limit] (ARTHRO:Crustacea) The telson and one or more abdominal somitescombined by fusion.plerergate see repleteplerocercoid n. [Gr. pleres, full; kerkos, tail; eidos, like](PLATY: Cestoda) An elongate metacestode developed froma procercoid.plerocercoid stage (PLATY: Cestoda) A third-stage larva ofPseudophyllidea and Proteocephalidea with a solid body.plerocercus stage (PLATY: Cestoda) In Trypanorhyncha, ametacestode in which the posterior forms a bladder (blastocyst)into which the rest of the body withdraws.plerocestoid n. [Gr. pleres, full; kestos, girdle; eidos, like](PLATY: Cestoda) The stage emerging from an oncospherethat upon development is known as a metacestode.plesioasters n.pl. [Gr. plesios, near; aster, star] (PORIF)Streptasters with few spines from a very short axis.plesiobiosis n. [Gr. plesios, near; biosis, manner of life] 1. A

Online Dictionary of Invertebrate Zoology 697primitive form of association approaching symbiosis. 2.(ARTHRO: Insecta) Living in close proximity, i.e., compoundnests of different species of Formicidae and Isoptera; rudimentaryform of social symbiosis.plesiomorphy n. [Gr. plesios, near; morphos, form] A termreferring to original or primitive characters being retained;normally used in cladistic taxonomy. see apomorphy,symplesiomorph.plesiotype n. [Gr. plesios, near; typos, type] A specimen uponwhich a subsequent or additional description or illustrationof a previously named species is based.pleura n.pl; sing. pleuron [Gr. pleura, side] (ARTHRO) A lateralregion on the sides of the body of certain arthropods; forcrustaceans see epimere. pleural a.pleural angle (MOLL: Gastropoda) In the plane through entireshell axis, angle between two straight lines lying tangentialto the last two whorls on opposite sides.pleural apophyseal pit (ARTHRO: Insecta) In Diptera, an externaldepression at the point of origin of the pleuralapophysis, usually situated at the lower end of the pleuralsuture.pleural apophysis (ARTHRO: Insecta) The internal arm of thepleural ridge that aids in resistance to the lateral elasticityof the thorax when in flight. see sternal apophyses.pleural area 1. (ARTHRO: Insecta) In Hymenoptera, the lateralarea of the propodeum, next to the metapleurum; dividedinto three parts, the first (front), second (middle), with thefirst and second usually united, and third (hind). 2. (MOLL:Polyplacophora) Side slopes, not including the jugal area orlateral areas where the latter are well defined.pleural arm see pleural apophysispleural coxal process (ARTHRO: Insecta) The process of thepleuron at the base of the pleural ridge with which the coxaarticulates.pleuralia n.pl. [Gr. pleura, side] (PORIF) Spicules protrudingfrom lateral surface.pleural lobe see epimere

698Maggenti and Gardnerpleural membrane (ARTHRO: Insecta) The membrane occurringbetween the tergum and sternum of a body segment.pleural ridge (ARTHRO: Insecta) A vertical strengthening ridgeabove the coxa that divides the pleuron into an anteriorepisternum and a posterior epimeron, well developed inwing bearing segments and continuing dorsally into thepleural wing process; the entopleuron. see pleuralapophysis.pleural sclerites see pleurapleural sulcus see mesopleural suturepleural suture 1. (ARTHRO: Crustacea) The line of separationof carapace in molting. 2. (ARTHRO: Insecta) A suture on athoracic pleuron extending from the base of the wing to thebase of the coxa, separating the episternum and epimeron;referred to as pro-, meso-, or metapleural ridge.pleural wing process (ARTHRO: Insecta) 1. The dorsal marginof the pleural ridge that articulates with the second axillarysclerite in the wing base. 2. In Culicidae mesothorax, locatedposterior to the basalare at the apex of the posteriormesanepisterum; in the metathorax, behind the basalare atthe apex of the metepisternum.pleurella see sternopleuritepleurembolic proboscis (MOLL) A partially invaginable probosciswith the distal part enclosed in a proboscis sheath.see acrembolic proboscis.pleurepimere see epimerepleurergate n. [Gr. pleuron, side; ergate, worker] (ARTHRO:Insecta) In Formicidae, a worker capable of ingesting liquidfood into its gaster until it becomes a spherical sac.pleurite n. [Gr. pleuron, side; -ites, nature of] (ARTHRO) A lateralsclerite of a somite; for crustaceans see epimere.pleurobranch n. [Gr. pleuron, side; branchia, gills] (ARTHRO:Crustacea) In Decapoda, a gill attached directly to the bodywall; pleurobranchia.pleurolophocercous cercaria (PLATY: Trematoda) A gymnocephaloustype cercaria with a pair of fin folds; parapleurolophocercouscercaria.

Online Dictionary of Invertebrate Zoology 699pleuron see pleurapleuropod see precoxapleuropodium n.; pl. -dia [Gr. pleuron, side; pous, foot] 1.(ARTHRO: Insecta) Lateral embryonic band formed by amodified abdominal leg. 2. (MOLL: Gastropoda) One of apair of mantle lobes.pleurosternal suture see mesopleurosternal suturepleurosternite see laterosternitepleurosternum n. [Gr. pleuron, side; sternon, chest] (ARTHRO:Insecta) A thoraxic sternal plate that facilitates the limbbases; the coxosternum. pleurosternal a.pleurostoma n. [Gr. pleuron, side; stoma, mouth] (ARTHRO:Insecta) The region of the subgena above the mandible.pleurostomal a.pleurostomal suture (ARTHRO: Insecta) The part of the subgenalsulcus above the mandible.pleurotergite n. [Gr. pleuron, side; L. tergum, back; Gr. -ites,nature of] (ARTHRO: Insecta) 1. A sclerite containing bothpleural and tergal elements. 2. In Diptera, the lateral areaof the mesopostnotum, above the metathoracic spiracle; inmosquitoes, divisible into lower and upper pleuotergites,represented by apodemes internally.pleurothetic a. [Gr. pleuron, side; thatos, placed] (MOLL: Bivalvia)Resting on its side, especially in regard to oysters.pleuston n. [Gr. pleustes, sailor] Free-floating macroorganisms.plexus n.; pl. plexuses [L. plexus, a twining] A network ofinterlaced nerves or blood vessels.plica n.; pl. -cae [L. plicare, to fold] 1. A bend, fold, wrinkles,crenulations or scallops; annulets. 2. (MOLL: Bivalvia) a. Alamellibranch gill in which the lamella are thrown into verticalfolds; the apex is farthest from the interlamellar cavity.b. Fold or costa involving the entire thickness of the shellwall; plication.plica analis see vannal foldplica jugalis (ARTHRO: Insecta) The jugal fold or radial line of

700Maggenti and Gardnerfolding of wings, setting off the jugal region from the vannalregion; axillary furrow, plica anojugalis.plicate a. [L. plicare, to fold] Folded; parallel ridges or striaeappearing as folds or pleats.plication n. [L. plicare, to fold] A minute fold or ridge. plicatulatea.plica vannalis see vannal foldpliciform a. [L. plicare, to fold; forma, shape] Having a plaitlikeform.ploidy n. [Gr. aploos, onefold; edios, like] A term referring tothe number of chromosome sets.plumbeous a. [L. plumbum, lead] Lead-colored.plume n. [L. pluma, feather] Feather-like structures. plumatea.plumicome n. [L. pluma, feather; coma, hair] (PORIF) A spiculewith plume-like tufts.plumoreticulate skeleton (PORIF) A type of skeletal constructionhaving fibers or spicule tracts diverge in plumosefashion, still retaining cross-connections. see plumoseskeleton.plumose a. [L. pluma, feather] Having fine processes on oppositesides; feather-like.plumose skeleton (PORIF) A type of skeletal constructionhaving diverging fibers or spicule tracts showing few if anycross-connections. see plumoreticulate skeleton.plurilocular a. [L. plus, more; loculus, little place] With 2 ormore loculi or compartments; multilocular.plurinuclear a. [L. plus, more; nuclear, kernal] Having manynuclei present, as in syncytium.pluriseptate n. [L. plus, more; septum, partition] With multiplesepta.pluteus larva, dipluerula (ECHINOD) A free-swimming, bilaterallysymmetrical larva of the echinoderm classes Ophiuroideaand Echinoidea, characterized by the cilia extendingonto arms projecting from body.plyopod n. [Gr. plynos, basin; pous, foot] (ARTHRO: Crustacea)

Online Dictionary of Invertebrate Zoology 701In Gnathiidea Isopoda, the first thoracopod of the male; itmay be flattened and cover the buccal cavity or in juvenilesbe shaped as a hook.pneumatization n. [Gr. pneuma, air] (ARTHRO: Insecta) Aprocess completed in an embryonic tracheal system whenliquid is replaced by gas. pneumatized a.pneumatized a. [Gr. pneuma, air] Having air cavities.pneumatocodon n. [Gr. pneuma, air; kodon, bell] (CNID: Hydrozoa)In Siphonophora, the external wall of a float.pneumatophore n. [Gr. pneuma, air; phoreus, bearer] (CNID:Hydrozoa) In Siphonophora, a muscular organ that possessesa gas secreting gland and functions as an air sacfloat of a colony.pneumatosaccus n. [Gr. pneuma, air; sakkos, sac] (CNID:Hydrozoa) In Siphonophora, an air sac; an internal subumbrellanwall.pneumostome n. [Gr. pneuma, air; stoma, mouth] (MOLL:Gastropoda) A pore connecting the pulmonate lungs withthe exterior.pneumotaxis n. [Gr. pneuma, air; taxis, arrangement] A reactionto gases, particularly carbon dioxide.poculiform a. [L. poculum, cup; forma, shape] Cup-shaped;goblet-shaped.pod n. [ME. pod, bag] (ARTHRO: Insecta) Eggs cemented togetherin a mass, particularly in Orthoptera.podeon see propodeum, metapodeonpodial opening/pore (ECHINOD: Asteroidea) The passagebetween ambulacrals for passage of the tube foot.podilegous a. [Gr. pous, foot; legere, to collect] (ARTHRO: Insecta)Having pollen baskets on the legs.podite n. [Gr. pous, foot] (ARTHRO) A limb segment; podomere.podium n.; pl. podia [Gr. pous, foot] (ECHINOD: Asteroidea)The cyclindrical outer part of the tube foot.podobranch n. [Gr. pous, foot; branchia, gills] (ARTHRO:Crustacea) Gills borne on the coxa of the thoracopod; po-

702Maggenti and Gardnerdobranchia.podocephalic glands (ARTHRO: Chelicerata) In actinotrochAcari, ancestrally four glands near the base of leg I; anterior,median, coxal, and lateral glands.podocyst n. [Gr. pous, foot; kystis, bladder] (MOLL: Gastropoda)A sinus in the foot.podocyte see plasmatocytepodomere n. [Gr. pous, foot; meros, part] (ARTHRO) An individualsegment of a limb; a podite.podophthalmite n. [Gr. pous, foot; ophthalmos, eye] (AR-THRO: Crustacea) In segmented eyestalks, one of 2 segmentsbearing the cornea.podosoma n. [Gr. pous, foot; soma, body] (ARTHRO: Chelicerata)In Acari, the region of the body that bears the legs.podospermia n. [Gr. pous, foot; sperma, seed] (ARTHRO: Chelicerata)A type of sperm transfer by the male chelicera(gonopod) of certain Acari, to the paired orifices of the femalereceptaculum seminis. see tocospermia.podous n. [Gr. pous, foot] A walking leg.poecilacanthous armature (PLATY: Cestoda) Armature withhooks on tentacles of differing sizes, shapes and arrangementswith chainettes present.poecilandry n. [Gr. poikilos, various; aner, man] More thanone form of male. see poecilogyny.poecilocyttares n.pl. [Gr. poikilos, various; kyttasos, comb](ARTHRO: Insecta) A type of nest of Vespidae in which thelayers of brood comb are supported by the outer coveringand a central support, as the limb of a tree, sometimes regardedas a group Poecilocyttares. see phragmocyttarous.poecilogeny n. [Gr. poikilos, various; gennaein, to produce](ARTHRO: Insecta) In Diptera, larval polymorphism withmore than one form, some being paedogenic and othersdeveloping normally into winged sexual adults.poecilogony n. [Gr. poikilos, various; gonos, progeny] 1. Developmentin certain invertebrate animals of the same speciesproducing two kinds of young, although the adults are

Online Dictionary of Invertebrate Zoology 703exactly alike. 2. The development of two or more larvalforms of the same sex. poecilogonous a. see poecilogeny.poecilogyny n. [Gr. poikilos, various; gyne, wife] (ARTHRO:Insecta) More than one form of female.poecilonymy, pecilonymy n. [Gr. poikilo, varied; onyma,name] 1. The use of two or more terms to indicate thesame thing. 2. A synonym, i.e., a systematic name, as of aspecies or genus, being designated and later regarded asan incorrect form, rejected and replaced with another morecorrectly applied.Pogonophora, pogonophorans n.; n.pl. [Gr. pogonophoros,wearing a beard] A phylum of sedentary marine wormsthat are the only nonparasitic metazoans that lack amouth, gut or anus, and are commonly called beardworms.poikilonymy n. [Gr. poikilo, varied; onyma, name] The combiningof names or terms from different systems of nomenclature.poikilosmotic a. [Gr. poikilos, various; osmos, impulse] Havingan internal osmotic pressure varying with the environmentalmedium.poikilothermal a. [Gr. poikilos, various; thermos, warm] Coldblooded;having a body temperature that rises or falls withthe environmental temperature; ectothermal.poikilotherm n. see homoiothermal.point mutation Intragenic mutation in which recombination isnot impaired.poiser see halterpoison glands 1. (ARTHRO: Insecta) a. In Apocritan Hymenoptera,modified accessory reproductive glands associatedwith the ovipositor or sting. b. In Lepidoptera larvae, epidermalglands associated with setae or spines. 2. (MOLL:Cephalopoda) The posterior salivary glands.poison sac see venom glandpoison seta 1. (ANN: Polychaeta) Elongate pungent chitinousbristles that project from the parapodia, may be hollow and

704Maggenti and Gardnerfilled with fluid, contain retrorse spinules along the staff, orbe needlelike in appearance. 2. (ARTHRO: Insecta) Hollowseta through which they discharge an irritating secretionfrom the venom glands.polar body A minute, functionless cell produced and discardedduring the development of an oocyte.polar cap (MESO) The eight anterior cells in the nematogen.polar field/plate (CTENO) One of two long ciliated depressionsin the floor of the statocyst.polarity n. [L. polus, axis] The condition of having oppositepoles or qualities.polarization n. [L. polus, axis] 1. A potential difference acrossa membrane. 2. Light that is filtered to vibrate in one planeonly.polar plates 1. (CNID) Balance organs of two narrow ciliatedbands in the transverse plane. 2. (CTENO) see polarfield/plate.polar ray see astral raypolian tubules/villi see contractile tubulesPolian vesicles (ECHINOD) In Holothuroidea and Asteroidea,elongated sacs in the coelom that open into the ring canaland function as expansion chambers.polian vessel see contractile vesselpollen basket see corbiculapollen brush/comb see scopapollen pocket (ARTHRO: Insecta) In Hymenoptera, a reservoirfor pollen beside a cell in some species of bumblebees; larvaeand adults have free access to the pollen.pollen pot (ARTHRO: Insecta) In Hymenoptera, soft cerumencontainer used to store pollen by stingless bees; larvae donot have direct access to the pollen.pollen rake (ARTHRO: Insecta) In Hymenoptera, a comblikerow of bristles at the apex of the hind tibia of a bee; apecten.pollen storers (ARTHRO: Insecta) In Hymenoptera, bumblebeesthat temporarily store pollen in abandoned cocoons.

Online Dictionary of Invertebrate Zoology 705pollex n. [L. pollex, thumb] 1. The thumb. 2. (ARTHRO: Insecta)In Lepidoptera, a finger-like process at the anal angleof the cucullus of Noctuidae. 3. (ARTHRO: Crustacea)see fixed finger.polliniferous, pollinigerous a. [L. pollen, fine flour; ferre, tocarry] Pollen bearing; formed for collecting pollen.pollinose a. [L. pollen, fine flour; -osus, full of] Covered with apowdery coating.polyact n. [Gr. polys, many; L. actum, deed] (PORIF) A megasclerespicule with many rays diverging from a central focus.polyadenous cercaria (PLATY: Trematoda) Cercaria with astylet and paired groups of penetration glands.polyandric a. [Gr. polys, many; aner, male] (ANN: Oligochaeta)Having testes in more segments than x-xi.polyandry n. [Gr. polys, many; aner, male] Females that matewith more than one male. polyandrous a.polyarthric see multiarticulatepolyaxon n. [Gr. polys, many; axon, axle] (PORIF) Spiculeswith several equal rays radiating from a central point.polybasic a. [Gr. polys, many; basis, base] 1. Having morethan one base. 2. Genera originated on a number of species.polycentric a. [Gr. polys, many; kentron, point] Having severalgrowth centers or centromeres.Polychaeta, polychaetes n.; n.pl. [Gr. polys, many; chaite,hair] The largest and very diverse class of the Phylum Annelida;commony called bristle worms, widely distributedthroughout the marine environment.polychromatic a. [Gr. polys, many; chroma, color] Havingmany colors.polydelphic a. [Gr. polys, many; delphys, womb] (NEMATA)Having more than four uteri.polydisk, polydisc n. [Gr. polys, many; diskos, disc] (CNID:Scyphozoa) The process of several ephyrae developing simultaneously,the most mature at the distal end. seemonodisk, strobilation.

706Maggenti and Gardnerpolydiverticulate a. [Gr. polys, many; L. diverticulum, digression](ANN) Referring to spermathecae with more than twodiverticula.polydomous a. [Gr. polys, many; domos, house] Inhabitingmany abodes or nests. see monodomous.polyembryony n. [Gr. polys, many; embryon, fetus] The formationof multiple embryos from a single egg. polyembryonica.polyethism n. [Gr. polys, many; ethisma, habit] (ARTHRO: Insecta)In social insects, the division of labor among membersof a colony. see age polyethism, caste polyethism.polygamy n. [Gr. polys, many; gamein, to marry] Polygynyand/or polyandry. polygamous a. see monogamy.polygenes n.pl. [Gr. polys, many; pan, all; gennaein, to produce]Genes that jointly, with a group of other genes, controla character. polygenic a. see oligogene.polygenic a. [Gr. polys, many; genos, descent] Dependent onthe interaction of genes; polygenetic. see monogenic.polygigeriate a. [Gr. polys, many; L. gigerium, gizzard] (ANN)Having several gizzards.polygonadal a. [Gr. polys, many; gone, seed] (ANN) Havingmore than four gonads.polygonal a. [Gr. polys, many; gonia, angle] Having many angles,many sides; more than 4 sided.polygoneutism n. [Gr. polys, many; gennaein, to produce]The ability to produce several broods in one season. polygoneutica.polygyny n. [Gr. polys, many; gyne, female] 1. The mating ofa male with more than one female. see monogamy. 2.(ARTHRO: Insecta) In Hymenoptera, the coexistance of severalto many queens in the same colony. a. Primary polygyny:Two or more queens found a colony together. b.Secondary polygyny: One queen founds a colony with othersadded after the colony is founded. polygynous a.polygyral see multispiralpolyhaline a. [Gr. polys, many; hals, sea] Pertaining to brackishwater of a wide range of salinities; 16 to 30 parts per

Online Dictionary of Invertebrate Zoology 707thousand.polyhedron n.; pl. -dra [Gr. polys, many; hedros, side] Manysided;many angled; a solid having many faces. polyhedrala.polykaric a. [Gr. polys, many; karyon, nut] Multinucleate.polylectic a. [Gr. polys, many; lektos, chosen] (ARTHRO: Insecta)In Hymenoptera, species of bees that take pollenfrom a wide variety of plants.polyloculate a. [Gr. polys, many; L. loculus, small room](ANN: Oligochaeta) Having several seminal chambers in thespermathecal diverticulum.polymer n. [Gr. polys, many; meros, part] A large moleculemade up of several to many smaller units called monomers.polymeric a. [Gr. polys, many; meros, part] Gene interactionin which genes of equivalent effect intensify each otherseffect.polymerization n. [Gr. polys, many; meros, part] Formationof polymers from monomers.polymorph n. [Gr. polys, many; morphos, shape] 1. An individualwithin a species exhibiting a change in shape, coloror structure. 2. (BRYO) A zooid that differs from feeding zooidsof the same stage of development; specialized zooid.polymorphic, polymorphous a. [Gr. polys, many; morphe,form] Having many forms or types of structure in the samespecies.polymorphism n. [Gr. polys, many; morphe, form] 1. The simultaneousoccurrence of two or more distinctive and discontinuousgenetic types existing in a population. 2. (AR-THRO: Insecta) In social insects, the coexistence of two ormore phases or castes, belonging to the same sex, withinan individual colony. a. In Formicidae, the occurrence ofnonisometric growth of size variation in a normal maturecolony, thus producing individuals of distinctly varying proportions.3. (BRYO) Repeated, discontinuous variation inzooid morphology in a colony.polymyarian n. [Gr. polys, many; mys, muscle] (NEMATA)

708Maggenti and GardnerMuscle arrangement in which there are many cells betweenadjacent hypodermal cords. polymyarial a. see meromyarian.polynemic a. [Gr. polys, many; nema, thread] Chromosomeswith a primarily multistranded structure, not the result ofendoreduplication.polyp n. [Gr. polys, many; pous, foot] (CNID) Any colonial orsolitary attached individual.polypalmate a. [Gr. polys, many; palma, palm] (BRACHIO) Amantle canal system with more than 4 principal canals ineach mantle.polypary n.; pl. -ies [Gr. polys, many; pario, to beget] (CNID:Hydrozoa) Structure/tissues in which the polyps of coralsand other compound forms are embedded; polypidom;polyparium.polyphagous a. [Gr. polys, many; phagein, to eat] Feeding onmany kinds of food. polyphagia n.polyphagy see polyphagouspolyphenism n. [Gr. polys, many; phaneros, visible] The occurrencein a population of several phenotypes that are notdue to genetic differences between individuals; polypheny.polyphenol layer A silver binding product exuded from the tipof the pore canals, formerly considered as a sublayer in theepicuticle.polyphyletic a. [Gr. polys, many; phyle, tribe] 1. Of mixedevolutionary origin, not derived from a common ancestor.2. Pertaining to a group whose most recent common ancestoris not cladistically a member of that group. 3. Pleophyletic.polyphyly n. see monophyletic, oligophyletic.polyphyly see polyphyleticpolypide n. [Gr. polys, many; pous, foot] (BRYO) The livingportions of the zooid.polypidian bud (BRYO) A newly developing polypide of a developingzooid.polypidian vesicle (BRYO) A polypidian bud, double-layered,with an undifferentiated internal epithelium lined centralcavity.

Online Dictionary of Invertebrate Zoology 709polypidom see polyparyPolyplacophora, polyplacophoran n. [Gr. polys, many; plax,tablet; phora, producing] A class of free-living molluskscommonly referred to as chitons or coat-of-mail shells;distinguished by having a shell with 8 dorsal calcareousplates that overlap each other; in some classifications listedas the class Amphineura.polyploid a. [Gr. polys, many; aploos, onefold] Referring to anindividual having more than two sets of chromosomes. seechromosome.polyploidy n. [Gr. polys, many; aploos, onefold] A condition inwhich the chromosome sets in the nucleus are a multiple ofthe normal diploid number.polypneustic a. [Gr. polys, many; pneustikos, of breathing](ARTHRO: Insecta) Having at least 8 functional spiracles oneach side, including the holopneustic, peripneustic, hemipneustic.polypneustic lobes see respiratoria, respiratory platespolypod larva (ARTHRO: Insecta) 1. An insect larval stagefound in Lepidoptera and some Hymenoptera with thoracicappendages and caterpillar-like abdominal locomotoryprocesses (prolegs); polypodeiform; eruciform larva. seeprotopod larva, campodeiform larva. 2. In parasiticHymenoptera, it has many different forms, often unlike anormal insect.polypodous a. [Gr. polys, many; pous, foot] Having manyfeet. see protopod, oligopod.polypoid see polyppolyprostatic a. [Gr. polys, many; prostates, stands before](ANN: Oligochaeta) Having more than six prostates in threesegments or over eight in two segments.polysaccharides n.pl. [Gr. polys, many; L. saccharum, sugar]A carbohydrate, one molecule of which can yield by hydrolysis,many monosaccharide molecules, usually structuralor storage, such as chitin, cellulose, starch and glycogen.polysaprobic a. [Gr. polys, many; sapros, putrid] Referring to

710Maggenti and Gardnera body of water with high decomposition rate and very lowoxygen.polysiphonous a. [Gr. polys, many; siphon, tube] (CNID: Hydrozoa)Pertaining to a hydrocaulis covered by stolons fromthe hydrorhiza. see monosiphonous.polysomatic a. [Gr. polys, many; soma, body] Tissues or individualshaving both diploid and polyploid cells.polysome n. [Gr. polys, many; soma, body] A multiribosomalstructure consisting of ribosomes bound by messengerRNA; very active in protein synthesis.polysomic a. [Gr. polys, many; soma, body] A diploid cell withone or more chromosomes represented three or four times,instead of two.polyspermy n. [Gr. polys, many; sperma, seed] Entry of severalsperm into the ovum.polystichous a. [Gr. polys, many; stichos, row] Arranged inmany rows; multifarious.polystomate, polystomatous a. [Gr. polys, many; stoma,mouth] 1. Having many mouths. 2. (ANN: Oligochaeta)Referring to nephridia with several nephrostomes.polytene chromosomes Giant chromosomes. see band.polytesticulate a. [Gr. polys, many; L. testiculus, small testicle](ANN: Oligochaeta) Having more than two pairs of testes.polythalamous gball (ARTHRO: Insecta) In Hymenoptera, achalcid gall containing more than one larval cell.polythecal a. [Gr. polys, many; theke, case] (ANN: Oligochaeta)Earthworm having more than one or two pair ofspermathecae per segment. see monothecal.polythetic a. [Gr. polys, many; tithenai, to place] Referring toa classification with each member of a group having themajority of a set of characters. see monothetic.polytopic a. [Gr. polys, many; topos, place] Occurring in severalgeographical locations.polytrophic a. [Gr. polys, many; trophein, to feed] 1. Havingnutrition supplied from more than one organism or source.

Online Dictionary of Invertebrate Zoology 711see oligotrophic. 2. Having many trophi.polytrophic ovariole (ARTHRO: Insecta) An ovariole in whichtrophocytes accompany each oocyte and are enclosedwithin the follicle; a polytrophic egg tube. see meroisticovariole.polytropic a. [Gr. polys, many, tropikos, a turning] (ARTHRO:Insecta) Visiting many kinds of flowers for nectar. seemonotropic, oligotropic.polytypic a. [Gr. polys, many; typos, type] A taxon containingsubordinate units.polyvoltine see multivoltinepolyxenic a. [Gr. polys, many; xenos, guest] The rearing ofone or more individuals of one species in association withmany other known species of organisms. see dixenic, axenic,synxenic, trixenic, xenic.Polyzoa, polyzoan see Bryozoapolyzoarium see zoariumpolyzoic a. [Gr. polys, many; zoon, animal] (PLATY: Cestoda)Strobila consisting of more than one proglottid.ponderous a. [L. pondus, weight] Of great weight; large;huge, bulky.pons n. [L. pons, bridge] A bridge; structure connecting twoparts.pons cerebralis see protocerebral bridgepopulation n. [L. populus, people] A group of individuals, especiallywith reference to numbers and statistics.population density The number of a group of individuals as tounit area or volume.population, local The individuals of a potentially interbreedingcommunity. see deme.porate a. [Gr. poros, channel] Bearing pores.porcate a. [L. porca, ridge between two furrows] With longitudinalridges and furrows.porcellaneous, porcelanous, porcelaneous a. [It. porcellana,procelain] Resembling porcelain; an enameled-like

712Maggenti and Gardnersurface; a nacreous luster.pore n. [Gr. poros, channel] A minute opening or orifice;ostium.pore canals 1. (ARTHRO: Insecta) Flat or ribbon-like twistedchannels of the procuticle, running through it perpendicularlyto its surface. 2. (ARTHRO: Crustacea) In Ostracoda, asmall tubular passageway extending through the shell.pore cells see porocytespore-chambers (BRYO) Small chambers where new zooids arebudded in the angles between the lateral and basal wallsthat are connected to the intrazooidial pores.pore diaphragm (PORIF) The closure of the porocyte.pore plates 1. (ARTHRO: Insecta) In the soft scale Towmeyellaparvicornis , groups of invaginated, biocular pores on thedorsal surface of the derm. see sensilla placodea. 2.(BRYO: Gymnolaemata) An interior chitinous or calcareouswall of a zooid with one or more minute pores throughwhich special cells project; part of the communication organ.pore space The insterstice between soil particles.Porifera n. [Gr. poros, channel; L. ferre, to bear] Phylum ofaquatic animals commonly called sponges; lacking organizedtissues and a digestive cavity.poriferous a. [Gr. poros, channel; L. ferre, to bear] Havingnumerous openings.poriform a. [Gr. poros, channel; L. forma, shape] Resemblinga pore; poroid.porocalyx n. [Gr. poros, channel; kalyx, cup] (PORIF:Demospongiae) In some Spirophorida, a specialized,sunken, inhalant and exhalant aperture.porocyte n. [Gr. poros, channel; kytos, container] (PORIF)Pinacocytes enclosing a pore that functions as an inhalantcanal.poroid a. [Gr. poros, channel; eidos, like] Pore-like; poriform.porophore n. [Gr. poros, channel; phorein, to carry] (ANN:Oligochaeta) Any area, protuberance or special structure

Online Dictionary of Invertebrate Zoology 713bearing a pore.porose a. [Gr. poros, channel] Containing pores; porous; perforate.porose area (ARTHRO: Chelicerata) Depressed areas on thecapitulum of certain mites and ticks.porphyrins n.pl. [Gr. porphyra, purple] Four pyrrole rings associatedwith various metals forming chlorophyll, hemoglobin,etc.porrect a. [L. por, before; regere, to stretch] Elongated forward;stretched out horizontally.portal of entry Point at which the invading parasite enters thebody of an animal; through either natural or unnaturalopenings.position effect The difference in the phenotypic expression ofa gene due to a change in their position with respect toother genes on the chromosome.positive geotropism Attraction toward the center of theearth.positive tropism/taxis The tendency to be attracted to asource of stimulus.postabdomen n. [L. post, after; abdomen, belly] 1. (ARTHRO)The usually slender, modified posterior segment of the abdomenof Crustacea and Insecta. 2. (ARTHRO: Chelicerata)The anal tubercle in spiders; in scorpions the metasoma orposterior narrower five segments of the abdomen. see telson.postacrostichal bristles see acrostichal bristlespostalar a. [L. post, after; ala, wing] (ARTHRO: Insecta) Behindthe wings.postalar arm (ARTHRO: Insecta) An extension behind the wingin many insects, connecting the postnotum to theepimeron; postalar bridge; postalare. see prealar arm.postalar bridge see postalar armpostalar bristles (ARTHRO: Insecta) In Diptera, bristles on thepostalar callus.posticum see apopore

714Maggenti and Gardnerpostalar callus (ARTHRO: Insecta) In Diptera, the prominentposterodorsal angle of the scutum.postalar declivity see postalar wallpostalare see postalar armpostalar tail (NEMATA: Secernentea) That segment of the tailposterior to the leptoderan bursa or caudal alae.postalar wall (ARTHRO: Insecta) In Diptera, the ventrolateralsurface below the postalar ridge; postalar declivity.postanal plate see telsonpostantennal organ (ARTHRO: Insecta) In some Collembola, avariously shaped structure (ring-like, rosette, or complex),immediately behind the antennal bases; comprised ofsense-cell and several enveloping cells, possibly functioningas a chemorecepter.postapical a. [L. post, after; apex, the tip] (MOLL: Bivalvia)Referring to lateral teeth situated behind the umbo orapex.postbasal a. [L. post, after; Gr. basis, a pedestal] Behind; beyond;near the base.postbascillary eyes (ARTHRO: Chelicerata) In Arachnida, theanterior median eyes that have the retinal nuclei behindthe light-sensitive rods. see prebascillary eyes.postcerebral glands see cephalic salivary glandspostclypeus n. [L. post, after; clypeus, shield] (ARTHRO: Insecta)In some insects, the posterior or upper division ofthe clypeus differentiated by a suture from the anteclypeus,the ginglymus of the mandible attaches here;nasus; prefrons. see anteclypeus.postcolon n. [L. post, after; colon, colon] (ARTHRO: Chelicerata)Region of the gut between the colon and the rectum incertain mites.postcornu n. [L. post, after; cornu, horn] (ARTHRO: Insecta) InHymenoptera, a single, supra-anal, sclerotized caudal spineof Symphyta larvae.postcorpus n. [L. post, after; corpus, body] (NEMATA) Theposterior part of the esophagus in which the esophageal

Online Dictionary of Invertebrate Zoology 715gland cells are found.postcoxal bridge (ARTHRO: Insecta) The post coxal part of thethoracic pleuron, often united with the sternum behind thecoxa.postembryonic a. [L. post, after; Gr. embryon, fetus] Pertainingto the life stage succeeding the embryonic.postepipleurite see surpedal areaposteriad adv. [L. post, after; -ad, toward] Directed backward,as opposed to anteriad.posterior a. [L. posterior, latter] 1. Situated behind; behindthe axis. 2. (MOLL: Bivalvia) Direction along the major axisin which the anus faces and the exhalant current flows.posterior apophysis (ARTHRO: Insecta) In female Lepidoptera,sclerotized, paired apodemes of the 8th abdominal segment,extending cephalad and serving for muscle attachment;apophyses posteriores.posterior area (MOLL: Bivalvia) Area on the surface of thevalve posterior to the posterior ridge.posterior bulb see esophageal bulbposterior callosity see postalar callusposterior cardiac lobe see intestinal regionposterior carina see intestinal regionposterior cell (ARTHRO: Insecta) In Diptera, one of the wingcells extending to the hind margin, between the third andsixth longitudinal veins.posterior cephalic foramen see foramen magnumposterior cribellum (ARTHRO: Chelicerata) In Arachnida, theposterolateral spinnerets in Stenochilidae.posterior cross vein (ARTHRO: Insecta) In Diptera, a wingcross vein at the apex of the discal cell.posterior flange (MOLL: Bivalvia) In oysters, the flange posteriorto the left valve separated from the main body of thevalve by the posterior radial groove.posterior gastric pit (ARTHRO: Crustacea) In Decapoda, oneof two small dorsal depressions midline on the exterior of

716Maggenti and Gardnercarapace identifying the point of insertion of the stomachmuscle.posterior lateral tooth (MOLL: Bivalvia) In heterodonts, thelateral tooth situated posterior to the beaks and ligament.posterior notch (MOLL) An indentation in the outer lip near thesuture.posterior orbit (ARTHRO: Insecta) In Diptera, part of the headbehind the eyes.posterior ridge (MOLL: Bivalvia) A ridge passing over or originatingnear the umbo and running diagonally towards theposteroventral area of the valve.posterior respiratory process (ARTHRO: Insecta) In Diptera,among Syrphidae larvae, caudal respiratory organ composedof two fused tubes.posterior sinus (MOLL: Polyplacophora) A recess in the posteriormedian line of a tail valve, formed by the tegmentumor in some forms by the articulamentum.posterior slope (MOLL: Bivalvia) The surface sector runningposteroventrally from the umbo of the valve.posterior spiracle (ARTHRO: Insecta) Spiracles on the caudalsegment or the most caudal pair of segments.posterior spiracular plate (ARTHRO: Insecta) In Diptera, theflattened tip of each tube that bears the posterior spiraclesof Syrphidae larvae.posterior stigmatal tubercle (ARTHRO: Insecta) In caterpillars,tubercles on the thoracic and abdominal segment.posterior tentorial arms (ARTHRO: Insecta) The apodemeextending anteriad from the posterior tentorial pits of thehead.posterior tooth (ARTHRO: Crustacea) In Decapoda, a midlinecarapace tooth between the posterior margin and the marginalgroove.posterobiprostatic a. [L. posterus, following; bis, twice; Gr.prostates, stands before] (ANN: Oligochaeta) With referenceto male terminalia, prostates in segment xix after lossof a pair in segment xvii of an acanthodrilin set.

Online Dictionary of Invertebrate Zoology 717posterodorsal margin (MOLL: Bivalvia) The margin of the dorsalpart of the shell posterior to the beaks.posterolateral a. [L. posterus, following; latus, side] Posteriorlyand toward the side.postesophageal commissure (ARTHRO: Insecta) The commissurethat joins the tritocerebral lobes of the brain andpasses beneath the stomodeum; tritocerebral commissure.postesophageal loop (SIPUN) An extra loop in the foregut ofspecies of Sipunculus and some Xenosiphon.post-fibers (ARTHRO: Crustacea) In Decapoda, giant nerve fibersin crayfish that supply the deep parts of the abdominalflexors and are responsible for escape reaction. see pre-fibers.postfrenum, postfroenum see postscutellumpostfrons n. [L. post, after; furca, fork] (ARTHRO: Insecta)That portion of the frons posterior to the antennary baseline.postfrontal ridge (ARTHRO: Insecta) In Culicidae, an apodemeexternally differentiated by the postfrontal suture.postfrontal suture (ARTHRO: Insecta) Facial sutures presentoccurring above the lateral ocelli and extending laterad ofthe antennal bases.postfurca n. [L. post, after; furca, fork] (ARTHRO: Insecta) Theforked sternal process or apodeme of the metathorax.postgena n.; pl. -ae [L. post, after; gena, cheek] (ARTHRO:Insecta) A sclerite on the posterior lateral surface of thehead. postgenal a.posthumeral bristle (ARTHRO: Insecta) In Diptera, one ormore bristle(s) on the anterolateral surface of themesonotum; near the inner edge of the humeral callus.postlabium see postmentumpostlarval stage (ARTHRO: Crustacea) A developmental stageafter completion of the megalopal or equivalent metamorphosis,differentiated by appearance of adult characters.postmandibular area (BRYO) Membranous part of the frontalwall on which the mandibular muscles insert.

718Maggenti and Gardnerpostmarginal vein (ARTHRO: Insecta) The fore wing vein alongthe anterior margin, beyond where the stigmal vein arises.postmentum n. [L. post, after; mentum, chin] (ARTHRO: Insecta)A primary division of the labium; the basal portion,proximad of the labial suture.post-mortem After death; post-mortem changes.postnodal cross veins (ARTHRO: Insecta) A series of shortwing cross veins behind the costal margin, between thenodus and stigma.postnotal plate see metapostnotum, mesopostnotumpostnotum n.; pl. -ta [L. post, after; Gr. notum, back] (AR-THRO: Insecta) The phragma-bearing plate in the dorsum ofa pterothoracic segment, originating from the acrotergite ofthe following notum. see mesopostnotum, metapostnotum.postoccipital ridge (ARTHRO: Insecta) The internal aspect ofthe postoccipital suture.postoccipital suture (ARTHRO: Insecta) The transverse sutureon the head immediately posterior to the occipital suture,and ending at the posterior tentorial pit on either side andalong which are inserted the dorsal prothoracic musclesthat move the head.postocciput n. [L. post, after; occiput, back of head] (ARTHRO:Insecta) The extreme narrow posterior rim of the head,between the postoccipital suture and the foramen magnum.postocellar area (ARTHRO: Insecta) In Hymenoptera, that parton the dorsal aspect of the head bounded by the ocellarand vertical furrows and the caudal margin of the head.postocellar bristles see postvertical bristlespostocellar glands (ARTHRO: Insecta) In Hymenoptera, amass of glands situated above the ocelli in the drone andqueen bees; detached lobes of the cephalic salivary glands.postoral a. [L. post, after; os, mouth] Behind the mouth.postorbital bristles (ARTHRO: Insecta) In Diptera, a row ofbristles behind and nearly parallel to the posterior of theeye.

Online Dictionary of Invertebrate Zoology 719postpalmars n. [L. post, after; palma, palm] (ECHINOD: Crinoidea)Any brachials after the tertibrachs.postpectus n. [L. post, after; pectus, breast] (ARTHRO: Insecta)The ventral surface of the metathorax.postpedes see anal prolegpostpedicel a. [L. post, after; pes, foot] (ARTHRO: Insecta)The third segment of the antenna.postpeltidium see schizopeltidpostpetiole n. [L. post, after; petiolus, little leg] (ARTHRO: Insecta)1. In Formicidae, the second segment of a two-segmentedpedicel. 2. In Ichneumonidae, where the petiole(first body segment) abruptly broadens near the spiracles.postphragma n. [L. post, after; Gr. phragma, fence] (ARTHRO:Insecta) 1. Internal plates developed from the antecostalridges at the front and back of the mesothorax and theback of the metathorax that provide attachment for thelarge longitudinal muscles moving the wings. 2. In Diptera,a well developed phragma at the posterior extension of thepostnotum.postpudendum n.; pl. -da [L. post, after; pudenda, externalgenitals of female] (NEMATA) The female genital tube thatproceed posteriorly from the vulva.post-pygidial gland (ARTHRO: Insecta) In Formicidae, a glandassociated with the membrane between abdominal terga 7and 8, sometimes large; function unknown. see pygidialglands.postreduction n. [L. post, after; reducere, to lead back] Reductionof the chromosome number to haploid in the secondmeiotic division.postscutellum n. [L. post, after; dim. scutum, a shield] (AR-THRO: Insecta) 1. A small transverse piece of a thoracicnotum immediately behind the scutellum or between theapex of the scutellum and the base of the propodeum;pseudonotum. 2. In Diptera, a convex, transverse swellingbelow the scutellum; subscutellum.postsegmental region see telsonpostsoma see metathorax

720Maggenti and Gardnerpoststernellum see spinasternumpoststigmatal primary tubercle (ARTHRO: Insecta) In caterpillars,a tubercle on the thorax.postsynaptic a. [L. post, after; Gr. synapsis, union] Pertainingto structures or events on the receiving side of a synapse.posttriangular cells see discoidal cellpostuterine sac (NEMATA) A reduced, degenerate uterus nonfunctionalin gamete production, usually posteriad to thevulva; may function as a storage organ for sperm in somespecies.postvertical bristles (ARTHRO: Insecta) In Diptera, a pair ofbristles behind the ocelli, generally on the posterior surfaceof the head.postvulvar uterine branch see postuterine sacpotamoplankton n. [Gr. potamos, river; plankton, wandering]Plankton of running water.potential n. [L. potens, having power] In electrophysiology,the difference in charge between two points; usually in millivolts.pouch n. [OF. poche] 1. A small or moderate size receptacle,sac or bag. 2. (ARTHRO: Insecta) In Hymenoptera, the foodholder for bumblebee larvae. 3. (CNID: Scyphozoa) An extensionof the stomach cavity.pouch-makers (ARTHRO: Insecta) Bumblebee species thatbuild special pollen-filled pouches next to groups of theirlarvae.praecoxa n.; pl. -ae [L. prae, before; coxa, hip] (ARTHRO:Chelicerata) In arachnids, a term used instead of coxa insome groups.praesoma n. [L. prae, before; Gr. soma, body] (ACANTHO) Theproboscis, neck, and attached muscles and organs.praniza n. (ARTHRO: Crustacea) In Isopoda, a parasitic larva offishes in the suborder Gnathiidea.prasinous a. [Gr. prasinos, leek green] Light green tending toyellow; the color of a leek.pratinicolous n. [L. pratum, meadow; incola, inhabitant] Liv-

Online Dictionary of Invertebrate Zoology 721ing in meadows or bogs.preadaptation n. [L. pre, before; adaptatus, fitted] The possessionof the necessary genotypic or phenotypic propertiesthat permit a shift into a new niche or habitat.prealar arm (ARTHRO: Insecta) An extension in front of thewings connecting the prescutum with the pleuron; prealarbridge; prealare. see postalar arm.prealar callus (ARTHRO: Insecta) In Diptera, a projection situatedjust above the root of the wing.prealare see prealar armpreanal region see remigiumpreanal ring (ARTHRO: Diplopoda) Post-segmental ring endingtrunk; usually has a tail, anal valves and scales; forms thetelson.preapical a. [L. prae, before; apex, tip] Before the apex.preapical bristle (ARTHRO: Insecta) In Diptera, a bristle on theouter border of the tibia, below the apex.preapical gland see phasmidpreaxial a. [L. prae, before; axis, axle] On the anterior borderor before the axis.preaxillary excision (ARTHRO: Insecta) In hind wings of Hymenoptera,a second notch of the apex of the first analfold, just anterior of the first anal vein, in addition to theaxillary notch.prebascillary eyes (ARTHRO: Chelicerata) In Arachnida, theanterior lateral, posterior lateral and posterior median eyesthat have the retinal nuclei in front of the light-sensitiverods. see postbascillary eyes.prebasilare n. [L. prae, before; basis, base] (ARTHRO: Diplopoda)In the gnathochilarium, a narrow transverse sclerite,just basal to the mentum.precardo n. [L. prae, before; cardo, hinge] (ARTHRO: Diplopoda)The distal joint of a two piece cardo.precheliceral a. [L. prae, before; Gr. chele, claw; keras, horn](ARTHRO: Chelicerata) Anterior to the chelicerae; the acronand the three or four embryological segments anterior to

722Maggenti and Gardnerthe cheliceral segment; segment I.precibarium n. [L. prae, before; L. cibarius, pertaining tofood] (ARTHRO: Insecta) A canal formed by the union of theepipharynx and the hypopharynx, providing a connectinglink between the food canal of the maxillary stylets and thecibarial pump.precipitin n. [L. praeceps, head long] A specific antibody developedin response to foreign protein in the blood.precocious stages 1. Premature development. 2. An organthat appears earlier in the development of a species than inthe development of other related species.preconnubia n. [L. prae, before; connubium, marriage] Thecoming together of animals before mating season.precornua n. [L. prae, before; cornu, horn] (ARTHRO: Insecta)In Diptera larvae, the cornua of the cephalo-basipharynx.precosta n. [L. prae, before; costa, rib] (ARTHRO: Insecta) Insome primitive forms, the small first wing vein.precoxa n. [L. prae, before; coxa, hip] 1. (ARTHRO: Crustacea)When present, the segment of the protopod proximal to thecoxa; pleuropod. 2. (ARTHRO: Insecta) see subcoxa. precoxala.precoxal bridge (ARTHRO: Insecta) That part of the thoracicpleuron anterior to the trochantin, usually continuous withthe episternum and the basisternum; precoxale.precursor n. [L. prae, before; currare, to run] 1. Element orsubstance that preceeds the final one. 2. Ancestor or ancestralpart. see anlage, rudiment.precursory cell A mother cell or metrocyte.predaceous, predacious a. [L. preda, prey] Having the characteristicsof a predator.predator n. [L. praedator, plunderer] An animal that kills orrenders its prey insensible in order to mostly or entirelyconsume it.predictive value The capability of a classification to make predictionson newly employed characters or newly discoveredtaxa.

Online Dictionary of Invertebrate Zoology 723pre-epipod(ite) n. [L. prae, before; Gr. epi-, on; pous, foot](ARTHRO: Crustacea) The laterally directed lobe of the coxa.pre-episternum n. [L. prae, before; Gr. epi-, on; sternon,chest] (ARTHRO: Insecta) The anterior part of the episternummarked off as a separate plate.prefemur see ischiopoditepre-fibers n. [L. prae, before; fibra, fiber] (ARTHRO: Crustacea)In Decapoda, 4 giant nerve fibers in crayfish, 2 medianmaking snaptic contact with the brain and with fibersfrom the anterior sense organs; 2 lateral ones are productsof the fusion of many cells. see post-fibers.preformation n. [L. prae, before; forma, shape] The archaictheory that the egg (or sperm or zygote) contains a preformedadult in minature, and only nourishment is requiredduring development.prefrons see postclypeuspregula n. [L. prae, before; gula, throat] (ARTHRO: Insecta) Inlarval Coleoptera, the anterior section of the gular plate, infront of a median gular suture in hydrophilid, staphylinid,etc.prehalteres n.pl. [L. prae, before; Gr. halter, weight] (AR-THRO: Insecta) In Diptera, the squamae.prehensile a. [L. prehendere, to seize] Adapted for grasping orholding; formed to coil around or cling.prehensile spines see grasping spinespreimago n. [L. prae, before; imago, image] (ARTHRO: Insecta)The last phase of pupal stage when the adult structuresare seen within the pupal covering. preimaginal a.preischium n. [L. prae, before; Gr. ischion, hip] (ARTHRO:Crustacea) When present, the segment of the endopodbetween the protopod and the ischium.prelarva n. [L. prae, before; larva, mask] (ARTHRO: Chelicerata)In Acari with a four stage development, the firstpostembryonic stage usually occurring in the egg, but maybe a non-feeding form after eclosion; prelarval phase.prelateral lobe (ARTHRO: Crustacea) In Stomatopoda, theproximal lateromarginal lobe of the telson.

724Maggenti and GardnerPre-Linnaean name A name published prior to January 1,1758, the starting date of zoological nomenclature.premandibular suture 1. (ARTHRO: Chilopoda) A suture thatrises posterior to the eyes, and extends transversely acrossthe head. 2. (ARTHRO: Insecta) Known as the epicranialsuture.premental gutter (ARTHRO: Insecta) In Diptera, the mediandorsal longitudinal groove of the prementum (theca) thathouses the fascicle (stylets); labial gutter; labial lumen.premental setae (ARTHRO: Insecta) In odonatan nymphs, setaeon the prementum which are of taxonomic importance.prementum n. [L. prae, before; mentum, chin] (ARTHRO: Insecta)The distal part of a labium in which all the labialmuscles have their insertion.premorse a. [L. prae, before; modere, to gnaw] Terminatingabruptly, as if bitten or broken off; having blunt or jaggedtermination.prenymph n. [L. prae, before; nympha, bride] (ARTHRO: Chelicerata)In Acari, a nonfeeding, quiescent stage in the lifecycle of Trombiculidae.preocellar band (ARTHRO: Insecta) In Odonata, a darkly pigmentedstripe in front of the ocelli.preoral cavity 1. The mouth cavity. 2. (ARTHRO: Chelicerata)In Acari, the space between the lips anterior to the oralcommissures.preoral sting (ARTHRO: Crustacea) In Branchiura, a retractilepiercing structure with a basal poison gland, between themaxillulae (suction discs).prepatent period The biological incubation period.prepectal carina (ARTHRO: Insecta) In certain Hymenoptera,an area near the front of the mesothorax, traversing themesosternum near the front, and continuing upward oneach side of the front part of the mesopleurum.prepectus n. [L. prae, before; pectus, chest] (ARTHRO: Insecta)The differentiated anterior portion of the mesepisternum,often forming a conspicuous plate on the lateralthorax between the pronotum and mesepisternum.

Online Dictionary of Invertebrate Zoology 725prephragma n. [L. prae, before; Gr. phragma, fence] (AR-THRO: Insecta) In Diptera, a phragma at the anterior marginof the mesonotum, often small or vestigial. seephragma, postphragma.prepuce n. [L. prae, before; Gr. posthe, penis] 1. (ARTHRO:Insecta) see preputium. 2. (MOLL: Gastropoda) In certainPulmonata, an extension of the distal end of the penissheath.prepupa n.; pl. -ae [L. prae, before; pupa, puppet] (ARTHRO:Insecta) Quiescent last larval instar before ecdysis to apupa; not ordinarily representing a distinct morphologicalstage; propupa. see pharate. a. In Thysanoptera and maleCoccidae, a morphological stage, a quiescent instar followingthe last larval instar, followed by a second quiescent,pupal instar. b. In Diptera, the third instar larva betweenpupariation and the larval-pupal apolysis. prepual a.preputial a. [L. prae, before; Gr. posthe, penis] Of or pertainingto the prepuce.preputial sac (ARTHRO: Insecta) An eversible sac(s) on thepenis bearing a small toothed plate that grips the wall ofthe female vagina during copulation; vesica; genital sac.preputium n. [L. prae, before; Gr. posthe, penis] The externalcovering of the penis.prepygidium n. [L. prae, before; Gr. pyge, rump] (ANN: Polychaeta)An area of segment addition anterior to the pygidium.prerectum n. [L. prae, before; rectus, straight] An identifiablesection of the alimentary canal between the mesenteronproper and the rectum. prerectal a.prereduction n. [L. prae, before; reducere, lead back] The reductionto haploid of the chromosome number in the 1stmeiotic division.presaepium n. [L. prae, before; sepes, fence] (ARTHRO: Insecta)In larvae of the ant tribe Camponotini, the shallowdepression on the venter of some anterior abdominalsomites; suggested to resemble the trophothylax of pseudomyrmecinaelarva.prescutal ridge (ARTHRO: Insecta) The internal strengthening

726Maggenti and Gardnerridge formed by the prescutal sulcus.prescutal sulcus (ARTHRO: Insecta) A transverse sulcus dividingthe notum into an anterior prescutum and a scutum.prescutellar area (ARTHRO: Insecta) In Diptera, the medianposterior area of the scutum, situated between the acrostichalarea and the scutellum; prescutellar space.prescutellar seta/bristles (ARTHRO: Insecta) In Diptera, setaoccurring in several rows on the anterior and/or lateralmargins of the prescutellar area.prescutellum n. [L. prae, before; scutum, shield] (ARTHRO:Insecta) The sclerite nearest the head when, on the rareoccasion, the upper part of the segment of the notum is dividedinto 4 parts.prescutum n. [L. prae, before; scutum, shield] (ARTHRO: Insecta)The first subdivision of the notum, usually followedby scutum and scutellum; the anterior division of themeso- or metanotum.presegmental region see acronpresocial a. [L. prae, before; socialis, of companionship] (AR-THRO: Insecta) Applied to groups that display some degreeof social behavior short of true social behavior. see subsocial,parasocial.presternum n. [L. prae, before; Gr. sternon, chest] (ARTHRO:Insecta) The first subdivision of the eusternum, followed bythe basisternum and sternellum.prestomal teeth (ARTHRO: Insecta) In Diptera, a row of teethprotruded by the labella, by means of blood-pressure, toallow food particles to traverse the pseudotrachae.presutural bristles (ARTHRO: Insecta) One or more thoracicbristles of Diptera, immediately in front of the transversesuture on either side.presynaptic a. [L. prae, before; Gr. synapsis, union] Pertainingto structures or events before a synapse.pretarsus n. [L. prae, before; Gr. tarsos, flat of the foot] 1.(ARTHRO) The terminal segment of the leg of various arthropods,usually consisting of the lateral claws (ungues),and one or more pad-like structures; dactyl; dactylo-

Online Dictionary of Invertebrate Zoology 727pod(ite). 2. (ARTHRO: Chelicerata) In Acari, a small, terminalpart of the tarsus with an endoskeleton of two sclerotizedpieces articulating with the apotele.preungual process (ARTHRO: Crustacea) In Malacostraca, astructure at the base of the dactyl of the 4th pereopod inPaguridae; thought to be sensory in function.preupsilon see sternal apophysesprevalence n. [L. prae, before; valens, to be strong] The totalnumber of cases of a particular disease at a particular time,in any given population. see incidence.prevulvar setae (ARTHRO: Insecta) In Coccidae, large setaefound anterior to the vulva on abdominal segments 6, 7, 8.prezoea n. [L. prae, before; zoe, life] (ARTHRO: Crustacea) Anewly-hatched postnaupliar larva covered by embryoniccuticle.Priapulida, priapulids n.; n.pl. [Gr. Priapos, god of male fertility]A phylum of burrowing, vermiform marine animalswith a variety of protuberances that are used in taxonomy.primary n. [L. primus, first] First; original.primary bud (BRYO) A hollow outward expansion of the bodywalls of the ancestrula.primary circlet (ECHINOD: Asteroidea) A ring of prominent ossicleson the aboral surface.primary culture A culture started from cells, tissues, or organstaken directly from organisms; if then subcultured, itbecomes a 'cell line'.primary epithelium The blastoderm.primary denticle (ARTHRO: Crustacea) In barnacles, denticlesfound on the sutural edges of the compartmental plate.primary fiber (PORIF: Desmospongiae) Fiber at right angles tothe surface; containing sand or debris taken up by thesponge.primary homonym Each of two or more identical speciesgroupnames that were proposed in combination with thesame generic name at the time of original publication.primary host see definitive host

728Maggenti and Gardnerprimary intergradation An intermediate zone between twophenotypically different populations, developed in situ as aresult of selection. see secondary intergradation.primary iris cells see corneal pigment cellsprimary ligament (MOLL: Bivalvia) Original ligamental structureconsisting of periostracum, lamellar layer and fibrouslayers; not secondary additions such as the fusion layer.primary ocelli see dorsal ocelliprimary/periodical pleometrosis (ARTHRO: Insecta) In socialHymenoptera, a colony founded by a group of queens,however, after emergence of the first workers, all but onefemale disperse. see secondary pleometrosis, temporarypleometrosis.primary pigment cells see corneal pigment cellsprimary reproductive (ARTHRO: Insecta) In Isoptera, thequeen or male termite derived from winged adults, thatestablish a colony. see adultoid reproductive, nymphoidreproductive, ergatoid reproductive.primary riblet (MOLL: Bivalvia) In shells with various strengthof riblets, the riblet appearing early in development andremaining stronger than later ones.primary royal pair see primary reproductiveprimary segmentation The segmental division of the bodyoriginating in embryonic metamerism.primary setae (ARTHRO: Insecta) In Lepidoptera, setae with adefinite arrangement found on caterpillars in all instars.primary sexual characters Gonads and associated ducts.primary shell layer (BRACHIO) Outer layer under the periostracum;deposited by columnar epithelium of the outermantle lobe.primary somatic hermaphrodite see intersexprimary spicule (PORIF) A major structural megasclere.primary teeth (BRACHIO) The cardinalia or central teeth belowthe umbones.primary zooid (BRYO: Gymnolaemata) In some Cheilostomata,the ancestrula or one to several zooids simultaneously

Online Dictionary of Invertebrate Zoology 729budded after larval metamorphosis; differing from subsequentzooids.primary zoological literature The literature dealing withanimals or zoological phenomena, not merely a listing ofnames.primaxil n. [L. primus, first; axis, axle] (ECHINOD: Crinoidea)The first axillary arm; the axillary primibrach.primibrachs n.pl. [L. primus, first; Gr. brachion, upper arm](ECHINOD: Crinoidea) All brachials of an unbranched arm;there are usually 2, the second of which is an axillary.primibrachial a.primitive a. [L. primus, first] Ancestral; original form; primordial.primitive streak see germ bandprimogyne n. [L. primus, first; Gr. gyne, female] The primarytype female of a species.primordial a. [L. primordialis, original] Original or primitive;having the simplest and most underdeveloped character.primordial soup The solution or suspension of organic moleculesthought to have given rise to life.primordial valve (ARTHRO: Crustacea) In Lepadomorpha andVerrucomorpha Cirripedia, one of 5 chitinous plates of cyrpidlarvae.primordiotrichy n. [L. primordialis, original] The hypotheticaltheory of chaetotaxy of ancestral types. see atactotrichy.primordium n.; pl. -dia [L. primordialis, original] 1. The origin;beginning. 2. The first cells that are identifiable as thebeginning development of an organ or structure; anlage;blastema; fundament.principalia n.pl. [L. principium, foundation] (PORIF) Spiculesconstituting main skeletal framework.priodont a. [Gr. prion, saw; odous, tooth] (ARTHRO: Insecta)In Coleoptera, referring to male Lucanidae bearing smallmandibles. see amphidont, teleodont.prionodont a. [Gr. prion, saw; odous, tooth] (MOLL: Bivalvia)With teeth developed transversely to the cardinal margin;

730Maggenti and Gardnersimilar to taxodont.priority n.; pl. -ties [L. prior, former, superior] The principlethat of two competing names for the same taxon (belowthe rank of an infraorder) the validity is based on whichwas published first, either by date or page (when in thesame journal).prisere n. [L. primus, first; serere, to join] A primary sere;complete natural succession of communities, from barehabitat to climax. see plagiosere.prismatic a. [Gr. prisma, prism] 1. In the shape of a prism;microscopically honeycombed; a needle-like prism structure.2. (MOLL: Bivalvia) Pertaining to a type of shell structurethat consists of calcite or aragonite prisms.proala n. [L. pro, before; ala, wing] (ARTHRO: Insecta) Theanterior wing; fore wing.proandry n. [Gr. pro, before; aner, male] 1. Anterior pair oftestes. 2. (ANN: Oligochaeta) Testes restricted to segmentX or homoeotic equivalent.probofossa see premental gutterprobolae n.pl. [Gr. probolos, any projecting prominence](NEMATA) Ornate cuticular structures often fringed and/orbranched, of the labial or cephalic region.proboscides n.pl. [Gr. pro, before; proboskis, trunk] (PLATY:Cestoda) Four long, tentacle-like, retractable structureswith rows of hooks in the order Trypanorhyncha.proboscidial fossa (ARTHRO: Insecta) In Hymenoptera, thedeep groove on the under side of the head of bees, inwhich the proboscis is folded in repose.proboscipedia n. [Gr. proboskis, trunk; L. pes, foot] (ARTHRO:Insecta) The anomaly of a labellum maturing as a leg.proboscis n.; pl. proboscises [Gr. proboskis, trunk] 1. Anyextended trunk or beaklike sucking mouth parts of numerousinvertebrates, as of leeches, planarians, dipteran insects,nemertine worms, acanthacephalans, annelids andmollusks. 2. (ECHI) Muscular food gathering and respiratoryorgan extending from the trunk near the mouth.proboscis bulb (PLATY: Cestoda) In Tranypanorhyncha, mus-

Online Dictionary of Invertebrate Zoology 731cular end of the proboscis sheath that causes the proboscidesto evert.proboscis pore (NEMER) An aperture through which the proboscisis everted; the rhynchostome.proboscis sheath (PLATY: Cestoda) In Trypanorhyncha, a tubeinto which the proboscides maybe retracted.proboscis worm The Nemertea, also called ribbon-worms.probursal a. [L. pro, before; bursa, purse] (PLATY: Turbellaria)In Tricladida, having the bursal stalk long and arching anteriorlyover the penis, so that the bursa lies anterior to thepenis. see retrobursal.procephalic lobes (ARTHRO: Insecta) In embryology of the cephalicregion, expansion of the neural ridges forming thefuture brain and divided into three neuromeres, known asproto-, deuto- and tritocerebrum; procephalon.procercoid n. [Gr. pro, before; kerkos, tail; eidos, like] (PLATY:Cestoda) The metacestode developing from the oncosphere,containing a body proper and caudal vestige of theoncosphere, the cercomere. see neotenic procercoid.process n.; pl. processes [L. processus, proceed] A markedprominence, projecting part, or outgrowth.processi longi see bacilliformprocessus ventralis (ARTHRO: Crustacea) A process on theposterior or lower side of the pars media, variable in shape,armed with thick, short spines, small in size or deeply cleft.proclinate a. [Gr. pro, before; klinein, to incline] Inclined forwardor downward.procoria a. [L. pro, before; corium, leather] (ARTHRO: Insecta)Referring to coria anterior to the prothorax.procorpus n. [L. pro, before; corpus, body] (NEMATA: Secernentea)In Tylenchida, the anteriormost cylindrical partof the esophagus, between the stylet and metacorpus (medianbulb).procrusculus n.; pl. -culi [L. pro, before; crusculus, little leg](PLATY: Trematoda) One or more stumpy, locomotive appendageson the posterior of a redia.

732Maggenti and Gardnerprocryptic colors Imitative colors useful for concealment as aprotection against enemies. see Batesian mimicry, Mullerianmimicry.proctal see analproctiger n. [Gr. proktos, anus; L. gerere, to bear] (ARTHRO:Insecta) Anal portion of the 10th abdominal segment.proctodaeal, proctodaeum see proctodeumproctodeal feeding (ARTHRO: Insecta) In Isoptera, a drop ofthe contents of the rectal pouch being obtained from theanus of another termite. see stomodeal feeding.proctodeal valve see pyloric valveproctodeum n. [Gr. proktos, anus; hodos, way] (ARTHRO) Theposterior ectodermal region of the alimentary canal; hindgut;proctodaeum.proctostome n. [Gr. proktos, anus; stoma, mouth] The"mouth" of Cnidaria and Turbellaria.procumbent a. [L. pro, before; cubare, to lean] Prostrate;trailing; leaning forward.procurved a. [L. pro, before; curvare, to curve] (ARTHRO: Chelicerata)In Arachnida, used to denote the curvature of theeyes when the lateral eyes are further forward than themedian eyes. see recurved.procuticle n. [L. pro, before; cutis, skin] (ARTHRO) The thickerlayer beneath the epicuticle consisting of endocuticle andexocuticle that lends mass and strength to the cuticle; itcontains chitin, sclerotin and also calcium carbonate andcalcium phosphate deposits in Crustacea.prodehiscence n. [L. pro, before; dehiscere, to divide] (AR-THRO: Chelicerata) In Acari, molting in which the splittingof the old cuticle occurs laterofrontally beside the frontalprotuberance.prodelphic a. [Gr. pro, before; delphys, womb] (NEMATA) Uteriparallel and anteriorly directed. see amphidelphic,monodelphic, didelphic, opisthodelphic.prodissoconch n. [L. pro, before; dis, two; concha, shell](MOLL: Bivalvia) 1. The embryonic shell. 2. Early shell secretedby the shell gland of the larva. 3. Later shell se-

Online Dictionary of Invertebrate Zoology 733creted by the mantle edge.prodorsal dehiscence (ARTHRO: Chelicerata) In molting, theline of weakness following the abjugal furrow between theaspidosoma and prodosoma.prodorsum n. [L. pro, before; dorsum, back] (ARTHRO: Chelicerata)The dorsal surface of the aspidosomal tagma; mayhave one or two transverse furrows.prodrome n. [Gr. prodromos, preceding] A premonitorysymptom, indicating the initial stage of a disease. prodromala.produced a. [L. producere, to produce] Elongated; extended;projecting. production n.proecdysis n. [Gr. pro, before; ekdysis, getting out of]Preparation for molting, especially in decapod crustaceans.proeminent see prognathousproenchium n. [Gr. pro, before; enchos, spear] (NEMATA) Hasbeen used for both prostome and mesostome.proepilobous a. [Gr. pro, before; epi, upon; lobos, projection](ANN: Oligochaeta) The prostomium slightly indenting thefirst segment.proepimeron n.; pl. -mera [Gr. pro, before; epi, upon;meros, part] (ARTHRO: Insecta) The epimeron of the prothorax.proepisternum n.; pl. -sterna [Gr. pro, before; epi, upon;sternon, chest] (ARTHRO: Insecta) The episternum of theprothorax.proepistome see interantennular septumprofile n. [L. pro, before; filum, outline] An outline as seenfrom the side or lateral view.profundal region In deep lakes from limnetic zone to bottom.profuse a. [L. profusus, abundant] Abundant.progenesis n. [Gr. pro, before; genesis, origin] 1. Retention ofjuvenile characters by precocious, sexually mature morphologicallyjuvenile stage. see paedogenesis. 2. (PLATY:Trematoda) Larval reproduction.progenital a. [L. pro, before; gignere, to beget] (ARTHRO:

734Maggenti and GardnerChelicerata) In Acari, referring to the area between theprimary and secondary genital opening and to the secondaryopening itself.progenital chamber (ARTHRO: Chelicerata) In Acari, thechamber between the primary and secondary genitalopening of Acariformes.progenital lips (ARTHRO: Chelicerata) In Acari, paired symmetricalvalves that close the progenital chamber of manyAcariformes.progenitor n. [L. pro, before; gignere, to beget] An ancestralspecies.progeny n. [L. pro, before; gignere, to beget] Offspring;young.proglottid n. [Gr. pro, before; glotta, tongue] (PLATY: Cestoda)One complete unit of reproductive organs in a strobila;usually corresponding to a segment.proglottis n.; pl. -ides [Gr. pro, before; glotta, tongue](PLATY: Cestoda) A proglottid.prognathous a. [Gr. pro, before; gnathos, jaw] Having mouthparts directed forward. see hypognathous, opisthognathous.progoneate a. [Gr. pro, before; gonos, offspring] Having thegenital opening in the anterior region of the body. see opisthogoneate.prograde a. [Gr. pro, before; L. gradus, step] (ARTHRO: Chelicerata)In spiders, having the dorsal surface of the leg uppermost.progredientes n.pl. [L. progrediens, advancing] (ARTHRO: Insecta)In Adelgidae, nymphs of the third generation thatsoon develop into wingless agamic females.progressive provisioning The practice of feeding the youngduring their development. see mass provisioning.progynous a. [Gr. pro, anterior; gyne, woman] (ANN: Oligochaeta)Having ovaries restricted to segment xii or ahomoeotic equivalent.prohaemocyte see prohemocyte

Online Dictionary of Invertebrate Zoology 735prohaptor n. [Gr. pro, before; haptein, to fasten] (PLATY: Trematoda)In Monogenea, the anterior adhesive and feedingorgans.prohemocyte, prohaemocyte n. [Gr. pro, before; haima,blood; kytos, container] (ARTHRO) A small, round, oval orelliptical hemocyte with a relatively large nucleus and intenselybasophilic cytoplasm that divides and gives rise toother types of cells; hemocytoblast; stem cell; urzellen.prolegs n.pl. [L. pro, before; ON. leggr, leg] (ARTHRO: Insecta)The fleshy abdominal legs of larvae; false legs.proleucocyte see prohemocyteproleucocytoid see prohemocyteproliferation n. [L. proles, offspring; ferre, to bear] An increasein size due to budding or cell division.proliferation zone (ARTHRO: Diplopoda) The place where newsegments are formed; between last segment and telson.prolobic a. [Gr. pro, before; lobos, lobe] (ANN: Oligochaeta)Referring to a prostomium demarcated from and without atongue in the peristomium.prolymphocyte see prohemocytepromentum n. [L. pro, before; mentum, chin] (ARTHRO: Diplopoda)A median sclerite in the gnathochilarium, anterior ofthe mentum or stipites.promerites n.pl. [Gr. pro, before; meros, part] (ARTHRO: Diplopoda)In male Julida, the eighth pair of body limbs usedin conjunction with the ninth pair of trunk legs (mesomerite)to draw out the female vulva.promesonotal suture (ARTHRO: Insecta) In Hymenoptera, thetransverse seam separating the pronotum from themesonotum of Formicidae.prometaphase n. [Gr. pro, before; meta, between; phasis,appearance] In meiosis and mitosis the stage at which thechromosomes move to the equatorial plate.prominence n. [L. prominens, projecting] A raised, producedor projecting area. prominent a.promitochondrion n.; pl. -ria [Gr. pro, before; mitos, thread;

736Maggenti and Gardnerchondros, grain] The possible precursor of a mitochondrion.promotion n. [L. pro, before; motio, move] (ARTHRO: Insecta)The movement of the coxa, resulting in protraction.promyal passage (MOLL: Bivalvia) In oysters, the exhalantwater passage found between the adductor muscle andmantle isthmus.pronotal comb (ARTHRO: Insecta) In Siphonaptera, the row ofstrong spines on the posterior margin of the pronotum.pronotum n. [Gr. pro, before; notos, back] (ARTHRO: Insecta)The dorsal sclerite of the prothorax.pronucleus n. [L. pro, before; nucleus, kernal] The spermatozoaand ova nucleus after maturation, prepared for fusionto form a zygote nucleus.pronymph n. [Gr. pro, before; nymphe, pupa] (ARTHRO: Insecta)An individual enclosed in an embryonic cuticle whichis shed during eclosion and left in the egg shell, or cast afterhatching; vermiform larva; primary larva.pronymphal membrane Embryonic cuticle covering the pronymphswith simple (hemimetabolus) or sometimes complete(holometabolus) metamorphosis, which are shed by aprocess similar to molting before or shortly after hatching;embryonic cuticle; paraderm.proorchic a. [Gr. pro, before; orchis, testicle] (NEMATA) Ananteriorly directed testis.proostracum n. [Gr. pro, before; ostrakon, shell] (MOLL:Cephalopoda) The anterior prolongation of the rostrum; ahorny pen. see gladius.propagate v. [L. propagare, to propagate] 1. To transmit awave of excitation along a nerve fiber. 2. To continue orcause to multiply.proparamere n. [Gr. pro, before; para, near; meros, part](ARTHRO: Insecta) 1. In some Dermaptera, a lateral scleritewhich may consist of anterior and posterior parts that supportthe parameres. 2. In Diptera (Cyclorrhapha), one oftwo parameral processes. see opisthoparamere.proparea n. [Gr. pro, before; pareia, cheek](BRACHIO:Inarticulata) One of a pair of roughly triangular

Online Dictionary of Invertebrate Zoology 737areas of the posterior sector of the shell.propedes n.pl. [L. pro, before; pes, foot] (ARTHRO: Insecta)The forelegs, or prolegs of larvae.propeltidium n. [Gr. pro, before; dim. pelte, shield] (ARTHRO:Chelicerata) In Arachnida, the covering of the prosoma, exceptfor plates V and VI.prophallus n.; pl. -li [Gr. pro, before; phallos, penis] (ARTHRO:Insecta) In Odonata, the penis in the floor of fenestra betweenhamuli; sheath of penis.prophases n.pl. [Gr. pro, before; phasis, appearance] Theearly stages of mitosis or meiosis.prophragma n. [Gr. pro, before; phragma, fence] (ARTHRO:Insecta) The anterior dividing wall of cuticular materialconnecting the pro- and mesothorax.prophylaxis n.; pl. -laxes [Gr. pro, before; phylaktikos,guard] Methods designed to preserve health and preventthe spread of disease.proplegma n.; pl. -ae [Gr. pro, before; plegma, plaited] (AR-THRO: Insecta) A single fold of the proplegmatium.proplegmatium n.; pl. -ia [Gr. pro, before; plegma, plaited](ARTHRO: Insecta) In scarabaeoid larvae, one of two areaswith a plicate surface inside, usually in front of a plegmatium;submarginal striae.propleural bristles (ARTHRO: Insecta) In Diptera, bristles situatedon the propleuron; just above the coxae of the forelegs.propleuron n.; pl. -pleura [Gr. pro, before; pleura, side] (AR-THRO: Insecta) The lateral portion of the prothorax.propneustic a. [Gr. pro, before; pneustikos, of breathing] (AR-THRO: Insecta) Having only the anterior pair of spiraclesopen and functioning. see oligopneustic.propodeal apophyses (ARTHRO: Insecta) In ichneumonid Hymenoptera,the posterior transverse carina (apical carina)with promontories at its junction with the lateral longitudinalcarinae.propodeon see propodeum

738Maggenti and Gardnerpropodeum n. [Gr. pro, before; podeon, neck] (ARTHRO: Insecta)1. In apocrite Hymenoptera the fused first abdominalsegment; median segment; propodeon also used. seealitrunk. 2. For Formicidae, a synonym for epinotum.propodite n. [Gr. pro, before; pous, foot; -ites, part] (ARTHRO)1. The next to last segment of a generalized limb. 2. (AR-THRO: Insecta) The tarsus. 3. (ARTHRO: Crustacea) seepropodus.propodium n. [Gr. pro, before; pous, foot] (MOLL: Gastropoda)The foremost divison of the foot, functioning in pushingaside sediment as the animal crawls.propodosoma n. [Gr. pro, before; pous, foot; soma, body](ARTHRO: Chelicerata) In Acari, the region of the podosomathat bears the first and second pairs of legs.propodus n. [Gr. pro, before; pous, foot] (ARTHRO: Crustacea)The 4th segment of an endopod, between the carpus anddactyl.propolar cells (MESO: Rhombozoa) In Dicymedia, the anteriortier of cells in the calotte.propolis n. [Gr. pro, before; polis, city] (ARTHRO: Insecta) InHymenoptera, a term for resins and waxes collected bybees for use in construction and sealing crevices in the nestwall.propped a. [ME. proppe, prop] (MOLL: Polyplacophora) Pertainingto teeth of the valves having edges thickened onthe outside.proprioceptor n. [L. proprius, ones own; receptor, receiver] 1.Internal sense organs that lie within the body cavity andrespond to internal conditions of the organism. 2. Mechanoreceptorsthat detect movements or position of thebody parts; in arthropods, cordotonal organs, campaniformsensilla, and hair plates.propupa n. [L. pro, before; pupa, puppet] (ARTHRO: Insecta)The instar preceding the pupa in Thysanoptera and maleCoccidae; sometimes also called prepupa.propus see propoditeprorhabdion n. [Gr. pro, before; rhabdion, little rod] (NEMATA)

Online Dictionary of Invertebrate Zoology 739The wall of the prostome. see rhabdion.prosartema n. [Gr. pros, forward; artema, earring] (ARTHRO:Crustacea) In Decapoda, a row of dense setae on the innermargin of the basal segment of the antennular peduncle;also called eye brush.proscolex n. [Gr. pro, before; skolex, worm] (PLATY: Cestoda)The anterior part of a divided scolex.prosiphonate lining (PORIF: Calcarea) In recent Sphinctozoa,the lining of the atrial cavity of one chamber growing forwardinto the base of the next-youngest chamber.prosochete n. [Gr. proso, forward; chetos, need] (PORIF) Aninhalant canal that lead to chambers.prosocline a. [Gr. proso, forward; klinein, to slant] 1. (MOLL:Bivalvia) Hinge teeth or shell sloping anteriorly. 2. (MOLL:Gastropoda) Usually referring to growth lines leaning forward(adapically) with respect to the direction of the helicocone.prosocyrt a. [Gr. proso, forward; kyrtos, curved] (MOLL: Gastropoda)Used to describe the growth direction of the helicoconecurving forward.prosodus n.; pl. -i [Gr. prosodos, procession] (PORIF: Desmospongiae)Tiny channels between the inhalant canalsystem and exhalant canals. see aphodus.prosogyrate a. [Gr. proso, forward; gyros, a circle] (MOLL: Bivalvia)Describing beaks anteriorly directed; prosocoelous.prosoma n. [Gr. pro, before; soma, body] 1. (ARTHRO) Theanterior part of the body, usually applied to the cephalothorax.2. (ARTHRO: Chelicerata) Fused imperceptably tothe opisthosoma in Acari. see proterosoma. 3. (ARTHRO:Crustacea) Commonly limited by the major articulation; inbarnacles, large saclike body in position of head in front of,and rostrad to, thoracic appendages; prosome. 4. (ARTHRO:Insecta) The head and the two succeeding fused segmentsof Coccoidea. prosomal a.prosome n. [Gr. pro, before; soma, body] The anterior bodyregion, specifically used in Phoronida.. see prosoma.prosopon n. [Gr. proso, forward; ponos, work] (MOLL: Bival-

740Maggenti and Gardnervia) The name proposed to replace surface ornament orsculpture.prosopore n. [Gr. proso, forward; poros, channel] (PORIF) Anaperture leading to a prosochete.prosopyle n. [Gr. proso, forward; pyle, gate] (PORIF) Theopening of the incurrent canal into the flagellated chamber;sieve area.prostal n.; pl. -ia [L. pro, before; stare, stand] (PORIF) Spiculesthat project from the sponge; marginal prostalia encirclethe osculum; pleural prostalia are on the body surface;basal prostalia form root or anchoring spicules.prostate/prostatic glands 1. (ANN: Oligochaeta) In earthworms,atrial glands of unknown function. 2. (MOLL) Anelaboration of the sperm canal that secretes a prostaticsolution. 3. (NEMATA: Secernentea) A gland emitting an adhesivesecretion at the distal end of the ejaculatory duct. 4.(PLATY: Turbellaria) The spermiducal glands.prosternal furrow (ARTHRO: Insecta) In many Reduviidae andPhymatidae in the Hemiptera, a cross-striated furrow;stridulation is produced by the rugose apex of the rostrumrubbing over it.prosternal process, spine or peg (ARTHRO: Insecta) In ElateridaeColeoptera, a process extending backward into themesosternal cavity.prosternum n. [L. pro, before; sternum, breast bone] (AR-THRO: Insecta) The sternum, or ventral sclerite of the prothorax.prostheca n. [Gr. pros, near; theke, case] (ARTHRO: Insecta)The small movable lobe-like process near the extremity ofthe mandible; the lacinia mobilis.prosthetic group A non-peptide portion of an enzyme (maybe organic or inorganic) that is responsible for the specificbiological action of the protein. see coenzyme, cofactor.prostome, prostom n. [Gr. pro, before; stoma, mouth](NEMATA) The anterior subdivision of the protostome. seemesostome, metastome.prostomial peaks (ANN: Polychaeta) Sclerotized antero-lateral

Online Dictionary of Invertebrate Zoology 741projections of the prostomium.prostomium n. [Gr. pro, before; stoma, mouth] 1. The anteriorpreoral unsegmented portion of a segmented animal'sbody. 2. An acron. 3. (ANN: Oligochaeta) The anterior protuberanceabove the mouth in the first segment; a preorallobe. prostomial a.protaesthesis n. [Gr. protos, first; aisthesis, sense] A primitivesensilla or sense-bud.protamphibion n. [Gr. protos, first; amphibios, double life](ARTHRO: Insecta) The hypothetical common ancestor ofPlecoptera, Ephemeridae and Odonata. see protentomon.protandrous hermaphrodite A hermaphrodite that functionsfirst as male and then transforms into female. see protogynoushermaphrodite.protandry n. [Gr. protos, first; aner, male] 1. Maturation ofthe male gonads, then of the female organs, within a hermaphroditicindividual. 2. Males appear earlier in the seasonthan females. protandrism n. see protogyny.protaspis larva (ARTHRO: Trilobita) Larval period after emergencefrom the egg, covered by a single, dorsal carapaceand consisting of an acron and four postoral segments. seemeraspis larva.protease n. [Gr. proteios, primary; -ase, enzyme] Any proteolyticenzyme.protective coloration/mimicry see cryptic colors, Batesianmimicry, Mullerian mimicry.protective zooid or polyp see dactylozooid, tentaculozooidprotegulal node (BRACHIO) The apical area of the adult shell;site of protegulum and further growth to brephic stage.protegulum n. [L. pro, before; tegulum, roof] (BRACHIO) Theembryonic shell of organic material secreted simultaneouslyby both mantles.proteiform a. [Gr. Proteus, changing god; L. forma, shape]Assuming different forms; variable.proteins n.pl. [Gr. proteion, primary] Complex organic compoundsof carbon, nitrogen, hydrogen, oxygen and often

742Maggenti and Gardnerother elements, yielding amino acids by hydrolysis; essentialin cells of all plants and animals.protelattosis n. [Gr. protos, first; elatton, smaller] (ARTHRO:Chelicerata) In Acari, regression of the first instar, particularlyregarding elattostase and calyptostase.protelean parasite A parasitic organism during larval or juvenilestages and free-living as adult.protentomon n. [Gr. protos, first; entoma, insect] (ARTHRO:Insecta) A hypothetical organism suggested as the ancestralform of winged insects. see protamphibion.proteolytic a. [Gr. proteios, primary; lysis, a loosing] Proteinsplitting.proterandry see protandryproterodehiscence n. [Gr. proteros, before; L. dehiscere, todivide] (ARTHRO: Chelicerata) In Acari, splitting of the oldcuticle in the anterior part of the body during molting.proterogenesis n. [Gr. proteros, before; genesis, origin]Young forms appearing similar to adult forms.proterogyny see protogynyproterosoma n. [Gr. proteros, before; soma, body] (ARTHRO:Chelicerata) In Acari, a combination of the gnathosoma andpropodosoma; pseudotagma.Proterostomia n. [Gr. proteros, before; stoma, mouth] Allphyla in which egg cleavage is of the determinent type; includesall bilateral phyla except chaetognaths, pogonophores,hemichordates and chordates.proterothesis n. [Gr. proteros, before; thesis, an arranging](ARTHRO: Insecta) In Hymenoptera, the laying of eggs bycertain solitary wasps and bees, which first produce femalesand then males.proterotype n. [Gr. proteros, before; typos, type] The originalprimary type, including all the material upon which theoriginal description is based.prothetely n. [Gr. pro, before; theein, to run; telos, completion]1. (ARTHRO) A neotenous adult arthropod having undergoneless than the normal number of molts. seemetathetely, hysterotely. 2. (ARTHRO: Insecta) Resulting

Online Dictionary of Invertebrate Zoology 743in two pairs of fully developed wings in essentially larval(nymphal) or pupal in somatic differentiation.prothoracic bristle (ARTHRO: Insecta) In Diptera, a bristleabove each of the front coxae.prothoracic glands (ARTHRO: Insecta) Specialized endocrineglands of larvae consisting of a pair of diffused glands atthe back of the head, the thorax, or at the base of the labiumproducing the molting hormone (ecdysone); usuallybreakdown after the final molt; thoracic glands; pericardialglands; ecdysial glands; ventral glands.prothoracic shield see cervical shieldprothorax n. [Gr. pro, before; thorax, chest] (ARTHRO: Insecta)The first segment of the thorax, bearing the frontlegs, but no wings; manitruncus; corselet. prothoracic a.protobranchite n. [Gr. protos, first; branchiae, gills] (ARTHRO:Insecta) Respiratory apparatus contained in the rectum ofnymphal Odonata. see branchial basket.protocephalon n. [Gr. protos, first; kephale, head] 1. (AR-THRO: Insecta) The procephalic part of the definitive headduring evolutionary stages. 2. (ARTHRO: Crustacea) see acron.protocerebral bridge, (pons cerebralis) (ARTHRO: Insecta) Amedian mass of neuropile of the protocerebrum, in the dorsaland posterior part of the pars intercerebralis, connectingwith many parts of the brain.protocerebral region (ARTHRO) That part of the primitive arthropodanbrain containing the ocular and other associationcenters.protocerebrum n.; pl. -bra [Gr. protos, first; L. cerebrum,brain] (ARTHRO) The anterior, (in hypognathous insectsdorsal), most complex part of an arthropod brain consistingof three pair of optic centers and other neuropiles functioningin intergrating photoreception, movement andthought to be centers for the initiation of complex behavior;the archicerebrum and prosocerebrum. protocerebrala.protocnemes n. [Gr. protos, first; kneme, wheel spoke] (CNID:Anthozoa) In Zoanthinaria, the original 6 pairs of mesen-

744Maggenti and Gardnertaries.protocoel n. [Gr. protos, first; koilos, hollow] (BRYO) The anteriorsection of the coelomic cavity; in Phylactolaemata,assumed to be the cavity of the epistome.protoconch n. [Gr. protos, first; konche, shell] (MOLL: Gastropoda)The embryonic shell of a univalve, indicated by theapical whorls of the adult shell being clearly demarcatedfrom later ones. see prodissoconch.protocooperation n. [Gr. protos, first; cum, with; operari, towork] Interactions between 2 populations that is favorableto both, but is not obligatory.protocorm n. [Gr. protos, first; kormos, trunk] (ARTHRO: Insecta)A long narrow 'tail' in the developing egg from whichthe trunk segments of insects form; primary trunk region.protocormic a.protodichthadiigyne n. [Gr. protos, first; dichthadios, double;gyne, woman] (ARTHRO: Insecta) In Doryline Hymenoptera,a fertile intermediate between ergatoid and dichthadiigyne.protogastric lobe/area (ARTHRO: Crustacea) In Decapoda, amedian part anterior to the cervical groove and posterior tothe frontal region.protogyne n. [Gr. protos, first; gyne, woman] A female thatresembles the male of the same species; a normal female.see primogyne, deutogyne.protogynous hermaphrodite A hermaphrodite that functionsfirst as a female and then transforms into a male. seeprotandrous hermaphrodite.protogyny, proterogyny n. [Gr. protos, first; gyne, woman]1. A condition of hermaphroditic individuals where the femalesex organs are active before the male; proterogyny.2. Females appearing earlier in the season than males. seeprotandry.protolog, protologue n. [Gr. protos, first; logos, work] Theoriginal description of a scientific name.protoloma n. [Gr. protos, first; loma, fringe] (ARTHRO: Insecta)The anterior margin of the primaries or fore wings.protomesal areolets (ARTHRO: Insecta) In Hymenoptera,

Online Dictionary of Invertebrate Zoology 745areolets between the costal cells and the apical margin ofthe wings.protonephridium n. [Gr. protos, first; nephron, kidney]Nephridium having a flame cell or solenocyte at its proximalend; found in coelomate, pseudocoelomate andacoelomate animals.protonephromixium n. [Gr. protos, first; nephron, kidney;mixis, mingling] A protonephridium that opens into thecoelomoduct. see nephromixium.protonymph n. [Gr. protos, first; nymphe, young woman](ARTHRO: Chelicerata) In Acari, the 1st stase of the nymphalphase; in Mesostigmata, the early, bloodsucking stagein the life cycle.protonymphon larva (ARTHRO: Chelicerata) In Pycnogonida,the 1st stage larva with 3 walking legs, with the mouthanterior to the chelicera.protoplasm n. [Gr. protos, first; plasma, formed or molded]Matter by which the phenomena of life are manifested.protoplasmic a.protoplast n. [Gr. protos, first; plastos, formed] The livingpart (protoplasm) of the cell covered by the cell membrane.protoplax n. [Gr. protos, first; plax, flat plate] (MOLL: Bivalvia)In Pholadidae, simple, nearly flat, dorsal chitinous or calcareousplate anterior to the umbo. see mesoplax, metaplax.protopod n. [Gr. protos, first; pous, foot] (ARTHRO: Crustacea)The part of an appendage, consisting of coxa and basis orprecoxa, coxa, and basis, sometimes fused; protopod(ite);sympod; sympodite.protopod(ite) n. [Gr. protos, first; pous, foot] (ARTHRO) Thebasal stalk of a segmented appendage; sympod or sympodite.see protopod.protopod larva (ARTHRO: Insecta) In some parasitic Hymenopteraand Diptera, the earliest phase with segmentationabsent or indistinct and with rudimentary appendages onlyon the head and thorax. see polypod larva, campodeiformlarva.

746Maggenti and Gardnerprotoscolex n. [Gr. protos, first; skolex, worm] (PLATY:Cestoda) In Taeniidae, a juvenile scolex budded within ahydatid or coenurus metacestode.protosoma, protosome n. [Gr. protos, first; soma, body] 1.(ARTHRO) The prosoma. 2. (POGON) The anterior tentacularregion bearing 1-200 tentacles and including the principalnerve ganglion. see prosome.protospecies n. [Gr. protos, first; L. species, kind] The preexistingtype from which other species evolved.protostasy n. [Gr. protos, first; stasis, standing] (ARTHRO:Chelicerata) In Acari, an orthostasic stage in a life cycle involvingsix stases. see orthostasy.protosternum n. [Gr. protos, first; sternon, chest] (ARTHRO:Chelicerata) In Acari, the sternite of the cheliceral segmentof the prosoma.protostome, protostom n. [Gr. protos, first; stoma, mouth]1. Metazoans with determinate spiral clevage and wherethe mesoderm can be traced to a single cell in the blastula,the mouth originates from the blastopore; includes mollusks,annelids, arthropods, nematodes and certain lesserphyla. see deuterostome. 2. (NEMATA) In rhabditid-likenematodes, the cylindrical midportion of the stoma, delimitedanteriorly by the cheilostome and posteriorly by thetelostome; the protostom may be further subdivided into:prostome, mesostome and metastome.Protostomia n. [Gr. protos, first; stoma, mouth] Formerly themain division between bilateral animals, including the mollusks,annelids, and arthropods.protostracum n. [Gr. protos, first; ostrakion, a shell] (MOLL:Bivalvia) 1. In larval forms, the first formed part of a prodissoconch.2. In oysters, the shell of the D-shaped larvalstage; straight-hinge veliger.protostyle n. [Gr. protos, first; stylos, piller] (MOLL) The stiffmucous rod of early mollusks that transports the foodstring along the esophagus into the stomach; the forerunnerof the crystalline style.prototaxy n. [Gr. protos, first; taxis, arrangement] The arrangementof organs in certain areas that are all consid-

Online Dictionary of Invertebrate Zoology 747ered ancestral.prototergite n. [Gr. protos, first; L. tergum, back] (ARTHRO:Insecta) The anterior dorsal segment of the abdomen.prototheca n. [Gr. protos, first; theke, case] (CNID: Hydrozoa)In corals, the surrounding walls of the calyx.prototrichy n. [Gr. protos, first; thrix, hair] Chaetotaxy inwhich certain areas have only idionymous ancestral setae.prototroch n. [Gr. protos, first; trochos, wheel] The preoralgirdle of cilia (first girdle) characteristic of a trochophorelarva.prototrochophore larva A young trochophore larva with anapical organ, prototrochal girdle and a digestive tract withmouth and anus.prototrochula larva (PLATY: Turbellaria) A free swimminglarva of some Polycladida supposed to be a precursor of thetrochophore larva of other animals.prototype n. [Gr. protos, first; typos, type] The original typespecies; the primitive or ancestral form.protozoea n. [Gr. protos, first; zoe, life] (ARTHRO: Crustacea)The postnaupliar substages in which the antennae andsome of the thoracic exopods are natatory. see zoea.protract v.t. [L. pro, before; tractus, a space drawn out] Toextend forward or outward; to protrude.protractive see prosoclineprotractor muscles 1. A contractile muscle that functions toextend an organ. 2. (NEMATA) Muscles attached to thestylet knobs or base and anteriorly to the body wall or headskeleton. 3. (SIPUN) In adult Xenosiphon and some larvalforms, an extra pair of muscles attached to the introvertnear the brain and to the body wall of the trunk anteriorly.protractor preputii see hood protractorprotriaenes n.pl. [L. pro, before; Gr. triaina, trident] (PORIF)Tetraxons, with three clads directed forward making an angleof less than 45° with the produced axis of the rhabdome.protrusile a. [L. pro, before; trudo, thrust] Capable of being

748Maggenti and Gardnerprotruded or withdrawn.protuberance n. [L. protuberare, to swell] An elevation, knobor prominence above the surface.prouterus see columellaproventricular valvule (ARTHRO: Insecta) In Diptera, a circularfold of the intestinal wall in Tipuloidea.proventriculus n.; pl. -li [L. pro, before; ventriculus, dim. ofventer, belly] An area of the foregut in annelids, insectsand crustaceans just anterior to the midgut, and variouslymodified for grinding or other uses; sometimes called gizzard.proventricular a.provinculum n. [L. pro, before; vinculum, a binding] (MOLL:Bivalvia) A primitive hinge consisting of very small teeththat develop before the permanent teeth are formed.provisional mandibles (ARTHRO: Insecta) In some Coleoptera,parts of the mandible found in the pupa, for escapingthe cocoon; imaginal cephalic cocoon-cutters.proxagalea see subgaleaproximad adv. [L. proximus, nearest; -ad, toward] Toward theend or portion nearest the body.proximal a. [L. proximus, nearest] 1. Toward or nearer theplace of attachment or reference of the center or midline ofthe body. 2. (BRYO) Toward the ancestrula.proximal chiasma A chiasma between an inversion loop andthe centromere.proximal gill wheal (MOLL: Bivalvia) In oysters, a low ridge(wheal) on the inner surface of the valve showing theproximal edge of the gills.proximal hemiseptum (BRYO: Stenolaemata) A hemiseptumprojecting from the proximal zooid wall.proximal sensory area see haptolachusprozona n. [Gr. pro, before; zone, belt] (ARTHRO: Insecta) Theanterior part of the pronotum. see mesozona, metazona.prozonite n. [Gr. pro, before; zone, belt] (ARTHRO: Diplopoda)The anterior portion of a diplosomite, when the tergum isdivided by a transverse groove. see metazonite.

Online Dictionary of Invertebrate Zoology 749pruinescence n. [L. pruinosus, frosty] (ARTHRO: Insecta) A'bloom' covering of whitish or waxy particles. pruinose a.Przibram's rule An empirical law of growth; as the volumeincreases by the cube of a number, the area increases bythe square; 1.26 or 3 √2.psammon n. [Gr. psammos, sand] Freshwater or marine organismsliving between sand grains; mesopsammon.psammous a.psammophilous a. [Gr. psammos, sand; philos, loving] Livingin or growing in sandy areas or sand; arenicolous. psammophilen.psammophore n. [Gr. psammos, sand; phoreus, bearer] (AR-THRO: Insecta) In Formicidae, fringes of long hairs on theposterior surface of the head.pseudanal segment (ARTHRO: Chelicerata) In acariform Acari,segment XIII and one of the paraproctal segments.pseudaposematic/pseudoaposematic color Mimicry of colorationor form of another organism possessing dangerousor disagreeable qualities; Batesian mimicry; allosematiccolor. see sematic.pseudarolium n.; pl. -olia [Gr. pseudos, false; arole, protection](ARTHRO: Insecta) 1. A pad at the apex of the tarsus,similar to an arolium. 2. In Miridae Hemiptera, a more lateralpair of processes present in some subfamilies at thebases of the claws.pseudepipod(ite) n. [Gr. pseudos, false; epi, upon; pous,foot] (ARTHRO: Crustacea) In Cephalocardia, the laterallobe arising from the distal point of the exopod.pseudepisematic color Having mimicry coloration for attractantor aggressive purposes. see episematic, sematic.pseudergate n. [Gr. pseudos, false; ergates, worker] (AR-THRO: Insecta) In Kalotermes Isoptera, a larval form functionallyequivalent to the worker caste in other species, butremains able to develop into other castes.pseudibacus n. [Gr. pseudos, false; bacca or baca, pearl] (AR-THRO: Crustacea) Postlarval stage of decapod Scyllaridae;nisto; puerulus.

750Maggenti and Gardnerpseudoacrorhagi n.pl.; sing. -us [Gr. pseudos, false; acron,top; rhax, berry] (CNID: Anthozoa) In some Actiniaria, hollow,foliose expansions without nematocysts.pseudoalleles n.pl. [Gr. pseudos, false; allelon, one another]Genes at closely adjacent loci that react in the allelism testas they were alleles and between which crossing over israre.pseudocardinal a. [Gr. pseudos, false; L. cardinalis, chief](MOLL: Bivalvia) Pertaining to irregularly shaped teeth closeto the beak.pseudo-annuliform see pseudoannulationpseudoannulation n. [Gr. pseudos, false; L. annulus, ring]Annulation involving cuticle only, does not involve thecoelom.pseudoaposematic colors see pseudaposematic colorspseudobaccus see pseudibacuspseudobranch n. [Gr. pseudos, false; branchia, gills] (MOLL:Gastropoda) In some aquatic Pulmonata, a secondary gillconsisting of folds of the mantle near the pneumostome.pseudobulb n. [Gr. pseudos, false; L. bulbus, bulb] (NEMATA)Muscular swelling of the esophagus lacking a valvular arrangement.pseudocardia see dorsal vesselpseudocephalon see hemicephalouspseudocercus see urogomphuspseudochrysalis see semipupapseudocircle of crochets (ARTHRO: Insecta) Crochets of larvaeconsisting of a well developed mesoseries and a row ofsmall hooks (lateroseries) on the lateral aspect of the proleg.pseudocoel, pseudocele n. [Gr. pseudos, false; koilos, hollow]A body cavity not lined with a mesodermal epithelium.see Aschelminthes, Pseudocoelomata.pseudocoel cells see coelomocytesPseudocoelomata n.; pl. -ates [Gr. pseudos, false; koilos,hollow] A group of phyla having a pseudocoelom, no matter

Online Dictionary of Invertebrate Zoology 751how derived, usually comprising the nematodes, rotifers,nematomorphs, gastrotrics, and kinorhynchs.pseudocoelomic membranes (NEMATA) A delicate sheath investingand supporting the internal organs, i.e., theesophagus, internal surface of muscle cells, and betweeneach pair of muscles to the hypodermis.pseudocoelomocytes see coelomocytespseudocompatability n. [Gr. pseudos, false; L. cum, with;pati, suffer] Fertilization occurring under unusual conditions,that would not normally happen.pseudocone a. [Gr. pseudos, false; konas, cone] (ARTHRO: Insecta)In certain Diptera and Odonata, a condition wherethe cone of the ommatidium is liquid-filled or gelatinousrather than a crystalline cone (eucone condition).pseudocopulation n. [Gr. pseudos, false; L. copula, bond](ARTHRO: Insecta) Pollinization of a flower by copulation ofa male insect mistakenly recognizing it as a female insect.pseudocrop n. [Gr. pseudos, false; A.S. crop, craw] (ARTHRO:Insecta) In Hemiptera, an enlargement of the anterior regionof the mid-gut dilated in a comparable manner as astomodeal crop.pseudocruralium n. [Gr. pseudos, false; crus, leg] (BRACHIO)Dorsal adductor impressions elevated above the valvefloor.pseudoctenodont shell (MOLL: Bivalvia) A shell with manyshort teeth transverse to the hinge margin that are ingroups related to others with some teeth longitudinally directed.see ctenodont shell.pseudoculus n.; pl. -culi [Gr. pseudos, false; L. oculus, eye](ARTHRO: Insecta) In Protura, a circular dome of thin, perforatedcuticle on the head, having 2-6 neurons with ciliarydendritic processes; thought to be a chemoreceptor, anantennal base, or organs of Tomosvary.pseudodeltidium see deltidiumpseudoderm n. [Gr. pseudos, false; derma, skin] (PORIF: Calcarea)In the most complex sponges of the Leucosolenia,the outermost asconoid bodies are fused together to form a

752Maggenti and Gardnerfalse surface.pseudoerucism n. [Gr. pseudos, false; L. eruca, caterpillar](ARTHRO: Insecta) Erucism caused by toxic setae in theadult female. see lepidopterism.pseudofaeces n.pl. [Gr. pseudos, false; L. faex, dregs] (MOLL:Bivalvia) Particulate matter from the gills and/or excessfood formed into masses by mucus for discharge from themantle cavity; particulate matter is not passed through thegut.pseudofertility see pseudocompatabilitypseudofertilization see pseudogamypseudogamy n. [Gr. pseudos, false; gamos, marriage] Apomicticparthenogenesis; development of a female gameteafter stimulation (without fertilization) by a male gamete;also termed pseudofertilization, pseudomixis, and also gynogenesis.pseudogaster n. [Gr. pseudos, false; gaster, belly] (PORIF) Acavity into which true oscula open and from which pseudoosculaopen to the exterior.pseudogastrula see amphiblastulapseudogermes n. [Gr. pseudos, false; germen, bud] (ARTHRO:Insecta) Multicellular fragments of braconid Hymenopteraembryonic membranes found in parasitized Pieris Lepidoptera,that become vacuolated and nuclei break down.pseudogiant fiber see giant fiberpseudogyne n. [Gr. pseudos, false; gyne, woman] (ARTHRO:Insecta) In Hymenoptera, a defective ant, characterized byhaving a female thorax with the stature, gaster and head ofthe worker, thought to result from having parasitic beetlesin their colony.pseudohalteres n.pl. [Gr. pseudos, false; halter, balancer](ARTHRO: Insecta) In Strepsiptera (stylopids), the anteriorwings represented by small club-like processes that functionlike the halteres of Diptera.pseudoheart n. [Gr. pseudos, false; A.S. heorte, heart] 1.(ANN) see commissural vessels. 2. (ECHINOD) The axialgland.

Online Dictionary of Invertebrate Zoology 753pseudointerarea n. [Gr. pseudos, false; inter, between; area,space] (BRACHIO:Inarticulata) Flattened posterior part ofthe shell, secreted by posterior part of the mantle, notfused with opposite valve.pseudolabia n. [Gr. pseudos, false; L. labium, lip] (NEMATA) InSpirurida, cuticular outgrowths arising around the oralopening.pseudolateral a. [Gr. pseudos, false; L. latus, side] (MOLL)The false lateral teeth; lateral tooth close to the beak.pseudolips see pseudolabiapseudomanubrium n. [Gr. pseudos, false; L. manubrium,handle] (CNID: Hydrozoa) A long subumbrellar extensioncontaining the radial canals.pseudometamerism n. [Gr. pseudos, false; meta, after;meros, part] 1. False segmentation. 2. (PLATY: Cestoda)Serial segmentation appearing like metamerism.pseudomixis see pseudogamypseudomonocyclic a. [Gr. pseudos, false; monos, one; kyklos,circle] (ECHINOD: Crinoidea) The presence in young andabsence in adults of the infrabasal plates; cryptodicyclic.pseudomyiasis n. [Gr. pseudos, false; myia, fly] Presencewithin a host of the larva of a Diptera not normally parasitic.pseudonchs n.pl. [Gr. pseudos, false; onkos, hook] (NEMATA)Structures in the pharynx that appear to resemble onchia.pseudonest n. [Gr. pseudos, false; A.S. nest] (ARTHRO: Insecta)In Bombidae, an accumulation of nest building materialsfound near the entrance to the nest that at timesshelter workers.Pseudoneuroptera n. [Gr. pseudos, false; neuron, nerve;pteron, wing] (ARTHRO: Insecta) Formerly, net-winged insectswith incomplete metamorphosis (Ephemeridae, Odonata,Plecoptera, Isoptera and Corrodentia); Archiptera.pseudonocytoid see oenocytoidpseudonotum see postscutellumpseudonuclei n.pl. [Gr. pseudos, false; L. nucleus, kernal]

754Maggenti and Gardner(ARTHRO: Insecta) During development, nodules of uric acidthat appear in the fat cells.pseudonychia n.pl.; sing. -ium [Gr. pseudos, false; onyx,claw] (ARTHRO: Insecta) In Collembola, a basal tooth-likeformation on the pretarsus.pseudonymph, semipupa see prepupapseudo-osculum n.; pl. -ula [Gr. pseudos, false; L. osculum,small mouth] (PORIF) The exterior opening of the pseudogaster;a pseudostoma.pseudopallium n. [Gr. pseudos, false; L. pallium, mantle](MOLL: Gastropoda) In some parasites of Echinoderms, aring-like fold of the anterior part of the snail growing overthe visceral mass and serving as a brood chamber.pseudopenis n. [Gr. pseudos, false; L. penis, male copulatoryorgan] (ANN: Oligochaeta) The eversible area of the bodywall or atrium tip.pseudoperculum n. [Gr. pseudos, false; L. operculum, lid](ARTHRO: Insecta) On the eggs of Heteroptera, an independentlyevolved cap-like structure.pseudopillar n. [Gr. pseudos, false; L. pila, pillar] (MOLL: Bivalvia)Low, broad inward projection of the shell wall.pseudoplacenta n.; pl. -tae [Gr. pseudos, false; L. placenta,cake] (ARTHRO: Insecta) Embryonic or maternal structuresof certain female viviparous insects that are presumed togive nourishment to the developing larvae; however, thephysiological evidence of the importance of this structure isuncertain.pseudoplacental viviparity (ARTHRO: Insecta) Referring toinsects that produce eggs, containing little or no yolk, thatare retained by the female in the ovariole up to the time ofhatching. see pseudoplacenta.pseudopod, pseudopodium n.; pl. -dia [Gr. pseudos, false;pous, foot] 1. Temporary protrusion of the cell, associatedwith flowing movement of protoplasm, functioning in locomotionand feeding. 2. (ARTHRO: Insecta) An outgrowth orfoot-like appendage of the larval body, assisting in locomotion.see parapodium.

Online Dictionary of Invertebrate Zoology 755pseudopolyploidy n. [Gr. pseudos, false; poly, many; aploos,onefold] Chromosome sets in groups of related specieshaving numerical relationship leading to erroneous interpretationas polyploids.pseudopore n. [Gr. pseudos, false; poros, passage] 1. (BRYO:Stenolaemata) In Cyclostomata, a pore in the calcified wallof a zooid that is obstructed by organic matter. 2. (PORIF:Calcarea) In Leucosolenia, a large opening through thepseudoderm.Pseudoptera n. [Gr. pseudos, false; pteron, wing] (ARTHRO:Insecta) Formerly an ordinal name for scale insects.pseudopuncta n.; pl. -ae [Gr. pseudos, false; L. punctum,small hole or spot] (BRACHIO) A type of shell punctationthat points inwardly, appearing on the internal surface as abump. pseudopunctate a. see endopuncta.pseudopupa n. [Gr. pseudos, false; L. pupa, puppet] (ARTHRO:Insecta) In Coleoptera and Meloidae, a larva in a quiescentpupa-like condition preceding one or more larval instarsbefore the true pupal stage; a coarctate larva; a semipupa.pseudopupillae n.pl.; sing. -a [Gr. pseudos, false; L. pupilla,dim. pupa, puppet] (ARTHRO: Insecta) In Odonata, blackspots on the compound eyes of live specimens.pseudorhabdite n. [Gr. pseudos, false; rhabdos, rod] (PLATY:Turbellaria) An amorphous mass of slimy material in theepidermal cells; possibly related to rhabdites.pseudorostrum n. [Gr. pseudos, false; L. rostrum, bill] (AR-THRO: Crustacea) In Malacostraca Cumacea, paired forwardprojecting plates on the anterior carapace.pseudosclerite n. [Gr. pseudos, false; skleros, hard] (ARTHRO:Chelicerata) In Acari, sclerotized area of the cuticle differingdistinctly from the soft cuticle.pseudoscolex n. [Gr. pseudos, false; skolex, worm] (PLATY:Cestoda) Distortion of the anterior proglottids into a holdfastwhere the true scolex is lost in early development; thedeutoscolex.pseudosegments n. [Gr. pseudos, false; L. segmentum,piece] (PLATY: Cestoda) The discreet, flattened sectionsmaking up the major part of the body; each being a repro-

756Maggenti and Gardnerductive packet; a proglottid.pseudoselenizone n. [Gr. pseudos, false; selene, the moon;zone, girdle] (MOLL: Gastropoda) A band of crescenticgrowth lines on the shell surface resembling a selenizone,but not identifiable as caused by a notch or slit in the aperture.pseudosematic see sematicpseudoserosa n. [Gr. pseudos, false; L. serum, whey] In embryology,membrane formed during splitting of the blastodermin the morula stage.pseudosessile a. [Gr. pseudos, false; sessum, sitting] (AR-THRO: Insecta) In Hymenoptera, appearing sessile due tohaving the abdomen usually basally constricted and its firstsegment fused with the metathorax.pseudosiphon n. [Gr. pseudos, false; siphon, tube] (MOLL: Bivalvia)In oysters, two opposing mantle edges that form ahole which is not functional.pseudospherule n. [Gr. pseudos, false; dim. sphaira, ball](CNID: Anthozoa) In Actinaria, a vesicle at the margin, oftenwith an aperture containing basitrichous isorhiza.pseudospondylium n. [Gr. pseudos, false; spondylos, joint](BRACHIO) A cup-shaped chamber accommodating theventral muscle field, contained between dental plates.pseudosternite see epiphalluspseudostigmatic organ (ARTHRO: Chelicerata) In Acari, oneof two organs of sensory setae, various in shape, arisingfrom a cupule or pit located on the cephalothorax ofOribatida; thought to detect air movements and thus avoiddesiccation.pseudostoma n. [Gr. pseudos, false; stoma, mouth] A mouthlikeopening.pseudosymmetry n. [Gr. pseudos, false; symmetria, due proportion]Approximate symmetry of a structure divided by aplane that divides the structure into halves that are lessthan symmetrical.pseudosymphile n. [Gr. pseudos, false; syn-, together;philein, to love] (ARTHRO: Insecta) In social insects, a

Online Dictionary of Invertebrate Zoology 757predator or parasite gaining nourishment from the trophallacticsecretions of the host larvae.pseudotagma n. [Gr. pseudos, false; tagma, a division] (AR-THRO: Chelicerata) In Acari, a region of a body division,such as gnathosoma, idiosoma, proterosoma and hysterosoma.pseudotaxodont a. [Gr. pseudos, false; taxis, arrangement;odon, tooth] (MOLL: Bivalvia) With numerous irregular shortteeth transverse to the hinge, but are not related to ctenodontor pseudoctenodont forms.pseudotela n.; pl. -ae [Gr. pseudos, false; tela, end](BRACHIO) One of a pair of external projections of the shellnear the pedicle (not beak ridges).pseudotetramerous a. [Gr. pseudos, false; tetra, four;meros, part] Appearing as having 4 joints, where there areactually 5.pseudotrachea n. [Gr. pseudos, false; tracheia, windpipe] 1.A trachea-like structure. 2. (ARTHRO: Crustacea) In terrestrialIsopoda, a respiratory structure developed in the pleopodsfor air-breathing. 3. (ARTHRO: Insecta) In Diptera,small, specialized channels of the labellum that open to theexterior of the oral lobes and pass liquid food to the foodcanal.pseudotrimerous a. [Gr. pseudos, false; treis, three; meros,part] Appearing as 3 jointed, when actually having 4 jointsor segments.pseudotroch n. [Gr. pseudos, false; trochos, wheel] (ROTIF)An enlarged arc of stiff cirri in the supra-oral region of thebuccal field.pseudovarium n. [Gr. pseudos, false; L. ovarium, ovary] Anovary producing pseudova. see pseudovum.pseudovelum n. [Gr. pseudos, false; L. velum, veil] (CNID:Scyphozoa) A narrow shelf-like flange with no musculesand nerves projecting inward from the margin of the bell.pseudovesicles n. [Gr. pseudos, false; L. vesicula, little bladder)(ANN: Oligochaeta) Structures, serially homologouswith seminal vesicles, on the posterior faces of 12/13 or13/14.

758Maggenti and Gardnerpseudovitellus see mycetomepseudovum n.; pl. -ova [Gr. pseudos, false; L. ovum, egg] Anunfertilized egg that can undergo development.pseudozoea n. [Gr. pseudos, false; zoe, life] (ARTHRO: Crustacea)In Hoplocarida, a larval form of carnivorous mantidshrimp with segmented abdomen bearing biramous appendagesand 2 pairs of appendages on the thorax (thesecond pair specialized as raptorial limbs); used to includethe erichthus and alima stages of Stomatopoda larvae ortheir early stages. see antizoea.pseudumbilicus n. [Gr. pseudos, false; L. umbilicus, navel](MOLL: Gastropoda) A depression or cavity in the shell baseonly in the last whorl; a false umbilicus.ptenoglossate a. [Gr. ptenos, feathered; glossa, tongue](MOLL: Gastropoda) Referring to a broad radula, lacking acentral tooth, having numerous, arcuate, sharp, similarlyshaped teeth in oblique rows, and increasing in size laterally.pteralia n.pl. [Gr. pteron, wing] (ARTHRO: Insecta) The wingflexingsclerites of the wing base; axillaries.pterate see alatepterergate n. [Gr. pteron, wing; ergates, worker] (ARTHRO:Insecta) In Hymenoptera, a worker or soldier ant with vestigialwings.pteridine n. [Gr. pteron, wing; eidos, like] Tetrazanaphthalinederivatives, widespread in nature; important in naturalpigmentation.pterine (pteridine) pigments A group of nitrogen-containingcompounds producing leucopterin (white), xanthopterin(yellow) the most widely distributed, isoxanthopterin (purpleflorescence) and biopterin (blue floresence); pigmentsimportant in the natural pigmentation of many invertebrates,as well as plants.pternotorma n.; pl. -mae [Gr. pterna, heel; torma, socket](ARTHRO: Insecta) In scarabaeoid larvae, a stoutly curvedprocess at the end of the laeotorma and occasionally of thedexotorma.

Online Dictionary of Invertebrate Zoology 759pterocardiac a. [Gr. pteron, wing; kardia, heart] (ARTHRO:Crustacea) In Decapoda, a gastric mill ossicle in the form ofa curved triangular plate articulating with the mesocardiacossicle along the broad base, with the bent apex connectedto the anterior process of the zygocardiac ossicle; in a fewspecies these ossicles are slightly elongated and straight.pterodinergate n. [Gr. pteron, wing; deinos, terrible; ergate,worker] (ARTHRO: Insecta) In Hymenoptera, a member ofthe soldier caste with vestigial wings.pteropleural bristles (ARTHRO: Insecta) In Diptera, bristles onthe pteropleuron.pteropleurites see mesepimeronpteropleuron n.; pl. pteropleura [Gr. pteron, wing; pleuron,side] (ARTHRO: Insecta) In Diptera, a sclerite on the side ofthe thorax, below the base of the wing; the upper part ofthe mesepimeron.pteropods n.pl. [Gr. pteron, wing; pous, foot] (MOLL: Gastropoda)Two orders of small swimming, pelagic Opisthobranchia,the shelled Thecosomata, and the naked Gymnosomatalacking a shell.pterostigma n.; pl. -mata [Gr. pteron, wing; stigma, mark](ARTHRO: Insecta) A thickened opaque spot along the costalmargin of the wing tip of several orders; stigma; bathmis.pterote see alatepterothecae n.pl. [Gr. pteron, wing; theke, case] (ARTHRO:Insecta) In larvae of Diptera, adhering sheaths of thewings.pterothorax n. [Gr. pteron, wing; thorax, chest] (ARTHRO: Insecta)Collectively, the meso- and metathoracic segmentsof certain wing-bearing insects; synthorax. pterothoracica.pterygium n.; pl. -gia [Gr. dim. pteryx, little wing] (ARTHRO:Insecta) 1. The small lobes at the base of the underwings.2. In Coleoptera, the lateral process of the snout.pterygobranchiate a. [Gr. pteryx, wing; branchia, gills] (AR-THRO: Crustacea) Having spreading, feathery gills.pterygoda see patagia

760Maggenti and Gardnerpterygogenea n.pl. [Gr. pteryx, wing; genos, race] (ARTHRO:Insecta) 1. Winged adult insects. 2. Descended fromwinged ancestors. see apterygogenea.pterygoid a. [Gr. pteryx, wing; eidos, like] Wing-like.pterygopolymorphism n. [Gr. pteryx, wing; polys, many;morphos, shape] (ARTHRO: Insecta) Occurrence of differentforms of wings in the same species.pterygostomial region (ARTHRO: Crustacea) In Decapoda, theanterolateral part on the ventral surface of the carapace,on opposite sides of the buccal cavity; jugal region; pterygostome.pterygostomial spine (ARTHRO: Crustacea) In Decapoda, aspine on the anterolateral angle.Pterygota, pterygotes n.; n.pl. [Gr. pterygotos, winged] (AR-THRO: Insecta) A subclass containing the winged and secondarilyapterous insects, with varied metamorphosis, andhave no pregenital abdominal appendages. see Exopterygota,Endopterygota.ptilinal suture (ARTHRO: Insecta) In Diptera, a crescentshapedgroove, situated on the lower part of the frons betweenthe bases of the antennae and the eyes, which usuallyextends ventrally into the facial area; frontal suture.ptilinum n.; pl. ptilina [Gr. ptilon, feather] 1. (ARTHRO: Insecta)In Diptera, a temporary bladderlike structure of apupa that can be inflated and thrust out through the frontal(ptilinal) suture, just above the bases of the antennae, thatpushes off the operculum of the puparium. 2. (NEMATA)Sometimes inappropriately used to describe horn-like orleaf-like ornamentation on the anterior extremity of parasiticforms.ptilota n. [Gr. ptilon, feather] (ARTHRO: Insecta) Winged insects.ptychoidy n. [Gr. ptyche, fold] (ARTHRO: Chelicerata) InOribatida, an articulation between the prosoma and opisthosoma,allowing the legs to be concealed by down foldingof the prosoma.ptycholophous a. [Gr. ptyche, fold; lophos, crest] (BRACHIO)A lophophore with brachia folded into one or more lobes in

Online Dictionary of Invertebrate Zoology 761addition to a median indentation. ptycholophus n.pubescence n. [L. pubescere, to grow hairy] A covering of finesoft hairs. pubescent a.pubic a. [L. pubes, adult] Referring to the area of the genitalia.pubic process (ARTHRO: Insecta) In Scarabaeoidea, fused pubicplates above the second valvifers (fused second valvulae).puce n. [L. pulex, flea] Dark brown or purplish brown.pudendum n. [L. pudenda, external genitals] External femalegenitalia; the vulva.puerulus n. [L. puerilis, childish] (ARTHRO: Crustacea) 1.Preadult stage of Decapoda Scyllaridae; nisto, pseudibacus.2. Preadult stage of Decapoda Palinuroidea.puffs n. [ME. puf] (ARTHRO: Insecta) In Diptera, a process inwhich the bands (chromomeres) of the chromosomes ofthe salivary glands undergo puffing which is usually correlatedwith the production of exportable proteins in theglandular cells; thought to reflect gene activity.pulmonarium n.; pl. -ria (ARTHRO: Insecta) A type of abdomenwith membranous connections between the scleritesof the terga and pleura of the abdominal rings.pulmonary a. [L. pulmo, lung] Pertaining to the lungs.pulmonary cavity/sac (MOLL: Gastropoda) In Pulmonata, apallial cavity formed by transverse vascularizations of theinterior dorsal wall.pulsatile vesicles (ANN: Hirudinoidea) Eleven small hemisphericalpulsing structures filled with coelomic fluid.pulsating vesicle (ROTIF) Small bladder-like excretory organinto which the flame bulb system empties.pulverulent a. [L. pulvereus, full of dust] Powdery; dusty;farinaceous.pulvilliform a. [L. pulvillus, little cushion] (ARTHRO: Insecta)Appearing lobelike or padlike; shaped like a pulvillus.pulvillus n.; pl. -li [L. pulvillus, little cushion] (ARTHRO: Insecta)In Diptera, the pad of the membranous lobe beneaththe tarsal claw, arising from the base of each auxilia. see

762Maggenti and Gardnerempodium.pulvinate a. [L. pulvinus, cushion] 1. Moderately convex orswelled. 2. Cushion-like.pulvinulus see aroliumpumping pharyngeal tube see food meatuspunctae n.pl.; sing. puncta [L. punctum, small hole or spot]Small pores, holes, or dots on a surface.punctate a. [L. punctum, small hole or spot] Covered withsmall pores, holes, or dots.punctulate a. [L. punctum, small hole or spot] Dotted withminute impressions.punctum n. [L. punctum, small hole or spot] A small pit orspot on a surface.puncture n. [L. punctura, hole] A small hole; a minute puncture-likedepression.pupa n.; pl. pupae [L. pupa, puppet] (ARTHRO: Insecta) Theusually quiescent stage between the larva and adult incomplete metamorphosis.pupa adectica (ARTHRO: Insecta) A pupa without articulatedmandibles for use by a pharate adult. see pupa dectica,pupa exarate, pupa obtect.pupa adheraena (ARTHRO: Insecta) A pupa which hangs headdown in a perpendicular manner.pupa angularis (ARTHRO: Insecta) A pupa bearing a pyramidalprocess or nose on its dorsal surface.pupa-chromogenic phase (ARTHRO: Insecta) The last pupalphase before the adult, in which pigmentation occurs.pupa-chromoptic phase (ARTHRO: Insecta) The pupal phase(after telemorphic) when pigmentation of the compoundeyes begin.pupa coarctate (ARTHRO: Insecta) Puparium or last larval skinenclosing the exarate pupa; found in many Diptera.pupa conica (ARTHRO: Insecta) A conical, nongular pupa.pupa custodiata (ARTHRO: Insecta) A pupa in a partially opencocoon.

Online Dictionary of Invertebrate Zoology 763pupa dectica (ARTHRO: Insecta) A pupa with articulated mandiblesthat can be used by the pharate adult. see pupaadectica.pupa dermata (ARTHRO: Insecta) A pupa retaining the larvalskin without indication of future limb placement.pupa exarate (ARTHRO: Insecta) An adecticous pupa in whichthe appendages are free and not cemented to the bodywall; pupa exarata. see pupa obtect.pupa folliculata (ARTHRO: Insecta) A pupa enclosed in a thecaor cocoon.pupa incompletae (ARTHRO: Insecta) A Lepidoptera pupa withmore than three movable abdominal segments.pupal-adult apolysis (ARTHRO: Insecta) In Diptera, the interimbetween phanerocephalic pupa and pharate adult.pupa larvata (ARTHRO: Insecta) A pupa in which the formingadult appendages are apparent on the surface of the thecaor cocoon; a masked pupa.pupa libera (ARTHRO: Insecta) A Lepidoptera pupa with manyfree segments.pupal respiratory horn see respiratory hornpupa nuda (ARTHRO: Insecta) An insect pupa free from attachment.pupa obtect (ARTHRO: Insecta) An adecticous pupa in whichthe appendages are more or less strongly cemented to thebody, assumed by tanning of protein in the molting fluid;pupa obtecta.pupariation n. [L. pupa, puppet] (ARTHRO: Insecta) In certainfamilies of Diptera, formation of a puparium by a thirdstage, nonfeeding larva; a post-feeding larva.puparium n. [L. pupa, puppet] (ARTHRO: Insecta) 1. In certainfamilies of Diptera, a case formed by the hardening of thenext to the last larval skin, in which the pupa is formed;pupa coarctate. 2. Sometimes used in a few parasitic Hymenopteraand Coleoptera for the cast exuviae held at theposterior end of the larval body. 3. In Diaspidine scales,used for the scale of mixed exuviae and wax or for the femaleenclosed in the unruptured cuticle of the last larval

764Maggenti and Gardnerstage. see pupillarium.pupa subterranean (ARTHRO: Insecta) A pupa submerged intothe soil during transformation; pupa subterranea.pupate v. [L. pupa, puppet] The transformation to a pupa.pupiferous a. [L. pupa, puppet; fero, bear] (ARTHRO: Insecta)In Hemiptera, the generation of aphids that produce sexedindividuals.pupiform a. [L. pupa, puppet; forma, shape] Cylindrical, withrounded ends; cocoon-shaped; a pupiform shell.pupigerous see pupa coarctatepupil n. [L. pupilla, pupil of eye] (ARTHRO: Insecta) The centralspot of an ocellus.pupillarium n. [L. dim. pupa, puppet] (ARTHRO: Insecta) InDiaspididae, the adult female shrinks inside the exuviae ofthe second larval stage and lives and lays eggs inside. pupillariala.pupillate a. [L. pupilla, pupil of eye] Having an eye-like center;a spot or mark.pupipara n. [L. pupa, puppet; parere, to beget] (ARTHRO: Insecta)In Diptera, a convenience group in which wings arereduced, direct reproduction of puparia, with developmenttaking place within the mother. see nymphipara.pupiparous a. [L. pupa, puppet; parere, to beget] (ARTHRO:Insecta) Bearing larva that are full grown and ready to pupate.pupoid a. [L. pupa, puppet; Gr. eidos, form] 1. Pupiform. 2.(ARTHRO: Diplopoda) The final embryo at hatching, withoutlegs or segmentation visible.pure line population Descendants through self-fertilization ofa single homozygous parent or highly inbred line of animalsobtained by long continued inbreeding.purine bases Nitrogen-containing organic cyclic bases thatpair with pyrimidine bases in DNA and RNA replication.purpuraceous a. [L. purpura, purple] Being purple in color.pustula, pustule n.; pl. -lae [L. pustula, blister] 1. An elevationresembling a pimple, blister or wartlike projection;

Online Dictionary of Invertebrate Zoology 765smaller than a tubercle. 2. (BRYO) A small regular skeletalstructure of crinkled laminae.putative a. [L. putare, to think] Commonly regarded as such;reputed to be; supposed.pycnosis n. [Gr. pyknos, dense] Degeneration of a cell nucleuscharacterized by condensation and an increased affinity forstain. pycnotic a.pygal a. [Gr. pyge, rump] Situated back, or pertaining to theposterior end of the back. pygidial a.pygidial fringe (ARTHRO: Insecta) In homopteran Coccoidea,the projecting ends of the lateral margin of the pygidium;the lateris.pygidial glands (ARTHRO: Insecta) 1. In Coleoptera, pairedorgans opening beneath the last abdominal tergite thatfunction to secrete a corrosive, pungent defense fluid, or asubstance that lowers surface tension of the water to increasepropulsion; also called anal glands. 2. In Hymenoptera,associated with the membrane between abdominalterga 6 and 7 of Formicidae, and when enlarged, produce adefensive secretion; also called anal glands. see post-pygidialgland.pygidial incision see anal cleftpygidial plate (ARTHRO: Insecta) In Hymenoptera, a flat platesurrounded by a carina or line, sometimes an apical projectionon the 6th gastral tergite in females and 7th inmales.pygidial setae see anal setaepygidium n.; pl. -dia [Gr. pygidion, narrow rump] 1. (ANN)The telotroch and anal region behind it, bearing cirri. 2.(ARTHRO: Insecta) The last dorsal segment of the body.pygal, pygidial a.pygofer n. [Gr. pyge, rump; L. fero, carry] (ARTHRO: Insecta)In Homoptera, the last abdomenal segment bearing lateralmargins.pygomere n. [Gr. pyge, rump; meros, part] (ANN: Oligochaeta)The terminal part of the body; sometimes calledanal segment, although some of the characters of a

766Maggenti and Gardnermetamere are missing.pygophore n. [Gr. pyge, rump; phoreus, bearer] (ARTHRO: Insecta)1. The pygofer. 2. In male Heteroptera, the 9th abdominalsegment. 3. In male Homoptera, the posterolateralextension of the 9th abdominal segment.pygopid loop (BRACHIO) A short ringlike loop with slightlyarched cross band.pygopods n. [Gr. pyge, rump; pous, foot] (ARTHRO: Insecta)The paired appendages of the 10th abdominal segment.pygostyle n. [Gr. pyge, rump; stylos, pillar] (ARTHRO: Insecta)In Hymenoptera, small lateral setigerous processes on the9th gastral tergite.pyllopod n. [Gr. pyle, gate; pous, foot] (ARTHRO: Crustacea) Ingnathiidean Isopoda, the second thoracopod; fused to thehead resulting in the appendages being second maxillipedesand in males are flat and cover the buccal area, butin females, a short palp with a large flat plate attached.pyloric valve 1. (ARTHRO: Insecta) A regulatory (sphincter) atthe entrance to the intestine from the stomach; usually locatedbehind the stomach in the anterior part of the proctodeum.2. (ARTHRO: Crustacea) see cardiac pyloricvalve.pylorus n. [Gr. pyloros, gatekeeper] 1. (ARTHRO: Insecta) Ashort distinct section of the proctodeum intervening betweenthe ventriculus and true intestinal tube, containingthe pyloric valve. 2. (BRYO) Ciliated part of the digestivetract into which the stomach part of the cardia empties.pyloric a.pyraform glands (ACANTHO) Glands in the tail of some males;function unknown.pyraform organ see esophageal bulbpyramid n. [Gr. pyramis, pyramid] 1. Any conical or triangularstructure. 2. (ECHINOD: Echinoidea) The five large calcareousscraping plates that compose the Aristotle's lantern.pyramidal a.pyramid of biomass Weight relationships between the trophiclevels in a food chain.

Online Dictionary of Invertebrate Zoology 767pyramid of energy Energy relationships between the trophiclevels in a food chain.pyramid of numbers Numbers of individuals at the differenttrophic levels in a food chain.pyriform a. [L. pyrum, a pear; forma, shape] Having theshape of a pear; round and large at one end, generally taperingto the other.pyriform vesicle see Muller's organ

QQ technique The analysis of association of pairs of taxa in adata matrix.quacking a. [D. kwakken] (ARTHRO: Insecta) In Hymenoptera,sound made by new queens in the cells in response to"piping".quadrangle n. [L. quadrus, fourfold; angulus, angle] 1. Anyfigure having 4 angles. 2. (ARTHRO: Insecta) In odonatanZygoptera, a cell beyond the arculus. quadrangular a.quadrat n. [L. quadratus, squared] A sample area of land forbiotic study, usually 1 square meter.quadrate a. [L. quadratus, squared] Having 4 sides in outline.quadrate plates (ARTHRO: Insecta) In Hymenoptera, the reduced9th abdominal tergite.quadricapsular a. [L. quadrus, fourfold; capsula, little box]Having 4 capsules.quadricolumella see columellaquadridentate a. [L. quadrus, fourfold; dentatus, tooth] Having4 teeth or tooth-like processes.quadrifid a. [L. quadrus, fourfold] Four rows; in 4 segment.quadrilateral a. [L. quadrus, fourfold; latus, side] 1. Formedor bounded by 4 sides; 4 lines. 2. (ARTHRO: Insecta) In zygopterousOdonata, the discal wing cell.quadrimaculate a. [L. quadrus, fourfold; macula, spot] Having4 spots.quadripartite a. [L. quadrus, fourfold; partitus, divided] In 4parts.quadripinnate a. [L. quadrus, fourfold; penna, feather] Having4 feather-like branches or clefts.quadriprostatic a. [L. quadrus, fourfold; Gr. prostates, onewho stands first] (ANN) Having 4 prostates.quadriradiate a. [L. quadrus, fourfold; radius, ray] (PORIF)

Online Dictionary of Invertebrate Zoology 769Having 4 rays; tetraxon, tetractine.quadrithecal a. [L. quadrus, fourfold; Gr. theke, case] (ANN)Having 4 spermathecae.quadrivalve a. [L. quadrus, fourfold; valva, fold] 4-valved.quartet see tetradquasisocial a. [L. quasi, as if; socius, companion] (ARTHRO:Insecta) In Hymenoptera, females of the same generationforming a colony and cooperating in brood care.queen n. [A.S. cwen, wife] (ARTHRO: Insecta) 1. A femalemember of the reproductive caste in semisocial and eusocialinsects; may or may not differ morphologically fromthe workers. 2. In Formicidae, a fully developed reproductivefemale characterized by a generalized hymenopterousthorax and functional but deciduous wings; sometimes referredto as 'the female' of the colony.queen control (ARTHRO: Insecta) In social Hymenoptera, inhibitoryinfluence of the queen on the reproductive activitiesof workers and other queens.queen substance (ARTHRO: Insecta) In Hymenoptera, pheromonesreleased by the queen honeybee that attracts andcontrols the reproductive activities of workers and otherqueens; Trans-9-Keto-2-decanoic acid is the most potentcomponent of the pheromone mixture.Quenstedt muscles (MOLL: Bivalvia) Paired, small musclesanterior to the ctenidial elevator muscles of oysters.quick muscle see phasic musclequiescence n. [L. quiescere, to become quiet] A condition oftemporary cessation of development, or other activity,during which the animal requires little nourishment, butshows exterior signs of life; directly referable to environmentalconditions.quiescent a. [L. quiescere, to become quiet] 1. To becomequiet. 2. (ARTHRO: Insecta) Applied to biological inactivityor prepupae and pupae with complete metamorphosis.quincunx n.; pl. -xes [L. quincunx, arranged in diagonal rows,five-twelfths] 1. An arrangement of five things in a square,having one in each corner and one in the center. 2. (ANN)

770Maggenti and GardnerSetaceous pattern. 3. (BRYO) Arrangement pattern of zooids.quincuncial a.quinone biochrome (ARTHRO: Insecta) Quinone pigments:anthraquinones formed from the condensation of threebenzene rings, and aphins, with a nucleus of seven condensedbenzene rings. see cochineal.quinones n.pl. [Ab.Am. quinine, bark of barks] 1. Variouscompounds formed from benzene and functioning in biologicaloxidation-reduction systems. 2. A hydrogen acceptorutilized in physiological experimentation.quinquedentate a. [L. quinque, five; dens, tooth] Having 5teeth.quinquefarious a. [L. quinque, five; farius, fold] Arranged infive rows, ranks, or columns.quinquelocular a. [L. quinque, five; loculus, cell] Consisting of5 cells, or 5 loculi.

Rrace n. [F. race; member of the same stock or lineage] Apopulation or aggregate of populations inhabiting a definedgeographical and/or ecological region possessing characteristicphenotypic and gene frequencies or features ofchromosome structures that distinguish it from other suchgroups.racemose a. [L. racemus, bunch] Bunch, as perhaps of grapes.racemose glands (SIPUN) Glandular structures on each side ofthe rectum; function unknown; buschelformigen Korper.rachidian, rhacidian a. [Gr. rhachis, backbone] (MOLL) Themedian or central tooth on the radula; the rachidian tooth.rachiform a. [Gr. rhachis, backbone; L. forma, shape] Shapedlike a rachis.rachiglossate, rhachiglossate a. [Gr. rhachis, backbone;glossa, tongue] (Moll) A radula with three longitudinal rowsof teeth: one median (may be simple or have severalcusps) and two lateral (rake-like with many cusps).rachis n.; pl. rachides, rachises [Gr. rhachis, backbone] 1.Any of various axial structures. 2. (NEMATA) The central oraxial chord in the ovary around which multiple rows ofgerminal cells are laid down.radial a. [L. radial, ray] 1. Extending from a center toward theperiphery like rays. 2. Pertaining to a radius.radial n. [L. radial, ray] (ECHINOD) 1. In Crinoidea, any proximal,undivided plate or ray bearing an anal plate. 2. InAsteroidea, a prominent ossicle on the surface in line withthe mid-line of the arm; part of the primary surface. 3. InEchinoidea, the ambulacrum.radial apophysis (ARTHRO: Chelicerata) In Arachnida, a copulatoryorgan on the male palp.radial canal (CNID: Scyphozoa) A canal in the mesoglea of amedusa running from the center to the edge, or at least inpart.

772Maggenti and Gardnerradial cell (ARTHRO: Insecta) A cell bordered anteriorly by abranch of the radial vein.radial gashes (MOLL: Bivalvia) Radial, sharp-edged cuts foundon the upper valve of Gryphaeidae.radial growth (MOLL: Bivalvia) Growth direction outward fromthe beak to the shell edge; marked by the costa or otherornamentation.radial lirae see carapace costaeradial masses (NEMATA: Adenophorea) In Enoplida, structuresconnecting the mandibular ring to the radial processes.radial-medial cross vein (ARTHRO: Insecta) A wing cross veinbetween the lower first fork of the radial sector and the upperfirst fork of the medial vein.radial muscles (NEMATA) The radial musculature of thenematode esophagus.radial plates (ECHINOD: Crinoidea) Tegmental armature in theform of calyx plates in primative stalked crinoids, oral tothe basal plates.radial processes (NEMATA: Adenophorea) In Enoplida, supportingstructures of the onchial plate.radial ribs (MOLL: Bivalvia) Ribs or bands of color meeting in apoint at the umbones and diverging toward the ventralmargin.radial sector (ARTHRO: Insecta) The posterior wing branch ofthe two main branches of the radius.radial skeleton (PORIF) Structural elements diverging from acentral point toward the surface.radial symmmetry Having similar parts arranged around acommon central axis. see bilateral symmetry.radial vein (ARTHRO: Insecta) Often the heaviest vein of awing, that forks near the middle of the wing, with the mainpart forming the radial sector vein.radianal plate (ECHINOD: Crinoidea) The calyx plate in theanal interradius in association with the anal tube.radiate v. [L. radius, ray] To send out rays or direct lines froma common point.

Online Dictionary of Invertebrate Zoology 773radiate a. [L. radius, ray] Radially symmetrical; radiating.radiate veins (ARTHRO: Insecta) The anal veins.radicate v. [L. radicatus, rooted] (MOLL: Bivalvia) Becomingpermanently established by a root-like organ used for attachment.radicicolus see radicolousradicle n. [L. radix, root] (ARTHRO: Insecta) The base of thescape of the antenna. radicular a.radicola n.; pl. radicolae [L. radix, root; cola, dweller] (AR-THRO: Insecta) In Homoptera, the root-infesting phylloxerans;radicicola.radicolous a. [L. radix, root; cola, dweller] Inhabiting roots;radicicolus.radii see raysradiobiology n. [L. radius, ray; Gr. bios, life; logos, discourse]The study of the effects of radioactivity on living organisms.radiocarbon n. [L. radius, ray; carbo, coal] A radioactive isotopeof carbon found naturally in the air and in organismsthat is used to date fossil and subfossil remains; also usedin physiological studies.radioecology n. [L. radius, ray; Gr. oikos, house; logos, discourse]Radiation ecology; study of effect and trophicpathways of radioisotopes in communities.radioisotopes n.pl. [L. radius, ray; Gr. isos, equal; topos,place] Unstable forms of elements that show radioactivity.radiole n. [L. dim. radius, ray] 1. (ANN: Polychaeta) Featherlikehead structures forming a crown, or modified into along stalked knob (operculum); functioning in filtering particlesfor food. 2. (ECHINOD: Echinoidea) The spine of seaurchins.radiomimetic a. [L. radius, ray; Gr. mimos, mime] Chemicalagents causing effects similar to ionizing radiation in livingsystems.radioresistant a. [L. radius, ray; re-, back; stare, to stand]Organisms or tissues resistant to damage by radiation.

774Maggenti and Gardnerradiosensitive a. [L. radius, ray; sentire, to feel] Sensitive toradiation effects.radius n.; pl. radii [L. radius, ray] 1. In radially symmetricalanimals, the primary axis of symmetry. 2. (ECHINOD: Crinoidea)One of 5 reference planes passing through the polaror central axis and median line. 3. (ARTHRO) a. InCrustacea (sessile barnacles), the lateral part of a compartmentalplate when marked off from the median triangulararea by change in direction of growth lines. b. In Insecta,the third longitudinal wing vein.radix n. [L. radix, root] 1. A primary source. 2. (ARTHRO: Chelicerata)In Arachnida, apophysis of male copulatory organ.3. (ECHINOD: Crinoidea) The rootlike distal anchorage ofthe stem; holdfast.radula n.; pl. radulae [L. radula, scrape] 1. (ARTHRO: Insecta)The raster. 2. (MOLL) A uniquely molluscan feeding rasplikeorgan, odontophore or lingual ribbon, armed with chitinousdenticles, found in nearly all mollusks, except clams.radula sac (MOLL) An evaginated pocket in the posterior wallof the buccal cavity containing on it's floor the radula. seeraster.radulifer n. [L. radula, scrape; fero, to bear] (BRACHIO) Ahook-shaped or rodlike crura on the ventral side of thehinge plate, projecting toward the pedicle valve.raft see egg-raftsrake see rastellumramal, rameal a. [L. ramus, branch] Branching or branch-like.ramate a. [L. ramus, branch] Branched.ramate mastax (ROTIF: Bdelloidea) A stout mastax, with reducedfulcrum and manubria.ramellose a. [L. dim. ramus, branch] Having small branches.ramellus n. [L. dim. ramus, branch] (ARTHRO: Insecta) In Ichneumonoidea,the distal stump of the medial vein of thefore wings.ramet n. [L. ramus, branch] An individual clone member.rami pl. of ramus

Online Dictionary of Invertebrate Zoology 775ramicorn a. [L. ramus, branch; cornu, horn] (ARTHRO: Insecta)Having a branched antennae.ramicostellate a. [L. ramus, branch; dim. costa, rib](BRACHIO) Having a costellae on the shell resultant frombranching.ramification n. [L. ramus, branch; ficare, to make] Branchingout in all directions; offshoot.ramiform a. [L. ramus, branch; forma, shape] Resembling orshaped like branches.ramify v.; -fied; -fying [L. ramus, branch; ficere, to make] Tosend forth outgrowth or branches.rami valvularum see ramusramose a. [L. ramosus, branching] 1. Branching, having lateraldivisions full of branches; branch-like; ramified. 2. (AR-THRO: Insecta) In immatures, setae with branches, usuallyoriginating at the base.ramp n. [OF. ramper, to climb] (MOLL: Gastropoda) Abapicallyinclined flattened band on the shell surface, limited abaxiallyby a ridge or angulation.ramus n.; pl. rami [L. ramus, branch] 1. A branch or outgrowthof a structure. 2. (ANN) The notopodium and neuropodiumthat form the two parts of a parapodium; the tworami. 3. (ARTHRO: Crustacea) The flagellum. 4. (ARTHRO:Insecta) a. One of paired structures linking valvulae andvalvifers of the eighth and ninth abdominal segments; ramivalvularum. b. In Collembola, the distal portions of the corpus.5. (ROTIF) One of two usually thick, triangular piecesextending from the fulcrum of the mastax.random fixation The complete loss of one allele, with fixationof the other, in a population owing to accidents of sampling.ranking v. [OF. ranc, row] The appropriate placement of ataxon in the hierarchy of categories.rapacious a. [L. rapaxacis, grasping] Subsisting on prey; predacious;voracious; predatory.raphe see rhapheraphide n. [Gr. rhaphidos, needle] (PORIF: Desmospongia) A

776Maggenti and Gardnerthin diactinal microsclere lacking ornamentation.raptorial a. [L. raptor, robber] Fitted for grasping prey.raptorial claw 1. (ARTHRO: Crustacea) The toothed dactylcurved backward on the propodus. 2. (ARTHRO: Insecta) InMantids, the spinose tibiae and femur that produce thehook.rasorial a. [L. rasor, scraper] Adapted for scratching.rasp n. [OF. rasper, to scrape] 1. (ARTHRO: Crustacea) One ormore rows of chitinous plates or scales on the pereopodalor uropodal surface segments. 2. (ARTHRO: Insecta) Aroughened surface for the production of sound by friction.see strigulating organs.Rassenkreis n. [Ger. Rasse, race; Kreis, circle] Polytypic species;rheogameon. see circular overlap.rastellum n. [L. dim. rastrum, rake] (ARTHRO: Chelicerata) InArachnida, a structure on the chelicera bearing numeroustooth-like projections, stout and rigid spines, or seta; thepaturon.rastellus n. [L. dim. rastrum, rake] (ARTHRO: Chelicerata) InArachnida, the teethlike projections on the chelicera borneby the rastellum or paturon.raster n.; pl. rastri [L. rastrum, rake] (ARTHRO: Insecta) Acomplex of bare areas, hairs and spines on the ventralsurface of the last abdominal segment, in front of the anusin Scarabaeoidea; comprised of septula, palidium, teges,tegillum in some groups, and campus in Coleoptera.rastrate a. [L. rastrum, rake] Having longitudinal scratchesover the surface.rataria larva (CNID: Hydrozoa) In some Siphonophora, freeswimminglarva, hourglass in shape, with an anterior disccollar; develops from the conarium larva.ratite a. [L. ratis, raft] Lacking a keel; a smooth ventralsomite; lacking ridges or raised lines. see carinate.rat-king cercariae (rattenkonig) (PLATY: Trematoda) Marinecercariae that occur in masses, with the tail tips attachedto a protoplasmic mass.rat-tailed larva/maggots (ARTHRO: Insecta) In Diptera, Syr-

Online Dictionary of Invertebrate Zoology 777phidae larva having a long flexible respiratory tube extendingfrom the end of the body.ray n. [L. radius, ray] 1. One of a number of fine lines radiatingfrom a center. 2. Each arm of the triradiate lumen ofnematodes and other pseudocoelomates. 3. A division of aradiate animal.reafference n. [L. re, again; afferre, to bring] Sensory impulsescaused by an animal's movements relative to theenvironment. see afference.reborded a. [F. rebord, rim] (ARTHRO: Chelicerata) In Acarina,pertaining to the distal thickened and strengthened end ofthe labium.recapitulation theory The theory that ontogeny recapitulatesphylogeny.recent n. [L. recens, new] Taxa still in existence.receptacle n. [L. recipere, to receive] Any organ that receivesand stores; acting as a repository.receptaculum n. [L. recipere, to receive] A receptacle.receptaculum seminalis/seminis see seminal receptaclereceptor n. [L. recipere, to receive] A structure specialized forreceiving a particular kind of stimulus.recessive allele 1. The failure of an allele to affect the phenotypeof the heterozygote. 2. A term applied to organismsdisplaying recessive characters. see double recessive,dominant allele.recessive character A character of one parent that manifestsitself in the offspring only if it is homozygous in the offspring.reciprocal feeding Trophallaxis.reclinate a. [L. re, back; clinare, to lean] Inclined backward.reclivous, reclivate a. [L. re, back; clivus, slope] 1. Havingthe form of a sigmoid curve; a convex and concave line. 2.(ARTHRO: Insecta) An insect wing vein having the front endfarther from the wing base than the hind end. see verticle,inclivous.recombinant a. [L. re, back; combinere, to join] Organisms or

778Maggenti and Gardnercells arising by genetic recombination.recombinant DNA DNA produced by recombination, particularlyDNA produced from 2 different species by techniquesof genetic engineering.recondite a. [L. reconditus, put away, hidden] Concealed; remotefrom ordinary or easy perception; hidden.recrudescence n. [L. recrudescere, to become raw again] Anew outbreak after a period of abatement or inactivity. recrudescenta.recruitment trail (ARTHRO: Insecta) In social Hymenoptera,an odor trail laid by a single scout worker to recruit nestmatesto an area where many workers are needed.rectal a. [L. rectus, straight] Of or pertaining to the rectum.rectal caecum (SIPUN) A small blind tube present on the posterioror rectal section of the gut; function unknown.rectal gills (ARTHRO: Insecta) In anisopteran Odonata nymphs,an elaborate system of folds in the wall of the rectum, thelatter chamber forming the branchial basket.rectal glands A term loosely applied to numerous glands adjacentto or associated with the anus; glands which often secreteeither a lubricant, silk-gum, or other specialized materialsuch as a gelatinous matrix for the protection ofeggs.rectal matrix glands see matrix glandsrectal muscles (NEMATA) Specialized muscles that function toopen and close the anal opening.rectal pad (ARTHRO: Insecta) Columnar epithelium (usually 6)extending longitudinally along the rectum, important in thereabsorption of water, salts and amino acids from theurine.rectal papillae (ARTHRO: Insecta) In some Diptera, a papilliformmodification of the rectal pads projecting into therectum enclosing intercellular sinuses separated from thegut lumen by cell junctions and connected indirectly withthe hemocoel.rectal pouch 1. (ARTHRO: Insecta) a. In some Coleoptera, anenlarged anterior part of the rectum opening into the hind-

Online Dictionary of Invertebrate Zoology 779gut; function unknown. b. In Isoptera, an enlargement ofthe colonic region of the hind gut that acts as a repositoryfor symbiotic protozoa. 2. (BRYO) That part of the digestivetract between the pylorus and anus.rectal tracheal gills (ARTHRO: Insecta) In some nymphs ofOdonata, lamellate structures in the rectum supplied withtracheae and tracheoles.rectal valve (ARTHRO: Insecta) A circular or lobate fold of thehind intestine separating the distal intestine and rectum.rectate a. [L. rectus, straight] Straight.rectification n. [L. rectus, straight; facare, to make] A propertyof some cell membranes that allow impulses to passmore easily in one direction that in the opposite direction,resulting in polarized transmission of nervous impulses.rectigrade a. [L. rectus, straight; gradus, step] 1. Walking in astraight line. 2. (ARTHRO: Insecta) Pertaining to larvae with16 legs that progress with a straight body, as opposed togeometrid.rectilinear a. [L. rectus, straight; linea, line] Straight; formedin or bound by straight lines.rectimarginate a. [L. rectus, straight; margo, edge](BRACHIO) Having a straight anterior commissure.rectum n. [L. rectus, straight] The posterior ectodermal portionof the enteron ending at the anus, in some groups thisincludes the entire proctodeum. rectal a. see proctodeum,hind-gut.recumbent a. [L. recumbere, to lie down] Reclining.recumbent spines (BRACHIO) Curved spines laying at an angleof less than 45° to the surface of the shell.recurrent n. [L. recurrere, run again] Returning; reappearingat intervals; recurrent species.recurrent collateral A collateral axon that turns back to endnear the cell body or a similar one.recurrent nerve (ARTHRO: Insecta) A nerve extending posteriorlyfrom the frontal ganglion along the mid-dorsal line ofthe esophagus, passing under the brain and then expandinginto a hypocerebral ganglion.

780Maggenti and Gardnerrecurrent vein (ARTHRO: Insecta) 1. In Hymenoptera, one oftwo transverse veins immediately posterior to the cubitalvein. 2. In Neuroptera, A vein at the base of the wing betweencosta and subcosta, extending obliquely from thesubcosta to the costa.recurved a. [L. re, back; curvus, bent] 1. Bent upward orbackward; curved or bent back or down. 2. (ARTHRO: Chelicerata)In Arachnida, lateral eyes farther back than themedian eyes. see procured.recurved ovary see reflexed ovaryredia n.; pl. rediae [NL. after Francesco Redi, naturalist](PLATY: Trematoda) In Digenea, a larval produced by asexualreproduction within a sporocyst or mother redia.reflected a. [L. re, again; flectere, to bend or turn] 1. Turnedback on itself; turned from the general course of thestructure. 2. (MOLL: Gastropoda) Referring to the outer andcolumellar lips.reflex a. [L. re, back; flexus, bend] A simple unconditioned response.reflex arc A series of neurons transmitting excitation from areceptor through the central nervous system to an effector.reflex bleeding (ARTHRO: Insecta) Blood as well as other fluidsdischarged through various body articulations; functioningin protection from predators.reflexed ovary Turned back upon itself, generally at the junctionof the ovary and oviduct; bent abruptly back.reflex immobilization see hypnosis, stereokinesisrefractive a. [L. re, back; frangere, break] To turn from a directcourse; turned aside.refractory n. [L. re, back; frangere, break] 1. Not readily infectible;not amenable to therapy. 2. Unresponsive; theintermission after excitation during which repetition of thestimulus fails to induce a response in nerves.refringent a. [L. re, back; frangere, to break] Refractive; todeflect rays of light.refugium n.; pl. -ia [L. re, back; fugere, flee] An area that hasescaped the great changes of the region as a whole, as un-

Online Dictionary of Invertebrate Zoology 781glaciated mountain tops in an ice age.regeneration n. [L. regenerare, to regenerate] The replacementof a part or parts lost through mutilation or otherwise.regenerative budding (BRYO: Gymnolaemata) Budding insidea broken zooid.regenerative cells (ARTHRO: Insecta) Cells of the stomach(ventriculus) that may be singly, in pairs beneath the columnarcells or grouped into clusters (nidi) or arranged incrypt-like outpocketings; functioning in renewal of otherepithelial cells when destroyed by secretion or degenerationduring molting or pupation.regression n. [L. re, back; gradi, to step] 1. Regressive evolution.2. A statistical method of comparing paired observations.regressive character A character being reduced or lost in thecourse of phylogeny.regressive evolution The appearance of characters in a taxonthat are usually considered primitive.regressive molting (ARTHRO: Insecta) In Isoptera, reversalduring metamorphosis, when they are already in the processof developing into a particular caste, back to a less differentiatedstage.regularization (ANN) Anatomical adjustments involved in reducingthe asymmetry due to unilateral splitting ofmesoblastic somites.regular triact (PORIF) A megasclere spicule with three equalrays separated by angles of 120 degrees.regulator gene A gene that controls the action of other genesthrough curtailing the rate of synthesis of the products ofother distant genes.reinfection n. [L. re, again; inficere, to make] A second infectionby the same microorganism after recovery from orduring the course of a primary infection.relic n. [L. reliquia, remnant] A present nonfunctional structurethat was originally useful; an isolated remnant of a oncewidespread population.

782Maggenti and Gardnerremiform a. [L. remus, oar; forma, shape] Oar-like in shape.remigium n. [L. remigare, to row] (ARTHRO: Insecta) The wingarea anterior to the claval furrow, in both fore and hindwings; if claval furrow is indistinct, may be described asforward of the posterior cubitis. remigial a.remigrant foramen (BRACHIO) The pedicle opening movingdorsally after an initial movement toward the ventral beak.remiped a. [L. remus, oar; pes, foot] Having oar-shaped feet;adapted for rowing.remotion n. [L. re, again; motus, move] (ARTHRO: Insecta) Inleg movements, the corresponding movement of the coxa.renal a. [L. renis, kidneys] Pertaining to a kidney.renal appendage (MOLL: Cephalopoda) A sacculate organfunctioning in providing blood pressure to carry bloodthrough the gills.renal cells Nephrocytes.renal sac (MOLL: Cephalopoda) One of four organs of thenephridium that receives pericardial filtrate via the renopericardialcanal and secretions from the large renal appendages.renette a. [L. dim. ren, kidney] (NEMATA) The ventral excretorygland cell(s).reniform a. [L. dim. ren, kidney; forma, shape] Kidneyshaped.reniform spot (ARTHRO: Insecta) In Noctuidae, a kidneyshapedspot at the end of the discal cell.renopericardial canal (MOLL: Cephalopoda) Ciliated canalconnecting the metanephridium with the pericardial cavity.renopericardial pore see nephrostomerepagula n.pl.; sing. -um [L. repagulum, bar] (ARTHRO: Insecta)In neuropteran Ascalaphidae, modified eggs thatoften fence the normal eggs, possibly guarding them fromthe attacks of predacious enemies.repand a. [L. re, back; pandus, bent] Wavy, with alternatesegments of circles and minute angles; having a wavy oruneven outline; sinuate.

Online Dictionary of Invertebrate Zoology 783repent a. [L. repens, creeping] Appearing as if creeping orcrawling.repetition-molt (ARTHRO: Chelicerata) A molt that results inno change in characters of form or size. see growingmolt.replacement name A substitute name.replacement reproductive see supplementary reproductivereplete n. [L. repletus, filled] (ARTHRO: Insecta) In Hymenoptera,individuals of certain ant species that are speciallyadapted with distended abdomens for the storage ofhoney; a living honey cask; plerergate.replicate n. [L. re, back; plicare, to fold] Doubled back over onitself.reproduction n. [L. re, back; producere, to lead forth] Theprocess of perpetuating the species from generation togeneration.reproductive isolation see isolaterepugnatorial a. [L. repugnans, offensive] Repellent; offensiveas to drive away.repugnatorial glands 1. (ARTHRO: Diplopoda) Stink glands. 2.(ARTHRO: Insecta) Glands secreting noxious liquids or vaporsto repel antagonists.reservoir n. [L. re, back; servo, keep] A case or cavity forstorage of certain fluids or secretions. see ampulla.reservoir host A definitive host in which the infection usuallyresides in nature.resilifer n. [L. resilire, to leap back; fero, bear] (MOLL: Bivalvia)A Modification of a bivalve shell to which the resilium isattached.resilin n. [L. resilire, to leap back] (ARTHRO: Insecta) A colorless,rubber-like protein found in elastic and extensible cuticleof insects that stores energy for tension release to restoreoriginal position.resilium n. [L. resilire, to leap back] (MOLL: Bivalvia) The internalligament, irrespective of composition; in oysters

784Maggenti and Gardnerrests in a subtrigonal central socket or fossa.resinous a. [Gr. resina, resin] Having the appearance of rosin;clear brownish yellow.resonator n. [L. re, again; sonare, to sound] (ARTHRO: Insecta)A structure functioning to intensify or activatesound; a thin vibrating plate or lamella.resonator ridge (ARTHRO: Insecta) In Diptera, a ridge on thehind femur that rubs against the stridulatory file to producesounds.resorption n. [L. re, again; sorbere, drink in] (MOLL: Gastropoda)The removal of a previously formed shell by action ofthe living gastropod.respiration n. [L. re, back; spirare, to breathe] The intake ofoxygen and giving off of carbon dioxide.respiratory funnel (ARTHRO: Insecta) In Diptera, a distinctivechitinous funnel attached to the host tracheal system sothat encapsulation does not impair the respiration in oldertachinid larvae.respiratory horn (ARTHRO: Insecta) 1. In Diptera, paired prothoracicprotuberances on the aquatic pupae of most Culicidaeand Ceratopogonidae; respiratory trumpet. 2. Asharply pointed post-abdominal siphon in some aquatic insectpupae that are thrust into the aerenchyma of aquaticplants.respiratory movements Movements designed to increase thesupply of oxygen or disperse carbon dioxide, such as abdominalmovements in insects or undulations of aquaticoligochaetes.respiratory siphon (ARTHRO: Insecta) In Diptera, the caudalbreathing tube of culicid larvae.respiratory tree (ECHINOD: Holothuroidea) Branched cloacaltubules thought to have a respriatory function.respiratory trumpet see respiratory hornresponse n. [L. responsum, reply, answer] A change of activitydue to change of external or internal conditions. responsivenessa. see stimulus.restiform a. [L. restis, rope; forma, form] Shaped like a rope

Online Dictionary of Invertebrate Zoology 785or cord; prominent cordlike masses.resting eggs (ROTIF: Monogononta) Fertilized mictic eggs ofcertain Ploima produced in response to environmental factorsor vitamin E; thick shelled eggs resistant to drying andother adverse environmental conditions, that always developinto amictic females.resting stage see growth stagerestitution n. [L. re, back; statuare, to put] Rejoining brokenchromosomes, thereby restoring prebreakage structure.restitution nucleus In either meiosis or mitosis, a nucleuswith double the normal number of chromosomes due tonon-disjunction.resupinate a. [L. resupinare, to bend back] Having the appearanceof being inverted, reversed, or upside down.rete n. [L. rete, net] 1. A net or network; a plexus. 2. (ACAN-THO) A thin-walled tubular network between the longitudinaland circular muscle layers, or inside the longitudinalmuscles. 3. Any structureless membrane or layer.retecious a. [L. rete, net] In the form of a network.reticular membrane (PORIF: Hexactinellida) A membraneformed by the fused bases of the choanocytes.reticulate a. [L. rete, net] Forming a network of obliquely intersectinglinear ridges or lines; a network; cancellated.see retiform.reticulate evolution Evolution dependent on repeated intercrossingbetween a number of lines.reticulosome n. [L. dim. rete, net; Gr. soma, body] Cytoplasmicinclusion thought to be involved in membrane formation.reticulum n.; pl. reticula [L. dim. rete, net] A network of anastomosingfibers or tubules.retiform a. [L. rete, net; forma, form] Having the form of anetwork; composed of crossing lines.retina n. [L. rete, net] The receptive apparatus of an eye.retinal a.retinaculum n.; pl. -la [L. retinaculum, holdfast] 1. A con-

786Maggenti and Gardnernecting or retaining band. 2. (ACANTHO) Muscular sheath ofa nerve. 3. (ARTHRO: Crustacea) In Malacostraca, smallhook at the tip of the appendix interna, interlocking theright and left pleopods; cincinnulus. 4. (ARTHRO: Insecta) a.In Lepidoptera, the frenulum; wing coupling device. b. InCollembola, hamula that holds the furcula in place inspringtails. c. In Hymenoptera, the ring that prevents thesting from being darted out too far. d. In Coleoptera larvae,a fixed sclerotized, tooth-like structure on the mandible.retinal cell The photosensitive neurosensory cells.retinal pigment cells (ARTHRO: Insecta) Pigment cells in theretinal region of the eye. see accessory pigment cells,corneal pigment cells, retinular pigment cells.retinula n.; pl. -lae [L. dim. rete, net] 1. Sensory neuron inthe eye. 2. (ARTHRO) A group of cells and their associatedrhabdoms that are surrounded by a sheath of pigment cellscontaining dense granules of red, yellow or brown pigmentsmaking up each ommatidium of the arthropod compoundeye. retinular a.retinular pigment cell/basal pigment cell (ARTHRO: Insecta)When present, a second sleeve of pigment cells thatsurrounds the proximal end of the retinulae. see cornealpigment cells, accessory pigment cells.retort-shaped organs (ARTHRO: Insecta) In Hemiptera, ovalareas of glandular tissue at the enlarged proximal ends ofboth pairs of the mouth stylets, that secrete a new stylet ateach nymphal molt.retractile a. [L. retractus, withdrawn] Capable of being drawninwards; having the tendency to retract.retractive see opisthoclineretractor n. [L. re, back; trahere, to pull] Any muscle thatserves to return an organ to its original position. see protractormuscle.retractor gubernaculi see gubernaculumretractor preputii see hood retractorretractor spiculi (NEMATA) Paired spicular muscles, each containinga nucleus in the sarcoplasm, arising from the spi-

Online Dictionary of Invertebrate Zoology 787cular head and extending to the hypodermis in the regionof the lateral chords.retroarcuate a. [L. retro, backwards; arcuare, to bow] Curvedbackwards.retrobursal a. [L. retro, backwards; bursa, purse] (PLATY: Turbellaria)In Tricladida, having the bursal stalk short, so thatthe bursa lies behind the penis; retrobursalia. see probursal.retrocerebral endocrine system (ARTHRO: Insecta) Systemcomprised of corpora allata, corpora cardiaca and ventralgland.retrocerebral organ (ROTIF) A small glandular organ, attachedto the epidermis above and behind the brain, comprisedof the retrocerebral sac and the subcerebral glands;function unknown.retrocerebral pore (CHAETO) A pore on the dorsal surface behindthe brain where the rectocerebral organs open.retrocerebral sac 1. (CHAETO) A pair of sacs imbedded in theposterior part of the cerebral ganglion, separated by amembrane but connected by a nerve proximally, andopening by means of the retrocerebral pore. 2. (ROTIF) Aforked duct opening on the apical field, often on a single orpaired papilla; part of the retrocerebral organ.retrocession n. [L. retro, back; cedere, to go] The act of retroceding;to move backward.retrocurrent see opisthoclineretrofection see autoinfectionretroflected a. [L. retro, backwards; flectere, to bend] Bendingin different directions; bent or turned backwards.retrogressive development Developmental trend in evolutionresulting in simplification of an organism, usually throughthe complete or partial loss of one or more structures; regressivedevelopment.retrorse a. [L. retrorsus, turned or bent backwards] Turned,bent, or directed backward; backward projecting. see antrorse,detrorse.retrovesicular ganglion (NEMATA) The largest ganglion, usu-

788Maggenti and Gardnerally posterior to the excretory pore.retuse a. [L. retusus, blunt] Terminating in a round end orapex with a slight depression.reunion n. [L. re, back; unire, to make one] Rejoining of brokenchromosomes with structural changes.reversed a. [L. reversare, to turn about] 1. Contrary to theusual. 2. (ARTHRO: Insecta) Deflexed wings; margins ofhind wings projecting beyond those of the fore wings. 3.(MOLL) A spiral shell turned in the opposite direction; sinistral.see dextral.reverse mutation Heritable mutation in a gene that returns itto its original function.reversion n. [L. re, back; vertere, to turn] A genotypic or phenotypicreturn to the wild-type of a mutant, may be eitherpartial or complete. revertant a.reviviscence n. [L. re, back; vivere, to live] The act of reviving;awakening from hibernation, torpor or dessication. reviviscenta.revolute a. [L. re, back; volutus, turn around] Curled or rolledbackwards, or downwards. see involute.revolving a. [L. re, back; volutus, turn around] 1. To comearound again. 2. (MOLL) Spiral lines on a shell that run parallelwith the sutures.rhabd n. [Gr. rhabdos, rod] (PORIF) A megasclere triaene withan odd, generally straight ray.rhabdiferous cell (PORIF) A cell that secretes mucopolysaccharide.rhabdion n. [Gr. rhabdos, rod] (NEMATA) That cuticularizedportion of the wall of the stoma. see cheilorhabdions,prorhabdion, mesorhabdions, metarhabdions, telorhabdions.rhabdites n.pl. [Gr. rhabdos, rod] 1. Rod or blade-like processesprojecting from the epidermis. 2. (PLATY: Turbellaria)Straight or slightly curved rods in the epidermis andsubepidermis.rhabditiform a. [Gr. rhabdos, rod; L. forma, shape] Havingthe shape of a rod.

Online Dictionary of Invertebrate Zoology 789rhabditoid a. [Gr. rhabdos, rod] (NEMATA: Secernentea) Havingcharacters of free-living bacterial feeding nematodes inthe genus Rhabditis.rhabditoid bursa see bursarhabditoid larva (NEMATA) A bacterial feeding larva amongfree-living or parasitoid forms, in which the esophagus isdivided into corpus, isthmus and a posterior valved bulb.rhabdocrepid a. [Gr. rhabdos, rod; krepis, boot] (PORIF) Adesma deposited on a diactinal monaxon.rhabdoid n. [Gr. rhabdos, rod; eidos, like] 1. Rod-like; anyrod-shaped body. 2. (CNID) Nematocysts that open at thetip with a definite cylindrical hempe. 3. (PLATY: Turbellaria)A group of epidermal and subepidermal inclusions (rhabdites,rhammites, and chondrocysts), consisting of a ridgedhull filled with a semifluid material.rhabdom n. [Gr. rhabdos, rod] (ARTHRO) A rodlike light-sensitivestructure formed by rhabdomeres in the ommatidiumof a compound eye.rhabdome n. [Gr. rhabdos, rod] (PORIF) A greatly elongatedray of a tetraxon spicule.rhabdomere n. [Gr. rhabdos, rod; meros, part] (ARTHRO) Thereceptive area of a retina cell.rhabdus see diactinal monaxonrhachidian see rachidianrhachiglossate see rachiglossaterhagon n. [Gr. rhax, grape] (PORIF) A larval stage of a sponge,conical in shape and tapering from a broad base to thesummit bearing the single osculum.rhammites n.pl. [Gr. rhamma, thread] (PLATY: Turbellaria)Long, slender, sometimes sinuous rhabdoids, longer thanthe thickness of the epithelium.rhamphoid a. [Gr. rhamphos, beak; eidos, form] Beakshaped.rhaphe n. [Gr. rhapis, rod] (ARTHRO: Insecta) A sclerotic baron the dorsal surface of the silk press of caterpillars.rhegmatocyte see spherule cell

790Maggenti and Gardnerrhegmatocytoid see spherule cellrheogameon n. [Gr. rheein, to flow; gamos, marriage; on,being] Rassenkreis; polytypic species.rheophile a. [Gr. rheein, to flow; philos, loving] Living in riversand streams; reophilic. rheophily n.rheoreceptor n. [Gr. rheein, to flow; L. recipere, to receive] Asensory structure that signals the presence or strength ofwater currents.rheotaxis n.; pl. -taxes [Gr. rheein, to flow; taxis, arrangement]Tactic response due to stimulation from movingfluid; rheotropism. a. Positive rheotaxis: migrating againstthe current of moving fluid. b. Negative rheotaxis: Movingwith the fluid. reotactic a.rhinarium n.; pl. -ia [Gr. rhinos, nose; -arium, place] (AR-THRO: Insecta) In Hemiptera, usually round or oval, sometimestransversely elongate secondary sense organs onantennae of Aphididae.rhinophores n.pl. [Gr. rhinos, nose; phorein, to bear] (MOLL:Gastropoda) 1. In Opisthobranchia, the second pair ofmodified tentacles commonly surrounded at the base by acollarlike fold, located behind the first pair; chemoreceptorsat base of the tentacles. 2. In Nautiloidea, a digitiformchemoreceptor present beneath each eye.rhipidoglossate a. [Gr. rhipis, fan; glossa, tongue] (MOLL:Gastropoda) Having a radula with each transverse row furnishedwith numerous long, narrow, hooked marginal teetharranged in a fan-like manner and usually five similar admedianson either side.rhizocaul, rhizocaulome see hydrocaulusrhizoclad n. [Gr. rhiza, root; klados, branch] (PORIF) A megascleredesma with rootlike processes; rhizoclonerhizoid n. [Gr. rhiza, root; eidos, like] (BRYO) A rootlike structurecomposed of one or more kenozooids.rhizoid spines (BRACHIO) Spines that serve to attach the animal,either by entanglement or by cementing themselvesto a foreign surface.rhizome n. [Gr. rhiza, root] (CNID: Hydrozoa) The stolon; the

Online Dictionary of Invertebrate Zoology 791hydrorhiza.rhizomorphous a. [Gr. rhiza, root; morphos, form] Root-like.rhizophagous a. [Gr. rhiza, root; phagein, to eat] Root-eating.rhodopsin n. [Gr. rhodon, rose; ops, eye] (ARTHRO: Insecta) Avisual pigment of the rhabdomeric microvilli, on which theprimary photoreceptor process depends.rhombogen n. [Gr. rhombos, revolve; gennaein, to produce](MESO: Rhombozoa) A stage in the life cycle in the adult ina sexually mature host; stage follows the nematogen phaseand produces infusorigens.Rhombozoa, rhombozoans n.; n.pl. [Gr. rhombos, revolve;zoon, animal] A class of Mesozoa; minute parasitic animalsin the renal organs of Cephalopoda.rhombus n. [Gr. rhombos, revolve] A parallelogram withoblique angles. rhomboidal a.rhopalium n.; pl. -lia [Gr. rhopalon, club] (CNID) A hollowtentacle or sense organ with endodermal statoliths andrarely ocelli, that lay in each notch between the lappets atthe end of a pedalium; lithostyle; statorhabd; tentaculocyst;statocyst; colletocystophore.rhopalocercous cercaria (PLATY: Trematoda) Cercaria possessinga tail as wide as, or wider than, the body.rhopaloneme n. [Gr. rhopalon, club; nema, thread] (CNID:Anthozoa) A nematocyst with the tube consisting of anelongate sac and a club-shaped thread with an adhesivenature.rhopalostyle n. [Gr. rhopalon, club; stylos, pillar] (PORIF) Alumpy megasclere spicule with a bifurcate head.rhynchocoel n. [Gr. rhynchos, snout; koilos, hollow] (NEMER)A dorsal fluid-filled tubular chamber that houses the eversiblemuscular proboscis.Rhynchocoela n. [Gr. rhynchos, snout; koilos, hollow] Formerlyused in place of Nemertea.rhynchocoel villus (NEMER) A blood vessel running in the midventralline of the rhynchocoel.rhynchodaeum n. [Gr. rhynchos, snout; demas, body] 1.

792Maggenti and Gardner(ANN: Hirudinoidea) A cavity at the anterior end of the digestivetract. 2. (NEMER) A tubular chamber anterior to theproboscis, opening anteriorly by means of the proboscispore.rhynchostome n. [Gr. rhynchos, snout; stoma, mouth] (NE-MER) The proboscis pore.rhynchoteuthis stage (MOLL: Cephalopoda) In Ommastrephidae,a juvenile form with tentacles fused into a rostrum ortrunklike proboscis; the tentacles separate later.rhypophagous a. [Gr. rhypos, dirt; phagein, to eat] Eating dirtor filth.rhythm n. [Gr. rhythmos, measured motion] Regular periodicchanges. see circadian, diurnal.rib n. [A.S. ribb, a rib] 1. In Gastropoda and Brachiopodashells, a long and narrow ridge; a costa. 2. (MOLL: Bivalvia)A broad and prominent elevation of the shell surface; usuallydirected radially; costa.Ribaga's organ (ARTHRO: Insecta) In some female Hemiptera,pouches on various places of the nongenital abdomen;hemocoelic fecundation instead of by means of the customaryducts; ectospermalege; Berlese's organ. seemesospermalege.ribbon n. [OF. ribon] (MOLL: Gastropoda) A flat spiral surfaceelevation.riblet n. [A.S. dim. ribb, rib] A small or rudimentary rib;costella.riboflavin n. [L. alteration of arabinose; flavus, yellow] 6,7-dimethyl-9-D-ribitylisoallozazine, a water-soluble yellowpigment, generally occurring in animal tissues in a form inwhich it is metabolically active.ribonucleic acid (RNA) Long chain polymers of ribose andcertain organic bases; differing from DNA in using the baseuracil and usually single stranded.ribose n. [L. alteration of arabinose] Pentose sugar which withcertain organic bases makes up RNA and DNA polymers.ribosome n. [L. alteration of arabinose; Gr. soma, body] Aggregationsof RNA and proteins that act in synthesis of

Online Dictionary of Invertebrate Zoology 793proteins.ridge n. [A.S. hrycg] Any raised line or strip on a surface.right valve (MOLL: Bivalvia) When holding the bivalve shellwith the hinge up and the apex or umbo pointed away fromand pallial sinus toward the holder, then the right valve ison the right.rimate a. [L. rima, fissure] 1. Provided with a very narrowcavity; a very small hole or crack. 2. (MOLL: Gastropoda)Referring usually to the umbilicus.rimose a. [L. rima, fissure] Having many clefts or excavations.rind cells The layer of nerve cell bodies on the surface of invertebrateganglia, consisting of perikaryon, glial and neuroncells; not nerve endings or synapses.ring n. [A.S. hring, ring] 1. A circle or annulus; circinate. 2.(ARTHRO: Diplopoda) A non-systematic and colloquial termfor the trunk segments; avoids the need to differentiatebetween single segments and diplosegments.ring canal 1. (CNID: Hydrozoa) A circular canal around themargin of the umbrella into which the radial canal join aspart of the gastrovascular system. 2. (ECHINOD) A circularpart of the water-vascular system encircling the esophagusringed gland (ARTHRO: Insecta) In Hemiptera, a gland, sometimespaired, situated dorsally or ventrally on the vagina,or on the vaginal pouch; sometimes ringed by annualsclerotizations known as ring sclerites.ringent a. [L. ringens, gaping] (MOLL: Bivalvia) Gaping, assome valves.Ringer's solution Used as a physiological saline for vertebratesand invertebrates.ring gland 1. (ARTHRO: Insecta) In higher Diptera, a glandularorgan surrounding the aorta just above the brain, formedby the combining of the corpora cardiaca and the corporaallata and the thoracic glands; Weismann's ring. 2. (PLATY:Trematoda) A ring of glands opening with the apertureabove to secrete a substance to digest the epidermal cellsof the host.ring nerve see nerve ring

794Maggenti and Gardnerring segments (ARTHRO: Insecta) Ring-like basal segment(s)of the flagellum, much smaller than the segments following.ring septum (BRYO: Stenolaemata) The centrally perforatedskeletal diaphragm in the living chamber of a zooid.ring vein see ambient veinring vessel see ring canalring wall see anellusriparian, ripicolous a. [L. ripa, bank] Frequenting rivers orstreams.rivose a. [L. rivus, groove] Marked with irregular furrows;nonparallel furrows or canals.RNA Ribonucleic acidrobust a. [L. robustus, hardy] Short, stout, robust.rod border see brush borderrod-shaped organ see organ of Belloncirooting tuft (PORIF) An aggregate of spicules protruding fromthe lower surface with root functions.root stalk (CNID: Hydrozoa) Hydrorhiza or stolon; horizontalroot of a colony.ropalocercous cercaria see rhopalocercous cercariarosaceous a. [L. rosa, rose] Having a quality of a rose, such ascolor or scent.rosette plate (BRYO: Gymnolaemata) In Cheilostomata, multiporous,subcuticular area in the verticle walls for passageof fibers between zooids; multiporous septulum.rosettes n.pl. [L. dim. rosa, rose] 1. A process resembling arose in shape, applied to organs or markings of many invertebrates.2. (BRYO) The clubbed-shaped cells of the funicularsystem (communication organs). 3. (ECHINOD) Fivelarge ossicles that maintain the shape and width of thesuckers on the tube feet; pellions. 4. (NEMATA) Patterns ofcuticle surrounding the genital papillae; the uvette of theDemanian vessels. 5. (PLATY: Cestoda) In Monogenea,elaborately fringed lips on the suckers.

Online Dictionary of Invertebrate Zoology 795rostel see rostellumrostelliform a. [L. rostellum, small beak; forma, shape]Shaped like a rostellum.rostellum, rostel n. [L. rostellum, small beak] 1. A small beakor rostrum. 2. (ARTHRO: Insecta) The tubular piercing andsucking mouth parts. 3. (BRACHIO) Low projection betweenanterior muscle scars to which internal oblique muscles areattached. 4. (PLATY: Cestoda) A rounded prominence on theanterior end of the scolex, often furnished with retractilespines or hooks; sometimes referred to as an aclid organ.5. (PLATY: Trematoda) An anterior holdfast; rhynchus.rostellar, rostellate a.rostrad adv. [L. rostrum, beak] Toward the anterior end;cephalad; toward the rostrum when anterior.rostral filaments see rostralisrostral incisure (ARTHRO: Crustacea) In Ostracods, a gap betweenthe rostrum in the anterior margin of the valve allowingfor protrusion of the antenna (second antenna);rostral notch.rostralis n. [L. rostrum, beak] (ARTHRO: Insecta) In Coccoidea,the modified mandibles and maxillae that pass through therostrum into the host plant.rostral latus (ARTHRO: Crustacea) In Lepadomorph branacles,a plate on each side of the rostrum or below the scutum.see rostrolateral.rostral notch see rostral incisurerostral plate (ARTHRO: Crustacea) In malacostracan Phyllocarida,the anteriorly projecting, movably articulated, medianextension of the carapace.rostral tooth (ARTHRO: Crustacea) On a Decapoda carapace, atooth on the rostrum, may be single or multiple, with theupper, lower and lateral teeth distinguished.rostrate a. [L. rostrum, beak] Having a rostrum or beak-likeprocess.rostriform a. [L. rostrum, beak, forma, shape] Having theform of a beak.rostrolateral (ARTHRO: Crustacea) In balanomorph barnacles,

796Maggenti and Gardnerone of a pair of compartmental plates overlapping on eachside of the rostrum, sometimes overlap is fused with therostrum laterally or to each other. see rostral latus.rostrulum n. [L. dim. rostrum, beak] A small beak or rostrum.rostrum n.; pl. -tra [L. rostrum, beak] 1. A beak or snout. seerostellum. 2. (ARTHRO: Chelicerata) The labrum of spiders.3. (ARTHRO: Crustacea) The median pointed process at theend of the cephalothorax. a. In thoracic barnacles, a valvebetween the lateral and opposite carina at the basiscutalend of the capitulum; simple and bearing alae in manybalanomorphs, but compound and overlapping the lateralsin higher balanomorphs. see compound rostrum. 4. (AR-THRO: Insecta) a. In Hemiptera, the beak. b. In Coleopterascarab beetles, a rigid, ventral extension of the paramere.5. (BRACHIO) Inner elevation of the brachial valve; a pair ofclub shaped elevations for muscle attachment for the brachialprotractor muscles. 6. (MOLL: Cephalopoda) a. Theanteriormost point of the upper and lower mandibles. seebeak. b. The spine anchored on the posterior end of a cuttlebone and some pens. 7. (NEMATA: Secernentea) InAphelenchida males, the beak-like projection ventrad nearthe proximal end of the spicule, joining the dorsal andventral spicular shafts.rotate v.i. [L. rota, wheel] To turn; to revolve; to turn aroundon its own center or axis.rotation n. [L. rota, wheel] Turning around an axis.rotelliform a. [L. dim. rota, wheel; forma, shape] (MOLL: Gastropoda)Almost lenticular, but with a low obtuse spire. seeumboniform.Rotifera, rotifers n.; n.pl. [L. rota, wheel; fero, bear] A phylumof aquatic pseudocoelomate animals, many with ananterior ciliated corona that looks like a rotating wheel;wheel animalcules.rotundate a. [L. rotundus, round] Rounded; nearly circular;rounded at the angles, sides, or endsround dance (ARTHRO: Insecta) In Hymenoptera, a dance ofbees indicating a source of food close to the hive.royal cell (ARTHRO: Insecta) 1. In Isoptera, a small pear-

Online Dictionary of Invertebrate Zoology 797shaped chamber in which the termite queen lays her eggs.2. In Hymenoptera, the large, oblong, waxen cell constructedby the honey bee workers to rear queen larvae;queen cell.royal jelly (ARTHRO: Insecta) In Hymenoptera, a complex materialsecreted by the pharyngeal salivary glands of theworker honey bee with proteolytic activity, rich in fatty acids,the B-vitamins and other substances, that is fed to thebrood at the start of larval life and induces queen developmentif continued as a diet.royal pairs (ARTHRO: Insecta) In social insects, the sexuallyactive males and females.r-strategist Species of organisms that use a survival reproductive'strategy' characterized by high fecundity, rapid development,early reproduction, small body size, and semelparity;populations controlled by density-independentfactors.R technique An analysis of association of characters in a datamatrix.rubescent a. [L. rubescere, to grow red] Being reddish, or becomingred.rubiginose, rubiginous a. [LL. rubiginosus, rusty] Being rustyor brownish red; rust-colored.rubineous a. [L. ruber, red] Ruby-like in appearance.rudiment n. [L. rudis, rough] The beginning of a structure orpart. see anlage, precursor.rudimentary n. [L. rudimentum, a beginning] An incompletestage of development; initial; early; undeveloped. seevestigial.rudimentary posterior uterine branch see postuterine sacruffles n.pl. [ME. ruffeln] (MESO: Rhombozoa) In Dicyemida,slender projections of the exterior surface.rufous a. [L. rufus, red] Being reddish, red-yellowish; rufescent.ruga n. [L. ruga, wrinkle] A wrinkle, fold or crease. rugose a.rugosissimus a. [L. rugosus, full of wrinkles; -issimus, very]

798Maggenti and GardnerBeing extremely rugose or wrinkled.rugosity n. [L. rugosus, full of wrinkles] The condition of beingrugose or corrugated.rugula n.; pl. -lae [L. dim. ruga, wrinkle] A small wrinkle.rugulose a. [L. dim. rugosus, full of wrinkles] Having finewrinkles.runcinate a. [L. runcinare, to plane off] Notched; in severaltransverse acute segments inclined backward.rutella n.pl.; sing. rutellum [L. dim. rutrum, shovel] (ARTHRO:Chelicerata) In Acari, paired hypertrophied setae on thesubcapitulum, thick, hard and dentate, associated with ingestionof solid food. rutellar a.rutilous a. [L. rutilus, red, golden red] Of a shining bronze redcolor.rypophagous see rhypophagous

Ssabulous, sabulose a. [L. sabulum, sand] Sandy, gritty.sac n. [L. saccus, bag] A bladder, pouch or bag-like structure.saccate a. [L. saccus, bag] Sac-shaped; gibbous or inflated atone end.saccharobiose n. [Gr. sakchar, sugar; bios, life] Sucrose.sacciform a. [L. saccus, bag] Having the shape of a sac orpouch; saccular.saccule n. [L. dim. saccus, bag] 1. A small sac or pouch. 2.Sometimes applied to a small invagination of the cuticle.sacculus n. [L. dim. saccus, bag] (ARTHRO: Insecta) In Lepidoptera,the inner basal process of the coxite of male externalgenitalia.saccus n. [L. saccus, bag] (ARTHRO: Insecta) In Lepidoptera,an internal, midventral, cephalad invagination of the vinculum.sacoglossa n. [Gr. sakos, shield; glossa, tongue] (MOLL: Gastropoda)In Opisthobranchia, having a single toothedradula.saddle n. [A.S. sadol] 1. (ANN: Oligochaeta) In Lumbricidae,the clitellum incomplete ventrally, extending from the backto below the lateral setae. 2. (ARTHRO: Insecta) In Diptera,a large sclerite on the dorsal and lateral surfaces of the10th abdominal segment of larval Culicidae and some othernematocerous insects. see annular.Saefftigen's pouch (ACANTHO) An elongate genital pouch ofmales inside the genital sheath, continuous with the spacesof the bursal cap, that functions to inject fluid for eversionof the bursa.sagittae see penis valvessagittal a. [L. sagitta, arrow] Of or pertaining to the verticalmedian anteroposterior plane in a bilaterally symmetricalanimal. see parasagittal.

800Maggenti and Gardnersagittal triact (PORIF) A three-rayed megasclere spicule havingone ray very unlike others, generally T-shaped.sagittal triradiates (PORIF) Tetraxon spicules with two equalangles and one dissimilar angle. see triradiate(s).sagittate a. [L. sagitta, arrow] Having the shape of an arrowhead;sagittiform.sagittocysts n. [L. sagitta, arrow; Gr. kystis, bladder] (PLATY:Turbellaria) Pointed vesicles with a protrusible rod or needle.salient a. [L. saliens, leaping] Projecting outward; prominent.saliva n. [L. saliva, spit] The secretion of the salivary glandsthat moisten the mouth parts, the food, and begins digestion;in many invertebrates it also contains active constitutents.salivarium n. [L. saliva, spit] 1. (ARTHRO: Chelicerata) InAcarina, the chamber in the buccal cone into which thesalivary ducts open. 2. (ARTHRO: Insecta) The small cavitybehind the hypopharynx and between it and the labiuminto which the salivary duct opens.salivary canal (ARTHRO: Insecta) 1. In Hemiptera, the mouthapparatus having separate food and salivary canals; theposterior of the two situated between the opposed styliformmaxillae, through which salivary fluids are secreted by asalivary pump. 2. In Diptera, a canal extending the lengthof the hypopharynx for passage of saliva from the salivarypump; the salivary outlet canal.salivary chromosomes (ARTHRO: Insecta) In Diptera,polytene chromosomes found in the interphase nuclei ofthe salivary glands of the larvae.salivary ducts (ARTHRO: Insecta) In Diptera, tubes throughwhich saliva passes from the salivary glands; anteriorlyfused forming the common salivary duct opening into thesalivary pump.salivary gland 1. (ARTHRO: Insecta) Glands that open into themouth, esophagus or at the beginning of the alimentarycanal, that secrete a digestive substance. see labial gland,esophageal glands, peptonephridia. 2. (MOLL: Cephalopoda)In Sepia and Octopus the second salivary glands se-

Online Dictionary of Invertebrate Zoology 801crete proteolytic enzymes.salivary pump (ARTHRO: Insecta) A modified salivarium intowhich the common salivary duct opens at the base of thehypopharynx.salivary syringe see salivary pumpsaltation n. [L. saltare, to leap] An evolutionary process thatproceeds by leaps and bounds through the production ofmutants that differ greatly from the progenitor(s). seeanamorphosis.Saltatoria n. [L. saltare, to leap] A name commonly misappliedto grasshoppers, crickets and their allies.saltatory a. [L. saltare, to leap] Adapted for leaping. see furcula.saltigrade a. [L. saltare, to leap; gradus, step] Leapingmovement as in insects and spiders.sanguine a. [L. sanguis, blood] Having the color of blood.sanguinivorous a. [L. sanguis, blood; vorare, to devour]Feeding on blood.sanidasters n.pl. [Gr. sanidion, small board; aster, star] (PO-RIF) Rod shaped streptasters; a small rod-like spicule withspines at intervals.sapphirine a. [Gr. sappheiros, sapphire] Sapphire blue.saprobe see saprobiontsaprobic a. [Gr. sapros, rotten] Living on decaying organicmatter.saprobiont n. [Gr. sapros, rotten; bios, life] Living in an environmentrich in decaying organic matter and low in oxygen.saprobiotic a.saprophagous a. [Gr. sapros, rotten; phagein, to eat] Feedingon dead or decaying animal or plant materials.saprophyte n. [Gr. sapros, rotten; phyton, plant] A plant thatlives on dead and decaying organic matter; sometimes incorrectlyextended to include animals as well as plants.saprophytic a. see saprozite.saprozoic nutrition 1. Feeding on decaying organic matter. 2.Deriving sustenance by absorption of dissolved salts and

802Maggenti and Gardnersimple organic nutrients from surrounding medium.saprozoite n. [Gr. sapros, rotten; zoon, animal] An animalthat lives on dead or decaying organic matter. see saprophyte.sarcobelum n. [Gr. sarx, flesh; belos, sting] (MOLL: Gastropoda)In Pulmonata, a glandular node projecting into theprepuce from the junction of the penis sheath and propuce.sarcode n. [Gr. sarx, flesh] Protoplasm.sarcolemma n. [Gr. sarx, flesh; lemma, covering] An outermembrane enclosing the nucleated sarcoplasm in which themuscle fibers are embedded.sarcolysis n. [Gr. sarx, flesh; lyein, to loosen] Phagocytosis ofmuscles.sarcolyte n. [Gr. sarx, flesh; lytos, broken] (ARTHRO: Insecta)In Diptera, spherical bodies filled with muscle fragments inthe blood of the pupae during metamorphosis.sarcomere n. [Gr. sarx, flesh; meros, part] Any one of a seriesof units occurring at regular intervals along a muscle fiber,each unit encompasses the actin and myosin filaments; inmost invertebrates each sarcomere is set-off by Z discs.sarcomeric a. see I-bands, T-tubule.sarcophagous a. [Gr. sarx, flesh; phagein, to eat] Feeding onflesh.sarcoplasm n. [Gr. sarx, flesh; plasma, formed or molded]The undifferentiated protoplasm of a muscle cell; betweenthe myofibrils.sarcoplasmic reticulum Endoplasmic reticulum in striatedmuscle fibers; surrounding the myofibrils.sarcosomes n. [Gr. sarx, flesh; soma, body] Former name formitochondria in muscle cells.sarcostyle n. [Gr. sarx, flesh; stylos, pillar] (CNID: Hydrozoa)The dactylozooid on a column; nematophore.sarcotheca n. [Gr. sarx, flesh; theke, case] (CNID: Hydrozoa)The sheath of a sarcostyle; nematotheca.sarothrum see scopasaw n. [A.S. sagu, saw] (ARTHRO: Insecta) a. In Symphyta,

Online Dictionary of Invertebrate Zoology 803transverse ridges provided on the fused 2nd valvulae. b. InDiptera, the anterior serrated plate of the spiracular apparatusof Mansoniini larvae.saw bristles (ARTHRO: Crustacea) A heavy row of setae betweenthe molar and incisor process on the gnathal lobe ofthe mandible.saxicavous a. [L. saxum, rock; cavus, hollow] Said of rockboringmollusks.saxicolous a. [L. saxum, rock; colere, to inhabit] Living amongrocky or stony areas.scabellum n. [L. scabellum, footstool] (ARTHRO: Insecta) InDiptera, the distal basal portion of the halteres.scabrous a. [L. scaber, rough] Rough; rugged; with little rigidpoints or minute irregularities.scalariform, scalaroid a. [L. scalaris, ladder; forma, shape]Ladder-like; having transverse bars and spaces like a ladder.scales n.pl. [OF. escale, husk] 1. A small, more or less flattened,plate-like exterior covering. 2. (ARTHRO) a. In Chelicerata,flattened, modified setae of Arachnida. b. In Crustacea,small calcareous plate on the peduncle oflepadomorph barnacles. see scaphocerite. c. In Insecta,flat unicellular outgrowths of the body-wall; highly modifiedclothing hairs of all Lepidoptera, many Collembola, in someThysanura, Coleoptera, Diptera and Hymenoptera. 3.(MOLL) a. In Bivalvia, localized projections of the outershell; usually on a rib. b. In Polyplacophora, small calcareousbodies decorating the dorsal side of the girdle, sometimesclosely set, overlapping and of various shapes, beingsmooth or with minute striations. 4. (NEMATA: Sacernentea)Thickened, retrorse modifications of the body annuli.scalids n.pl. [Gr. skalidon, hoe] 1. (KINOR) Circlets and longitudinalrows of spines on the protrusible cone-shaped headand neck. 2. (LORI) In Nanaloricus mysticus, many recurvedspines on the cone-shaped anterior end (introvert)on its lateral surface. 3. (PRIAP) Longitudinal riblike, conicalprojections arranged in circles and longitudinal rows on thebarrel-shaped anterior proboscis region (introvert).

804Maggenti and Gardnerscalloped a. [OF. escalope, shell] Indented, cut at the edgesinto rounded hollows or segments of circles; crenate.scalp n. [Dan. skalp, shell] (MOLL) A bed of shellfish, especiallyof mussels or oysters.scalpellum see lancetscalpriform a. [L. scalprum, chisel; forma, shape] Chiselshaped.scanning electron microscope (SEM) A microscope with anelectron beam that scans the specimen producing an imageof the surface on a florescent screen.scansorial a. [L. scandere, to climb] Adapted for climbing orclinging.scape, scapus n. [L. scapus, shaft] 1. A stem or shaft. 2. (AR-THRO: Chelicerata) A structure associated with the epigynumof some female Arachnida, partially covering thevulva. 3. (ARTHRO: Insecta) The first or basal segment ofan antenna; in Diptera, the two basal segments of the antenna.4. (CNID: Anthozoa) a. In Alcyonaria, the main stemof Pennatulacea. b. In Actinaria, the lower thick-walled regionof the column.scaphe n. [Gr. skaphe, boat] (ANN: Polychaeta) In Amphictenidae,a flattened caudal appendage bearing the anus.scaphiform, scaphoid a. [Gr. skaphe, boat] Boat-shaped.scaphium n. [Gr. skaphe, boat] 1. A boat-shaped structure. 2.(ARTHRO: Insecta) In male Lepidoptera, a dorsal sclerotizationof the genitalia, below the uncus, and above the anus.see subscaphium.scaphocerite n. [Gr. skaphe, boat; keras, horn] (ARTHRO:Crustacea) The flattened exopod of the antenna; a scale; asquama.scaphognathite n. [Gr. skaphe, boat; ganthos, jaw] (ARTHRO:Crustacea) In Decapoda, the exopod of the maxilla, oftenused to produce the respiratory current in the gill chamber;bailer or gill bailer.Scaphopoda n. [Gr. skaphe, boat; pous, foot] A class of Molluscacontaining the tusk or tooth shell that are bilaterallysymmetrical with an elongate, gently curved, tubular shell

Online Dictionary of Invertebrate Zoology 805open at both ends; an exclusively marine dweller.scapula see parapsisscapulus n.; pl. -li [L. dim. scapus, stem] 1. (CNID: Anthozoa)In Actinaria, the short upper part of the scape/scapus. 2.(NEMATA) The enlarged sensory portion of a metaneme.scapus see scapescarabaeiform larva (ARTHRO: Insecta) A grublike larva witha well sclerotized head, and poorly sclerotized body, butwell developed thoracic legs and abdomen, without prolegs,and is usually short-legged and inactive.scarabaeoid a. [L. scarabaeus, beetle; Gr. eidos, like] 1.Scarab-like. 2. (ARTHRO: Insecta) In Coleoptera, a memberof the Scarabaeoidea; third and fourth instar larva of theMeloidae, the blister beetles.scarified a. [L. scarifico, to scratch] To scratch or cut.scariose a. [F. scarieux, membranous] Thin, dry and scaly.scatophagous a. [Gr. skatos, dung; phagein, to eat] Eatingdung or excrement; merdivorous; coprophagous.scavenger n. [ME. skavawer, collector of a toll] Any organismthat feeds on dead plants or animals and decaying matteror animal wastes.scent brush/tuft Hairs or scales that function in diffusion ofodorous secretions.scent glands (ARTHRO: Insecta) Glands that manufacture andstore for subsequent release, volatile, usually highly odoriferoussubstances. see brush organs, pheromone.scent pore see ostiolescent scales (ARTHRO: Insecta) Scales distinguished fromclothing scales by their extreme length, sometimes calledhairs. see androconia.sceptrules n. [Gr. dim. skeptron, royal staff] (PORIF: Sclerospongiae)Microscleric monactinal triaxonic spicules that includeclavules with terminal umbels or smooth heads.schemochrome n. [Gr. schema, shape; chroma, color] (AR-THRO: Insecta) Colors produced by physical or structuralsurfaces, devoid of pigment, as the iridescent colors of a

806Maggenti and Gardnerbutterfly wing. see biochrome.schistosomula n.; pl. -lae [Gr. schizein, split; dim. soma,body] (PLATY: Trematoda) In Schistostomatidae, the postpenetrationstage in the vertebrate definitive host; the juvenilestage between a cercaria and an adult.schizeckenosy n. [Gr. schizien, to split; eckenos, empty out](ARTHRO: Chelicerata) In Acari, a system of waste eliminationwith blindly ending midgut by a lobe from the ventriculusbreaking free and being expelled though a split inthe posterodorsal cuticle.schizochroal n. [Gr. schizien, to split; chroa, superficial appearance](ARTHRO: Trilobita) Bound isolated lenses thatform around semicircular facets. see holochroal.schizocoel, schizocele n. [Gr. schizein, to split; koilos, hollow]A coelomic cavity formed from the splitting of themesodermal band or plate.schizodont a. [Gr. schizein, to split; odous, tooth] (MOLL: Bivalvia)With a two cusped-tooth.schizogamy n. [Gr. schizein, to split; gamos, marriage] (ANN:Polychaeta) Fission into a sexual and an asexual individual.schizogenesis see fissionschizolophe n. [Gr. schizein, to split; lophos, crest] (BRACHIO)A lophophore indented to form a pair of branchia bearing arow of paired filamentous appendages. schizolophous a.schizopeltid n. [Gr. schizein, to split; pelte, shield] (ARTHRO:Chelicerata) The prodorsal shield (peltidium) subdivided byone or more transverse scissures, composed of propeltidium,mesopeltidium and metapeltidium, or propeltidiumand postpeltidium.schizopod larva see mysis stageschizorhyses n.pl. [Gr. schizein, to split; rhysos, delivering](PORIF) Canals in the dictyonal framework that runs longitudinallyor obliquely from gastroderm to the dermis andare lined by flagellated chambers.Schmidt's layer (ARTHRO: Insecta) The zone of deposition ofnew cuticle during molting; the exact nature of this zone isnot known.

Online Dictionary of Invertebrate Zoology 807Schwann cell (ARTHRO: Insecta) An elongate cell into whichmotor axons sink and become suspended by a suspensoryfold; lemnoblast; neurilemma cell.scientific name The formal nomenclatural designation of ataxon.scissorial area (ARTHRO: Insecta) In Coleoptera, the cuttingarea on the mandible of a Scarabaeoidea larva; betweenthe dentes and molar area.scissure n. [L. scindere, to cut] 1. A cleft or split in a body orsurface. 2. (ARTHRO: Chelicerata) In Acari, a relativelynarrow band of soft skin that cuts the sclerotized cuticleinto plates.sclerification see sclerotizationsclerite n. [Gr. skleros, hard] 1. (ARTHRO) Any sclerotized areaof cuticle limited by suture lines or flexible, membranousportions of cuticle. 2. (BRYO) A thickened line in the operculum,mandible or frontal membrane. 3. (CNID) A calcareousskeletal member of the mesogloea.scleritization n. [Gr. skleros, hard; facere, to make] (ARTHRO:Insecta) The formation of sclerites.scleroblasts n.pl. [Gr. skleros, hard; blastos, bud] (PORIF)Special amoebocytes in sponges responsible for secretingthe skeleton; consisting either of spicules, fibers of sponginor both.sclerocyte n. [Gr. skleros, hard; kytos, container] (PORIF)Cells that secrete spicules.sclerophagous see duraphagoussclerosepta n.pl.; sing. -um [Gr. skleros, hard; septum, partition](CNID: Hydrozoa) Calcareous rods of corals projectingfrom the basal plate in a fan-like shape between the mesenteriesof the polyp.sclerotin n. [Gr. skleros, hard] (ARTHRO) A colorless orquinone tanned amber or brown material occurring in thecuticle that accounts for much of the stiffening of the surfacestructures. sclerotic a.sclerotization n. [Gr. skleros, hard] Hardening by depositionof sclerotin or other substances in the cuticle. sclerotic,

808Maggenti and Gardnersclerotized a.scoleces pl. of scolexscolecid, scoleciform, scolecoid a. [Gr. skolex, worm]Scolex-like.scolex n. [Gr. skolex, worm] (PLATY: Cestoda) The head orholdfast organ.scolopale n.; pl. -ia [Gr. skolos, pointed object; L. palus,stake] (ARTHRO: Insecta) A variously shaped cup or conewith longitudinal ridges and a central filament connectingwith the process of a central nerve cell; may have a terminalbutton; sensory cell of the scolopidium; scolops; cuticularsheath; corpus scolopale.scoloparium see proprioceptorscolopidium n.; pl. -ia [Gr. dim. skolos, pointed object] Amechanoreceptor (part of a chordotonal organ) consistingessentially, of three cells: sensory neuron (scolopale), envelopingcell, and an attachment, or cap cell; scolopophore;sensillum scolopophorum. see myochordotonalorgan.scolopoid sheath see scolopalescolopophore, scolophore n. [Gr. skolos, pointed object;phoreus, bearer] (ARTHRO: Insecta) 1. Complex sensillaconsisting of a bundle of sensory cells whose endings areseparated from the body by one or more accessory cells,that are receptive to mechanical stimuli; scolopidium. 2. Asense organ perceiving continuous vibration. see tangoreceptor.scolopophorus organ see chordotonal organscolops see scolopalescolus n.; pl. scoli [Gr. skolos, pointed object] 1. Thorny processesof the body-wall. 2. (ARTHRO: Insecta) a. In Coleoptera,long branched projection of coccinellid beetles. b. InLepidoptera, characteristic of nymphalid and saturniid larvae;sphingid larvae also have a similar process in the analhorn.scolytoid larva (ARTHRO: Insecta) A fleshy larva resemblingthe larva of scolytid beetles.

Online Dictionary of Invertebrate Zoology 809scopa n.; pl. -ae [L. scopa, broom] (ARTHRO: Insecta) In Hymenoptera,special hairs (pollen brush) or modified to forma corbicula (pollen basket). scopate a.scopiform a. [L. scopa, broom; forma, shape] Formed like abrush.scopula n.; pl. -ae [L. dim. scopa, broom] A small, dense tuftof hair; scopa.scopules n.pl. [L. dim. scopa, broom] (PORIF) Sceptrules withfew spines arranged in a regular cluster.scopuliferous, scopuliform a. [L. dim. scopa, broom] Brushlike.scopulipedes a. [L. dim. scopa, broom; pes, foot] (ARTHRO:Insecta) In Hymenoptera, bees with pollen gatheringstructures on the feet.scotopic see superposition eyescraper n. [A.S. scrapian, scraper] 1. Any structure or specializedpart of a structure adapted for rasping or scraping. 2.(ARTHRO: Insecta) In Orthoptera, the sharpened anal angleof the front wing that functions as a stridulating mechanism.see file.screening a. [OF. escren, barrier] Selective procedures to isolateanimals or chemicals from populations, complex mixtures,or background material.screw dislocation (BRYO) Spiral growth resulting from latticedefects in calcite crystals making up their skeletal units.scrobe n. [LL. scrobis, ditch] A groove or furrow for the receptionof an appendage.scrobicula n. [LL. dim. scrobis, ditch] (ECHINOD: Echinoidea) Abare area surrounding a boss (base of a spine) on the test;areola.scrobicular tubercles (ECHINOD: Echinoidea) Secondary tubercleswith spines encircling the base of a spine on thetest.scrobiculate a. [LL. dim. scrobis, ditch] Marked with pits orhollows.scrobicules n. [LL. dim. scrobis, ditch] (ECHINOD: Echinoidea)

810Maggenti and GardnerSmall secondary spines on the scrobicular tubercles of thetest.scrobiculus n. [LL. dim. scrobis, ditch] A pit or depression.scrobis n.; pl. -es [LL. scrobis, ditch] (ARTHRO: Insecta) InScarabaeoidea larvae, a sunken lateral mandibular regiondefined by two apically converging lateral carinae.scrotal membrane (ARTHRO: Insecta) The peritoneal envelopecovering the testes; sometimes pigmented.scrotiform a. [L. scrotum, pouch; forma, shape] Purse- orpouch-shaped.scrotum see scrotal membranesculpture n. [L. sculptura, carving] The pattern or marking ofimpressions or elevations on the surface of an animal.sculptured a.scutal angle (ARTHRO: Insecta) In Diptera, an angular projectionof the scutal margin anterior to the prescutal suture,or in front of the prespiracular area.scutal margin (ARTHRO: Crustacea) In thoracic barnacles, theedge of the tergum, articulating with the scutum or theedge of any other plate adjacent to the scutum.scutate a. [L. scutum, shield] In the shape of a shield; escutcheon;clypeate; peltate.scute n. [L. scutum, shield] (ARTHRO: Insecta) An externalscale.scutel see scutellumscutellar angle (ARTHRO: Insecta) The expanded wing angle ofthe elytra adjacent to the scutellum.scutellar bridge (ARTHRO: Insecta) In Diptera, a ridge on bothsides of the scutellum connecting with the scutum.scutellar bristles (ARTHRO: Insecta) In Diptera, bristles alongthe posterior margin of the scutellum.scutellate a. [L. dim. scutum, shield] Divided into small platelikeareas.scutellum n.; pl. scutella [L. dim. scutum, shield] 1. (ARTHRO:Insecta) a. A sclerotic subdivision of the thoracic notum. b.In Coleoptera, Hemiptera, and Homoptera, the scutellum

Online Dictionary of Invertebrate Zoology 811(mesoscutellum); large and usually triangular or subtriangular.c. In Diptera, a posterior rounded or triangular lobe.2. (NEMATA: Secernentea) One of a pair of large caudalchemosensory organs opening in the lateral fields in somespecies of the Hoplolaiminae.scutiform a. [L. scutum, shield; forma, shape] In the shape ofa shield; peltate.scutigerous a. [L. scutum, shield; gerere, to bear] Having ashield-like structure.scutoscutellar suture (ARTHRO: Insecta) The sulcus dividingthe mesonotum into the scutum and scutellum; V of V-shaped sulcus with arms diverging posteriorly.scutulis see scutellumscutum n.; pl. scuta [L. scutum, shield] 1. Any long, horny orchitinous plate. 2. (ARTHRO: Chelicerata) In Acari, thelarge, anteriodorsal sclerite. 3. (ARTHRO: Crustacea) Inthoracic barnacles, a paired plate or valve. a. In Lepadomorpha,one on each side of the occludent margin of thecapitulum. b. In Verrucomorpha, a fixed scutum, one of 4principal plates, and a movable scutum, 1 of 2 opercularplates. c. In Balanomorpha, one of 4 opercular plates. 4.(ARTHRO: Insecta) The middle division of the thoracic notum,anterior to the scutellum. a. In Hymenoptera, themajor part of the dorsum of the mesothorax in wingedFormicidae. b. In Diptera, sometimes referred to as theeunotum. 5. (BRYO: Gymnolaemata) In anascanCheilostomata, a broad, flat, lateral, marginal spine overhangingthe frontal area.scyphistoma n. [Gr. scyphos, cup; stoma, mouth] (CNID) Ajellyfish polypoid larval stage attached to the bottom thatgives rise to free-swimming medusae; a strobila. see hydra-tuba.scyphomedusae see ScyphozoaScyphozoa, scyphozoans n.; n.pl. [Gr. scyphos, cup; zoon,animal] An exclusively marine class in the Phylum Cnidaria,in which the medusoid stage predominates having 8notches in the margin of the bell; jellyfishes.sealing bar (ARTHRO: Insecta) In eggs, a structure formed

812Maggenti and Gardnerfrom a thin layer of resistant endochorion and a thick amberlayer that joins the cap to the rest of the chorion.seam n. [A.S. seam] A visible line of juncture between parts; asuture.seam cells (NEMATA) The central cell row in the lateral chordsthat have no membranous extension beneath the cuticle.sebaceous a. [L. sebaceus, tallow] Pertaining to secretion, orcomposed of oily or fatty substances.sebific duct/gland Tubes of the collaterial glands.Secernentea, secereneteans n.; n.pl. [L. secernere, toseparate] One of the two major classes of the PhylumNemata, including most of the plant- and animal-parasiticnematodes; formerly Phasmidia. see Adenophorea.second antennae (ARTHRO: Crustacea) 1. Antennae of thesecond cephalic segment. 2. Antennae of some males areuniramous; two-jointed structures used to clasp femalesduring mating.secondary fiber (PORIF) A fiber that connects primary fibersand is not oriented to the surface.secondary host see intermediate hostsecondary intergradation The intergradation or hybridizationof two distinct and previously isolated populations thathave reestablished contact. see primary intergradation.secondary iris cells see accessory pigment cellssecondary ocelli (ARTHRO: Insecta) Ocelli of the larvae ofholometabolous insects; lateral ocelli.secondary pigment cells see accessory pigment cellssecondary pleometrosis (ARTHRO: Insecta) In Hymenoptera,a process in a colony in which a founding queen is laterjoined by others to form a pleometrotic association. seepleometrosis.secondary reproductive see nymphoid reproductivesecondary riblet (MOLL: Bivalvia) A riblet appearing later indevelopment, however, weaker than primary riblets.secondary segmentation Any form of body segmentation notconforming with the embryonic metamerism.

Online Dictionary of Invertebrate Zoology 813secondary setae (ARTHRO: Insecta) In some caterpillars, setaeof indefinite locations and numbers; usually not present onfirst instar.secondary sexual characters Characters that distinguish thesexes, though not functioning directly in reproduction.secondary shell layer (BRACHIO) Shell deposited by outerepithelium median of outer mantle lobes. a. In Articulata,secreted intracellularly as fibers. b. In Inarticulata, if present,never fibrous.secondary sockets (BRACHIO) A pair of small depressions behindthe cardinal process lobes that receive the secondaryteeth.secondary somatic hermaphrodite see gynandromorphsecondary spicules (PORIF) Microscleres distributed throughoutthe mesenchyme.secondary teeth (BRACHIO) In Stropheodontidae, two projectionsfrom the ventral process that fit into sockets of thebrachial valve.second axillary (ARTHRO: Insecta) 1. A sclerite articulatingpartly with the preceding sclerite and partly with the baseof the radius; submedia. 2. An articulation sclerite of an insectwing along the first axillary that touches the base ofthe radial vein anteriorly, with a ventral portion of thesclerite set below the wing surface; intra-alare.second-form reproductive see nymphoid reproductivesecond longitudinal vein see second veinsecond maxillae 1. (ARTHRO: Chilopoda) The fourth pair ofhead appendages. 2. (ARTHRO: Crustacea) The fifth andlast pair of head appendages. 3. (ARTHRO: Insecta) Thethird pair of gnathal appendages; united in the labium.second trochanter (ARTHRO) The second segment of the leg;prefemur; ischiopodite.second valvifers (ARTHRO: Insecta) In the ovipositor, a basalpair of lobes or oblong plates supporting the base of thesecond valvulae.second valvulae (ARTHRO: Insecta) In the ovipositor, a dorsalelongate pair of processes, uniting to form the sting sheath

814Maggenti and Gardnerenclosing the 1st valvulae.second vein (ARTHRO: Insecta) In Diptera, when present, lyingimmediately behind the subcostal vein, always united withthe radial sector vein.secretion n. [L. secretio, separation] A substance or fluid producedin the body by a cell or gland; the passage of thissubstance to the outside of the cell or gland. secretory a.secretory granules (NEMATA) Proteinaceous granules producedin the salivary (esophageal) glands, then transportedanteriorly to the gland ampullae where breakdown occurs;thought to release digestive enzymes to be injected intothe food cell during feeding.section n. [L. sectare, to cut] 1. Pertaining to a subdivision ofa taxon or a series of related elements in one portion of ahigher taxon. 2. A thin slice of an organism or part of oneused for microscopic study.sectorial cross vein (ARTHRO: Insecta) A cross vein betweenthe two branches of the radial sector.secund a. [L. secundus, following] Having parts or organs onone side only; pointed one way; unilateral.secundibracts n. [L. secundus, following; brachium, arm](ECHINOD: Crinoidea) Brachials between the first and 2ndaxillaries; dicostalia.securiform a. [L. securis, ax; forma, shape] Hatchet-shaped.sedentary a. [L. sedere, to sit] Remaining in one place; stationary.seductor gubernaculi see gubernaculumseed n. [A.S. saed, seed] (MOLL: Bivalvia) A young oyster; notdesignated by a specific size range.seed galls (NEMATA) Seedheads converted to galls containingcryptobiotic nematode larvae or adults.segment n. [L. segmentum, piece] 1. A part or subdivision of abody or appendage that is marked off or separate betweenjoints or articulations. 2. (ANN) A portion of the body, alongthe anteroposterior axis, between two consecutive intersegmentalfurrows and the associated septa. 3. (AR-THRO: Crustacea) A podomere. see article.

Online Dictionary of Invertebrate Zoology 815segmental blood vessel (ANN) A blood vessel in the bodywall, connecting anteriorly from dorsal to ventral arteries,and posteriorly by plexes around the gut.segmental spines (ARTHRO: Insecta) In Diptera, 12 majorbristles occurring in transverse rows on each segment ofsyrphid fly larvae.segmentation n. [L. segmentum, piece] 1. The division of ajointed appendage or limb. 2. Cleavage.segmentation cavity see blastocoelsegmentation nucleus Nucleus formed by union of male andfemale pronuclei during fertilization.segregate n. [L. segregare, to separate] An individual thatdiffers in some genetic characters from the parental stockdue to segregation of genes.segregation n. [L. segregare, to separate] 1. The act of placingapart; separation. 2. The separation of the two genes ofan allelomorphic pair during meiosis.seizing jaws see grasping spinessejugal a. [L. se, apart; jugare, to join] Indicating the furrowor interval separating divisions or segments of an invertebratebody.selection see natural selectionselection pressure The effect of the environment in selectingindividuals best suited for survival and reproduction. seenatural selection.selenaster n. [Gr. selene, moon; aster, star] (PORIF) A microscleresimilar to a stellaster, but based on a spiraster.seleniform a. [Gr. selene, moon; L. forma, shape] In theshape of a full moon.seleniform cell see plasmatocytesselenizone n. [Gr. selene, moon; zone, girdle] (MOLL: Gastropoda)In dibranchiates, a spiral band of crescentric growthlines or threads (lunulae) on the shell surface due to thesemicircular end of a notch or slit on the outer lip; a slitband; corresponds to the anal fasciole of some othergroups.

816Maggenti and Gardnerself-cleansing (MOLL: Bivalvia) Removal and ejection ofpseudofeces.self-fertilization The union of gametes derived from the sameindividual; autogamy; automixis. see cross-fertilization.selfing see self-fertilizationself-sedimentation (MOLL: Bivalvia) In oysters, pseudofecesand feces that are ejected.sellate a. [L. sella, saddle] Saddle-shaped.seller groove (ARTHRO: Crustacea) In Decapoda, a shorttransverse groove on the carapace, dorsally anterior to thecervical groove of Nephropidae.selva n. [L. silva, wood] A tropical rain forest.selvage n. [A.S. self; edge, its own proper edge] (ARTHRO:Crustacea) In Ostracoda, the principal ridge of the contactmargin sealing the valves closed.sematic a. [Gr. sema, sign] Functioning as a warning of danger,as signalling colors of insects, or disagreeable odors ofcertain poisonous or dangerous animals. see allosematic,antiaposematic, aposematic, parasematic, pseudosematic,episematic, pseudepisematic, pseudaposematic.sematophore see spermatophoresemelparity n. [L. semel, once; parere, to bear] Producingyoung only once in a lifetime. semelparous a.semiaquatic a. [L. semis, half; aqua, water] Living in wetplaces, or partially in water.semidominant see codominantsemifenestra a. [L. semis, half; fenestra, window] (NEMATA:Secernentea) In Heterodera one of a pair of openings in thevulval cone separating the vulval bridge. see circumfenestrate.semigeographic speciation see parapatric speciationsemilunar a. [L. semi, half; luna, moon] A half-moon shapedmarking with sharp ends.seminal a. [L. semen, seed] Pertaining to structures in whichsperm are involved.

Online Dictionary of Invertebrate Zoology 817seminal bursa (PLATY: Turbellaria) A term used to describe thesac for receiving sperm during copulation that will bestored for a period of time; bursa seminalis. see bursacopulatrix.seminal canal (ARTHRO: Insecta) In female Coleoptera, a ductor canal that connects the spermatheca with the vagina,functioning in sperm transport.seminal ducts see vas deferensseminal funnel (ANN: Oligochaeta) The internal opening of thevas deferens.seminal furrows/grooves (ANN) Referring to distinct markingsin the epidermis associated with male, or prostaticpores, through which sperm and/or prostatic secretionsmove at the time of copulation.seminal receptacle Diverticulum of oviduct or pouch externalto the oviduct for storing spermatozoa delivered by themale; receptaculum seminalis. see spermatheca, bursacopulatrix, copulatory pouch, copulatory sac, seminalbursa, spermatheca.seminal vesicle 1. A male sac-, tube- or pouch-like structurein which spermatozoa is stored before being discharged;seminal reservoir; vesicula seminalis. 2. (ANN) A pouchusually formed in a posterior septum of a testicular segmentwhere the latter stages of spermatogenesis occur.semination n. [L. semen, seed] Discharge of sperm. see insemination.semiochemical n. [Gr. semeion, mark or signal; chemeia,transmutation] Chemicals involved in the chemical interactionsbetween individual organisms, subdivided into twomajor groups, pheromones and allelochemics.semipupa n. [L. semis, half; pupa, puppet] (ARTHRO: Insecta)In hypermetamorphosis, the interpolated stage betweenthe active larva and the true pupa; the stage preceding pupate;prepupa.semisocial a. [L. semis, half; scocius, ally] (ARTHRO: Insecta)In Hymenoptera, female bees of the same generation livingin a colony with some individuals being primarily egg layersand some primarily workers (auxiliaries).

818Maggenti and GardnerSemper's cells see cells of SemperSemper's larva (CNID: Anthozoa) In Zoantharia, pelagic larvawith long cilia.Semper's rib (ARTHRO: Insecta) In Lepidoptera, a degeneratetrachea present in the wing, alongside a functioning tracheawithin the vein cavity.senescence n. [L. senescere, to grow old] The gradual deteriorationof function in an organism leading to an increasedprobability of death; the ageing process.senility n. [L. senex, old] Old age.senior homonym The earliest published of two or more identicalnames for the same or different taxa. see homonym,junior homonym.senior synonym The earliest published of two or more availablenames for the same taxon. see synonym, juniorsynonym.sense club see rhopaliumsense cone/peg (ARTHRO: Insecta) 1. A minute cone or peg,sensory in function. 2. Sense cone of Hayes, see nesium.sense organ A simple or multicellular receptor organ, comprisedof at least one sensory cell and accessory structures.sensilla n.; pl. -ae [L. sensus, sense] see sensillum.sensilla candelari (ARTHRO: Insecta) In the fulgorid Pyropsfolded sensory plaque organs having numerous bipolarneurons arranged in groups; may have evolved from acluster of basiconic sensilla.sensilla circumfila (ARTHRO: Insecta) Thin-walled chemoreceptorswith pores on fine surface ridges of elaboratelylooped sensilla on the antennae of cecidomyids.sensilla pouch (NEMATA) An expansion of the amphidial tube,containing the sensory elements of the sensilla situatedposterior to the amphidial pouch; fusus amphidialis.sensillium see sensillum.sensillum n.; pl. -la [L. sensus, sense] 1. A receptor complexcomposed of a sense cell or units of sense cells plus associatedstructures: innervated hair, flat sensory plate, or sen-

Online Dictionary of Invertebrate Zoology 819sory pit. 2. A small epithelial sense organ or nerve ending;a simple receptor complex.sensillum ampullaceum A sense organ in which the sensecone is a flask- or pouch-shaped cavity with no externalstructure evident; ampullaceous sensillum; sensory flasks.sensillum auriforme (ARTHRO: Chelicerata) In Acari, a senseorgan with flattened disks, similar to sensillum campaniformium.sensillum basiconicum A sense organ with an external processin the form of a minute cone or peg; basiconic sensillum.sensillum campaniformium A thin, flexible, dome-shapedsense organ that has no pore or opening, sometimes occurringin groups, that respond to strains on the cuticle, asopposed to individual muscle movement; sensory cupolum.sensillum chaeticum A sense organ with an external processin the form of a spine- or bristle-like seta, tactile in function.sensillum coeloconicum A sense organ with an externalprocess in the form of a thin-walled conical or peg-likeprojection in a shallow pit below the surface of the bodywall; coeloconic sensillum; sensory pit-peg.sensillum coelosphaericum (ARTHRO: Insecta) Olfactory receptor,lacking pore tubules, found on the last antennalsegment of Nicrophorus, composed of a complicated networkof filaments.sensillum coleum A sense organ that is completely coveredwith a sheath except for the internal canal.sensillum insiticum A sense organ that shows no evidence ofan external structure or pore, but the ciliary process ormodified cilia are embedded in the cuticle.sensillum opticum A light perceiving sense organ; an ommatidiumof a compound eye.sensillum placodeum A sense organ in the form of a flat,plate-like external membranous cover over an enlargedpore tubule, with the outer surface continuous with thegeneral surface; maybe olfactory in function; sensory

820Maggenti and Gardnerplates.sensillum rhinarium see rhinariumsensillum scolopophorum see scolopidiumsensillum styloconicum A sense organ having a terminalsensory cone, usually in a pit in the cuticle, innervated bynerve fibers running to its tip; thought to be olfactory infunction; sensilla styloconica; terminal sensory cone.sensillum squamiformium (ARTHRO: Insecta) A sense organwith a scale-like external appearance with nerve fiber endingsat its base; usually occurring on the wing veins andabdomen; sensory scales.sensillum trichodeum A sense organ bearing an elongateseta, articulated with the body wall by a membranoussocket so that it is free to move; a mechanoreceptor or lessoften as a chemoreceptor; trichoid sensillum; a tactile sensillum.sensitization n. [L. sensus, sense] The process or state ofsensitiveness or hypersusceptibility to specific substancesin contact with the body tissues.sensorium n.; pl. -riums, -ria [L. sensus, sense] The sensoryapparatus, comprising sense organs and their nerve centers.sensory a. [L. sensus, sense] Having communication with thesensorium.sensory cell A unicellular receptorsensory cell, type I Bipolar nerve cells in or beneath the epidermisof the body wall, or the epithelium of the ectodermalparts of the alimentary canal and their distal processesare usually connected with specific ectodermal sense organs.sensory cell, type II Bipolar or multipolar sense cell in theinner surface of the body and on the wall of the alimentarycanal, their distal processes go to the epidermis, connectivetissue, somatic muscles, splanchnic muscles or alimentaryepithelium.sensory neuron A neuron that acts as a receptor or receivesexcitation directly from a receptor that is not a neuron; an

Online Dictionary of Invertebrate Zoology 821axonic connection usually to the central nervous system.sensu lato L. In a broad sense; S.L.sensu proprio L. In the original sense; S.Pr.sensu stricto L. In the strict sense; a limited sense; S.S.senti n.pl.; sing. sentus [L. sentire, to feel] (ARTHRO: Insecta)In Hemiptera, unbranched, cone-like projections of thebody wall with a few short, stout setae on the trunk of larvaeof coccinellids.septa pl. septumseptal a. [L. septum, partition] Pertaining to a septum.septal filaments (CNID: Anthozoa) Thread-like processes arrangedalong the free edges of the septa that contain glandcells and nematocysts.septalial plates (BRACHIO) Crural plates forming the floor ofthe septalium and joining with the earlier-formed part ofthe median septum.septalium n. [L. septum, partition] (BRACHIO) Troughlikestructure of the brachial valve between hinge plates, consistingof septial plates enveloping and supported by themedian septum.septal plate (BRACHIO) When present, one of two plates thatfuse forming the duplex median septa in the brachial valveand bearing the outer plate on their ventral surface.septasternum see pleurosternumseptate a. [L. septum, partition] Partitioned off into septa.septiform a. [L. septum, partition; forma, shape] Having theshape of an enclosure or septum.septula pl. septulumseptula n.; pl. -ae [L. dim. septum, partition] (ARTHRO: Insecta)In Scarabaeoidea larvae, a narrow bare region of theraster: between a transverse palidium and base of thelower anal lip, or between a pair of oblique palidia divergingbackward to the end of the anal slit, or between a pair ofbackward diverging, or parallel, or curved palidia to the insideends of the anal slit.septulum n.; pl. -tula [L. dim. septum, partition] 1. A small

822Maggenti and Gardnerseptum. 2. (BRYO) An internal membrane of a communicationorgan. see dietella.septum n.; pl. -ta [L. septum, partition] 1. Any dividing wall,membrane or partition separating cavities or masses of tissue;a dissepiment. 2. (ANN) Two layers of peritoneal cellsenclosing muscle fibers, and blood vessels that separateadjacent segments. 3. (ARTHRO: Crustacea) For barnacles,see transverse septum. 4. (BRACHIO) Long, narrow, elevationof the secondary (shell) layer, usually bladelike. a.In Articulata, within underlying floor of valve with high,narrow deflections of fibrous calcite starting near the primarylayer. b. In Inarticulata, comparable deflections ofthe shell lamellae. 5. (MOLL: Cephalopoda) A calcareoustube that supports the siphuncle. 6. (MOLL: Gastropoda) Atransverse plate secreted with early formed whorls of shell.sere n. [L. serere, to join] A chain of communities that followone another in sequence, prisere (primary sere) to a climaxtypical of a particular climate and geographical area. seehydrosere, xerosere, lithosere.serial a. [L. series, a row of things] Pertaining to or consistingof or arranged in a series or row.serial crochets (ARTHRO: Insecta) Crochets of larvae, the distributionof the bases or points of attachment. see uniserialcircle, biserial crochets, multiserial crochets.sericate a. [L. sericus, silken] Having short, thick, silky down;sericeous.sericin n. [L. sericus, silken] (ARTHRO: Insecta) In Lepidoptera,a protein containing a high content of the amino acid serine,that hardens in air to form the glue surrounding thethreads emitted from the spinneret of the silkworm.sericose n. [L. sericus, silken; os, mouth] (ARTHRO: Insecta) InHymenoptera, the opening for the duct of the silk glands.serictery, sericterium n.; pl. -teria, -teries [L. sericus,silken] (ARTHRO: Insecta) The spinning gland or glands. a.In ant larvae, used as shuttles in weaving nests. b. Thesilk-producing glands of a caterpillar. see silk gland.series n. [L. series, succession] In taxonomy, the sampletaken in the field by the collector, or the sample available

Online Dictionary of Invertebrate Zoology 823for taxonomic study. see hypodigm.serific glands (ARTHRO: Insecta) Glands of silk production thatsecrete a viscous fluid that solidifies passing through theorifice of the spinneret, emerging as two semi-crystallinethreads.serology n. [L. serum, whey; Gr. logos, discourse] The studyof sera and the nature, and interactions of antigens andantibodies.serosa n. [L. serum, whey] (ARTHRO: Insecta) The outer embryonicenvelope.serosal cuticle (ARTHRO: Insecta) An embryonic covering incorporatingthe vitelline membrane on the outside, andconsisting of a chitinous endocuticle (white cuticle), with anepicuticle (yellow cuticle) having a second wax layer.serotinal a. [L. serus, late] Appearing later in the season thanis customary with related species.serous a. [L. serum, whey] Secreting a watery, colorless serum.serpentinous a. [OF. serpentine, greenish mineral] A dirty,dark green.serra n. [L. serra, saw] A saw-like structure.serrate a. [L. serra, saw] Marginal teeth or notches like a saw.serration n. [L. serra, saw] A saw-like formation.serratulate a. [L. serrula, small saw] Having little teeth orserrations.serriform a. [L. serra, saw; forma, shape] Saw-toothed; havingthe form of a series of notches.serrula n. [L. dim. serra, saw] (ARTHRO: Chelicerata) In spiders,a serration on the lateral margin of each maxillarylobe for cutting into prey.serrulate a. [L. dim. serra, saw] Finely serrate; having smallfine teeth or minute notches.serum ; pl. -a n. [L. serum, whey] The liquid part of the blood;the secretion of a serous membrane.sesquiocellus n. [L. sesqui-, one and one half; dim. oculus,eye] A large ocellate spot including a smaller one.

824Maggenti and Gardnersessile n. [L. sedere, to sit] Incapable of movement from placeto place; attached directly, without a stem or petiole; permanentlyattached.sessoblast n. [L. sedere, to sit; Gr. blastos, bud] (BRYO: Phylactolaemata)A statobast cemented to the substrate.seston n. [Gr. sesis, sifting] Microplankton; all organisms livingor dead, swimming or floating in aquatic habitats. seenekton, neuston, plankton.seta n.; pl. setae [L. seta, bristle] 1. A bristle, hair or filamentprocess of the cuticle with which it articulates or throughwhich it protrudes. see poison seta, penial seta. 2. (ANN)Chaeta. 3. (ARTHRO: Insecta) Hollow structures formed asextensions of the epidermal layer; macrotrichia or scales.4. (ARTHRO: Crustacea) In Cirripedia, a bristle or spine ontrophi and cirri. setal, setate a.setaceous a. [L. seta, bristle] Bristlelike, slender.setal membrane The membranous floor of a hair socket.setal sac (ANN: Polychaeta) A pocket of the parapodial ramicontaining a single cell at the base, that continually producenew setae as the old are lost.setate a. [L. seta, bristle] Provided with bristles.setiferous a. [L. seta, bristle; ferre, to carry] Bearing setae orbristles; setigerous; chaetiferous.setiform a. [L. seta, bristle; forma, shape] Having the shape ofa bristle or seta.setigenous a. [L. seta, bristle; Gr. genitus, to produce] Givingrise to setae.setiger n. [L. seta, bristle; gerere, to bear] (ANN: Polychaeta)A segment carrying setae.setigeris n. [L. seta, bristle; gerere, to bear] (ARTHRO: Insecta)A structure on the protibia similar in form and use asthe strigil or scraper; the tibial comb.setigerous a. [L. seta, bristle; gerere, to bear] Bearing setae;setiferous.setigerous lobe (ANN: Polychaeta) The lobe of the parapodiumthat bears the setae.

Online Dictionary of Invertebrate Zoology 825setigerous tubercles (ARTHRO: Insecta) In Diptera, bumpsoccurring on the scutellum or legs, each bearing a spine orbristle at the apex.setireme n. [L. seta, bristle; remus, oar] (ARTHRO: Insecta) Inaquatic forms, the hairy, oar-like leg.setula n.; pl. -lae; setule n.; pl. setules [L. dim. seta, bristle](ARTHRO) Slender hair- or bristle- or thread-like, fragilesetae.setulose a. [L. dim. seta, bristle; -osus, full of] Set with short,blunt bristles.sex n. [L. sexus, sex] The physical characteristics by which ananimal is classed as male or female.sex cell see gametessexual congress The association of males and females forsexually reproductive purposes.sex chromosome A special chromosome, not occurring inidentical number or structure in the two sexes, usually determinessex; the X and Y chromosomes. see chromosome,autosome.sex hormone A hormone that influences primary and secondarysexual characters and sexual behavior.sex-limited character A character occurring in only one sex.see secondary sexual characters, sex-linked character.sex-linked character A character controlled by a gene locatedin a sex chromosome. see sex chromosome.sex-linked genes Genes in the sex chromosomes, linked inheredity to the genes determining sex.sex mosaic Intersex; gynandromorph.sexprostatic a. [L. sex, six; Gr. pro-, before; stare, stand](ANN) Having 6 prostates in 3 consecutive segments.sexradiate a. [L. sex, six; radius, ray] Having 6 radii; hexactinal.sex ratio The percentage of males and females of a specifiedage distribution in a population.sex reversal To change from one sex to the other, either by

826Maggenti and Gardnernatural phenomena, pathology, or artificial means.sexthecal a. [L. sex, six; Gr. theke, case] (ANN) Having 3 pairsof spermathecae.sexual cell see gametessexual dimorphism The notable phenotypic difference betweensexes of the same species. see polymorphism.sexuales n.pl. [L. sexus, sex] (ARTHRO: Insecta) In the life-cycleof aphids and adelgids, apterous forms produced on theprimary host; the eggs the females lay hatch in the autumn,giving rise to nymphs of the apterous fundatrices.sexual hybrid A hybrid in which the DNA is recombined by thefusion of haploid nuclei of different mating types.sexual pore see gonoporesexual reproduction Reproduction involving the fusion of twocells (gamete nuclei), resulting from meiosis.sexual zooid (BRYO) a. In Gymnolaemata, autozooid in whichsex cells develop, may or may not show skeletal modification.b. In Cheilostomata, it may loose the feeding ability.sexupara n.; pl. -ae [L. sexus, sex; parere, to bear] 1. Productionof male and female offspring by parthenogenesisthen available for sexual reproduction. 2. (ARTHRO: Insecta)The later generation of parthenogenetic viviparousAphididae females originating from alienicola.shaft n. [A.S. sceaft, shaft] The cylindrical part of a limb orstructure.shagreened a. [Turk. saghri, crupper] Having numeroustooth-like projections.sheath n. [A.S. sceth, shell or pod] A covering enclosing anorganism, part or organ.sheath laminae (BRYO: Stenolaemata) A concentrically enclosedstylet core, continuous with zoarial sheaths, butnormally at right angles to them.sheath of penis see ligulashell n. [A.S. scell, shell] A hard, rigid, calcareous or chitinousstructure covering an animal or part of an animal.shell fold 1. (ARTHRO: Crustacea) The part of the carapace be-

Online Dictionary of Invertebrate Zoology 827hind the cephalon. 2. (MOLL: Bivalvia) The outer fold of themantle edge that houses the periostracal glands at itsbase.shell gland 1. (ARTHRO: Crustacea) see maxillary gland. 2.(MOLL) Specialized epithelium that secretes the shell mantle.3. (PLATY: Trematoda) Mehlis' gland.shield n. [A.S. scyld, shield] 1. A dorsal cover; carapace;scutellum; scutum; clypeus. 2. (ARTHRO: Crustacea) In Decapoda,the anterior part of the cephalothorax of Paguridae.3. (ARTHRO: Diplopoda) The second tergite. 4.(NEMATA) The interlabium.shoulder a. [A.S. sculdor, shoulder] 1. Any obtuse angulation.2. (MOLL: Gastropoda) The angulation of the shell whorls,forming the abaxial edge of the sutural ramp or shelf;shoulder angle.shovel n. [A.S. scofl, shovel] (ARTHRO: Insecta) In Ephemeroptera,the expanded, flattened leg joints.sibling species True species populations that are reproductivelyisolated, but morphologically identical or nearly so;cryptic species.side n. [A.S. side, side] (MOLL: Gastropoda) The surface of ashell, when present, between the shoulder and abapicalsuture or margin of the base.Siebold's organ see crista acousticasieve area (PORIF) The area containing inhalant apertures.sieve plate 1. (ECHINOD) see madreporite. 2. (PORIF) Aplate-like porous structure below the osculum.sieve tracheae (ARTHRO: Chelicerata) In Ricinulei, bundles oftracheae that arise from a tubule of an ectodermal invaginationon the 8th somite. see tube tracheae.sigillum n.; pl. sigilla (ARTHRO: Chelicerata) 1. In some spiders,the impressed, suboval, clear areas on the sternum.2. In Acari, the external mark of a muscle insertion.sigma n. [Gr. the 16th letter, sigma] 1. (ARTHRO: Insecta) Seefurca. 2. (PORIF) A C-shaped diactinal microsclere.sigmaspires n.pl. [Gr. the 16th letter, sigma; speira, twist](PORIF) Diactinal microsclere sigmas that are spirally

828Maggenti and Gardnertwisted.sigmoid a. [Gr. the 16th letter, sigma; eidos, form] Shapedlike the letter S; sigmoidal.sigmoid curve see logistic curvesigna n.pl.; sing. signum [L. signum, sign] (ARTHRO: Insecta)In female Lepidoptera, spines or dentate or roughenedpatches on the inner wall of the corpus bursae, thought tofunction in holding or breaking up spermatophores.silicalemma n. [L. silex, flint; Gr. lemma, peel] (PORIF) A unitmembrane enclosing the axial filament of a siliceous spicule.siliceous, silicious a. [L. silex, flint] Of or pertaining to silica.silicoblasts n.pl. [L. silex, flint; Gr. blastos, bud] (PORIF) A cellthat secretes all or part of a siliceous spicule.siliquiform a. [L. siliqua, a pod; forma, shape] Having theshape of a silique; long, tubular and narrow like a pod.silk n. [Gr. serikos, silk] 1. A secretion that hardens so rapidlyon extrusion that it may be produced as a long continuousthread. 2. (ARTHRO: Chelicerata) Secreted by specializedsalivary glands in Acari; anterior of the abdomen in Araneae;the galea of Pseudoscorpionida. 3. (ARTHRO: Insecta)Secreted from dermal openings on the abdomen in someColeoptera; foretarsi in Embioptera and some empididDiptera; malpighian tubes discharging at the anus in Neuroptera,some Coleoptera and Hymenoptera; mouth cavity(usually modified salivary glands) in Psocoptera, Siphonaptera,some Diptera, Trichoptera, Lepidoptera and Hymenoptera.silk glands Glands that secrete the liquids that produce silk onexposure to the air.silk press (ARTHRO: Insecta) In Lepidoptera larvae, a structuresimilar to a typical salivary pump in which the silk ismolded to a thread; silk regulator; thread press.silvicolous a. [L. silva, forest; colere, to dwell] Inhabiting orgrowing in forests or woodlands.simple a. [L. simplex, simple] Without embellishment; notmodified, forked, toothed, branched or divided.

Online Dictionary of Invertebrate Zoology 829simple eyes (ARTHRO: Insecta) The ocelli.simple seta see unjointed setasimple skeletal wall (BRYO: Stenolaemata) Having the wallcalcified only on edges and one side.simple velum (ARTHRO: Crustacea) In Ostracoda, a velatestructure of flange- or ridgelike form.simple-walled colony see fixed-walled colonysinciput n. [L. semi-, half; caput, head] 1. Upper or forepart ofthe head. 2. (ARTHRO: Insecta) The head area between thevertex and clypeus, especially in Coleoptera.single band of crochets see mesoseriessingle-walled colony see fixed-walled colonysinistral a. [L. sinistra, left] Pertaining to the left; to the left ofthe median line.sinistral gastropods (MOLL) Having the genitalia on the leftside of the head-foot mass or pallial cavity, and commonlythe shell, when viewed with the apex uppermost, with theaperture on the left. see dextral gastropods.sinistron n. [L. sinistra, left] The left side of the body.sinistrorse a. [L. sinistra, left; vertere, to turn] An organismspirally twisting to the left. see dextrorse.sinuate a. [L. sinus, curve] Wavy; tortuous; curving in andout.sinuatolobate a. [L. sinus, curve; Gr. lobos, lobe] Sinuate andlobed.sinuosity a. [L. sinus, curve] Series of curves or bends.sinupalliate a. [L. sinus, curve; pallium, mantle] (MOLL: Bivalvia)Having a pallial sinus or recess in the posterior part ofthe pallial impression due to the retraction of the siphons.sinus n. [L. sinus, curve] A depression; bend; embayment.sinus gland (ARTHRO: Crustacea) Storage release site forneurosecretory material synthesized within the cell bodiescontaining hormones produced by x-organ and other sitesof the central nervous system.siphon n. [Gr. siphon, tube] Any tubular or siphon-like struc-

830Maggenti and Gardnerture. siphonal a.siphonal area (MOLL: Bivalvia) The posterior sector of the shellsurface, usually demarcated anteriorly by the umbonalridge; secreted at the openings in the mantle edge or elevatedto form siphons.siphonal canal (MOLL: Gastropoda) A tubular or troughlikeextension of the aperture for the enclosure of the siphon.siphonal fasciole (MOLL: Gastropoda) The curved growth linesnear the foot of the columella marking successive positionsof the siphonal notch.siphonal fold (MOLL: Gastropoda) A ridge corresponding to thesiphonal notch that winds spirally around the columella.siphonal notch (MOLL: Gastropoda) A narrow sinus of the aperturalmargin near the base of the columella functioningfor protrusion of the inhalant siphon.siphonal retractor muscles (MOLL: Bivalvia) Muscles that retractsiphons into the shell.siphonal tube (MOLL: Bivalvia) A tube composed of agglutinizedparticles derived from boring and fused to the siphonoplax.see chimney.siphonoglyph n. [Gr. siphon, tube; glyphein, to engrave](CNID: Anthozoa) A special groove or canal from the mouthto the actinopharynx, functioning to circulate fluid throughthe coelenteron.siphonoplax n. [Gr. siphon, tube; plax, plate] (MOLL: Bivalvia)A chitinous or calcareous structure secreted by the mantlediverging or fused to form a tube on the posterior marginof the valves; probably for protection of the siphons.siphonostomatous a. [Gr. siphon, tube; stoma, mouth](MOLL: Gastropoda) Having the apertural margin notched orformed with a canal for the protrusion of the siphon.siphonozooid n. [Gr. siphon, tube; zoon, animal; eidos, form](CNID: Anthozoa) A small, modified polyp with reduced orlacking tentacles, having a well developed siphonoglyph topropel water through the canal system of the colony.siphons see gastrozooidsiphuncle n. [Gr. dim. siphon, tube] 1. (ARTHRO: Insecta) see

Online Dictionary of Invertebrate Zoology 831cornicle. 2. (MOLL: Cephalopoda) A tubular vascular extensionborne at the apex of the visceral hump, that runsthrough the outer chambers of the nautiloid shell and secretesgas into them for buoyancy. siphunculate a.Siphuncula, sipunculans, sipunculids n.; n.pls. [Gr. dim.siphon, tube] A phylum of bilaterally, unsegmented, cylindrical,deposit-feeding, benthic marine worms, with tentaclesand mouth located at the anterior extremity of the introvert.sistentes n. [L. sistere, to stop] (ARTHRO: Insecta) The firstgeneration of apterous exules on the secondary host thatgive rise to the alate sexuparae and apterous progredientesin the genus Adelges.sitopore n. [Gr. sitos, food; poros, pore] (ARTHRO: Insecta)The basal part of the cibarial floor of the hypopharynx ofgeneralized chewing insects.sitophore sclerite see esophageal scleritesitus n. [L. situs, place] The locality; site; situation; relativeposition.skeletal duplicature (ARTHRO: Crustacea) In some Cephalocarida,the outer chitinous body covering that is shed duringecdysis.skeleton n. [Gr. skeletos, dried, body] A hardened frame workof an organism functioning for support and protection ofsofter parts; may be external or internal and solid orjointed. skeletal a.skin n. [ON. skinn, skin] The cuticle; the covering.skin bodies (SIPUN) A group of glandular cells often present onthe surface of the trunk.skin gill see papulaskin rings see annularskototaxis n. [Gr. skotos, darkness; taxis, arrangement] Theorientation of an organism towards darkness.slavery see dulosisslime tubes see Cuvierian organsslit n. [A.S. slutan, to tear] 1. A long cut or incision. 2. (MOLL)

832Maggenti and Gardnera. In Polyplacophora, an abrupt indentation in the insertionplate. b. In Gastropoda, a shallow incision to deep fissue inthe outer margin of the aperture.slit band see selenizoneslit ray (MOLL: Polyplacophora) A shallow groove or row ofpores or pits beginning at a slit and extending to the apexof the valve on the ventral side.slit sense organs see lyriform organsslit sensilla (ARTHRO: Crustacea) In Decapoda, small pits lyingjust distal to the walking leg joints; insertions of the dendritesof the joint proprioceptors of Homarus.slope-faced (MOLL: Bivalvia) Referring to the face of the shell,i.e., central, anterior or posterior slope.snout n. [ME. snoute, snout] (MOLL: Gastropoda) In Prosobranchia,a non-retractable, short, mobile eminence at theanterior end on which the mouth is formed.social facilitation (ARTHRO: Insecta) An increase of activityfrom seeing or hearing others engaged in the same activity.social hierarchy see hierarchysocial homeostasis (ARTHRO: Insecta) The steady statemaintenance either by control of microclimate in the nest,or the control of population density, behavior and physiologyof the society members.social hormones see pheromonessocial insects (ARTHRO: Insecta) 1. The ants, termites andsome bees and wasps in which individuals of the same speciescooperate in caring for the young, a reproductive divisionof labor is present, and an overlap of at least two generationsin life stages contributing to the colony; eusocialinsects. 2. A social insect that belongs to either a presocialor eusocial species.social interaction (ARTHRO: Insecta) Relationships among individualsof a colony in which the behavior of one or a fewindivduals influences others in the colony; social facilitationand social homeostasis are two interactions.social parasite (ARTHRO: Insecta) A symbiont found in the

Online Dictionary of Invertebrate Zoology 833nests of social insects, that feeds upon the food stores ofthe colony.social parasitic castration (ARTHRO: Insecta) Pertaining to aFormicidae colony becoming parasitic on another colony ofa different species and eliminating the reproductives of it'shost colony.social parasitism (ARTHRO: Insecta) The coexistence of twospecies of social insects in the same nest, in which one isparasitically dependent on the other. see symphile.society n. [L. socius, companion] An organized cooperativegroup of individuals of the same species; communicationbetween members is implied.socii n.pl.; sing. -us [L. socius, companion] (ARTHRO: Insecta)In male Lepidoptera, lightly sclerotized, paired, hairy padson the caudal margin of the tegumen near the base of theuncus in the genitalia. For Odonata, see superior appendages.sociobiology n. [L. socius, companion; bios, life; logos, discourse]The study of all aspects of communication and socialorganization.sociotomy see colony fissionsocket n. [OF. soket, plowshare] (MOLL: Bivalvia) A cavity inthe hinge to receive the tooth of the opposite valve.sodium pump A mechanism of neurones to move sodium ionsout of the cell during the recovery phase.soft-part polymorph (BRYO: Gymnolaemata) In Cheilostomata,a zooid with sexual features, brood chamber, orelongate tentacles to produce exhalant currents with no increasedskeletal covering.soldiers n. [L. solidus, a coin solider's pay] (ARTHRO: Insecta)In Isoptera, members of a worker subcaste specialized forcolony defense.solenia n.pl.; sing. -ium [Gr. solen, pipe] (CNID: Anthozoa)Endodermal tubes connecting polyps in some colonies.solenidion n.; pl. -ia [Gr. dim. solen, pipe] (ARTHRO: Chelicerata)In Acari, a hollow, microcephalic, pili-, baculi- orclaviform, seta-like formation of the tegument with thin

834Maggenti and Gardnerwalls, and large open roots, on the palp or legs; sensefunction unknown.soleniform a. [Gr. solen, pipe; L. forma, form] Shaped like arazor handle.solenocyte n. [Gr. solen, pipe; kytos, container] Speciallymodified tubular, ciliated or flagellated cells occurring inprotonephridia and nephridia of some invertebrates andlower chordates. a. In protonephridial systems called flamecells or flame bulb; collectively all the flame bulbs, theircollecting tubes, 'bladder' when present, and external orifices;present in such invertebrates as: platyhelminths,nemertines, priapulids, rotifers, kinorhynchs, gastrotrichsand some annelids; function uncertain, may be excretory,osmotic pressure regulator or both. b. In nephridial systemsof some invertebrates and lower chordates its functionis attributed to excretion; structure similar to flamebulb system, but supplied with blood vessels, to help filtrationand absorption from blood; archinephridium.solenomerite n. [Gr. solen, pipe; meros, part] (ARTHRO: Diplopoda)In Julida, the tubular part of the opisthomerite withthe sperm channel and flagellum channel or groove.solenophage n. [Gr. solen, pipe; phagein, to feed] (ARTHRO) Ablood-feeder whose mouthparts pierce directly into a bloodvessel to feed.solid ramose colony see dendroidsolitaria n. [L. solus, alone] (ARTHRO: Insecta) The low densityphase of locusts and some caterpillars. see gregaria,kentromorphism.solitary n. [L. solus, alone] Living alone or in pairs, not incolonies or groups.solute n. [L. solvere, to loosen] 1. In a solution; a substancedissolved in another. 2. Wholly separate; free. see adnate.soma n. [Gr. soma, body] The body of an animal, with the exceptionof the germ cells. somatic a.somatic cells Any cells of the body of an individual, except thegerm cells.somatic chaetae see somatic setae

Online Dictionary of Invertebrate Zoology 835somatic crossing-over Reciprocal chromatin exchange betweenhomologous chromosomes during somatic mitosis.somatic hybrid Non-sexual or vegetative hybrid.somatic layer The external layer of the mesoderm.somatic musculature 1. Muscles of the body. 2. (NEMATA)Longitudinally oriented muscle cells, usually spindleshaped,containing a noncontractile portion and a contractileportion that control body movement.somatic mutation Mutation in any cell other than a germ cellor its precursor.somatic setae 1. Any setae on the body. 2. (ANN) Setae of thesomatic segments that function in locomotion.somatoblast n. [Gr. soma, body; blastos, bud] A cell thatgives rise to somatic cells.somatocoel n. [Gr. soma, body; koilos, hollow] (ECHINOD) Theposterior of the three regions of coelomic sacs of the embryoniccoelom, anterior (axocoel), and middle (hydrocoel).somatocyst n. [Gr. soma, body; kystis, bladder] (CNID: Hydrozoa)In Siphonophora, the beginning of the stem gastrovascularcanal that may contain an oil droplet.somatoderm n. [Gr. soma, body; derma, skin] (MESO) Theouter rings of cells around the body; jacket cells.somato-esophageal muscles Muscles common to the esophagealregion.somato-intestinal muscles Muscles found in the region of theintestine, extending from the body wall.somatome n. [Gr. soma, body; tome, cutting] A somite.somatoplasm n. [Gr. soma, body; plasma, formed or molded]The body-tissues.somatopleure n. [Gr. soma, body; pleura, side] The somaticlayer.somatotheca n. [Gr. soma, body; theke, case] (ARTHRO: Insecta)Area of pupa covering the abdominal rings. seegasterotheca.somite n. [Gr. soma, body] A division of the body; a bodysegment of a metamerically segmented animal; a soma-

836Maggenti and Gardnertome.sonication n. [L. sonus, sound] The disruption of cells bysound waves.sonifaction n. [L. sonus, sound; facere, to make] The productionof sound; sonorific.sordid a. [L. sorditus, dirty] Of a dirty or muddy color; dull.sorotrochous a. [Gr. soros, heap; trochos, wheel] (ROTIF)Bearing a compound wheel organ or trochal disc.spadix n. [L. spadix, palm frond] 1. (CNID: Hydrozoa) A centralcore on which the sex cells ripen on the blastostyle. 2.(MOLL: Cephalopoda) In male Nautilus sp., tentacles thatform a specialized reproductive structure.spado n. [Gr. spadon, a eunuch] (ARTHRO: Insecta) In hymenopteranbees and ants, a worker or neuter individual.spanandry n. [Gr. spanios, rare; andros, male] Progressivedecrease in number of males.spanogamy n. [Gr. spanios, rare; gamos, wife] Progressivedecrease in females.spanogyny n. [Gr. spanios, rare; gyne, female] (ARTHRO: Insecta)The disappearance of mosquito colonies requiringblood meals when maintained on a plant food source.sparganum n. [Gr. sparganon, swaddling band] (PLATY:Cestoda) A second stage larva of Pseudophyllidea, with anelongated shape and lack of cystic cavity; a plerocercoid.spat n. [A.S. spaetan, to spit] (MOLL: Bivalvia) A microscopiclarval stage.spatfall n. [A.S. spaetan, to spit; A.S. feallan, fall] (MOLL: Bivalvia)The en masse settlement of larva.spatha n. [Gr. spathe, blade] (ARTHRO: Insecta) In Hymenoptera,a dorsal lobe of the aedeagus.spathulate see spatulatespatulate a. [L. spatula, spoon] Spatula-like in form; flattened,while broad apically and narrowed basally.spear see styletspecialization n. [L. specialis, special] An animal or structure

Online Dictionary of Invertebrate Zoology 837that has adapted to a habitat or condition during the courseof evolution.speciation n. [L. species, kind] The division of a phyletic line;the process of species multiplication; the origin of discontinuitiesbetween populations resulting from the developmentof reproductive isolating mechanisms. see allopatry,sympatric speciation.species n.; sing. & pl. [L. species, kind] A group of interbreeding(or potentially interbreeding) natural populationsthat are reproductively isolated from other such groups.see subspecies, isolate.species group A group of closely related species, usually withpartially overlapping ranges.species inquirenda A species of doubtful status due to inadequatedescription and lack of preserved specimens.species name 1. A scientific name of a taxon at the rank ofspecies. 2. A binomen, the combination of a generic nameand a specific name.species nova New species; sp. nov.; sp. n.specific character A common feature or structure in all individualsof a species.specific density see economic densityspecific epithet see specific namespecificity n. [L. species, kind] Condition of an individual orgroup of organisms being specific to a host, locale, etc. seehost specificity.specific name The second name in a binomen and in a trinomen.specophile see sphecophilespectrum n.; pl. spectra [L. spectrum, appearance] A statisticalsurvey of species distribution.specular membrane see mirrorspeculum n.; pl. -ula, ums [L. dim. specere, to look at] 1. Anocellus. see eyespots 2. (ARTHRO: Insecta) a. In Lepidoptera,the brilliant metallic markings, or transparent spotson the wing. b. The thin, delicate membrane of the tym-

838Maggenti and Gardnerpanal organ. c. The shiny areas of some caterpillars. d. Inichneumonid Hymenoptera, a slight, polished or sculpturedprominence on the upper hind part of the mesepisternum.sperm n.; pl. & sing. [Gr. sperma, seed] Any male gamete;spermatozoid; spermatozoa.spermaduct n. [Gr. sperma, seed; L. ducere, to lead] Any ductfor carrying sperm; spermiduct; sperm duct; vas deferens.spermagonium n.; pl. -ia [Gr. sperma, seed; gonos, offspring](NEMATA) The sperm-producing structure of a digonicfemale.spermalege see ectospermalege, mesospermalege, Ribaga'sorganspermary, spermarium n. [Gr. sperma, seed] The male gonad,in which the sperm cells are produced.spermatangium n. [Gr. sperma, seed; angon, jar] (MOLL:Cephalopoda) Evaginated spermatophores ready to releasesperm; sperm sacs; sperm bladders; sperm bulbs.spermateleosis n. [Gr. sperma, seed; teleiosis, completion]Spermiogenesis.spermatheca n.; pl. -ae [Gr. sperma, seed; theke, case] Asaccate genital structure in female invertebrates in whichsperm from the male is received and may or may not bestored; seminal receptacle; copulatory sac; copulatorypouch; seminal bursa; seminal receptical; ectospermalege.spermathecal chaeta (ANN: Oligochaeta) In tubificids, chaeta(seta) usually in ventral fascicles on segment x; shape isusually different from somatic chaeta.spermathecal gland (ARTHRO: Insecta) A special gland openinginto the duct of the spermatheca, or near the junctionof the latter with the vagina.spermatid n. [Gr. sperma, seed] One of four haploid cells ofthe male after the meiotic divisions; an immature spermatozoon.spermatocyst n. [Gr. sperma, seed; kystis, bladder] (MOLL:Gastropoda) In some Opisthobranchiates, a sperm storagesac proximal to the bursa copulatrix.spermatocyte n. [Gr. sperma, seed; kytos, container] An

Online Dictionary of Invertebrate Zoology 839auxocyte of males that give rise to the spermatids.spermatodactyl n. [Gr. sperma, seed; dactylos, finger] (AR-THRO: Chelicerata) In Acari, modification of the chelicera inorder for sperm transfer from the male's gonopore to thefemale copulatory receptacles.spermatogenesis n. [Gr. sperma, seed; genesis, beginning]The formation and development of spermatozoa.spermatogonial cyst see sperm cystspermatogonium n.; pl. -ia [Gr. sperma, seed; gonos, offspring]The gonads of male animals that give rise to thespermatocytes.spermatolophis n. [Gr. sperma, seed; lophos, crest] (ARTHRO:Insecta) In certain Thysanura, sperm packets thought to beformed in the nongranular portion of the vas deferens.spermatophore n. [Gr. sperma, seed; pherein, to bear] Apacket or capsule of spermatozoa for transfer from male tofemale.spermatophore cup (ARTHRO: Insecta) In some Orthopteraand Neuroptera, a cup-like cavity at the anterior end of theejaculatory duct; in recent literature called a mold.spermatophore sac 1. (ARTHRO: Insecta) a. In male Caelifera,the sac into which the gonopore opens. b. For Ensifera seeendophallic cavity. 2. (MOLL: Gastropoda) In Prosobranchia,Neritidae and Phenacolepadidae, a large spermatophoricsac associated with the vagina. 3. (MOLL: Cephalopoda)A large diverticulum of the male reproductive systemfunctioning in storage for spermatophores.spermatophoric sac see Needam's sac/organspermatophory n. [Gr. sperma, seed; pherein, to carry] Atype of fertilization in which stalked spermatophores areplaced on the substrate for the females to take up into hergenital tract. see gonopody.spermatophragma see sphragisspermatopositor n. [Gr. sperma, seed; ponere, to place] (AR-THRO: Chelicerata) In Acari, a small evaginable male organfor depositing spermatophores; penis.spermatotheca see spermatheca

840Maggenti and Gardnerspermatozeugma n. [Gr. sperma, seed; zeugma, join] Unitedby fusion of two or more spermatozoa.spermatozoon n.; pl. -zoa [Gr. sperma, seed; zoon, animal]The matured and functional male sperm cell.sperm bladders/bulbs see spermatangiumsperm cell A small, usually motile gamete.sperm conceptacles (ARTHRO: Insecta) In Hemiptera, pairedenlargements of the wall of the common oviduct of femaleCimicidae.sperm cyst (ARTHRO: Insecta) A cellular capsule within thetestis containing the spermatocytes.sperm duct (ANN) Ducts or tubes conveying sperm from themale funnels towards the exterior. see spermaduct, vasdeferens.spermiducal glands 1. Glands associated with the spermducts of many invertebrates. 2. (ANN) see prostateglands.spermiducts n.pl [Gr. sperma, seed; L. ducere, to lead] Themale gonoducts; spermaducts; spermoducts; vas deferens;sperm ducts.sperm induction (ARTHRO: Chelicerata) In Arachnida, the passageof spermatozoa from the genital orifice beneath thebase of the abdomen into the receptacle in the malepalpus.spermiogenesis n. [Gr. sperma, seed; genesis, beginning]The formation of spermatozoa from the spermatids producedduring the meiotic divisions of spermatocytes; spermateleosis.spermoduct see sperm ductspermora n. [Gr. sperma, seed; L. os, mouth] (ARTHRO: Insecta)In Isoptera, the external opening of the spermathecalduct.sperm sacs 1. (ANN) Seminal vesicles or testis sacs or spermathecae.2. (MOLL: Cephalopoda) see spermatangium.sperm web (ARTHRO: Chelicerata) In Arachnida, a web onwhich male spiders deposit the semen before taking it into

Online Dictionary of Invertebrate Zoology 841the palpus.sphaeridium n.; pl. -idia [Gr. dim. sphaira, ball] (ECHINOD)Minute, spherical bodies covered by ciliated epidermis,usually lodged in pits in the test or almost completely enclosed;confined to the ambulacral areas around the mouthor scattered along the entire ambulacra; believed to begravity receptors.sphaeroclone n. [Gr. dim. sphaira, ball; klon, twig] (PORIF) Amegasclere spicule with a subglobular desma produced byswelling of the centrum.sphecology n. [Gr. sphex, wasp; logos, discourse] The studyof wasps.sphecophile n. [Gr. sphex, wasp; philos, love] (ARTHRO: Insecta)A symbiont of wasps; any organism that must spendat least a portion of its life cycle in a wasp colony.sphenoid a. [Gr. sphen, wedge; eidos, like] Wedge shaped;cuneate; cuneiform.spherasters n. [Gr. sphaira, ball; aster, star] (PORIF) A largecenteredspicule with many definite rays.spheres n.pl. [Gr. sphaira, ball] 1. Any globular body. 2. (PO-RIF) Rounded bodies in which growth is concentric around acenter.spherocyte see spherule cellspheroidocyte n. [Gr. sphaira, ball; eidos, form; kytos, container](ARTHRO: Insecta) Round hemocytes with fat-likedroplets, granular and other inclusions and occasionallycrystals.spherula n. [Gr. dim. sphaira, ball] A small sphere.spherular cell see spherule cellspherulate a. [Gr. dim. sphaira, ball] Having one or more rowsof minute tubercles.spherule cell (ARTHRO: Insecta) Hemocytes, varying in shape,that possess few to many, acidophilic inclusions, that mayfill the whole cell. see spherulocyte.spherulocyte n. [Gr. dim. sphaira, ball; kytos, hollow] (AR-THRO: Insecta) Ovoid or round hemocytes, variable in size,

842Maggenti and Gardnercontaining spherules reported to contain neutral or acidmucopolysaccharide, glyco-mucroproteins, lipochrome,trosinase and sulfated sialomucin. see spherule cell.spherulous cell (PORIF) Cells with multiple, large vesiclescontaining coarse granular material.sphincter n. [Gr. sphinkter, binder] Any ring-like muscle thatcontracts, constricts, or closes an orifice.sphingiform larva (ARTHRO: Insecta) A larva with a cylindricalbody with short or no setae, and a mediodorsal horn orbutton on the 8th abdominal segment.sphragis n. [Gr. spragis, seal] (ARTHRO: Insecta) In someLepidoptera, a structure formed by male glandular secretionsor actual male genital parts remaining in the femaleafter insemination that inhibits subsequent copulations ofthe female; spermatophragma; mating plug.spicate a. [L. spica, spike] Spike-shaped; possessing spikes.spiciform a. [L. spica, spike; forma, form] Spike-shaped, assome setae.spicula pl. of spiculumspicular sheath (NEMATA) A conical or tubular extension of thecuticle distally sheathing the spicules beyond the body profile.spicular muscles (NEMATA) Muscles for the protraction andretraction of the spicules.spicular pouch (NEMATA) A cuticular lined pouch that containsthe spicules and is formed from the spicular primordia.spicule n. [L. spicula, small spike] 1. Any minute pointed spineor process. 2. (MOLL: Polyplacorphora) The dorsal girdledecorations of various size, shape and frequency. 3.(NEMATA) Blade-like, sclerotized male copulatory organs,usually paired, located immediately dorsad to the cloaca. 4.(PORIF) An element of the sponge skeleton, composedmainly of silica or calcium carbonate, and rarely spongin.spicule hair (ARTHRO: Insecta) In Lepidoptera, irritative hairusually formed by one or more trichogen cells; size, shape,internal cell components, and body arrangement are variable.see spine hairs.

Online Dictionary of Invertebrate Zoology 843spiculiferous a. [L. spicula, small spike; fero, bear] Providedwith spicules.spiculiform a. [L. spicula, small spike; forma, shape] Spiculeshaped.spiculose a. [L. spicula, small spike] Bearing spicules.spiculum n.; pl. spicula [L. spicula, small spike] Spicularstructures, as the spines of echinoderms and dart of certainsnails.spigots n.pl. [L. spica, spike] (ARTHRO: Chelicerata) In Arachnida,conical spinning tubes on the spinnerets.spiked-tail stage (NEMATA: Secernentea) In Heteroderidae,the pointed tail of the second stage larval cuticle retainedduring initial expansion of the vermiform body.spina n.; pl. spinae [L. spina, thorn] 1. A spine. 2. (ARTHRO:Insecta) a. The medium apodemal process of the spinasternum.b. The medium apodeme.spinasternum n. [L. spina, thorn; sternum, breast plate] (AR-THRO: Insecta) An instersegmental sclerite of the thoracicventer bearing a spina, associated with or united with thesternal sclerite immediately anterior to it; the intersternite.spinate a. [L. spina, thorn] Bearing spines; spiniform.spination n. [L. spina, thorn] The development or arrangementof spines.spindle n. [A.S. spinnal, to spin] 1. Fusiform; tapering graduallyat both ends. 2. (PORIF) A straight monaxial spicule.spindle cell see plasmatocytesspine n. [L. spina, thorn] A pointed process or outgrowth;thorn-like.spine base (BRYO) A collar-like skeletal inflation at the base ofa spine.spine hairs (ARTHRO: Insecta) Poisonous weapons of manycaterpillars, usually of multicellular origin and provided withpointed tips, that upon penetration into human skin arebroken, causing irritation; primitive setalike normal hairs.spiniform a. [L. spina, thorn] Resembling a spine in shape.spiniger n. [L. spina, thorn; gerere, to carry] (ANN: Poly-

844Maggenti and Gardnerchaeta) Composite seta with terminal blades tapering tofine tips; spines.spinigerous a. [L. spina, thorn; gerere, to carry] Spine-bearing.spinneret n. [A.S. spinnan, to spin] 1. (ARTHRO: Chelicerata)In spiders, three pairs of glands at the subcaudal end ofthe abdomen, covered with minute tubes. see fusula;sericose. 2. (ARTHRO: Insecta) An external apparatus fromwhich silk exudes and is spun; produced by dermal glandopenings on the abdomen in Coleoptera; fore tarsi in Embiopteraand some Diptera; by the Malpighian tubes dischargingat the anus in Neuroptera, some Coleoptera andHymenoptera; discharged from the mouth cavity, usuallymodified salivary glands in Psocoptera, Siphonaptera, someDiptera, Trichoptera, Lepidoptera and Hymenoptera; in larvalbees, the salivarium. 3. (NEMATA: Adenophorea) Theterminal pore of the caudal glands; the cement glands.spinning bristle (ARTHRO: Insecta) In Embioptera, hollow,seta-like silk ejectors on the ventral surface of the fore tarsus.spinning glands 1. (ARTHRO) Glands that secrete a silky material;silk glands. 2. (ANN: Polychaeta) Glands of theparapodia that secrete the tube forming material.spinose, spinous a. [L. spina, thorn] Full of spines; beset withspines; armed with sharp spines.spinulate a. [L. dim. spina, thorn] Having very small spines.spinule n. [L. dim. spina, thorn] A minute spine.spinulifer n. [L. dim. spina, thorn; ferre, to bear] (BRACHIO) Aradulifer with laterally compressed crura.spinulose, spinulous a. [L. dim. spina, thorn] Having smallspines.spiracle n. [L. spirare, to breathe] (ARTHRO) A breathing poreor orifice leading to the tracheal or respiratory system;stigma. spiracular a.spiracular area (ARTHRO: Insecta) In Hymenoptera, the firstpleural area.spiracular atrium (ARTHRO: Insecta) A cavity from which the

Online Dictionary of Invertebrate Zoology 845trachea extend into the body.spiracular cleft (ARTHRO: Insecta) In some larvae, spiraclesfound in a closed or open cleft; in closed cleft, one or twoliplike structures are usually present; stigmatic cleft.spiracular depressions (ARTHRO: Insecta) In Coccoidea, usuallyfound on the margin at the base of the spiracular setae.spiracular disk (ARTHRO: Insecta) In Diptera, a flat area onthe caudal segment containing the spiracular openings ofaquatic larvae.spiracular gills (ARTHRO: Insecta) In some aquatic pupae, thelong processes formed by the peritreme and atrial regionsof one or more pairs of spiracles; adapted both for aquaticand aerial respiration.spiracular grooves see spiracular cleftspiracular line (ARTHRO: Insecta) The colored or pigmentedline adjacent to or coinciding with the line of the spiraclesof caterpillars.spiracular muscles (ARTHRO: Insecta) The occlusor and dilator.spiracular plate see peritremespiracular processes (ARTHRO: Insecta) In some Scarabaeoidea,dendriform trabeculae that form the filter apparatus.spiracular sclerite (ARTHRO: Insecta) In Diptera, a sclerite ofthe metapleuron below the metathoracic spiracle.spiracular setae (ARTHRO: Insecta) In Coccoidea, setae ofvarious shapes and sizes terminating each spiracular poreband.spiracular sieve plate (ARTHRO: Insecta) A platelike scleritecovering the spiracle that functions to exclude entry of dustor water into the tracheal system.spiracular spines (ARTHRO: Insecta) In Coccoidea, large setausually associated with each spiracular pore cluster.spiraculate a. [L. spirare, to breathe] With spiracles.spiraculiform a. [L. spirare, to breathe; forma, shape] Spira-

846Maggenti and Gardnercle-shaped.spiral n. [L. spira, coil] A curved line or surface extending outwardwith continuously increasing radius of curvature.spiral amphid (NEMATA: Adenophorea) A coiled amphid tubebeneath the cuticle that appears as a spiral.spiral cleavage A type of early embryonic cleavage in which,after the first few divisions, the cells of the upper quartet inthe eight-celled stage lie above and between the cells ofthe lower quartet and thus tend to form a spiral pattern.spiral conic (MOLL: Gastropoda) In Trochidae, an advancingspiral, winding around an axis and forming a cone shape.spiralia n.pl.; sing. spiralium [L. spira, coil] (BRACHIO) Twospirally coiled supports of the secondary shell for the plectolopheor spirolophe.spiral thread/filament see taenidiumspiramen n. [L. spiramen, vent] (BRYO) A median pore, notconnected to the ascus, in the frontal wall on the proximalside of the orifice.spirasters n.pl. [L. spira, coil; aster, a star] (PORIF) Spirallytwisted streptasters.spire n. [L. spira, coil] (MOLL: Gastropoda) The complete seriesof whorls of a spiral shell except the last.spire angle (MOLL: Gastropoda) In plane through entire shellaxis, angle between two straight lines that touch all thewhorls on opposite sides; these lines can only be drawn ifthe rate of the whorl increase is constant.spirignath, spiritrompe see galeaspirocyst n. [L. spira, coil; Gr. kystis, bladder] (CNID: Anthozoa)In Zoantharia, a type of nematocyst with a thin, single-wallcapsule that is acidophilic and contains a long,spirally coiled, unarmed thread of uniform diameter. seenematocyst.spirogyrate a. [L. spira, coil; gyratus, circular] (MOLL: Bivalvia)1. Umbones coiled outward from the saggital plane. 2.In oysters, having the beak in a distinct spiral.spiroid a. [L. spira, coil] Spiral-shaped.

Online Dictionary of Invertebrate Zoology 847spirolophe n. [L. spira, coil; Gr. lophos, crest] (BRACHIO) Alophopore with brachia spirally coiled and bearing singlerows of paired filamentary appendages.splanchnic a. [Gr. splanchnon, entrail] Of or pertaining to theviscera.splanchnic layer (ARTHRO: Insecta) The inner layer of themesoderm applied to the wall of the alimentary canal;splanchnopleure.splanchnic nerves (ARTHRO: Insecta) Nerves originating fromthe last abdominal ganglion and continuing to the hind intestineand the reproductive system.splanchnopleure see splanchnic layersplendent a. [L. splendens, shining] Shining; glossy; reflectinglight intensely.splicing a. [D. splissen, to split] Methods of attaching onepiece of DNA to another; gene splicing.split sense organs (ARTHRO: Chelicerata) In Arachnida, cuticularsense organs of spiders responding to cuticularstress and vibrations.splitter n. [MD. splitten, to split] In taxonomy, an individualwho divides taxa expressing minute shades of differenceand relationship, through the formal recognition of separatetaxa and their elaborate categorical ranking.spoil, spoile see exuviaspondylium n. [Gr. spondylos, vertebra, joint] (BRACHIO) A U-shaped ridge formed by the fusion of the distal ends of thedental plates that accommodate the ventral muscles.sponge n. [L. spongia, sponge) 1. The common name for thePorifera. 2. (ARTHRO: Crustacea) In Malacostraca, the usuallyorange egg mass brooded by female crayfish.spongicolous a. [L. spongia, sponge; colere, to inhabit] Livingin sponges.spongiform a. [L. spongia, sponge; forma, form] Sponge-like;soft and porous.spongin n. [L. spongia, sponge] (PORIF) Collagenous materialof the skeleton formed of homogeneous fibers or plaques.

848Maggenti and Gardnerspongioblasts see spongocytespongiocoel see spongocoelspongioplasm n. [L. spongia, sponge; Gr. plasma, formed ormolded] The a, H, and I bands of fibrillar bundles of muscles.spongiose a. [L. spongia, sponge] Sponge-like.spongocoel(s) n. [L. spongia, sponge; Gr. koilos, hollow] (PO-RIF) A canal(s) or cavity(ies) that conveys water from theflagellated chambers.spongocyte n. [L. spongia, sponge; Gr. kytos, container] (PO-RIF) A cell that secretes spongin.spontaneous generation Abiogenesis.spoon see bouton, flabellumsporadic a. [Gr. sporas, scattered] Occasional occurrence.sporoblast n. [Gr. spora, seed; blastos, bud] A cell mass thatwill develop into a sporocyst within an oocyst.sporocyst n. [Gr. spora, seed; kystis, bladder] 1. A stage ofsporozoan development, usually within a protective envelope;the oocyst. 2. (PLATY: Trematoda) An asexual stageof development.sporogony n. [Gr. spora, seed; gonos, offspring] The multiplefission of a zygote; a sporont.sporont n. [Gr. spora, seed; on, a being] An undifferentiatedcell mass within an oocyst.sporosac n. [Gr. spora, seed; sakkos, bag] (CNID: Hydrozoa)In Siphonophora, gonophores held in place and not releasedinto the water during larval development.sporozoite n. [Gr. spora, seed; zoon, animal] The stage of developmentof a sporoblast which has divided and exited theoocyst into the hemocoel and migration begins; the malarialstage found in the salivary glands of insects.spout n. [ME. spouten, to vomit] (MOLL: Gastropoda) A rudimentarysiphonal canal.spraing n. [Scot. of Scand. origin, sprang, stripe] A brightstreak or stripe.

Online Dictionary of Invertebrate Zoology 849spring tide A series of tides with a relatively large tidal range,occurring at or soon after the new or the full moon. seeneap.spur n. [A.S. spora, spur] 1. A movable spine-like process. 2.(ARTHRO: Crustacea) a. In Cirripedia, a pendent-like projectionfrom the basal margin of the tergum. b. In Ostracoda,a flattened spine-like projection in some dimorphicgenera.spur fasciole (ARTHRO: Crustacea) In Cirripedia, a slight depressionon the outer surface of the tergum to the apex inline with the spur.spur furrow (ARTHRO: Crustacea) In Cirripedia, a groove onthe outer surface of the tergum to the apex in line with thespur.spurious a. [L. spurius, false] Morphologically untrue; false.spurious claw (ARTHRO) A false claw; a claw-like stout bristle.spurious legs see prolegsspurious vein (ARTHRO: Insecta) A fold or thickening of thewing membrane between two true veins.squama n.; pl. -mae [L. squama, scale] 1. Any decumbentscale. 2. (ARTHRO: Crustacea) A scale-like exopod of theantenna. see scaphocerite. 3. (ARTHRO: Insecta) a. InHymenoptera, a dorsolateral lobe of the phallobase; inants, the first abdominal segment. b. In Hemiptera, thefimbriate or spine-like marginal process of coccoids; plates;scaly hairs. c. In Lepidoptera, the scale-like structure coveringthe wing base of the fore wings. see patagium. d. InDiptera, the calypters; palpiger; alar squama; antisquama;alula; in mosquitoes, the short broad scales on the wingveins; median scale; flat scale. e. In Odonata, the lateralexpansion of the mentum. f. In Diaspidinae, see glandspines. 4. (MOLL: Bivalvia) A thin, long, concentric imbrication.squamate, squamiform a. [L. squama, scale] Scale-like;squamoid.squamous, squamose a. [L. squama, scale] Covered withscales.

850Maggenti and Gardnersquamul alaris see alar squamasquamulate, squamulose a. [L. dim. squama, scale] Havingsmall scales.squarrose a. [L. squarrosus, rough] Rough with projectingscale-like processes, divided into upright and nonparallelwith the plane.squat a. [OF. esquatir, to press down] More broad in proportionthan to height.stabilamentum, stabilimentum n. [L. stabilis, firm; amentum,strap] (ARTHRO: Chelicerata) In Arachnida, one of aseries of obvious zigzag lines at the hub of certain orb spiderwebs that warn birds to avoid them.stadium n.; pl. stadia [L. stare, to stand] 1. The stage or periodin an animals life. 2. The interval between molts of alarva; stade. see instar.stage see stadiumstalk n. [A.S. stel, stalk] A supporting structure, such as apedicel.staphyla n.; pl. staphylae [Gr. staphyle, bunch of grapes] Agroup of gongylidia used as food by Attine ants that growthe fungus.stase n. [Gr. stasis, standing] (ARTHRO: Chelicerata) 1. One ofthe successive instars of the postembryonic development ofa specific species. 2. In Acari, an instar independent ofgrowing molts, that is distinct within a species and can behomologized with the corresponding instars of other species.stasis n. [Gr. stasis, standing] The stopping of normal processes,i.e., growth, fluid movement, etc.stasoid a. [Gr. stasis, standing; eidos, like] (ARTHRO: Chelicerata)The life cycles of some instars that cannot be homologizedwith corresponding instars of other species of thesame group.statary phase (ARTHRO: Insecta) In Hymenoptera, a period inthe army ant cycle in which the colony does not move fromsite to site; the queen lays eggs, and the brood is mostlyeggs and pupae. see nomadism.

Online Dictionary of Invertebrate Zoology 851static a. [Gr. statikos, to cause to stand] Pertaining to rest orequilibrium. see dynamic.statis organ see statocyststatis sense The sense of balance or maintenance in the air orwater.statistical method Special mathematical methods for the elucidationof quantitative variations affected by a multiplicityof factors.statoblast n. [Gr. statos, fixed; blastos, bud] (BRYO: Phylactolaemata)A sessile or free, ovoid or discoid chitinized bud,with large yolky cells and organized germinal tissue, thatgive rise to polypides; resting buds; winter eggs. seefloatoblast.statocone n.; pl. -ia [Gr. statos, fixed; koni, dust] A minutecalcareous granule in a statocyst.statocyst n. [Gr. statos, fixed; kystis, bladder] An organ ofbalance found in many invertebrates, variable in structurefrom an open canal, vesicle, or closed chambers composedof one to many cells (lithocytes), that contains a concretionof granules of sand, lime, diatom shells or quartz grains(statolith), or capsules of ciliated cells enclosing a fluid withone or more statoliths suspended within; otocyst.statocyte see lithocytestatolith n. [Gr. statos, fixed; lithos, stone] A movable concretionof granules of sand, lime, diatom shells, or quartzgrains contained in a statocyst, that functions in equilibrium;lithite.statorhabd see rhopaliumstauractine a. [Gr. stauros, cross; aktis, ray] (PORIF) A tetractinalspicule with all four rays in a single plane.stegasimous a. [Gr. stege, roof] (ARTHRO: Chelicerata) InAcari, having the prodorsal sclerite project over the chelicerae.see astegasimous.stellate a. [L. stella, a star] Star-shaped; resembling the raysof a star.stellate cells Stelliform plasmatocyte-like cells often adheringto internal tissues. see plasmatocyte.

852Maggenti and Gardnerstelliform a. [L. stella, a star; forma, form] Star-shaped.stelocyttarous a. [Gr. stele, pillar; kyttaros, partition] (AR-THRO: Insecta) Pertaining to nests, especially of socialwasps, in which the brood combs are attached to the supportby pillars and not connected with the envelope. seeastelocyttarous.stem see hydrocaulusstemapoda, stemapod n. [Gr. stema, penis; pous, foot] (AR-THRO: Insecta) In larval Noctuoidea, elongated anal prolegs.stem cell see prohemocytestemma n.; pl. stemmata, stemmatas [Gr. stemma, garland](ARTHRO: Insecta) The lateral ocelli of larval holometabolousinsects that vary in number from one on each sidein tenthredinid larvae to 6 on each side in lepidopterouslarvae; a simple eye; an ocellus.stem nematogen (MESO: Rhombozoa) A young nematogenwith the same number and arrangement of cells as thelarva, but with many agamete cells that give rise to ordinarynematogens.stenobathic a. [Gr. stenos, narrow; bathys, depth] An organismrestricted to a narrow vertical range of movement. seeeurybathic.stenobenthic a. [Gr. stenos, narrow; benthos, depth of thesea] An organism living within a narrow range of depth ofthe sea bottom. see eurybenthic.stenocephalous a. [Gr. stenos, narrow; kephalon, head]Having a narrow, elongated head.stenogamous a. [Gr. stenos, narrow; gamos, union] (ARTHRO:Insecta) Pertaining to Culicidae that require only a smallenclosure when mating in captivity. see eurygamous.stenogastric a. [Gr. stenos, narrow; gaster, stomach] With ashortened abdomen or gaster.stenoglossate a. [Gr. stenos, narrow; glossa, tongue] (MOLL:Gastropoda) Pertaining to the radula consisting of 1-1-1 or0-1-0 rows of teeth.stenohaline a. [Gr. stenos, narrow; halinos, saline] Any or-

Online Dictionary of Invertebrate Zoology 853ganism capable of withstanding only slight variations of salinityin its environment; stenosalinity. see euryhaline.stenohygric a. [Gr. stenos, narrow; hygros, moist] Pertainingto an organism tolerating only a narrow atmospheric humidityrange.Stenolaemata, stenolaemates n.; n.pl. [Gr. stenos, narrow;laimos, throat] A class of "tubular bryozoans", exclusivelymarine, with circular lophophores lacking an epistome.stenomorphic a. [Gr. stenos, narrow; morphe, shape] 1. Generawith limited morphological characters. 2. Dwarfed.stenonoty n. [Gr. stenos, narrow; notos, back] A small thorax.stenophagous a. [Gr. stenos, narrow; phagein, to eat] Existingon only a limited variety of foods. see euryphagous,omnivorous.stenopodium n. [Gr. stenos, narrow; pous, foot] (ARTHRO:Crustacea) Slender, sometimes setose, elongate appendage,composed of rod-like segments.stenopterous a. [Gr. stenos, narrow; pteron, wing] Having anarrow, complete wing.stenosaline see stenohalinestenosis a. [Gr. stenos, narrow] Constriction of vessels, ducts,etc.stenotele n. [Gr. stenos, narrow; telos, the end] (CNID) Astinging nematocyst; a sprially coiled thread armed withspiral rows of projections that is provided at its distal endwith a lid (operculum); a penetrant.stenothermal a. [Gr. stenos, narrow; therme, heat] Confinedto living within a narrow range of temperatures. see eurythermal.stenotopic a. [Gr. stenos, narrow; topos, place] Organismshaving a limited geographical distribution or occurring inrestricted habitats. see eurytopic.stenovalent a. [Gr. stenos, narrow; L. valens, strong] An organismrestricted to few types of environmental conditions.see euryvalent.stenoxenous a. [Gr. stenos, narrow; xenos, host] Having a

854Maggenti and Gardnernarrow host range.steppe n. [Russ. step', lowland] Short grass plains, generallytreeless.stercoral a. [L. stercus, dung] 1. Pertaining to excrement. 2.Living in or feeding on dung.stercoral pocket (ARTHRO: Chelicerata) A dilated portion ofthe proctodeum of certain spiders in which fecal matter andexcreta temporarily accumulate.stereoblastula n. [Gr. stereos, solid; blastos, bud] An early,solid blastula larva, all of whose cells reach the externalsurface.stereogastrula n. [Gr. stereos, solid; gaster, stomach] A generalterm for solid metazoan larvae.stereoisomer n. [Gr. stereos, solid; isos, equal; meros, part]Different three-dimensional configurations of organic moleculesthat have different light rotational properties.stereokinesis n. [Gr. stereos, solid; kinesis, movement] A reflexsensitivity inhibition due to passive contact stimuli;thigmotaxis.stereom(e) n. [Gr. stereos, solid] 1. The rigid material of theinvertebrate skeleton. 2. (BRYO: Stenolaemata) The extrazooidalskeletal deposits, additions to structural skeleton,or to the vesicle roof skeleton.stereotaxis n.; pl. -taxes [Gr. stereos, solid; taxis, arrangement]The directive response of an organism to contactwith solids; thigmotaxis. a. Positive stereotaxis: toward thecontact. b. Negative stereotaxis: away from the contact.stereotactic a.stereotropism n. [Gr. stereos, solid; tropos, turn] A movementin direction determined by contact with a solid body.a. Positive stereotropism: toward contact. b. Negativestereotropism: away from contact. stereotropic a.sterile a. [L. sterilis, unfruitful] Incapable of producing viablegametes.sterilization n. [L. sterilis, unfruitful] 1. Rendering an animalincapable of reproduction. 2. Rendering a substrate free oforganisms.

Online Dictionary of Invertebrate Zoology 855sterinx n. [Gr. sterinx, support] (ARTHRO: Crustacea) In Ostracoda,one of a pair of connecting pieces lateral to the tropisin the male copulatory apparatus.sterna pl. of sternumsternacosta n. [Gr. sternon, chest; L. costa, rib] (ARTHRO: Insecta)An internal transverse ridge connecting the bases ofthe sternal apophyses.sternacostal suture (ARTHRO: Insecta) The external suture ofthe thoracic sternum through the apophyseal pits separatingthe basisternum from the sternellum.sternal a. [Gr. sternon, chest] (ARTHRO: Insecta) Pertaining tothe sternum.sternal apophyseal pits (ARTHRO: Insecta) In higher insects,an external indentation marking the point of origin of thesternal apophysis.sternal apophysis (ARTHRO: Insecta) One of a pair of lateralapodemal arms of the eusternum marked by pits joined bya sulcus, thus dividing the eusternum into a basisternumand a sternellum; in higher insects they arise in the midlineand separate internally, forming the Y-shaped furca. seepleural apophysis.sternal canal (ARTHRO: Crustacea) In Decapoda, an internalskeletal structure of some crabs formed by the meeting ofthe sternal apodemes from opposite sides of the bodyabove the nerve cord; sternum canal.sternal coxal process (ARTHRO: Insecta) 1. A projection ofthe sternum serving for the ventral point of articulationwith the coxa. 2. In Culicidae, a winglike expansion of themeso- and metabasisterna; ventral process.sternal laterale (ARTHRO: Insecta) A plate on each side of thesternum or presternum in some lower insects.sternal plastron see sternumsternal process (ARTHRO: Crustacea) In Mysidacea, a projectionarising from the midsection of the sternite.sternal spatula see breastbonesternal taenidium (ARTHRO: Chelicerata) In Opilioacariformes,a surface canal in the sternal region of the podosoma ex-

856Maggenti and Gardnertending from the coxal gland orifice, between coxae I andII, to the subcapitular gutter.sternal verrucae (ARTHRO: Chelicerata) In Opilioacariformes,paired wart-like structures in the sternal region.sternannum see basisternumsternapophysis n. [Gr. sternon, chest; apo-, separate; physein,to grow] (ARTHRO: Chelicerata) In Acari, protuberance(single, paired or three) in the sternal region of leg I.sternaulus n.; pl. -li, -lices [Gr. sternon, chest; aulos, tube](ARTHRO: Insecta) In ichneumonid Hymenoptera, a horizontalgroove on the lower edge of the mesopleurum fromthe prepectal carina backwards, sometimes reaching thebase of the middle coxa; the dividing line between themesosternum and mesopleurum.sternellum n. [Gr. dim. sternon, chest] (ARTHRO: Insecta) Apart of the eusternum posterior to the sternacostal suture.sternellar a.sternite n. [Gr. sternon, chest] (ARTHRO) The main ventralsclerite of a somite.sternopleural bristles (ARTHRO: Insecta) In Diptera, bristleson the sternopleuron.sternopleurite n. [Gr. sternon, chest; pleuron, side] (ARTHRO:Insecta) The ventral sclerite of the thoracic pleuron thatarticulates with the coxa and becomes fused with the sternum;a sternopleuron.sternopleuron see sternopleuritesternum n.; pl. sterna [Gr. sternon, chest] 1. (ARTHRO) Theprimary ventral portions of the somites, or the compositeventral sclerite of a segment. 2. (ARTHRO: Chelicerata) Thesclerotized plate of spiders between the coxae marking thefloor of the cephalothorax.sternum canal see sternal canalsterols n.pl. [Gr. stereos, solid] Alcohols of high molecularweight containing benzene-rings found in plants and animals.sterrasters n. [Gr. sterrhos, solid; aster, star] (PORIF: Desmospongiae)Large centered, globular spicules with rays

Online Dictionary of Invertebrate Zoology 857reduced to small projections from the spherical surface.sterrula n. [Gr. sterrhos, solid] (CNID: Anthozoa) A solid freeswimminglarva of Alcyonaria; stereoblastula.stethidium n. [Gr. stethos, breast] 1. (ARTHRO: Chelicerata) InAcari, the nonsclerotized prodorsum. 2. (ARTHRO: Insecta)The thorax and its appendages.stethosoma n. [Gr. stethos, breast; soma, body] (ARTHRO:Chelicerata) In Acari, that part of the body from the circumcapitularfurrow to the disjugal furrow; prosoma withoutthe gnathosoma.Stewart's organs (ECHINOD: Echinoidea) In cidaroids,coelomic pouches associated with Aristotle's lantern, functioningfor interchange of gases.stichic a. [Gr. stichos, row] Pertaining to a row parallel to thelongitudinal axis.stichocyte n. [Gr. stichos, row; kytos, container] (NEMATA:Adenophorea) An individual cell of a stichosome.stichosome n. [Gr. stichos, row; soma, body] (NEMATA: Adenophorea)A longitudinal series of cells (stichocytes) thatform the posterior esophageal glands.sticklac n. [A.S. sticca, stick; Skr. laksa, lac] (ARTHRO: Insecta)Branches or twigs covered with the dried lac of scaleinsects. see lac.stigma n.; pl. stigmata [Gr. stigma, mark] 1. A spiracle orbreathing pore. 2. (ARTHRO: Chelicerata) In Acari, a scleritesurrounding a spiracle. 3. (ARTHRO: Insecta) a. A coloredwing spot. see monostigmatous. b. In Odonata, a tickeningof the wing membrane along the costal border nearthe apex. c. In Diptera, An apodeme at the base of theventral surface of the postgenital lobe of female mosquitoes;basal median (longitudinal) apodeme; a sclerite surroundinga spiracle on a maggot. 4. (PLATY: Trematoda) InSchistosomatoidea, an operculum-like area of an eggshellthrough which the miracidium hatches.stigmal vein (ARTHRO: Insecta) A short vein extending posteriorlyfrom the costal margin of the wing; stigma.stigmatal field (ARTHRO: Insecta) An area around the spiracles

858Maggenti and Gardnerof larvae; spiracular disk; respiratory disk. see spiracularlinestigmatal line see spiracular linestigmatal spine (ARTHRO: Insecta) In larval Diptera, the extrusiblestructure (modified terminal spiracles) in the analsiphon.stigmatic cord (ARTHRO: Insecta) In some larvae, a delicatecord running from the scar of a nonfunctional spiracle to anadjacent part of the tracheal system.stigmatic scar (ARTHRO: Insecta) The mark on the surfacemade by the ecdysial tube after molting.stigmatiferous a. [Gr. stigma, mark; L. ferre, to bear] (AR-THRO: Insecta) Bearing spiracles or stigmata.stigmergy n. [Gr. stigma, mark; mergere, to dive] (ARTHRO:Insecta) In social insects, the directing of work by individualcolony members based on work previously accomplishedas opposed to direct signals from nestmates.stimulus n.; pl. stimuli [L. stimulus, a goad] Any change ofexternal or internal conditions resulting in a change in theactivities of an organism.sting apparatus (ARTHRO: Insecta) In female Hymenoptera,the modified ovipositor of aculeates and many terebrantes,usually containing the venom gland and one accessorygland, the Dufour gland; others may sometimes be present:the Koshevnikov or Koshewnikow gland, the Bordas'gland, the sting sheath gland, or anal gland.sting autotomy (ARTHRO: Insecta) In Hymenoptera, enlargedbarbs on the sting apparatus that remain at the sting site;autothysis.stinging button (CNID) A group of nematocysts on a jellyfishtentacle, especially the Portuguese man-of-war.sting sheath (ARTHRO: Insecta) In Hymenoptera, the cover ofthe sting formed by the lateral halves of the third valvulae.sting sheath gland/sheath gland (ARTHRO: Insecta) In Hymenoptera,a gland in the sting sheath valves of variousbees, in the form of a high palisade gland epithelium beneatha strongly sclerotized strip on the outer sides of the

Online Dictionary of Invertebrate Zoology 859sheaths; function unknown.stipe n. [L. stipes, a stem] 1. A stem or stalk-like appendage.2. (ARTHRO: Crustacea) In Eucarida, a stemlike basal partof an appendage with sometimes squamate or othershapedexpopod, i.e., the second joint of the antenna-likeappendage.stipes n.; pl. stipites [L. stipes, a stem] 1. (ARTHRO: Chelicerata)The distal end of the embolus (copulatory organ) ofspiders. 2. (ARTHRO: Diplopoda) The lateral lobes of thegnathochilarium. 3. (ARTHRO: Insecta) a. The second segmentor division of a maxilla that bears endite lobes, thelacinea and galea on its inner apical angle and the telopodite(palpus) laterally; may be combined with basi-, disti-,etc. b. In Diptera, a rodlike structure located inside thehead ventral to the tentorial arms. 4. (ARTHRO: Pauropoda)One of the three articles of the first maxilla, along withcardo and lacinia. 5. (ARTHRO: Symphyla) Two pairs ofmaxillae similar to those of insects, except lacking a jointseparating the cardo and stipes.stipiform a. [L. stipes, a stem; forma, shape] Resembling astalk.stipital a. [L. stipes, a stem] Pertaining to the stipe(s).stipple n. [D. stippelen, to spot] Numerous circles or dots;shading effects produced by dots, circles or small marks.Stobbe's gland (ARTHRO: Insecta) In Lepidoptera, paired multicellularaphrodisiac pheromone producing glands in thesecond abdominal segment of male noctuids.stock n. [A.S. stocc, stem, race] (ANN: Polychaeta) The sexualindividuals from which other individuals arise asexually.stolon n. [L. stolo, a branch] 1. (ANN) Individuals that arebudded or fragmented asexually off of other individuals. 2.(BRYO: Stenolaemata) In Stolonifera, a tubular kenozooidor extension of an autozooid from which autozooids arebudded. 3. (CNID: Anthozoa) A stem-like structure fromwhich polyps arise. see hydrocaulus.stolonate a. [L. stolo, a branch] Having stolons; stoloniferous.stoloniferan n. [L. stolo, a branch; ferre, to bear] (BRYO:Stenolaemata) An autozooid budded from a single kenozo-

860Maggenti and Gardneroid.stoma n.; pl. stomata [Gr. stoma, mouth] 1. Any of varioussmall, simple mouth openings of invertebrates. 2. (NEMATA)The mouth or buccal cavity, from the oral opening andusually includes the anterior end of the esophagus(=pharynx).stomach n. [Gr. stoma, mouth] The digestive cavity of invertebrates.stomata pl. of stomastomatal a. [Gr. stoma, mouth] Pertaining to the stoma.stomate a. [Gr. stoma, mouth] 1. Bearing a mouth. 2. (ANN) Anephridium with a funnel; an open nephridium.stomatodaeum see stomodeumstomatogastric see recurrent nerve, stomogastric nervoussystemstomatostyle, stomatostylet n. [Gr. stoma, mouth; stylos,pillar] (NEMATA: Secernentea) A stylet or protrusible hollowspear found in fungus feeding plant parasitic and insectparasitic nematodes of the suborders Tylenchina andAphelenchina, presumed to have evolved from the walls ofthe stoma.stomatotheca n. [Gr. stoma, mouth; theke, case] (ARTHRO:Insecta) That part of the pupal covering over the mouthstructures.stomoblastula n. [Gr. stoma, mouth; blastos, bud] (PORIF:Calcarea) A developmental period of the amphiblastula,when the blastula opens and ingests adjacent choanocytes.stomocnide see injectorstomodeal bridge (ARTHRO: Chilopoda) A commissure thatanteriorly connects the tritocerebral glanglia.stomodeal canal (CTENO) Paired canals lying parallel to thestomodeum or pharynx; the pharyngeal canal.stomodeal feeding (ARTHRO: Insecta) A mixture of salivarysecretions and regurgitated intestinal contents receivedfrom another insect. see proctodeal feeding.stomodeal nervous system see stomatogastric sympa-

Online Dictionary of Invertebrate Zoology 861thetic nervous systemstomodeal valve see cardiac valvestomodeum, stomodaeum n. [Gr. stoma, mouth; hodos,way, road] The anterior ectodermal portion of the alimentarycanal; the fore-intestine or foregut.stomogastric nerve see recurrent nervestomogastric nervous system (ARTHRO: Insecta) The nervoussystem directly connected to the brain, innervating thefore and middle intestine, heart and certain other parts;the esophageal nervous system; sympathetic system.stone canal (ECHINOD: Asteroidea) A vertical canal containingcalcareous deposits in its wall, that descends to the oralside of the disc, joining a circular canal (the water ring) atthe inner side of the ossicles that ring the mouth.storage pots (ARTHRO: Insecta) In Hymenoptera, containersconstructed of cerumen for food storage by social bees; ahoney pot.strahl n.; pl. strahlen [Ger. strahl, ray] A ciliary process, rayor barbule.straight-hinge veliger see protostracumstrangulated a. [L. strangulare, to strangle] Constricted; contracted;held in.strata pl. of stratumstratification n. [L. stratum, a cover; ficare, to make] Act orprocess of being made up of layers.stratum n.; pl. -ta [L. stratum, a cover] 1. A layer of tissue orcells that compose an organ. 2. A group of organisms inhabitinga particular geographical area. 3. A layer of vegetation,usually at the same stage of development. 4. Alayer of sedimentary rock or earth.strepsilaematous a. [Gr. strepsis, twisting; laimos, throat]Having a pharynx rotated along its length. see euthylaematous.streptasters n.pl. [Gr. strepsis, twisting; aster, star] (PORIF)Short, spiny, microscleric monaxon spicules.streptoneury n. [Gr. strepsis, twisting; neuron, nerve] (MOLL:

862Maggenti and GardnerGastropoda) Equivalent to chiastoneury.stria n.; pl. striae [L. stria, furrow] A groove or depressedline. striate a.striation n. [L. stria, furrow] A longitudinal ridge or furrow.stricture n. [L. stringere, to bind tight] A binding or contraction,as of a passage in a body.stridulating organs The impact of some part of the bodyagainst the substratum; friction method, rubbing two partsof the body together; vibrating membrane; sound producedby a pulsed air stream.stridulation n. [L. stridere, to make a creaking or gratingnoise] Any sound produced by a lower animal.stridulatory a. [L. stridere, to make a creaking or gratingnoise] Pertaining to or the nature of stridulation.striga n.; pl. strigae [L. striga, furrow] A narrow, transverseline or streak.strigate a. [L. striga, furrow] Marked with fine, closely setgrooves.strigil n. [L. strigilis, scraper] (ARTHRO: Insecta) 1. A curvedstructure at the apex of the fore tibia of many insects thatfunctions as a scraper, a tibial comb or antenna cleaner. 2.In some Hemiptera, a currycomb-like structure situated onthe dorsal surface of the abdomen.strigilation n. [L. strigilis, scraper] (ARTHRO: Insecta) In Hymenoptera,licking secretions from the body of anotheranimal.strigilator n. [L. strigilis, scraper] One who licks the surface ofanother to collect secretions from the body.strigose a. [L. striga, furrow] Covered with strigae; markedwith fine, closely set grooves.strigose ventral areas (ARTHRO: Insecta) In Hemiptera, theinner side of the hind tibiae containing wart-like tubercles,each bearing a subapical tooth; rubbing against the femurproduces an audible sound.strigula n.; pl. -ulae [L. striga, furrow] A fine, short transversemark or line.

Online Dictionary of Invertebrate Zoology 863strike n. [OE. strican, to stroke, level out] (ARTHRO: Insecta)The deposition of Diptera eggs or larvae on a living host.string reef (MOLL: Bivalvia) Oysters crowded into a long, narrowaccumulation.striola a. [L. dim. stria, furrow] Finely impressed parallel lines.stripe n. [MD. strijp, stripe] A longitudinal color marking.strobila n.; pl. -lae [Gr. strobilos, anything twisted, pine cone]1. An organism, or stage of an organism, from which successiveannular disc embryos bud off. 2. (CNID: Scyphozoa)A scyphistoma larva of a jellyfish consisting of ephyrae. 3.(PLATY: Cestoda) A tapeworm, consisting of scolex, 'neck',immature, mature and usually gravid proglottids.strobilation, strobilization n. [Gr. strobilos, anything twisted,pine cone] 1. The formation of a chain of body segmentationinto zooids. 2. (CNID: Scyphozoa) The ephyrae of jellyfish.see monodisk, polydisk. 3. (PLATY: Cestoda) Theproglottids.strobilocercoid n. [Gr. strobilos, anything twisted, pine cone;kerkos, tail; eidos, like] (PLATY: Cestoda) In Schistotaenia ,a cysticercoid that undergoes some strobilation.strobilocercus n. [Gr. strobilos, anything twisted, pine cone;kerkos, tail] (PLATY: Cestoda) A simple cysticercus withevidence of strobilation.stroma n.; pl. stromata [Gr. stroma, bed] Connective tissueframework of an organ.strombiform a. [Gr. strombos, a top, a spiral shell; L. forma,shape] (MOLL: Gastropoda) Roughly biconical, with expandedouter lip; said of the shell of Strombus .stromboid notch (MOLL: Gastropoda) In Strombus , a curve ornotch in the outer lip, above the anterior notch.strongylaster n. [Gr. strongylos, rounded; aster, star] (PORIF)A star-shaped spicule with small center and rays withrounded edges.strongyle n. [Gr. strongylos, rounded] 1. (NEMATA: Secernentea)A common name for the order Strongylida. 2.(PORIF) A diactinal monaxon (spicule) rounded at bothends.

864Maggenti and Gardnerstrongyloxea n. [Gr. strongylos, rounded; oxys, sharp] (PO-RIF) A monactinal megasclere with one end rounded andthe other pointed.strophe n. [Gr. strophos, twisted] (ARTHRO: Insecta) In malesof higher Diptera, spiral curling of parts of the postabdomeninto a protected position at rest.structural colors Colors resulting from structure rather thanpigment.structural gene Any gene that determines the structure of apolypeptide through the production of messenger RNA.structure n. [L. structus, build] Any organ, appendage or partof an organism.struma n.; pl. -ae [L. struma, scrofulous tumor] (ARTHRO: Insecta)In most Coccinellidae larvae, distinct tubercles of thebody wall bearing spines. strumose a.stupeous a. [L. stupa, coarse fiber of flax or hemp, tow] Coveredwith fiber-like filaments.stupulose a. [L. stupa, coarse fiber of flax or hemp, tow] Coveredwith coarse decumbent hairs.stylamblys see appendix internastylate a. [Gr. stylos, pillar] With a style; stylelike.style, stylus n.; pl. styli [Gr. stylos, pillar] 1. (ARTHRO: Chelicerata)The embolus of spiders. 2. (ARTHRO: Crustacea) seetelson. 3. (ARTHRO: Insecta) a. Any slender, tubular orspinelike appendage at the end of the abdomen. b. In someDiptera, a bristlelike process at the terminal segment of theantenna. 4. (BRYO: Stenolaemata) A general term for arodlike skeletal structure forming a spinose projection onthe zoarial surface; canaliculus; stylet. see acanthopore.5. (CNID: Hydrozoa) A calcareous projection. 6. (MOLL) seecrystalline style. 7. (PORIF) A monactinal spicule dissimilarat the two ends. stylate a.style sac (MOLL) The posterior conical region of the stomach,lined with cilia, but devoid of chitin.stylet n. [Gr. stylos, pillar] 1. Any small rigid bristle or needlelikeappendage or organ. 2. (ARTHRO: Crustacea) see caudalramus. 3. (ARTHRO: Insecta) One of the piercing

Online Dictionary of Invertebrate Zoology 865structures in the sucking mouth parts; the shaft of the ovipositor.4. (BRYO: Stenolaemata) A rodlike skeletal structureoriented almost perpendicular to the zoarial surfaceand parallel to the zooecia. 5. (CNID) The large, lowermostthorn on the hampe (butt) of a stenotele nematocyst. 6.(NEMATA) A sclerotized, usually hollow, structure used forfeeding, releasing secretions and entering plants and animals(Arthropoda); a spear. see stomatostyle, odontostyle.7. (NEMER) A nail-shaped structure on the end ofthe proboscis that typically reaches 50-200 m, used in thecapture of prey.stylet extension see odontophorestylet knobs (NEMATA) Various thickenings (apodemes) at thebase of the stylet, usually 3 in number, that serve as attachmentpoints for the protractor muscles. see basalknobs.styletocytes n.pl. [Gr. stylos, piller; kytos, container] (NEMER)Large epithelial cells in which the stylets are formed.stylet sac see trophic sacstylet sheath (ARTHRO: Insecta) In aculeate Hymenoptera, thedorsal part of the terebra.styli pl. of style and stylusstyliferous a. [Gr. stylos, pillar; L. fero, bear] Having one ormore styli.styliform a. [Gr. stylos, pillar; L. forma, shape] Shaped like astyle or stylet; formed of parallel-sides and a pointed apex.styliger plate (ARTHRO: Insecta) In Ephemeroptera, a scleriteon the posterior portion of sternum 9, variable in shape,which on the posterior margin gives rise to a pair of slenderand usually segmented appendages called forceps or claspers;a subgenital plate.stylocerite n. [Gr. stylos, pillar; keras, horn] (ARTHRO: Crustacea)A rounded or spiniform process on the outer part ofthe proximal segment of the antennular peduncle; antennularscale.styloconic sensilla see sensillum styloconicumstylode n. [Gr. stylos, pillar; eidos, like] (ANN: Polychaeta) A

866Maggenti and Gardnersmall, longer than wide, projection on the parapodium.styloid a. [Gr. stylos, pillar; eidos, like] Long and slender; belonoid;aciform.stylopization n. [Gr. stylos, pillar; ops, eye] (ARTHRO: Insecta)The endoparasitism by the coleopterous female Strepsiptera(Stylops), of other insects; stylopized.stylose a. [Gr. stylos, pillar] Bearing a style or several styli.stylostome n. [Gr. stylos, pillar; stoma, mouth] (ARTHRO:Chelicerata) In acarid Trombiculidae, a hard, tube-likestructure formed by the host's tissues under the influenceof secretions by the feeding mites.stylote a. of stylestylus n.; pl. styli [Gr. stylos, pillar] Style; stylet; a shortslender, fingerlike process.subalar sclerite (ARTHRO: Insecta) A sclerite behind the pleuralprocess into which wing movement muscles are inserted.subalternate a. [L. sub, under; alternus, alternate] Not quiteopposite, yet not regularly alternate.subanal lobe/appendage see catoprocesssubanal scale see anal scalesubantennal groove (ARTHRO: Insecta) In Diptera, a facialgroove that facilitates the scape.subantennal ridge (ARTHRO: Insecta) In Diptera, the innersupporting ridge of the subantennal suture of Culicidae.subantennal suture (ARTHRO: Insecta) 1. Sutures ventral tothe antennal socket. 2. In Culicidae larvae, a short line laterallybelow the antennal prominence, associated with thesubantennal ridge.subapical lobe (ARTHRO: Insecta) In the genitalia of male Culicidae,a mesal lobe found at or distal to the middle of thegonocoxite.subapotorma n. [L. sub, under; Gr. apo, from; tormos,socket] (ARTHRO: Insecta) In Scarabaeoidea larva, a heavilysclerotized process extending forward from thesubtorma on each side mediad of the longitudinal row of

Online Dictionary of Invertebrate Zoology 867inwardly directed, closely set, phobae of the hypopharynx.subapterous see brachypteroussubassociation n. [L. sub, under; ad, to; socius, companion]This term has been used by various authors as a substitutefor the term association when not in agreement with thedefinition: a group assemblage of organisms, in a specificgeographical area with one or two dominant species.subbasal a. [L. sub, under; Gr. basis, base] Just distad of thebase.subbiramous a. [L. sub, under; bis, two; ramus, branch](ANN: Polychaeta) Parapodia in which the notopods are reducedand neuropods are well developed.subbranchial a. [L. sub, under; Gr. branchia, gills] Beneaththe gills.subbranchial region (ARTHRO: Crustacea) In Brachyura, theventral part of the carapace beneath the gill area.subcapitular a. [L. sub, under; capitalis, relating to the head](ARTHRO: Chelicerata) In Acari, pertaining to the ventralsurface of the infracapitulum.subcapitular apodeme (ARTHRO: Chelicerata) In Acari, asclerotized continuation of the mentum internally, to whichseveral tendons are attached.subcapitular gutter (ARTHRO: Chelicerata) In anactinotrichidAcari, the median taenidium on the ventral surface of theinfracapitulum; the deutosternum.subcarina n. [L. sub, under; carina, keel] (ARTHRO: Crustacea)In Lepadomorpha, a small, unpaired plate below the carina.subcarinate a. [L. sub, under; carina, keel] Shaped like ashallow keel.subcastes n.pl. [L. sub, under; castus, pure] (ARTHRO: Insecta)In Hymenoptera, the various forms of mature Formicidaeof a caste. see major worker, media worker, minorworker.subcellular a. [L. sub, under; cellula, small cell] Applies to organellesin a cell.subcephalic a. [L. sub, under; Gr. kephale, head] (NEMATA)

868Maggenti and GardnerLocated posterior to the cephalic region.subcerebral glands (ROTIF) Paired glands of the retrocerebralorgan/sac.subchela n. [L. sub, under; Gr. chele, claw] (ARTHRO: Crustacea)The distal end of a limb developed as a prehensilestructure by the folding back of a dactyl against the propodusor widest part of it; may arise from propodus foldedback against the carpus; gnathopod.subchelate a. [L. sub, under; Gr. chele, claw] 1. (ARTHRO)Having an appendage in which the terminal podomere thatcan fold back like a pincer against the subterminal podomere.2. (ARTHRO: Crustacea) Provided with subchela.subclass n. [L. sub, under; classis, division] In classification, amajor subdivision of a class, comprised of related orders.subclimax n. [L. sub, under; Gr. klimax, ladder] 1. The stagepreceding the climax in a complete sere. 2. A geographicallysmaller area than that of a 'climax'.subclypeal pump see cibarial pumpsubclypeal tube see pseudotracheasubcolony n. [L. sub, under; colonia, farm] (BRYO: Stenolaemata)A functional grouping within a colony, in which theskeletons may or may not be of the same structure.subcosta n. [L. sub, under; costa, rib] (ARTHRO: Insecta) Alongitudinal vein between the costa and the radius.subcoxa n. [L. sub, under; coxa, hip] 1. (ARTHRO) A secondaryproximal subdivision of the coxopodite. 2. (ARTHRO: Crustacea)see precoxa.subcoxal pleurites 1. (ARTHRO: Insecta) Sclerites that areseparated primitively or fused, that form the pleural supportfor the coxa. 2. (ARTHRO: Chilopoda) Small, variouslyshaped sclerites associated with the bases of the coxa.subcutical n. [L. sub, under; cutis, skin] (ARTHRO: Insecta)Newly secreted basal cuticle whose granular ultrastructureshows microfibrils that have not undergone orientation.subdentate a. [L. sub, under; dens, tooth] Small teeth ornotches.

Online Dictionary of Invertebrate Zoology 869subdiscal/subdiscoidal vein (ARTHRO: Insecta) The wingvein forming the posterior margin of the third discoidal cell.subdorsal a. [L. sub, under; dorsum, back] Pertaining to thesector between the dorsal and lateral surface. subdorsaln.subdorsal keel/plate see dorsal platessubdorsal line (ARTHRO: Insecta) In caterpillars, a subdorsallongitudinal line between dorsal and lateral; if addorsal linepresent, between it and the lateral line.subdorsal ridge (ARTHRO: Insecta) In some Hymenoptera caterpillars,an elevated longitudinal line along the subdorsalrow of abdominal tubercles.subesophageal body (ARTHRO: Insecta) A number of largebinucleate cells in the body cavity closely associated withthe inner end of the stomodeum in Orthoptera, Plecoptera,Isoptera, Mallophaga, Coleoptera and Lepidoptera.subesophageal ganglion The nerve plexus below the esophagus.subfamily n. [L. sub, under; familia, family] A category of thefamily group containing related tribes or genera, and endingin -inae.subfossorial a. [L. sub, under; fossor, digger] Adapted fordigging.subgalea n. [L. sub, under; galea, helmet] (ARTHRO: Insecta)An inner sclerite of the maxillary stipes; parastipes; sometimesfused with the lacinia or merged into the stipes.subgenal areas (ARTHRO: Insecta) The narrow lateral marginalareas of the head setoff by the subgenal sulcus above themandibles and maxillae.subgenal ridge (ARTHRO: Insecta) A submarginal structure onthe inner surface of the head arising from the subgenal sulcus.subgenal sulcus (ARTHRO: Insecta) The lateral suture belowthe gena, and above the base of the mandibles and maxillae.subgeneric name see subgenus

870Maggenti and Gardnersubgenital plate (ARTHRO: Insecta) A platelike sternite thatunderlies the genitalia, usually in the 9th abdominal sternumin males, and 7th or 8th in females; in some ichneumonidHymenoptera, the 7th sternite in males, the 6th infemales; vulvar lamina.subgenual organ (ARTHRO: Insecta) A cordotonal organ situatedin the proximal part of the tibia; when a two-part organ,the one more proximal is known as the "true subgenualorgan."subgenus n.; pl. subgenera [L. sub, under; genus, tribe] Thename of an optional category between the genus and species;capitalized and placed in parentheses following thegenus name.subhepatic carina (ARTHRO: Crustacea) In Decapoda, a narrowridge extending posteriorly from the branchiostegalspine.subhepatic region (ARTHRO: Crustacea) In Decapoda, thatpart on the ventral surface of the carapace below the hepaticregion, bounded by the pterygostomial and suborbitalregions.subimago n. [L. sub, under; imago, image] (ARTHRO: Insecta)In Ephemeroptera, the first of two winged instars after itemerges from the water surface, or underwater. subimaginala.subjective synonym Two or more synonyms based on differenttypes, but recognized as referring to the same taxon bytaxonomists who hold them to be synonyms.subliminal a. [L. sub, under; limen, threshold] A stimulus insufficientor inadequate to illicit a perceptible response. seeliminal.sublingual gland see pharyngeal gland, ventralsublittoral, sublittoral zone 1. A lake bottom too deep forrooted plants to grow. 2. In oceans, a zone from the intertidalzone to the end of the continental shelf.submalleate a. [L. sub, under; malleus, hammer] (ROTIF) Amodified malleate mastax.submargin n. [L. sub, under; margo, margin] (MOLL: Bivalvia)

Online Dictionary of Invertebrate Zoology 871One of the dorsal edges of the shell body which adjoins thelower border of the auricle in Pectinacea.submarginal a. [L. sub, under; margo, edge] Placed within themargin.submarginal area (ARTHRO: Insecta) In the hind wings, asection between the anterior (costal) margin and the firststrong vein.submarginal cell (ARTHRO: Insecta) In Hymenoptera, one ormore cells just behind the marginal cell.submarginal striae see proplegmatiumsubmarginal tubercles (ARTHRO: Insecta) In Coccidae, roundtuberacles, when present, variable in number, surroundinga central invaginated tube, occurring in the dorsal submarginalarea of the body.submarginal vein (ARTHRO: Insecta) In Chalcidoidea, a veinjust behind and paralleling the costal margin of the wing.submedia see second axillarysubmedian cell (ARTHRO: Insecta) In Hymenoptera, a cell behindthe median cell, in the basal posterior of the wing.submedian denticle (ARTHRO: Crustacea) In Stomatopoda,the small projection(s) just laterad of the midline on theterminal margin of the telson (medial to submedian teeth).submedian groove (ARTHRO: Crustacea) In Decapoda, a longitudinalgroove in the submedian dorsal part of the carapace,contiguous with the postrostal carina.submedian lobes (NEMATA: Secernentea) In the superfamilyCriconematoidea in Tylenchina, the paired, reduced,strongly modified subdorsal and subventral lips.submedian tooth (ARTHRO: Crustacea) In Stomatopoda, thestrong spinelike or blunt projection just laterad of the midlineon the terminal margin of the telson.submentum n. [L. sub, under; mentum, chin] (ARTHRO: Insecta)1. The basal sclerite of a labium. 2. In some Coleoptera,a distinct sclerite defined by a suture interveningbetween the mentum and the gula; in others, has alsobeen applied to the undifferentiated anterior margin of thegula. submental a.

872Maggenti and Gardnersubmentapleural carina (ARTHRO: Insecta) In certain Hymenoptera,the lower margin of the lower division of themesopleurum, between the bases of the middle and hindcoxae.subneural a. [L. sub, under; Gr. neuron, nerve] Under thecentral nervous system or ventral nerve cord.subocular sulcus (ARTHRO: Insecta) In smaller Ichneumonidae,a sharp groove extending from the base of the eye tothe mandibular socket.suboesophageal see subesophagealsuborbital region (ARTHRO: Crustacea) In Brachyura, a narrowregion bordering the lower margin or orbit.suborbital spine (ARTHRO: Crustacea) In a decapod carapace,a spine slightly below and posterior to the middle of the orbit.subphylum n. [L. sub, under; Gr. phyle, tribe, race] A majorsubdivision in classification between phylum and class.subquadrangle n. [L. sub, under; quadri-, four; angulus, angle](ARTHRO: Insecta) In odonatan Zygoptera, a cell justbehind the quadrangle.subradular organs (MOLL: Polyplacophora) Two eversiblepads, probably of chemoreceptive function, at the base ofthe subradular sac.subradular sac (MOLL: Polyplacophora) A blind sac of theposterior wall of the buccal cavity containing cushionshapedsensory structures (subradular organs) hangingfrom the roof.subrostrum n. [L. sub, under; rostrum, beak] (ARTHRO: Crustacea)In Lepadomorpha Cirripedia, a single plate below therostrum.subscaphium n. [L. sub, under; scaphium, hollow vessel] (AR-THRO: Insecta) In male Lepidoptera, a ventral sclerotizationof the genitalia, below the anus; gnathos.subscutellum n. [L. sub, under; dim. scutum, shield] (AR-THRO: Insecta) In some Diptera, especially Tachinidae, theanterior region of the mediotergite differentiated as a convex,transverse ridge or lobe; often called postscutellum.

Online Dictionary of Invertebrate Zoology 873subsocial n. [L. sub, under; socius, companion] (ARTHRO: Insecta)Applied to adults caring for their young for some periodof time. see presocial.subsocies n.pl. [L. sub, under; socius, companion] A termused by various authors when there is disagreement as tothe definition of the word associes.subspecies n. [L. sub, under; species, kind] A subdivision of aspecies inhabiting a geographic subdivision of the range ofthe species and differing taxonomically from other populationsof the species.substitute see supplementary reproductivesubstitute king see supplementary reproductivesubstitute name A name proposed to replace a preoccupiedname that assumes the same type and type-locality.substrate n. [L. sub, under; stratum, bed] 1. A substance onwhich an enzyme acts. 2. see substratum.substrate race A local race selected by nature to have a similarityof coloration with that of the substratum.substratum n.; pl. substrata [L. sub, under; stratum, bed]The ground or other surface in or upon which organismslive, walk, crawl or are attached.subsume n. [L. sub, under; sumere, to take] To include under;to put under another as belonging to it, i.e., in zoologicalclassification.subtegular ridge (ARTHRO: Insecta) A transverse ridge nearthe upper edge of the mesopleurum, below the tegula andbase of the front wing.subtegulum n. [L. sub, under; tegulum, covering] (ARTHRO:Chelicerata) In Arachnida, one of the sclerotized plates thatprotect the hematodocha of the male papal organ of somespiders.subtorma n. [L. sub, under; Gr. tormos, socket] (ARTHRO: Insecta)In Coleoptera, the heavily sclerotized, transverse,curved process of certain Scarabaeoidea larvae, locatednear the proximal border of the hypopharynx.subtriangle n. [L. sub, under; tri, three; angulus, angle] (AR-THRO: Insecta) In Odonata Anisoptera, A cell or group of

874Maggenti and Gardnercells in the wing behind the triangle.subtribe n. [L. sub, under; tribus, tribe] In classification, arank below the tribe and above the genus.subtylostyle n. [L. sub, under; Gr. tylos, knot; style, pillar](PORIF) 1. A monactinal megasclere with a sub-apical expansion.2. A tylostyle with an indistinct knob at one endand pointed at the other. see tylostyle.subulate a. [L. subula, awl] Shaped like an awl; slender andtapering to a point, with sides convex.subumbrella n. [L. sub, under; dim. umbra, shade] (CNID)The concave oral surface of a medusa or jellyfish. seeexumbrella.subventral esophageal glands (NEMATA) Esophageal salivaryglands lying in the subventral sectors of the posterioresophagus.subvibrissal setae/setulae (ARTHRO: Insecta) In Diptera, thesetae/setulae along the anteroventral margin of the gena.succession see seresuccinct a. [L. sub, under; cingere, to gird] Compact; contracted;reduced.succursal nest (ARTHRO: Insecta) In social insects, a restingor hiding place constructed by workers, but not qualifyingas a true nest due to the absence of brood rearing.sucker n. [A.S. sucan, to suck] An organ creating a vacuum,utilized by various invertebrates for locomotion, ingestingor holding food, or adhering to the substrate.suctorial a. [L. sugere, to suck] Having vacuum organs;adapted for sucking.suffused a. [L. suffusus, to pour beneath] To overspread, aswith fluid or color; to cover the surface. suffusion n.sugent, sugescent a. [L. sugere, to suck] Suctorial.sulcate a. [L. sulcus, furrow] Having a groove or furrow.sulci n.pl. [L. sulcus, furrow] (ARTHRO: Insecta) Grooves of apurely functional origin, such as strengthening ridges of thehead.sulciform a. [L. sulcus, furrow; forma, shape] Being groove-

Online Dictionary of Invertebrate Zoology 875like or groove-shaped.sulculus n. [L. dim. sulcus, furrow] (CNID: Anthozoa) In diglyphicActiniaria, having the second, sometimes small, siphonoglyphssituated at the dorsal end of the pharynx. seesulcus.sulcus n.; pl. sulci [L. sulcus, furrow] 1. A furrow, groove orfissure. 2. (ARTHRO: Insecta) A suture formed by an infoldingof the body wall. see sulci. 3. (BRACHIO) The major depressionof the valve surface, externally concave in transverseprofile and radial from the umbo. 4. (CNID: Anthozoa)A groove leading into the gullet. see siphonoglyph. 5.(MOLL: Bivalvia) The radial depression of the shell surface.sulcus, radial posterior (MOLL: Bivalvia) A groove that setsoff the posterior flange from the main shell body.sulcation n. [L. sulcus, furrow] 1. Scored by furrows orgrooves. 2. Encircled by channels.summer egg A thin-shelled, rapidly developing egg; tachyblastic.see winter egg.summit n. [L. summum, the highest point] 1. The apex; thetop. 2. (MOLL: Bivalvia) The highest dorsal point of the shellprofile when the cardinal plane is horizontal.superclass n. [L. super, over; classis, a division] In classification,above the class and below the phylum.superfamily n. [L. super, over; familia, family] In classification,above the family and below the order.superfemale see metafemalesuperficial epicuticular layer see cerotegumentsupergenus n. [L. super, over; genus, race] In classification,above the genus and below the family.superior appendages (ARTHRO: Insecta) In Odonata, lateralmovable, paired appendages on the 9th or 10th abdominalsegment; well developed in the males, reduced or vestigialin females.superior hemiseptum see proximal hemiseptumsuperlinguae n.pl. [L. super, over; lingua, tongue] (ARTHRO:Insecta) The two lateral lobes of the hypopharynx of

876Maggenti and Gardneradults; paragnath.supermale n. [L. super, over; dim. mas, male] (ARTHRO: Insecta)Abnormal male with one x-chromosome for 3 sets ofautosomes in Drosophila.supernumerary crossveins (ARTHRO: Insecta) Crossveinsadded to the normal number.supernumerary segment (ARTHRO: Insecta) In CecidomyidaeDiptera, a segment intercalated between the head and theprothorax.supero-marginal plates (ECHINOD: Asteroidea) Upper marginalplates that form the outline of the arm of sea-stars.see infero-marginal plates.superoptimal stimuli Sensory stimuli reponse stronger thanthe natural stimuli for which the response had been selected.superorder n. [L. super, over; ordo, order] In classification, agroup below class and above order.superorganism n. [L. super, over; Gr. organon, organ] A colonyof social organisms, or organisms and their environment,of interdependent relationships which may be studiedas though they were a single organism.superposed a. [L. super, over; ponere, to place] Placed oneupon another; superimposed; placed directly over someother part.superposition eye (ARTHRO) In nocturnal or crepuscular arthropods,an eye that permits the passage of light throughthe non-pigmented wall of one ommatidium to the iris of aneighboring one; an adaptation to protect sensitive photoreceptorsfrom overstimulation during the day; clear-zoneeye. see apposition eye.superposition image (ARTHRO) A less distinct but brighter imagedue to the lens system focusing the light to the retina.see mosaic image.supersedure n. [L. super, over; sedere, to sit] (ARTHRO: Insecta)In Hymenoptera, the replacement of an old or sickqueen by a new queen in a honeybee colony.superspecies n. [L. super, over; species, kind] A monophyletic

Online Dictionary of Invertebrate Zoology 877group of mainly or entirely allopatric species that are morphologicallytoo different to be included in a single speciesor are reproductive isolates; an artenkreis.supertribe n. [L. super, over; tribus, tribe] In classification,below the subfamily and above the tribe.supplement n. [L. supplere, to fill up] 1. (ARTHRO: Insecta) InOdonata, an adventitious vein formed by a number ofcrossveins lining up to form a continuous vein behind andmore or less parallel to one of the main longitudinal veins.2. (NEMATA) Variously sized, often paired, papilliform sensorynerve terminations in the male ventral caudal area;genital papillae.supplementary organs (NEMATA) Secondary sexual characteristicsalong the body of male nematodes either sensoryor glandular. see supplement.supplementary reproductive (ARTHRO: Insecta) In Isoptera,a queen or male, in the form of adultoid, nymphoid or ergatoid,that take over as a functional reproductive after theremoval of the primary reproductive of the same sex.supporting walls (BRYO) Zooidial walls that support orificialwalls.supra adv. [L. supra, above] In scientific terms, a prefix, denotingabove or higher; on the dorsal side; opposite to infra.supra-alar bristles (ARTHRO: Insecta) In Diptera, a longitudinalrow of bristles on the lateral portion of the mesonotum,above the root of the wing.supra-anal see superior appendagessupra-anal hook see uncussupra-anal opening (MOLL: Bivalvia) The opening of the excurrentcanal.supra-anal pad (ARTHRO: Insecta) The reduced epiproct, belowthe posterior of the tenth tergum.supra-anal plate (ARTHRO: Crustacea) In Notostraca, usuallytongue-shaped, but may be spatulate to rounded, platesituated posteriorly on the dorsal side of the telson.supra-apical foramen (BRACHIO) A pedicle foramen in the

878Maggenti and Gardnerventral umbo away from the apex of the delthyrium.suprabranchial a. [L. supra, above; Gr. branchia, gills] (MOLL)Above the gills.supracerebral glands see pharngeal glands, lateralsupracheliceral limbus (ARTHRO: Chelicerata) In Acari, anextension of part of the tegulum above the chelicera ofGamasida.supraclypeal area see postclypeussupraesophageal ganglion (ARTHRO) The brain; the nervemass above the esophagus.supraneural pore see coelomoporessupraneuston n. [L. supra, above; Gr. neustos, able to swim]Small animals living on the surface film of water.supraorbital carina see gastroorbital carinasupraspecific a. [L. supra, above; species, kind] Applied to acategory or evolutionary phenomenon above the specieslevel.suprasquamal ridge (ARTHRO: Insecta) In Diptera, a ridgebetween the base of the lower calypter to the anterolateralangle of the scutellum.supratidal a. [L. supra, above; A.S. tid, time] Pertaining to theocean; above the high tide mark; a subdivision of theneritic zone.supratympanal organ see subgenual organsuranal a. [L. supra, above; anus] Above the anus; supraanal.suranal plate (ARTHRO: Insecta) A heavily sclerotized area onthe dorsum of the last abdominal segment; a plate or lobedorsad of the anus; epiproct; anal plate. see ectoproct.surface ornamentation (MOLL: Bivalvia) A regular relief patternon the surface of many shells.surface pheromone A pheromone active only on or very closeto the body; contact or near contact must be made.surface tension Surface film on liquids caused by cohesion ofthe molecules of the liquid at the free surface.

Online Dictionary of Invertebrate Zoology 879surpedal area or lobe (ARTHRO: Insecta) In Hymenoptera, alobe or area just above the prolegs and below and behindthe spiracle on the abdomen of Symphyta larvae; suprapedalarea; postepipleurite.surstyli n.pl.; sing. -lus [L. supra, over; Gr. stylos, pillar] (AR-THRO: Insecta) In Diptera, paired appendages of the ninthabdominal tergite (epandrium); suprastyli.suspensor n. [L. sub, under; pendere, hang] 1. (ARTHRO: Insecta)In Hymenoptera, a structure composed of carton orwax attaching the comb nests of bees and wasps. 2.(NEMATA: Adenophorea) Muscles associated with the spicules,enclosing the distal part of the spicules ofParatrichodorus and other males in Diphtherophorina.suspensorium n.; pl. -ria [L. sub, under; pendere, to hang] 1.Anything that suspends a part. 2. (ARTHRO: Insecta) a. InBlattoidea, a pair of linear sclerites extending toward thelateral mouth angle on each side of the proximal half of thehypopharynx. b. In Coleoptera, extends from the adoralface upwards to end in the lateral walls of the stomodeum;fultura. c. Suspensory ligaments that insert into the bodywall or dorsal diaphragm suspending developing ovaries inthe hemocoel.suspensory fold of the Schwann cell see mesaxonsuspensory muscles see dilatorsustentacular cells Supporting cells of organs as differentiatedfrom the cells that provide the function of the organ.sustentor/sustentator n. [L. sustinere, to sustain] (ARTHRO:Insecta) One of two hooks on the posterior part of a butterflypupa; cremaster.sutural angle see sutural slopesutural edge (ARTHRO: Crustacea) In Cirripedia, the margin ofthe compartmental plate along the suture.sutural laminae (MOLL: Polyplacophora) Apophyses plates;anterior plate-like projections of the articulamentum extendingfrom either side of an intermediate or tail valve;may be separated by a sinus or partially joined by a laminarextension of the articulamentum.

880Maggenti and Gardnersutural plate (MOLL: Polyplacophora) Lamina of the articulamentumacross the jugal sinus of the intermediate and tailvalve, extending between the sutural laminae.sutural shelf (MOLL: Gastropoda) A horizontally flattened bandthat may contact the adapical suture of the whorls.sutural sinus see jugal sinussutural slope (MOLL: Gastropoda) An angle between the sutureand plane perpendicular to the axis; sometimesequated to the sutural angle.suture n. [L. sutura, seam] 1. Line of junction of 2 parts generallyimmovably connected. 2. (ARTHRO: Crustacea) InCirripedia, a line or seam at the juncture of two compartmentalplates; weakly calcified areas of the integument forseparation at ecdysis. 3. (ARTHRO: Insecta) Grooves markingthe line of fusion of two former plates; a narrow membranousarea between sclerites; line of juncture of elytra inColeoptera. 4. (MOLL: Gastropoda) The continuous spiralline on the shell surface where whorls adjoin. sutural a.swarming n. [A.S. swearm, swarm] (ARTHRO: Insecta) In socialinsects: a. The departure of a queen and workers fromthe parental nest to establish a new colony of highly eusocialbees. b. In ants and termites, often applied to themass departure of reproductive forms from the nests at thebeginning of the nuptial flight.swimmeret n. [A.S. swimman, to swim] (ARTHRO: Crustacea)An abdominal appendage functioning as a swimming organ;pleopod.swimming bell (CNID) Any bell or umbrella-shaped cnidarianthat moves through the water by contractions, especiallySiphonophora; nectocalyx; nectophore.swimming plate (CTENO) A short ridge bearing large fusedcilia, arranged in eight meridional rows that function in locomotion.switch gene The gene influencing the epigenotype to switch toa different developmental pathway.sycon n. [Gr. sykon, fig] (PORIF) A sponge in which the choanocytelayer shows folding accompanied by superficialthickening of the mesohyl.

Online Dictionary of Invertebrate Zoology 881sylleibid n. [Gr. syllektos, gathered together] (PORIF) An aquiferoussystem transitional between syconoid and leuconoidconditions, with elongate choanocyte chambers groupedaround a common exhalant channel.sylvan, silvan a. [L. sylva, silva, forest] Pertaining to or inhabitingthe forests or woodland areas.sylvatic, silvatic a. [L. sylva, silva, forest] In disease ecology,a parasite existing normally in the wild and not in the humanenvironment. see synanthropism.symbiology n. [Gr. symbiosis, life together; logos, discourse]The study of symbioses.symbion(t) n. [Gr. symbiosis, life together; on, being] Anyorganism that exists in a relationship of mutual benefit withanother organism; a symbiote.symbiosis n. [Gr. symbiosis, life together] 1. The mutuallybeneficial living together of individuals of two different species.2. Interrelationship of different species of organisms,ranging from beneficial, to neutral, to dehabilitating. symbiotica. see mutualism, commensalism, parasitism.symbiote n. [Gr. symbiosis, life together] An organism living insymbiosis; symbiont.symmetry n. [Gr. symmetria, due proportion] The mode ofbody organization. symmetical a. see bilateral symmetry,radial symmetry.sympathetic system 1. That portion of the autonomic nervoussystem directly connected with the brain and innervatingthe fore and middle intestine, heart and certain other parts.2. (ARTHRO: Insecta) see stomogastric nervous system,ventral sympathetic nervous system.sympatric hybridization The production of hybrid individualsbetween two sympatric species.sympatric speciation Speciation with geographic isolation;the reproductive isolation occurring between segments of asingle population.sympatry n. [Gr. syn, together; patria, native country] Theoccurrence of two or more populations in the same area;usually referring to areas of overlap in species distributions.

882Maggenti and Gardnersympatric a.symphile n. [Gr. syn, together; philein, to love] (ARTHRO: Insecta)A symbiont that is accepted by a host colony as amember of their group and is licked, fed, protected, transportedor even reared with the host's own larvae; a trueguest.symphily n. [Gr. syn, together; philein, to love] (ARTHRO: Insecta)In Hymenoptera, the relationship of ants and theirnest guests, that abide with them, with mutual benefit orfondness; commensalism. symphilic, symphilous a.symphynote a. [Gr. symphysis, junction, seam; notos, back](MOLL: Bivalvia) Having the valves firmly fixed or solderedat the hinge.symphysis n. [Gr. symphysis, junction, seam] A union betweentwo parts.symplesiomorphy n. [Gr. syn, together; plesios, near; morphe,form] Shared primitive homologous character states;normally used in cladistic taxonomy. see plesiomorphy.sympod, sympodite see protopodsymptomatology n. [Gr. symptoma, anything that has befallenone; logos, discourse] A branch of medical scienceconcerned with symptoms of diseases.synanthropism n. [Gr. syn, together; anthropos, man] Thepropensity of an organism to live in or around humandwellings.synapomorphy n. [Gr. syn, together; apo, separate; morphe,form] The sharing of derived characters by several species.see plesiomorphy.synapse, synaptic junction, neurosynapse The centralmechanism of intercommunication of nerve impulses passingfrom neuron to neuron. synaptic a.synapsis n.; pl. -ses [Gr. synapsis, union] The intimate conjunctionof homologous chromosomes that occurs duringthe prophase of the meiotic division.synaptene n. [Gr. synapsis, union] The zygotene of meiosis.synaptic junction see synapse

Online Dictionary of Invertebrate Zoology 883synaptic knobs Swellings on the axon ends where contact ismade with dendrites of another nerve cell.synapticulum n.; pl. -la [Gr. synapsis, union] (CNID) One ofnumerous conical or cylindrical calcareous processes connectingthe septa. synapticular a.synaptinemal complex Organelle present during pachytenestage of eukaryote meiosis visable in electron micrographs.synaptorhabdic a. [Gr. synapsis, union; rhabdos, rod] (MOLL:Bivalvia) Pertaining to ctenidia where filaments are connectedat their interlamellar edges by strands of cellulartissue; organic interfilamentary junctions. see eleutherorhabdic.synaptychus n. [Gr. syn, together; apo-, away from; ptychos,fold] (MOLL: Cephalopoda) Double calcareous plates fusedwith other paired plates. see anaptychus.syncerebrum n. [Gr. syn, together; L. cerebrum, brain] Thesupraesophageal glanglia or brain of many invertebrates.synchronic speciation Speciation that occurs at the sametime level. see allochronic speciation.synchronizer n. [Gr. syn, together; chronos, time] An environmentalfactor that influences the phenomena of circadianrhythm to conform to a daily cycle instead of wandering.synclerobiosis n. [Gr. syn, together; keros, chance; bios, life](ARTHRO: Insecta) In Hymenoptera, a temporary associationof two species of ants of independent colonies.synconoid grade (PORIF) A grade of construction intermediatebetween the asconoid and the leuconoid, in which each radialcanal is subdivided into elongate-flagellate chambersgrouped around a common excurrent channel. see leuconoidgrade, asconoid grade.syncyte n. [Gr. syn, together; kytos, container] A polyploid ormultinucleate cell.syncytium n.; pl. syncytia [Gr. syn, together; kytos, container]A continuous mass of protoplasm with several ormany nuclei; a multinucleate cell. syncytial a.syndesis n. [L. syndesis, a binding together] 1. Binding to-

884Maggenti and Gardnergether. 2. Synapsis. 3. A membrane connecting two separateparts permitting movement between them.syndiacony n. [Gr. syn, together; diakonos, servant] (ARTHRO:Insecta) A form of commensalism between ants and plantswith both obtaining benefit.syndrome n. [Gr. syn, together; dramein, to run] Signs andsymptoms characteristic of a particular disease.synecete see synoeketesynechthran n. [Gr. syn, together; echtos, hate] An insectguest that is persecuted by its host, and manages to stayalive by greater speed and agility or the use of defensivemechanisms; an animal engaged in synechthry. see metochy.synechthry n. [Gr. syn, together; echtos, hate] The relationshipbetween a symbiont, generally a scavenger, parasiteor predator, that is treated in a hostile manner by the host;metochy.synecology n. [Gr. syn, together, oikos, household; logos, discourse]The relationship of populations and communities tobiotic factors in the environment. see autecology.synectic a. [Gr. syn, together; nektikos, habitual] Pertaining tocells that retain their relative position during gastrulation.synergism n. [Gr. synergos, associate] The cooperative actionof two entities to effect a greater difference than both together,i.e., hormones, parasites, muscles. synergistic a.syngamy n. [Gr. syn, together; gamos, marriage] 1. Union ofmale and female gametes following fertilization to form azygote; gametogamy; hylogamy. see pseudogamy. 2.Permanent union of both female and male reproductiveunits; male element sometimes greatly reduced and parasiticin the female.syngenesis n. [Gr. syn, together; genesis, beginning] 1. Reproductionbetween two sexually dimorphic parents; sexualreproduction. 2. The theory that the germ of the offspringis derived from both parents, not from either alone.syngenic see isogenicsyngonic a. [Gr. syn, together; gone, seed] The production of

Online Dictionary of Invertebrate Zoology 885both sperm and eggs by the same gonad; hermaphroditicreproduction. see digonic, amphigonic.synhaploid n. [Gr. syn, together; haploos, single] A conditionderived from the fusion of two or more haploid nuclei. seedouble haploid.synhesmia n. [Gr. syn, together; hesmos, swarm] A group oforganisms swarming together in consequence of a reproductivedrive. see androsynhesmia, gynosynhesmia.synistate a. [Gr. syn, together; histos, tissue] (ARTHRO: Insecta)In Neuroptera, referring to the ligula being reducedto the condition of a median and sometimes slightly bilobedprocess, or totally atrophied.synizesis n. [Gr. syn, together; hizein, to sit] The clumping ofchromosomes in early prophase of the first meiotic division;may be either normal or abnormal.synkaryon n. [Gr. syn, together; karyon, nucleus] A zygotenucleus formed by fusion of two gametic nuclei.synlophe n. [Gr. syn, together; lophos, crest] (NEMATA: Secernentea]In numerous Trichostrongylidae, an enlargedlongitudinal or oblique cuticular ridge on the body surfacethat serves to hold the nematodes in place on the gut wall.synoecius, synoecious a. [Gr. synoikos, living in the samehouse] Producing both male and female gametes.synoecy n. [Gr. synoikos, living in the same house] 1. Commensalisminvolving social insects where the guests are indifferentlytolerated by the hosts. 2. An association betweentwo species where one is benefited without harm tothe other. see symphily, synechthry.synoekete n. [Gr. synoikos, living in the same house] A toleratedguest of a host colony.synoenocytes n. [Gr. syn, together; oenos, wine colored; kytos,container] (ARTHRO: Insecta) In dipteran Chironomidae,localization of oenocytes as distinctive organs.synomone n. [Gr. syn, together; omone, mimics the ending ofhormone] A chemical substance produced or acquired byan organism, that upon contact with an individual of anotherspecies, evokes a behavioral or physiological re-

886Maggenti and Gardnersponse favorable to both emitter and receiver. see allelochemic.synonyms n.pl. [Gr. syn, together; onyma, name] In nomenclature,two or more names for the same taxon. see senior,junior, objective, subjective synonym. synonymousa.synonymy n. [Gr. syn, together; onyma, name] A chronologicallist of scientific names applied to a given taxon, includingdates of publication and authors of the names.synopsis n.; pl. -es [Gr. syn, together; opsis, view] In taxonomy,a general summary of current knowledge of a group.synoptic a. [Gr. syn, together; opsis, view] Pertaining tostructures that upon comparison, are virtually identical.synoptical key The arrangement of the more essential charactersin order to identify specific taxa by selecting onlythose that apply.synscleritous a. [Gr. syn, together; skleros, hard] (ARTHRO)The joining of a tergite and a sternite to form a completering. see discleritous.syntagma see tagmasyntelic a. [Gr. syn, together; telos, fulfillment] In mitosis,centromeres of the two chromatids of each chromosome ifthey are oriented to the same spindle pole at the first meioticdivision.synthesis n.; pl. -ses [Gr. syn, together; titheni, to place] Theformation of a more complex substance from simpler ones.synthetic a. [Gr. syn, together; titheni, to place] Combiningthe structural characters of two or more dissimilar groupsor forms into one group or form.synthetic lethals Lethal chromosomes derived from normallyviable chromosomes by crossing over.synthetic theory The evolutionary theory, with mutation andselection as the basic elements.synthorax n. [Gr. syn, together; thorax, chest] (ARTHRO: Insecta)The meso- and metathorax fused as a single unit ofwing-bearing insects; pterothorax.

Online Dictionary of Invertebrate Zoology 887syntrophy n. [Gr. syn, together; trophon, food] (ARTHRO: Insecta)In social insects, the accidental feeding of symphilesor synoeketes during normal brood care.syntype n. [Gr. syn, together; typos, type] Every specimen ina type-series in which no holotype or lectotype was designated.syntypic a. [Gr. syn, together; typos, type] Referring to thesame type.synxenic a. [Gr. syn, together; xenos, guest] The rearing ofone or more individuals of a single species along with oneor more known species of organisms. see axenic, dixenic,monoxenic, polyxenic, trixenic, xenic.synzoea n. [Gr. syn, together; zoe, life] (ARTHRO: Crustacea)In Malacostraca, pelagic juvenile stages of Stomatopod larvae.syringe see salivary pumpsyringium n. [Gr. syrinx, pipe] (ARTHRO: Insecta) 1. The salivarypump in Hemiptera. 2. An organ for ejecting disagreeablefluids in some insect larvae.systematics n.pl. [Gr. syn, together; histani, to place] Taxonomy.systematist n. [Gr. syn, together; histani, to place] A studentof taxonomy.systole n. [Gr. systole, contraction] The contraction of anycontractile cavity, i.e., the heart. systolic a. see diastole.syzygy n.; pl. syzygies [Gr. syzygos, united] 1. The combiningof organs without loss of identity. 2. (ECHINOD: Crinoidea)Having each nodal columnal closely and rigidlyjointed to the internodal columnal below it by short elasticfibers, and as such lacking flexibility.

Ttabula n.; pl. -ae [L. tabula, table] 1. (CNID: Anthozoa) Horizontalpartitions across the vertical canals of corals. 2.(ECHINOD: Asteroidea) A flat elevated dorsal plate of seastars.tabular a. [L. tabula, table] Arranged in a flat surface.tachyauxesis n. [Gr. tachys, quick; auxesis, growth] Rapidgrowth; a part or structure that grows at a quicker ratethan the organism as a whole. see bradyauxesis, isauxesis.tachyblastic a. [Gr. tachys, quick; blastos, bud] Referring tothin shelled eggs that begin cleavage immediately afteroviposition and develop quickly; summer egg. see opsiblastic.tachygen n. [Gr. tachys, quick; gennaein, to produce] Anevolutionary structure of abrupt origination.tachygenesis n. [Gr. tachys, quick; genesis, beginning] Theshortening or acceleration of embryonic development byomitting one or more developmental stages. see bradygenesis.tachytelic a. [Gr. tachys, quick; telos, completion] Evolution ata faster rate than usual. see horotelic.-tactic a. [Gr. taktikos, comb. form] Used in adjectives formedfrom nouns ending in -taxis.tactile a. [L. tactus, touch] Pertaining to the organs of thesense of touch.tactile combs (CNID: Hydrozoa) Patches of long stiff hairs onthe bell margin of hydromedusae.tactile sensillum see sensillum trichodeumtactoreceptors n.pl. [L. tactus, touch; receptor, receiver]Hairs, bristles, or other epidermal structures that functionin touch where the organism comes in contact with thesubstratum, vibration of the substratum or high intensity

Online Dictionary of Invertebrate Zoology 889airborne sounds.taenia n. [Gr. taenia, band or ribbon] A band, such as of nerveor muscle.taeniate a. [Gr. taenia, band or ribbon] Having a broad longitudinalmarking.taenidium n.; pl. -nidia [L. dim. taenia, band or ribbon] 1.(ARTHRO: Chelicerata) In Acari, a ribbon-like canal on thesurface of the tegument. 2. (ARTHRO: Insecta) A circular orspiral chitinous thickening, strengthening the inner wall ofthe trachea.taenioglossate radula (MOLL: Gastropoda) A radula with numeroustransverse rows of lingual teeth, usually seven to arow; median tooth frequently has cusps, the largest in themiddle, broad cuspidate admedians and narrow, hooklikemarginals.tagma n.; pl. tagmata [Gr. tagma, an arrangement] 1. Amajor division of body regions of a metamerically segmentedanimal, particularly arthropods. see pseudotagma.2. (ARTHRO: Chelicerata) The prosoma and opisthosoma.3. (ARTHRO: Insecta) The head, thorax, pediceland gaster of Formicidae.tagmosis n. [Gr. tagma, an arrangement] The division of abody into groups of segments, forming distinct trunk sectionsor tagmata.tail n. [A.S. taegel, tail] 1. (ARTHRO: Insecta) The cauda; insome Lepidoptera and Neuroptera, the elongated processeson the hind wings. 2. (NEMATA) That portion of the body invermiform adults posterior to the anus.tailfan see caudal fantail valve (MOLL: Polyplacophora) The posterior valve.Takakura's duct (NEMER:Enopla) In Carcinonemertidae, acommon efferent canal in the male reproductive systemthat links the testes and discharges into the intestine nearthe anus.talon n. [L. talus, heel] Shaped like a claw; unguiculate.talus n. [L. talus, heel] (ARTHRO: Insecta) The juncture of thetibia and tarsus.

890Maggenti and Gardnertandem a. [L. tandem, at length] One behind the other; twoconnected or attached together.tangent a. [L. tangere, to touch] Touching; coming together ata single point.tangoreceptor n. [L. tangere, to touch; receptor, receiver] Asimple tactile sense organ, consisting of one sense cell.tanylobous a. [Gr. tanaos, stretched; lobos, lobe] (ANN: Oligochaeta)Pertaining to the tongue of the prostomium extendingthrough segment i to the groove between segmentsi and ii, dividing the peristomium dorsally. seeepilobous, prolobous, zygolobous.tapetum n. [L. tapete, carpet] 1. A reflecting surface within aneye. 2. (ARTHRO: Insecta) A light reflecting surface withinclear-zone eyes, formed by tracheae that run through theeye parallel with the ommatidia forming a layer aroundeach one, and reflecting the light back into the ommatidia.tapetal a.tapinoma-odor (ARTHRO: Insecta) In Hymenoptera, a rancidbutter smell secreted from the anal glands of some ants ofthe Dolichoderinae.Tardigrada, tardigrades n.; n.pl. [L. tardus, slow; gradus,step] A phylum of small, multicellular coelomates, commonlycalled water bears, or bear animaecules due to alumbering, bearlike gait.tarsal a. [Gr. tarsos, sole of foot] Pertaining to the foot or tarsus.tarsal claw (ARTHRO) A claw at the apex of the tarsus; unguis.tarsal comb see pedal stridulating organtarsal formula (ARTHRO: Insecta) Referring to the number oftarsal segments on the front, middle, and hind tarsi.tarsal pulvillus see euplantulatarsation n. [Gr. tarsos, sole of foot] (ARTHRO: Insecta) Communicationby touching with the tarsi.tarsomere, tarsite [Gr. tarsos, sole of foot] (ARTHRO) A subdivisionor segment of the tarsus.tarsungulus n. [Gr. tarsos, sole of foot; L. dim. unguis, claw]

Online Dictionary of Invertebrate Zoology 891(ARTHRO: Insecta) The fused tarsal segment and claw ofmany coleopteran larvae.tarsus n. [Gr. tarsos, sole of foot] 1. The foot. 2. (ARTHRO) Themost distal part of the leg, immediately beyond the tibia,usually subdivided into two to five segments, bearing theclaws and pulvilli.taste bud (ARTHRO: Insecta) In Lepidoptera, specialized tastecells located on the tarsi.tautonym n. [Gr. tautos, the same; onyma, name] In the binomialsystem, the same name given to a genus and oneof its species or subspecies.taxis n.; pl. taxes [Gr. taxis, arrangement] Movement of amotile animal in response to a source of stimulation. a.Positive taxis : toward the stimulus. b. Negative taxis :Away from the stimulus.taxodont a. [Gr. taxis, arrangement; odon, tooth] (MOLL: Bivalvia)With many short interlocking teeth, some or alltransverse to the hinge margin; similar to prionodont.taxometrics see numerical taxonomytaxon n.; pl. taxa [Gr. taxis, arrangement] Any taxonomicgroup sufficiently distinct to merit being distinguished byname, i.e., phylum, class, order, etc.taxon cycle A cycle of expansion and contraction of the geographicrange and population density of a species or highertaxonomic category.taxonomic a. [Gr. taxis, arrangement; nomos, law] Pertainingto the classification of organisms.taxonomist n. [Gr. taxis, arrangement; nomos, law] One whostudies the theory and practice of classifying organisms.taxonomy n. [Gr. taxis, arrangement; nomos, law] The studyof the theory, procedure, and rules of classification of organisms,based on similarities and differences. see classicaltaxonomy, cytotaxonomy, numerical taxonomy,experimental taxonomy, classification, systematics.tectiform a. [L. tectum, roof; forma, shape] Roof-like; sloping.tectostracum see cerotegument

892Maggenti and Gardnertectum n. [L. tectum, roof] 1. (ARTHRO: Chelicerata) In Acari,the blade-shaped prolongation of the exoskeleton to protectan organ or joint; epistome; cervix. 2. (ARTHRO:Crustacea) The central portion of the carina of barnacles.teeth n. [A.S. toth, tooth] 1. Hardened growths on mandibles,maxillae or stomatal walls. 2. (CNID: Hydrozoa) Deep orvery shallow indentations on the hydrothecal margins; peglikechitinous growths just inside the margins. 3. (MOLL:Polyplacophora) Portions of the articulamentum betweenthe slits; may be pectinated or propped (outside edgesthickened), sharp and smooth.teges see setategillum n.; pl. -a [L. teges, mat] (ARTHRO: Insecta) In Scarabaeoidealarvae, a paired patch of hooked or straight setaeon each side of the venter of the tenth abdominal segmentbeside paired palidia; part of the raster.tegmen n.; pl. -mina [L. tegmen, cover] 1. A tegument orcovering. 2. (ARTHRO: Insecta) a. In Coleoptera, a single ordivided sclerite proximad of the penis (phallobase); may bedivided into basal piece and parameres. see tegumen. b.In some Orthoptera, Dictyoptera and Homoptera, the hardenedleathery fore wing. 3. (ECHINOD: Crinoidea) An oralwall covering the calyx cup.tegmentum n. [L. tegere, to cover] (MOLL: Polyplacophora)The outer, sometimes softer and porous calcareous layer ofthe valve below the periostracum.tegula n.; pl. -lae [L. tegula, roofing tile] (ARTHRO: Insecta) 1.A small convex, scalelike lobe overlying the base of the forewing; paraptera. 2. In Diptera, small anterior sclerites locatedin an incision of the lateral region of the notum. 3. InLepidoptera, well developed, and carried on a specialtegular plate of the notum, supported by a tegular armarising from the base of the pleural wing process.tegular arms (ARTHRO: Insecta) Internal structures supportingthe tegular plate.tegular plate (ARTHRO: Insecta) In Lepidoptera, a notalstructure bearing the tegulae of the fore wings.tegulum n. [L. tegulum, roof] (ARTHRO: Chelicerata) In Acari,

Online Dictionary of Invertebrate Zoology 893the dorsal region of the cheliceral frame extending from thecheliceral base to the rostrum.tegumen n. [L. tegumen, cover] (ARTHRO: Insecta) 1. Tegmen.2. (ARTHRO: Insecta) In male Lepidoptera, a dorsal roof orhoodlike structure of the genitalia.tegument n. [L. tegumentum, covering] 1. Any natural outercovering. 2. (ACANTHO) The non-cellular body wall or cuticle.tegumentary a.tegumentary glands (ARTHRO: Chelicerata) In Acari, specializedsecretory glands, located in or immediately beneaththe hypodermis.tela n.; pl. -ae [L. tela, web] (BRACHIO) One of a pair of pointsat the end of the beak ridges that project into and beyondthe pedicle opening.telaform larva (ARTHRO: Insecta) In certain heteromorphicHymenoptera first instar larva, a sharp, tail-like caudalhorn curved anteriorly, body constricted between a largeanterior part (cephalothorax) and an elongated posteriorpart.telamon n. [Gr. telamon, strap] 1. A supporting band. 2.(NEMATA: Secernentea) A thickening of the anterior cloacalwall in the order Strongylida, that acts as an accessoryguiding structure for the spicules; sometimes erroneouslyapplied in plant parasites to the gubernacular capitulum.telegonic see panoistic ovarioleteleiochrysalis n. [Gr. teleios, perfect; chrysallis, goldenthing] (ARTHRO: Chelicerata) In Acari, the third stagenymph enclosed in the integument of the preceeding nymphalstage.telenchium n. [Gr. telos, end; enchos, spear] (NEMATA: Secernentea)Sometimes used to denote the shaft of thestylet in plant parasites in the order Tylenchida. seemetenchium.teleoconch n. [Gr. teleios, complete, konche, shell] (MOLL:Gastropoda) The entire shell, excluding the protoconch.teleodont a. [Gr. teleios, complete; odon, tooth] 1. (ARTHRO:Insecta) In Coleoptera Lucanidae, referring to males bear-

894Maggenti and Gardnering large mandibles. see amphiodont; priodont. 2.(MOLL: Bivalvia) Hinge with cardinal and lateral teeth, butwith additional elements, as Venus.teleology n. [Gr. teleios, complete; logos, discourse] A theoryin biology that evolution or nature is guided by a purpose.teleotrocha see trochophoretelepod see telopodtelescope v.i. [Gr. tele, far; skopos, watcher] To have theability to evert and invert a body part. telescopic a.telioderma n. [Gr. teleios, complete; derma, skin] (ARTHRO:Chelicerata) In Acari, the cuticle of the previous stagenymph (apoderma) covering the tritonymph.teliophan see tritonymphtelmophage n. [Gr. telma, pool; phagein, to eat] (ARTHRO) Ablood feeding arthropod that severs skin and blood vessels,causing a small blood hemorrhage so as to feed.telocentric a. [Gr. telos, end; kentron, center of circle] Chromosomesin which the centromere is terminal. see acrocentric.telodendria n. [Gr. telos, end; dendros, tree] The branchingterminals of an axon.telofemur n. [Gr. telos, end; L. femur, thigh] (ARTHRO: Chelicerata)In Acari, a distal segment of the femur separatedfrom the basifemur by the basifemoral ring.telogonic see panoistic ovarioletelolecithal egg An egg cell with abundant yolk concentratedtoward the lower side of the cell. see centrolecithal egg.telomitic see telocentrictelophase n. [Gr. telos, end; phasis, aspect] The final stagesof mitosis during which the chromatids (daughter chromosomes)are formed and the cytoplasm divides.telophragma see Z-band or disctelopod n. [Gr. telos, end; pous, foot] 1. (ARTHRO: Crustacea)Part of an appendage distal to the coxa. 2. (ARTHRO: Diplopoda)In males, a modified leg, serving a copulatory function,on one of the posterior segments.

Online Dictionary of Invertebrate Zoology 895telopodite n. [Gr. telos, end; pous, foot] (ARTHRO: Insecta)The primary shaft of a limb distal to the coxopodite; thebasipodite.telorhabdions n.pl. [Gr. telos, end; rhabdos, rod] (NEMATA)The posterior wall plates of the telostome. see rhabdion.telostome, telostom n. [Gr. telos, end; stoma, mouth](NEMATA: Secernentea) The posterior part of a stoma. seeprotostome.telosynapsis, telosyndesis see acrosyndesistelotarsus n. [Gr. telos, end; tarsos, sole of foot] (ARTHRO) InChelicerata and Chilopoda, the distal of the two principaltarsomeres of the tarsus.telotaxis n. [Gr. telos, end; taxis, arrangement] Movementdirected towards a goal, with a minimum of deviation in thepath taken. see kinotaxis, tropotaxis.telotroch n. [Gr. telos, end; trochos, wheel] 1. (ANN: Polychaeta)The preanal girdle of cilia near the posterior end. 2.(PHORON) A ciliary ring on the posterior of the trunk,probably a locomotor organ.teletrocha see trochophoreteletrophic ovariole (ARTHRO: Insecta) An ovariole in whichall the trophocytes are terminal in the germarium, andconnect to the egg by a slender trophic chord; acroptrophicovariole; telotrophic egg tube. see polytrophic ovariole.telson n. [Gr. telson, end] 1. (ARTHRO) The terminal portion ofan arthropod body (not considered a true somite), usuallycontaining the anus; the periproct. 2. (ARTHRO: Chelicerata)In scorpions, the distal stinging caudal spine. 3. (AR-THRO: Crustacea) The posterior projection, sometimes withcaudal furca; the last body unit/segment in which the anusis not terminal; postsegmental region; style. 4. (ARTHRO:Diplopoda) The preanal ring. 5. (ARTHRO: Insecta) a. The12th abdominal segment of primitive insects and some insectembryos. b. In scale insects, the lateral cuticular extensionof the 8th segment. telosonic a.template n. [F. dim. temple, used in weaving] 1. A patternfrom which objects are copied. 2. In genetics, a strand ofDNA acting as template for a strand of RNA, which in turn

896Maggenti and Gardnerserves as a template for nucleic acids or proteins.temporal isolation Non-interbreeding between species as aresult of time differences, i.e., diurnal versus nocturnal.temporal organs see organs of Tomosvarytemporary haplometrosis (ARTHRO: Insecta) In early colonydevelopment of social insects, a single female (queen) initiatesdevelopment and is either joined by its offspring orfemales from other colonies, producing a pleometrotic society.see functional haplometrosis, permanenthaplometrosis.temporary parasite A parasite that comes in contact with itshost to feed and then departs; intermittent parasite; micropredator.temporary pleometrosis (ARTHRO: Insecta) In social insects,a colony in which two or more females share a nest thatwas founded by a single female; non-founding females donot cooperate in nest development, and later disperse andfound individual colonies. see permanent pleometrosis.temporary social parasitism (ARTHRO: Insecta) In Hymenoptera,a parasitic queen entering an alien nest replacingthe alien queen by killing or sterilizing it and eventuallydominating the nest.tenacipeds n.pl. [L. tenere, to hold; pes, foot] (ARTHRO: Chilopoda)In Lithobiida, ambulatory legs of segments 14 and15, elongated and apparently used for mating and captureof prey.tenaculum see retinaculumtenent a. [L. tenere, to hold] Adapted for clinging, i.e., hairs.teneral a. [L. tener, soft] (ARTHRO) A term applied to anynewly emerged soft-bodied individual; callow worker.tensor a. [L. tendere, to stretch] A muscle that stretches apart of a body or renders it of use.tentacle n. [L. tentaculum, feeler] Any elongate flexible appendageusually near the mouth. tentacular a.tentacle crown (BRYO) Tentacles expanded into an externalposition as for feeding.

Online Dictionary of Invertebrate Zoology 897tentacle sheath (BRYO) That part of the body wall that supportsand encloses the tentacles when everted and retracted.tentacular atrium (BRYO) A cavity inside the tentacle sheath,with tentacles retracted.tentacular bulb (CNID) Swelling at the base of a medusoidtentacle that serves primarily in digestion and manufactureof nematocysts and sometimes bears an ocellus or othersensory structure; ocellar bulb.tentacular cirrus (ANN: Polychaeta) Sensory projection(s) ofthe peristomium or cephalized segment.tentacular club (MOLL: Cephalopoda) A terminal suckered pad,comprised of carpus, manus and dactylus.tentacular crown see branchial crowntentacular fold (MOLL: Bivalvia) The central fold of the oystermantle edge that bears the tentacles in two rows.tentacular palp (ANN: Polychaeta) A grooved, food-gatheringappendage in many sedentary species.tentaculocyst see rhopaliumtentaculozooid n. [L. tentaculum, feeler; Gr. zoon, animal;eidos, form] (CNID: Hydrozoa) A modified polyp in the formof a single tentacle, usually found at the outermost part ofthe colony; a protective zooid. see tentaculozooid, gastrozooid.tentilla n. [L. tentaculum, feeler] (CNID: Hydrozoa) In Siphonophora,lateral contractile tentacular branches.tentorial bar (ARTHRO: Insecta) The right or left half of thetentorium, consisting mainly of the united anterior andposterior arms.tentorial bridge (ARTHRO: Insecta) The apices of the twoposterior arms fused medially; incomplete or absent inmost Diptera.tentorial fovea see tentorial pitstentorial macula (ARTHRO: Insecta) The depressions or darkspots marking the points of union of the dorsal tentorialarms and the epicranal wall near the antennae.

898Maggenti and Gardnertentorial pits (ARTHRO: Insecta) External depressions on thesurface of the head marking points of union of the armswith the outer wall of the head; usually two in the epistomalsuture and one at the lower end of each postoccipitalsuture.tentorium n.; pl. -oria [L. tentorium, tent] (ARTHRO: Insecta)Two anterior and two posterior apodemes (arms) that formthe internal skeleton of the head, serving as a brace for thehead and for the attachment of muscles; in Culicidae, theright and left halves are not connected.tenuous a. [L. tenuis, thin] Thin, slender, delicate.teratocyte n. [Gr. teras, monster; kytos, container] (ARTHRO:Insecta) In Lepidoptera Pieridae, unicellular forms resultingfrom the embryonic membranes of parasitic Braconidae.teratogen n. [Gr. teras, monster; genes, producing] Any substancethat causes or increases the incidence of congenitalabnormalities in a population.teratogenesis n. [Gr. teras, monster; genesis, beginning] Theproduction of monstrous fetuses or growths.teratogyne n. [Gr. teras, monster; gyne, woman] (ARTHRO:Insecta) In Hymenoptera, the aberrant form of female in aFormicidae colony, characterized by overdeveloped legsand antennae, and excess pilosity of the body or defectivewings; formerly referred to as beta-females. see alphafemale.teratology n. [Gr. teras, monster; logos, discourse] The biologicalstudy of structural malformations and monstrosities.terebella see terebraterebra n.; pl. -bras, -brae [L. terebra, borer] 1. A borer orpiercer. 2. (ARTHRO: Insecta) a. In Hymenoptera, thestylets and stylet-sheath. b. In Odonata and Hymenoptera,the gonapophyses of segments 8 and 9. 3. (MOLL) a. In Bivalvia,the anterior margin of the valve. b. In carnivorousGastropoda, the radula. terebrant, terebrate a.teres n. [L. teres, rounded] Nearly cylindrical. terete a.terga pl. tergumtergal a. [L. tergum, back] Situated on the back.

Online Dictionary of Invertebrate Zoology 899tergal fissure (ARTHRO: Insecta) In Symphyta and primitiveforms of many orders, a membranous line from one lateralmargin to the other, behind the anterior notal wing processes.tergal fold see epimeretergal margin (ARTHRO: Crustacea) In Thoracica Cirripedia,the edge of the scutum adjacent to the tergum, or edge ofany plate abutting the tergum.tergal suture (ARTHRO: Insecta) In many larvae, a Y-shapeddorsal suture of the head.tergal valves see cercustergite n. [L. tergum, back] (ARTHRO) A dorsal sclerite of asegment.tergolateral margin (ARTHRO: Insecta) In Cirripedia, in thosepossessing upper laterals, the angular edge of the scutum.tergopleural a. [L. tergum, back; pleuron, side] Referring tothe upper and lateral portion of a segment.tergopore n. [L. tergum, back; porus, pore] (BRYO: Stenolaemata)In Tubuliporina, a type of kenozooecium on the backside of a colony, having a polygonal aperture.tergum n.; pl. terga [L. tergum, back] (ARTHRO) The dorsalsurface of any body segment.termen n. [L. terminus, boundary] (ARTHRO: Insecta) Theouter, or distal margin of the wing.terminal a. [L. terminus, boundary, end] At the end; formingthe end of a series or part; at the extreme end.terminal anecdysis When maximum size is reached, no moreecdyses occur. see anecdysis.terminal arborizations Branching fibrils ending the axon andcollateral ends. see telodendria.terminal cirri (ARTHRO: Crustacea) In Ascothoracica, cirri locatedat the posterior end of the thorax, except for firstpair.terminal claw spines (ARTHRO: Crustacea) In Cladocera,toothlike projection, varying in size, at the concave end ofthe postabdomen.

900Maggenti and Gardnerterminal filament (ARTHRO: Insecta) A cellular end thread ofthe female ovariole that forms a common thread unitingwith that from the ovary of the opposite side.terminal diaphragm (BRYO: Stenolaemata) A membranous orcalcified diaphragm that separates the body cavity from theenvironment.terminalia n.pl. [L. terminus, boundary, end] Collectively, anyterminal part or structure.termitarium n.; pl. -ia [L. termes, woodworm] (ARTHRO: Insecta)An elaborate nest wherein a colony of termites live.termitophile n. [L. termes, woodworm; philos, loving] A symbiontof termites.terranes n.pl. [L. terra, earth] Fragments of former continentsthat make up the present day continents.terrestrial a. [L. terrestris, of the earth] Belong to or living onthe ground or earth; opposed to aquatic and arboreal.terricolous a. [L. terra, earth; colare, to inhabit] Soil inhabiting.territory n. [L. territorium, domain] An area defended by ananimal against other members of its own or other species.tertiary a. [L. tertius, third] Third in degree of standing in classification.tertiary parasite A parasite of a hyperparasite.tertiary reproductive (ARTHRO: Insecta) In Isoptera, an ergatoidreproductive; a third-form reproductive.tertibrach n. [L. tertius, third; brachium, upper arm] (ECHI-NOD: Crinoidea) Any ray plate of the third branchitaxis;palmars. tertibrachial a. see postpalmars.tessellate a. [L. tessellatus, mosaic] Marked or colored in thepattern of squares, or oblong areas; checkerboard-like.test n. [L. testa, a shell] A rigid external covering or supportingstructure.testaceology n. [L. testa, shell; logos, discourse] The study ofshells; conchology.testaceous a. [L. testaceus, covered with a shell] Bearing atest or hard covering; of the nature of a shell. see con-

Online Dictionary of Invertebrate Zoology 901chiferous.test-cross see back-crosstestis n.; pl. testes [L. testis, testicle] That portion of themale reproductive system producing spermatozoa; a spermary.testisac n. [L. testis; testicle; saccus, sac] (ANN: Hirudinoidea)The testis sac.testis sac (ANN: Oligochaeta) A membranous sac around thetestis, seminal vesicle and the funnel to the vas deferens.testudinate a. [L. testudo, tortoise] In the form of the shell ofa tortoise; arched; vaulted.tetanus, tetany n. [Gr. tetanos, stiffness] State of contractionof a muscle caused by continuous stimulation either naturalor electrical.tetracerous, tetracerate a. [Gr. tetra, four; keras, horn] Havingfour horns.tetraclad n. [Gr. tetra, four; klados, branch] (PORIF) A megascleredesma with rays bearing terminal couplings, or basedon a calthrops, or both; tetraclone .tetracladine, tetracrepid (PORIF) A tetraxonid desma.tetracotyle n. [Gr. tetra, four; kotyle, cup-shaped] (PLATY: Trematoda)A metacercaria in the family Strigeidae.tetractine see tetraxontetrad n. [Gr. tetra, four; -ad, collective noun] Any set of four.tetradelphic a. [Gr. tetra, four; delphys, womb] (NEMATA)Having four uteri.tetramerous a. [Gr. tetra, four; meros, part] 1. Having a fourjointed tarsus. 2. Having body parts arranged in fours.tetramorphic a. [Gr. tetra, four; morphe, form] (CNID: Hydrozoa)Having four distinct forms in one individual.tetraploid n. [Gr. tetraple, fourfold; eidos, like] A polyploidwith four haploid chromosome sets.tetrapod n. [Gr. tetra, four; pous, foot] Having 2 pair of legs.see bipod.tetrapterous a. [Gr. tetra, four; pteron, wing] Having 4 wings.

902Maggenti and Gardnertetrasomic a. [Gr. tetra, four; soma, body] Polysomic cellswith one chromosome represented 4 times in a normaldiploid; 2n+2.tetrathyridium n. [Gr. tetra, four; thyridion, window] (PLATY:Cestoda) A cysticercoid of Mesocestoides which has a solidbody and a scolex not surrounded by special membranes.tetrathyridial a.tetraxon n. [Gr. tetra, four; axon, axis] (PORIF) A spicule of 4equal and similar rays meeting at equal angles; tetractine;quadriradiate. tetraxonid a.thalassophilous a. [Gr. thalassa, sea; philos, loving] Inhabitingor dwelling in the sea; pelagic; thalassic.thallus n. [Gr. thallos, young shoot] The body or colony of acompound animal.thamnophilous a. [Gr. thamnos, shrub; philos, loving] Inhabitingthickets or dense shrubbery.thanatocoenosis n. [Gr. thanatos, death; koinos, common]An assemblage of fossils comprised of the remains of organismsbrought together after death. see biocenosis.thanatosis n. [Gr. thanatos, death] Feigning death; letisimulation.theca n.; pl. thecae [Gr. theke, case] 1. A sheath or sac-likecovering or structure for an organ or organisms, as proboscis,tubes, shells, pupa or larvae. 2. (ANN: Oligochaeta)Spermatheca. 3. (ARTHRO: Insecta) A fold or sheath fromphallobase enclosing the aedeagus. 4. (ECHINOD: Crinoidea)The skeleton. thecal, thecate a.thelycum n. [Gr. thelykos, feminine] (ARTHRO: Crustacea) Insome female Decapoda, an external pocket on the ventralside of the thorax, functioning as a seminal receptacle.thelygenous a. [Gr. thelys, female; genes, producing] Producingmostly or only female offspring; arrhenogenous.thelygenesis n.thelyotoky n. [Gr. thelys, female; tokos, offspring] A type ofparthenogenesis in which unfertilized eggs develop into females;thelytoica. thelyotokous a. see arrenotoky,deuterotoky, amphitoky.

Online Dictionary of Invertebrate Zoology 903theory of probabilities A mathematical theory used by taxonomists,whereby they assume that no two individuals willsimultaneously have the same combination of characters asthose of a given species; in mathematics, the theory ofchance.thermocline n. [Gr. therme, heat; klinein, to slope] In thestrata of rapidly changing temperatures in lakes, the narrowdividing stratum between the epilimnion andhypolimnion.thermophile n. [Gr. therme, heat; philos, loving] Living athigh temperatures; hot springs fauna.thermophobe n. [Gr. therme, heat; phobos, hate] An organismthat lives at low tempertures.thermoreceptor n. [Gr. therme, heat; L. recipere, to receive]A sensory receptor that reacts to temperature stimuli.thermotaxis n. [Gr. therme, heat; taxis, arrangement] A taxisin which heat is the response initiating stimulus; regulationof body temperature.thesocytes n.pl. [Gr. thesis, deposit; kytos container] (PORIF)In hibernating fresh water sponge gemmules, binucleate,highly vitelline archaeocytes.thickener cells (PORIF) Cells influencing ray thickness duringsecretion of calcareous spicules.thickness n. [A.S. thicce, thick] (MOLL: Bivalvia) 1. See inflation.2. Measurement from the inner to outer shell surface.thigmotaxis n.; pl. taxes [Gr. thigma, touch; taxis, arrangement]The taxis of contact; stereotaxis. a. Positive thigmotaxis:toward the contact. b. Negative thigmotaxis:away from the contact. thigmotactic a.thigmotropism n. [Gr. thigma, touch; tropos, turn] Tropism inwhich direction is determined by contact with a solid body;stereotropism.third axillary (ARTHRO: Insecta) A Y-shaped sclerite of thewing, with a flexor muscle inserted into the crotch of the Yand usually articulating with the posterior notal processand a group of anal veins.third-form reproductive (ARTHRO: Insecta) In Isoptera, an

904Maggenti and Gardnerergatoid reproductive; a tertiary reproductive.thoracic a. [Gr. thorax, chest] Associated with the thorax.thoracic ganglia (ARTHRO: Insecta) The first three ganglia ofthe ventral nerve cord, one in each thoracic segment, controllingthe locomotory organs.thoracic glands see prothoracic glandsthoracic region (ARTHRO: Insecta) The second of three regionsof the embryonic trunk; the future locomotor center.thoracic squama (ARTHRO: Insecta) In some Diptera, one ofthree membraneous lobes in the region of the wing baseappearing to be derived from the posterior margin of thescutellum. see alula, alar squama.thoracomere n. [Gr. thorax, chest; meros, part] (ARTHRO:Crustacea) A thoracic segment.thoracopod(ite) n. [Gr. thorax, chest; pous foot] (ARTHRO:Crustacea) Any appendage of the thoracic somite; a cormopod.see phyllopod, maxilliped, pereopod.thorax n.; pl. thoraxes, thoraces [Gr. thorax, chest] 1. (AR-THRO: Chelicerata) In Arachnida, fused with the head toform the cephalothorax of spiders. 2. (ARTHRO: Crustacea)The tagma between the cephalon and abdomen comprisingthe anterior part of the trunk; cormus; pereon. 3. (ARTHRO:Insecta) a. The body region behind the head, bearing thelegs and wings and encompassing the pro-, mesoandmetathorax. b. In Hymenoptera, the second tagma of thebody consisting of pro-, meso-, metathorax and the epinotumof Formicidae.thread n. [A.S. thraed, twist] 1. A fine linear surface elevation.2. (MOLL: Bivalvia) A narrow elevation on the shell surface.3. (MOLL: Gastropoda) The silky fibers of the byssus.thread capsule see nematocystthread cell (CNID) The cnidoblasts.thread press see silk pressthylacium n. [Gr. thylax, sack] (ARTHRO: Insecta) An externalgall-like cyst in the abdomen of the host containing theDryinidae parasitic larva.

Online Dictionary of Invertebrate Zoology 905thylacogen n. [Gr. thylax, sack; genes, producing] A chemicalproduced by parasites that cause hypertrophy of host tissue.thyridium n; pl. -ia [Gr. dim. thyris, window] (ARTHRO: Insecta)1. A small whitish spot in the wings of Neuroptera,Hymenoptera and Trichoptera. 2. In ichneumonid Hymenoptera,a scar-like area on each side of the second abdominaltergite, between the middle and base; the third tergiterarely may have tyridia. thyridial a.thyroid n. [Gr. thyra, oblong shield] (ARTHRO: Insecta) InDiptera, a shield-shaped plate on the posterior wall of thebeak.thysanuriform larva see campodeiform larvatibia n.; pl. -iae [L. tibia, shin] 1. (ARTHRO: Chelicerata) Thefifth segment of a spider leg, between the patella andmetatarsus. 2. (ARTHRO: Insecta) The fourth segment ofthe leg, between the femur and tarsus.tibial comb (ARTHRO: Insecta) A strigil or scraper.tibial epiphysis see epiphysistibial process/thumb (ARTHRO: Insecta) In Anoplura Pediculus, a delicate modification of the tibia as a holdfastagainst the powerful claw of the tarsus.tibial spur (ARTHRO: Insecta) A large spine usually located onthe distal end of the tibia.tibiotarsal organ (ARTHRO: Insecta) In Collembola Sminthurides, a sac-like swelling and an enlarged hair occurringnear the distal ends of the tibiotarsus of the third pair oflegs.tibiotarsus n. [L. tibia, shin; Gr. tarsos, sole of foot] (ARTHRO:Insecta) Fused tibia and tarsus; the tibiotarsal segment.Tiedemann's bodies (ECHINOD: Asteroidea) Tiny, 9 sphericalswellings on the inner wall of the ring canal that have beenreported to produce amebocytes.tiled a. [ME. tile] Appearing as a tiled roof; transverse and longitudinalstriae on the cuticle.timbal see tymbal

906Maggenti and Gardnertinctorial a. [L. tenctorius, of dyeing] Of or pertaining to color,i.e., staining.tine n. [A.S. tind, spike] Any slender, pointed, projecting part.tissue n. [F. tissu, tissue] A layer or group of cells of a particulartype, or at most a few types, with intercellular materialof essentially a particular type.tissue culture Tissues appropriated from animals and maintainedor grown in vitro for more than 24 hours.titillae n.pl.; sing. titilla [L. titillo, tickle] (NEMATA) Small projectionson the distal part of the protrusile gubernaculum.titillator n. [L. titillo, tickle] (ARTHRO: Insecta) A terminal,small process (spines or small plates) at the distal extremityof the aedeagus.tocopherol n. [Gr. tokos, birth; pherein, to carry] Vitamin E.tocospermal a. [Gr. tokos, birth; sperma, seed] Direct transferof sperm between male and female.tocospermia n. [Gr. tokos, birth; sperma, seed] 1. (ARTHRO:Chelicerata) A type of sperm transfer by the male chelicera(gonopod), to the female vagina. see podospermia. 2.(MOLL: Cephalopoda) The direct transfer of spermatophoresto the female vagina by the male gonopod.tocostome, tokostome n. [Gr. tokos, birth; stoma, mouth](ARTHRO: Chelicerata) In Acari, the female genital aperture.tomentum n. [L. tomentum, stuffing of wool] Covered withclosely matted scale-like hair or spines on the body or appendagesthat cannot be separated; downy. tomentose a.tone see tonustonic muscle (MOLL: Bivalvia) White, opalescent part of theadductor muscle that reacts slowly, but can hold for longperiods of time; catch muscle.tonofibrillae n.pl [Gr. tonos, stretching; L. dim. fibra, fiber]Fine connective fibrils extending from the ends of theskeletal muscles into the cuticle.tonus, tone n. [Gr. tonos, stretching] 1. The normal, maintainednerve impulse traffic. 2. The normal prolongedsteady contracture of muscle fibers. tonic a.

Online Dictionary of Invertebrate Zoology 907topochemical sense The sense of smell.topogamodeme n. [Gr. topos, place; gamos, marriage;demos, the people] Individuals inhabiting a particular geographiclocality that form a deme.topomorph n. [Gr. topos, place; morphe, form] An environmentalmorphologic variant. topomorphic a.toponym n. [Gr. topos, place; onoma, name] The name of alocation thought to be the place of origin of a plant or animal.topotype n. [Gr. topos, place; typos, type] A specimen collectedat the original type-locality.tori pl. of torustorma n.; pl. -mae [Gr. tormos, socket] (ARTHRO: Insecta) 1.In Diptera, sclerotic processes between the labrum andclypeus. 2. In Scarabaeoidae larvae, heavily chitinizedstructures on the ends of the clypeo-lateral suture thatextend toward the mesal line, sometimes meeting andfusing on the mesal line.tormogen n. [Gr. tormos, socket; genes, producing] (ARTHRO:Insecta) An epidermal cell associated with a seta that secretesthe cuticle of the socket and bounds the receptorlymph cavity.tornote n. [L. tornatus, rounded with a lathe] (PORIF) A diactinalmonaxon, lance-headed at each end.tornus see anal angletorose a. [L. torus, elevation] A swelling into knobs; cylindricaland swollen at intervals; torous.torpid a. [L. torpidus, to be numb] Dormant; inactive. seeaestivation, hibernation.torqueate a. [L. torquatus, with a necklace] Having a ring orcollar.torsion n. [L. torquere, to twist] 1. Spiral bending; twisting. 2.(MOLL: Gastropoda) The theory in ancestral gastropods thata 180-degree counterclockwise twisting occurred thatcaused the crossing of the pleural-visceral connectives inthe nervous system to form a figure eight. see chiastoneury,detorsion.

908Maggenti and Gardnertortuose a. [Gr. torquere, to twist] Twisting; winding; irregularlycurved.torulose a. [L. torulus, little bulge] Having knob-like swellings;moniliform.torus n.; pl. tori [L. torus, swelling] 1. A blunt, rounded, ridgeor protuberance. 2. (ANN: Polychaeta) Low ridges providedwith rows of acicular hooks or minute setae or uncini. 3.(ARTHRO: Insecta) In Diptera, the pedicel of the antenna. 4.(PORIF) A more or less doughnut-shaped space around theorganism, concerned with water circulation.totipotent a. [L. totus, all; potens, capable] Said of isolatedblastomeres capable of becoming complete embryos.totomount n. [L. totus, all; mons, mountain] The mount of awhole organism for microscopic study.toxa n. [Gr. toxon, bow] (PORIF) A bow-shaped diactinal microsclere.toxicognath n. [Gr. toxikon, poison; gnathos, jaw] (ARTHRO:Chilopoda) The forcipulate poison fangs.toxicology n. [Gr. toxikon, poison; logos, discourse] The scienceof poisons.toxin n. [Gr. toxikon, poison] A poisonous substance in the secretionsor excretions of a parasite.toxinosis n. [Gr. toxikon, poison] A disease caused by the actionof a toxin.toxoglossate n. [Gr. toxon, bow; glossa, tongue] (MOLL: Gastropoda)Having a radula always enclosed in the radularsac; marginal teeth harpoon-shaped, filled with venom andloosely arranged in two rows.toxoid n. [Gr. toxikon, poison; eidos, form] A toxin releasedfrom its toxic properties, but not from its antigenic properties.trabecula n.; pl. -lae [L. trabecula, little beam] 1. A small bar,rod, bundle of fibers, or septum together with other trabeculaewhich form part of the framework of various organs.see internuncial process. 2. (MOLL: Cephalopoda) Insquid and cuttlefish, a support from the edge of the arminward for the protection of membranes of the arm.

Online Dictionary of Invertebrate Zoology 909trabeculate a. [L. trabecula, small beam] (ANN: Oligochaeta)Used to describe seminal vesicles that develop as connectivetissue proliferations from a septum that have numerousirregular spaces that remain minute until spermatogoniabegin to enter. trabeculated a.trachea n.; pl. tracheae [L. trachia, windpipe] 1. The windpipe.2. (ARTHRO: Chelicerata) For Arachnida, see tubetrachae, sieve trachea. 3. (ARTHRO: Insecta) The largertubes of the respiratory system, lined with taenidia, openingto the outside through the spiracles and terminatinginternally in the tracheoles. 4. (MOLL: Gastropoda) seectenidia. 5. (ONYCHO) In Peripatus, short tubes withoutspiral thickenings, neither branching nor anastomosing,opening externally through numerous minute spiracles.tracheate a.tracheal gills (ARTHRO: Insecta) In aquatic larvae and someaquatic pupae, filiform, lamellate structures supplied withtrachae and tracheoles, usually borne on the abdomen. seespiracular gills, blood gills.tracheal system (ARTHRO) A system of cuticle-line tubeopening to the outside through spiracles, functioning inrespiration.tracheoblast n. [L. trachia, windpipe; Gr. blastos, bud] (AR-THRO: Insecta) Cells derived from the epidermal cells liningthe trachea, that give rise to the tracheoles.tracheoles n. [L. dim. trachia, windpipe] (ARTHRO: Insecta)The fine intracelluar terminal branches of the respiratorytubes. tracheolar a.trachychromatic a. [Gr. trachys, rough; chroma, color]Strongly staining.tract n. [L. tractus, region] 1. An area, region or parts of asystem, as a bundle of nerve fibers between parts of thecentral nervous system. 2. (PORIF) A fascicular column ofspicules.Tragardh's organ (ARTHRO: Chelicerata) In Acari, a long, conicalhyaline protuberance of the articulation between thebody of a chelicera, and its movable jaw; oncophysis.tragus n. [Gr. tragos, goat] (ARTHRO: Insecta) In Diptera, a

910Maggenti and Gardnersomewhat elaborate lobe on the rim of the pinna of a laticorntrumpet of some culicid pupae.transad n. [L. trans-, across; Gr. ad, makes collective nouns]Closely related organisms separated by an environmentalbarrier.transcoxa n. [L. trans-, across; coxa, hip] (ARTHRO: Chelicerata)A term used instead of coxa in some groups.transcurrent a. [L. trans-, across; currens, running] 1. Extendingtransversely. 2. (MOLL: Gastropoda) Passing continuouslyaround whorls crossing growth lines.transect n. [L. trans-, across; secare, to cut] A cross sectionor profile of an area for study, as with organisms and/orvegetation.transection n. [L. trans-, across; secare, to cut] Cut across ortransversely; a transverse section.transformation zone In males, that part of the testis folliclein which the spermatids develop into spermatozoa; knownas spermiogenesis. see maturation zone.transient a. [L. trans-, across; ire, to go] A passing phenomenon;of short duration.transient polymorphism Polymorphism existing in a breedingpopulation during the period when an allele is being replacedby a superior one. see balanced polymorphism.transitional cell see chromophiletranslocation n. [L. trans-, across; locus, place] The shift of asegment of a chromosome to another chromosome, notchanging the total number of genes present.translucent a. [L. trans-, across; lucere, to shine] Allowing thepassage of light, but not necessarily transparent; semitransparent.transmission n. [L. trans-, across; mittere, to send] 1. Horizontal:the transfer of an infectious agent from one organismto another. 2. Vertical: transmission from one generationto another.transposed hinge condition (MOLL: Bivalvia) A condition ofteeth usually found in the hinge of one valve being foundon the opposite one.

Online Dictionary of Invertebrate Zoology 911transscutal suture (ARTHRO: Insecta) 1. In many orders, atransverse suture connecting the lateral margins behindthe anterior notal wing process, dividing the scutum into ananterior and posterior region. 2. In some Hymenoptera, asuture dividing the posterior part of the scutum into twoposterolateral areas called the axillae.transstadial a. [L. trans-, across; stadium, stage] The retentionof microorganisms from one stage of the host to thenext; may be part or all of the host's life cycle.transtilla n.; pl. -lae [L. trans-, across; stilla, drop] (ARTHRO:Insecta) In Lepidoptera, a transverse bar, or variouslyshaped process, connecting dorso-proximal angles of themale valva; part of the fultura superior; the anterior end ofthe dorsal extension of the 9th sternum or the vinculum.transverse a. [L. trans-, across; vertere, to turn] Crossing atright angles to the longitudinal axis; lying across or between.transverse band of crochets (ARTHRO: Insecta) In larva, crochetsbeing arranged transversely or across the longitudinalaxis of the body in a single uniserial or multiserial band,or in two such bands.transverse costal vein (ARTHRO: Insecta) A wing cross vein inthe costal cell.transverse cubital vein (ARTHRO: Insecta) A transverse wingvein connecting the marginal and cubital veins.transverse fission A form of asexual reproduction by divisionof an organism at right angles to the long axis. see binaryfission.transverse impression see genal groovetransverse marginal vein (ARTHRO: Insecta) A wing crossvein in the marginal cell.transverse notal suture see prescutal sulcustransverse partition (BRYO) A wall separating members of asuccessive line of zooids.transverse plane A plane or section perpendicular to the longitudinalaxis.transverse radial vein (ARTHRO: Insecta) A transverse mar-

912Maggenti and Gardnerginal wing vein.transverse septum (ARTHRO: Crustacea) In Cirripedia, thethin walled, normal to longitudinal septum, parallel to basis,dividing the parietal tubes into a series of cells.transverse striation A circular groove or arc whose plane isperpendicular to the longitudinal axis.transverse suture (ARTHRO: Insecta) In Diptera, a sutureacross the middle of the mesonotum of some species; usuallyincomplete in the center of the notum; in Tipulidae it isV-shaped.transverse wall (BRYO: Gymnolaemata) One of a pair of wallsseparating individual zooids in a linear series; perpendicularto direction of growth.trapezium n. [Gr. trapezion, small table] A four-sided figure,having no two sides parallel; trapeziform.trapezoid n. [Gr. trapezion, small table; eidos, shape] A planefour-sided figure in which two sides are parallel and twoare not. trapezoidal, trapeziform a.trema n.; pl. tremata [Gr. trema, hole] (MOLL: Gastropoda)An orifice in the outer wall of some shells, excretory infunction; may occur singly or in a series.Trematoda n. [Gr. trema, hole; eidos, form] A class of Platyhelminthes,commonly call flukes; all are endoparasiticflatworms.trenchant a. [OF. trenchier, to cut] Having a sharp edge.trepan n. [Gr. trypanon, borer] (ANN: Polychaeta) Part of theeversible pharynx containing chitinized teeth anteriorly, especiallySyllidae.triact n. [Gr. treis, three; aktis, ray] (PORIF) A microsclere spiculewith three rays. see regular triact, saggital triact.triactinal a. [Gr. treis, three; aktis, ray] (PORIF) Having athree-pointed or rayed spicule. see diactinal, tetractinal,monactinal.triad n. [Gr. treis, three; -ad, forms collective noun] An arrangementof three; a trinity.triaene n. [Gr. triaina, trident] (PORIF) A tetraxonid spicule

Online Dictionary of Invertebrate Zoology 913with three rays shorter than the fourth.triage n. [F. a culling] The process of grading.triangle n. [L. triangulus, having three angles] (ARTHRO: Insecta)In Odonata, a small triangular cell or group of cellsnear the base of the wing; discoidal triangle; cardinal cell.triangulate a.triangular plates (ARTHRO: Insecta) In Hymenoptera, the secondof three pairs of movable plates associated with thesting. see quadrate plates, oblong plates.triaulic a. [L. tres, three; aulos, pipe] (MOLL: Gastropoda) Inopisthobranch hermaphroditic snails, the female part havingtwo separate openings and the male part one. see diaulic,monaulic.triaxial symmetry A type of symmetry such as biradial- orbilateral symmetry, with three axes known as sagittal, longitudinal,and transverse.triaxon n. [Gr. tries, three; axon, axle] (PORIF) A spicule withthree axes.tribe n. [L. tribus, tribe] A taxonomic category containing agroup intermediate between the genus and the subfamily;names of tribes end in -ini.tribocytic organ (PLATY: Trematoda) In Strigeiudea, a glandular,pad-like organ behind the acetabulum.trichite n. [Gr. trix, hair] (PORIF) Hair-like siliceous spicule.trichobothrium n.; pl. -ria [Gr. thrix, hair; bothros, pit] (AR-THRO: Chelicerata) A compound structure of many groupsconsisting of a small cavity (bothridium) and variouslyshaped setae (bothridial setae) that function as vibro- andanemoreceptors.trichobranchia n.pl. [Gr. thrix, hair; branchia, gill] (ARTHRO:Crustacea) A gill with a series of filamentous lateralbranches arising from the main stem or branchial axis.trichobranchiate a.trichocerous a. [Gr. thrix, hair; keras, horn] (PLATY: Trematoda)Pertaining to cercaria having a tail provided with conspicuousspines or bristles.trichodes see tricomes

914Maggenti and Gardnertrichodragmata n.pl. [Gr. thrix, hair; dragma, sheaf] (PORIF:Desmospongiae) In Axinellidae ( Tragosia ), raphidesgrouped into bundles.trichogen n. [Gr. thrix, hair; genes, producing] (ARTHRO: Insecta)An epidermal cell that secretes the cuticle of theseta or peg, the scolopale and the pore tubules.trichoid a. [Gr. thrix, hair; eidos, form] Formed like a hair.trichoid sensilla see sensillum trichodeumtrichomes, trichodes n.pl. [Gr. thrix, hair] 1. (ARTHRO: Insecta)Modified tufts or hair on certain myrmecophilous andnon-myrmecophilous insects that aid in the disseminationof appeasement or pheromone substances. 2. (ARTHRO:Diplopoda) Hollow spines or setae of the bristly millipedes.trichophore n. [Gr. thrix, hair; pherein, to bear] (ANN) A saclikestructure or cavity from which setae emerge.trichopore n. [Gr. thrix, hair; poros, channel] (ARTHRO: Insecta)A pore in the cuticle through which a sensory hair orbristle is formed.trichosors n.pl. [Gr. thrix, hair] (ARTHRO: Insecta) In Neuroptera,thickenings of the wing margin bearing several hairs;a single trichosor between each pair of vein-endings inadults.trichostichal bristles see metapleural bristlestrichotomous a. [Gr. tricha, in three parts; tome, a cutting]Divided into three parts; three-forked.trichroism n. [Gr. treis, three; chros, color] The condition ofhaving three color forms in different individuals of the samespecies.tricolumella see columellatricostate a. [Gr. treis, three; costa, rib] Having three ribs orridges.tricrepid a. [Gr. treis, three; krepis, base] (PORIF) A triaxoniddesma.tricuspid, tricuspidate a. [Gr. treis, three; cuspis, a point]Divided into three cusps or points.tridactyl a. [Gr. treis, three; daktylos, finger] (ARTHRO) Per-

Online Dictionary of Invertebrate Zoology 915taining to an appendage, ambulacrum, or claw with threeungues. see monodactyl, bidactyl.trident a. [L. tres, three; dens, tooth] Having three teeth;three-pronged. tridentate a.trifid a. [L. tres, three; findere, to split] Having three clefts,parts, or branches.trifid nerve (BRYO) A three-branched peripheral motor nerveconnected to the retractor muscle, esophagus, and alongthe tentacle sheath to the direct nerve.trifurcate a. [L. tres, three; furca, fork] Having three branchesor forks; trichotomous.triglycerides n.pl. [Gr. treis, three; glykys, sweet] Esters offatty acids with glycerin that form fats and oils.trignathan a. [Gr. treis, three; gnathion, jaw] (ARTHRO) Havingmandibles and two pair of maxillae, such as Chilopoda,Symphyla and Insecta. see dignathan.trigonal a. [Gr. treis, three; gonia, angle] Pertaining to, or inthe form of a triangle.trigoneutism n. [Gr. treis, three; gonos, offspring] The productionof three broods in one season.trilabiate a. [L. tres, three; labium, lip] Having three lips.trilateral a. [L. tres, three; latus, side] Three-sided.trilobate a. [Gr. treis, three; lobos, lobe] Bearing three lobes.trilocular a. [L. tres, three; loculus, small place] With threecavities or cells.trimorphic a. [Gr. treis, three; morphe, form] Having threedistinct forms in one individual, as certain hydrozoan colonies.trimorphism n.Trinominal nomenclature An extension of the binominalsystem of nomenclature consisting of three words: the genericname, the specific name, and the subspecific name,together constituting the scientific name of a subspecies.triordinal crochets (ARTHRO: Insecta) Crochets of larvae withproximal ends in a single row, but distal ends of three alternatinglengths. see ordinal.tripartite a. [L. tres, three; partitus, divided] Divided into

916Maggenti and Gardnerthree parts, divisions or segments.tripectinate a. [L. tres, three; pecten, comb] Having threerows of comb-like branches.triplet n. [L. tres, three; plus, more] Three successive nucleotidebase pairs that code for an amino acid.triploblastic a. [Gr. triploos, threefold; blastos, bud] Derivedfrom three embryonic germinal layers: ectoderm, endodermand mesoderm.triploid a. [Gr. triploos, threefold] A cell or individual havingthree haploid chromosome sets in their nuclei; a form ofpolyploidy.triquetral, triquetrous a. [L. triquetrus, three sided] Havingthree angles or arms; triangular in section.triradiate(s) a. [L. tres, three; radius, spoke of wheel] 1.Having three radiating process. 2. (PORIF) Spicules havingthe three rays somewhat in the same plane. see sagittaltriradiates.tritocerebral commissure see postesophageal commissuretritocerebral segment see tritocerebrumtritocerebrum n. [Gr. tritos, third; L. cerebrum, brain] (AR-THRO) The posterior (third) small part of an arthropod brainthat gives rise to nerves that innervate the labium, the digestivetract (stomatogastric nerves), the chelicerae ofchelicerates, and the second antennae of crustaceans. seemetacerebrum.tritonymph n. [Gr. tritos, third; nymphe, young woman] (AR-THRO: Chelicerata) In Acari, the third stage nymph.tritosternum n. [Gr. tritos, third; sternon, chest] (ARTHRO:Chelicerata) In Mesostigmata, a secondary, ventral, bristlelikesensory organ just behind the gnathosoma.triturate v.t. [L. tritum, rub to pieces] To rub or grind to a finepowder; masticate; pulverize.triungulin, triungulinid n. [L. tres, three; ungula, claw] (AR-THRO: Insecta) First-instar larva of some hypermetamorphicNeuroptera, Coleoptera, Hymenoptera, and the Strepsiptera(triungulinid), which are active, compodeiform

Online Dictionary of Invertebrate Zoology 917oligopods. see planidium.trivial name An obsolete designation by Linnaeus for the specificname; vernacular name.trivium n. [L. trivium, crossroads] (ECHINOD: Asteroidea) Collectively,the three rays of a sea star farthest from themadreporite. see bivium.trivoltine n. [L. tres, three; It. volta, time] (ARTHRO: Insecta)Having three annual broods, especially in the silkworms ofBombycidae.trixenic a. [Gr. treis, three; xenos, guest] The rearing of oneor more individuals of one species in association with threeknown species of organisms. see axenic, dixenic, monoxenic,polyxenic, synxenic, xenic.troch n. [Gr. trochos, wheel] A band of cilia found on trocophoresand related larvae.trochal disc (ROTIF) Anterior ciliated disc functioning in locomotionand/or food ingestion.trochalopodous a. [Gr. trochos, wheel; pous, foot] (ARTHRO:Insecta) Refers to a posterior coxae having an articulationof a ball and socket joint. see pagiopodous.trochantellus n. [Gr. dim. trochanter, runner] (ARTHRO: Insecta)In Hymenoptera, the proximal end of the femur;sometimes appearing as a second segment of the trochanter.trochanter n. [Gr. trochanter, runner] (ARTHRO) A segment orsegments of an insect or acarine leg that articulate basallywith the coxa and distally with the femur; a pivot or rockingjoint; the first cheliceral segment.trochanteral organ (ARTHRO: Insecta) In Collembola, a groupof short setae on the trochanter.trochantin n. [Gr. trochanter, runner] (ARTHRO: Insecta) Anysmall intercalated sclerite of an insect appendage. a. Thebasal segment of the trochanter when two-jointed. b. Asmall sclerite in the thoracic wall, just anterior to the baseof the coxa.trochiform a. [Gr. trochos, wheel; forma, shape] 1. Shapedlike a top. 2. (MOLL: Gastropoda) In Trochidae, a flat-sided

918Maggenti and Gardnerconical shell, without a highly acute spire and rather flat atthe base.trochlea n. [Gr. trochilia, pulley] A pulley-like structure, short,circular, compressed and contracted in the middle of thecircumference.trocholophous a. [Gr. trochos, wheel; lophos, crest](BRACHIO) A lophophore with a simple disk around themouth, bearing usually a single row of unpaired filamentaryappendages, rarely a double row of paired appendages.trochophore n. [Gr. trochos, wheel; phora, bearing] An invertebratefree-swimming larva found in many groups,marine turbellarians, nemerteans, brachiopods, phoronids,bryozoans, mollusks, sipunculids, and annelids, commonlypear-shaped and provided with a prominent equatorialband of cilia and sometimes one or two accessory ciliarycirclets.trochosphere see trochophoretrochus n.; pl. trochi [Gr. trochos, wheel] (ROTIF) The inner,anterior circlet of coronal cilia along the margin of the apicalband; cingulum.troglobiont n. [Gr. trogle, hole; bios, life] A cave dwelling organism;troglobite.troglodytic a. [Gr. trogle, hole; dyein, to enter] Living undergroundonly.troglophile n. [Gr. trogle, hole; philein, to love] 1. Cave-loving.2. (ANN: Oligochaeta) Many species of earthworms arereferred to in this manner, however, they are not obligatorytroglophiles.trogloxene n. [Gr. trogle, hole; xenos, guest] 1. A cave guest.2. Sometimes used to characterize organisms that do notcomplete all of their life cycle in caves.tropeic a. [Gr. tropis, keel] Resembling a keel; cariniform.trophallaxis n. [Gr. trophe, food; allaxis, exchange] (ARTHRO:Insecta) The mutual or unilateral exchange of alimentarycanal liquid, from the mouth or anus, among colony membersof social insects or guests; trophobiosis. trophallactica.

Online Dictionary of Invertebrate Zoology 919trophamnion n. [Gr. trophe, food; amnion, membrane aroundthe fetus] (ARTHRO: Insecta) An envelope surrounding theembryonic mass in the polyembryonic ova of mainly parasiticHymenoptera, formed by cytoplasm in the egg associatedwith the paranuclear mass, and functioning in relayingnutrients from the host.trophi n.pl.; sing. trophus [Gr. trophe, food] 1. (ARTHRO) Themouth parts, especially of insects and barnacles, collectively.2. (ROTIF) The mastacatory apparatus of themastax. trophal , trophic a.trophic chord (ARTHRO: Insecta) In telotrophic ovarioles, slenderchords connecting the nurse cells to the eggs.trophic egg (ARTHRO: Insecta) In Apis, an egg that is fed tothe colony members, usually degenerate and nonviable.trophic sac/pouch (ARTHRO: Insecta) In Siphunculata (Anoplura),a pouch opening off the cibarium housing threeclosely compressed stylets, with only the anterior end exposed,functioning in piercing the skin for blood meals.trophic symbiosis A form of symbiosis between a social insectand another organism; tended by the social insect for thesake of the food or secretions they derive from them. seetrophallaxis, trophobiont.trophidium n. [Gr. dim. trophe, food] (ARTHRO: Insecta) InHymenoptera, the first larval stage of some Formicidae.trophobiont n. [Gr. dim. trophe, food; bios, life; ont, one who](ARTHRO: Insecta) An organism living in a social speciesnest, or cared for and protected by a social species in returnfor secretions which are then consumed. see mutualism.trophobiosis n. [Gr. trophe, food; biosis, manner of life] Aform of symbiosis in which there is a mutual exchange offood; trophallaxis. trophobiotic a. see trophic symbiosis.trophocytes n.pl. [Gr. trophe, food; kytos, container] 1. Cellsthat provide nutritive material. 2. (ARTHRO: Insecta) Cellsof the fat body of the embryo. 3. (PORIF) In fresh-watersponges, nurse cells involved in the initial stages of gemmuleformation; archaeocytes.

920Maggenti and Gardnertrophodisc n. [Gr. trophe, food; diskos, disc] (CNID: Hydrozoa)In the female gonophore, endodermal tissue that nourishessperm or ova.trophogeny n. [Gr. trophe, food; genes, producing] (ARTHRO:Insecta) In social insects, caste difference determined bynutritional mechanism.trophoporic field (ARTHRO: Insecta) In social insects, the environmentfrom which the colony gains food.trophorhinium n. [Gr. trophe, food; rhine, rasp] (ARTHRO: Insecta)In Hymenoptera, two striated plates located withinthe mouth of Myrmeciinae larvae that grind their food pellets.trophosome n. [Gr. trophe, food; soma, body] 1. (CNID: Hydrozoa)All of the asexual structures of a polyp or polypoidhydrozoan colony. see gonosome. 2. (NEMATA) A foodstorage area of certain parasitic nematodes formed bymodification of the intestine.trophotaxis n. [Gr. trophe, food; taxis, arrangement] A responseto the stimulation of food. see telotaxis, klinotaxis.trophothylax n. [Gr. trophe, food; thylax, sack] (ARTHRO: Insecta)In Hymenoptera Formicidae, a specialized pouch ofPseudomyrmecinae larvae located on the ventral part ofthe thorax just beneath the mouth parts that receives foodpellets; a feed bag.trophozooid see gastrozooidtrophus see pl. trophitropis n. [Gr. tropus, keel] 1. (ARTHRO: Crustacea) In Ostracods,a heavy chitinous (or two unfused rods) connectingthe zygum to the sternix and pastinum. 2. (NEMATA: Adenophorea)In Enoplida, a hollow tooth-like structure formedby a subventral wall of the buccal capsule.tropism n. [Gr. tropos, turn] A movement, orientation or locomotionof a motile organism in response to a stimulus. a.Positive tropism: toward the stimulus. b. Negative tropism:away from the stimulus. see taxis.tropotaxis n. [Gr. tropos, turn; taxis, arrangement] A type of

Online Dictionary of Invertebrate Zoology 921taxis in which an animal directs itself in relation to a sourceof stimulation by comparing the amount of stimulation oneither side of it, i.e., spiders in their web retrieving theirprey. see klinotaxis, telotaxis.trumpet n. [OF. trompe, trumpet] (ARTHRO: Insecta) In Diptera,paired, usually movable respiratory structures, locatedon the dorsal portion of the cephalothorax of culicidpupae. see laticorn trumpet, angusticorn trumpet.truncate a. [L. truncus, cut off] Terminating abruptly; endingsquarely with a cut-off edge. truncation n.trunk n. [L. truncus, cut off] 1. (ANN) a. In Polychaeta, thebody between the peristomium and the pygidium. b. In Oligochaeta,the body between the peristomium and periproct.2. (ARTHRO: Crustacea) The postcephalic portion ofthe body. 3. (ARTHRO: Insecta) The thorax.trypsin n. [Gr. tryein, to rub down; pepsis, digestion] An enzymethat catalyzes the hydrolysis of proteins. tryptic a.tryptophan, tryptophane n. [Gr. tryein, to rub down; phanein,to appear] An amino acid existing in proteins, fromwhich it is set free by tryptic digestion, that gives a red orviolet color on oxidation; it is essential to animal life.T-tubule Invaginations of the plasma membrane into the musclefiber between the Z- and H-bands.tube n. [L. tubus, tube] Any hollow, cylindrical structure.tube-feet (ECHINOD) Small, fluid-filled tubes of the water vascularsystem functioning in locomotion, adhesion, foodcapture and transport to the mouth; some are sensory andmay assist in respiration.tubercle n. [L. dim. tuber, hump] 1. A small knoblike orrounded protuberance. see torus. 2. (ARTHRO: Insecta) InDiptera, sometimes used for an elongate facial swelling.tuberculate , tuberculose a.tubercula pubertatis (ANN: Oligochaeta) A glandular swellingnear the ventrolateral margin of the clitellum of matureadult earthworms during copulatory phase; differs in size,shape and continuity.tuberiferous a. [L. dim. tuber, hump; fero, bear] Bearing tu-

922Maggenti and Gardnerbercles.tube tracheae (ARTHRO: Chelicerata) In Opiliones, Solifugaeand most spiders, tube-like tracheae; usually unbranchedectodermal invaginations. see sieve tracheae.tubicolous a. [L. tubus, tube; colere, to dwell] Inhabiting atube; a tubular spider web.tubifacient a. [L. tubus, tube; facere, to make] Tube constructing.tubule n. [L. dim. tubus, tube] A minute tube.tubulus n. [L. dim. tubus, tube] (ARTHRO: Insecta) In Lepidoptera,a tubular, telescoping ovipositor.tubus n. [L. tubus, tube] (NEMATA) A cuticular projection surroundingthe spicules beyond the body outline; cloacaltubus.tuft sensilla (ARTHRO: Crustacea) In Decapoda, smallbranched hairs over pores in the carapace with two orthree attached neurons, functioning in vibration and watermovement detectors.Tullgren funnel Apparatus designed by A. H. Tullgren for extractionof animals from duff and litter; the sample isplaced on a sieve and heat is applied from above to drivethe animals downward into a funnel with a collecting vesselbelow; similar to a Baerman funnel that uses a water interfacebetween sample and collecting vessel.tumefaction n. [L. tumere, to swell; facere, to make] Abnormaltissue formations in invertebrates having characteristicsin common with vertebrate neoplasms, however, precisenature is unknown.tumescence n. [L. tumescere, to swell up] Slightly tumid orenlarged.tumid a. [L. tumere, to swell] Swollen; enlarged; abnormallydistended.tumulus n. [L. tumulus, mound] (ARTHRO: Insecta) In Apis, apile of earth at the mouth of an underground burrow.tun n. [L. tunica, garment] (TARDI) A cryptobiotic shriveled,state of tardigrades produced by evaporation of surroundingwater film.

Online Dictionary of Invertebrate Zoology 923tunic n. [L. tunica, garment] A covering membrane or tissue.tunica n.; pl. -cae [L. tunica, garment] 1. A covering or envelopingmembrane or tissue; a tunic. 2. (ARTHRO: Insecta)For Lepidoptera see diaphragm.tunica adventitia Outermost fibro-elastic layer of various tubularorgans, such as vas deferens, esophagus, uterus,ureter, etc.tunica intima An inner lining or membrane.tunica propria (ARTHRO: Insecta) In females, an elastic membrane,with or without fine fibrils, that encloses the ovarioleand terminal filament.tunicary a. [L. tunica, garment] Pertaining to a covering membraneor a tunic.tunicate a. [L. tunica, garment] 1. Having a tunic. 2. (ARTHRO)Applied to coupling joint of antennae.turbinate a. [L. turbo, a whirl] Top-shaped; nearly conical witha round base; turbiniform.turbinate eye (ARTHRO: Insecta) In male Baetidae Ephemeroptera,eyes enlarged, divided into lower and outer pigmentedovals and raised on a broad stalk, with larger upperand inner portion usually pale with large facets.turgid a. [L. turgidus, swollen] Swollen; distended.turreted a. [L. turris, a tower] Tower-shaped.turriculate a. [L. dim. turris, tower] (MOLL: Gastropoda) Havingan acutely conical spire comprised of numerous flattishwhorls; turriform; turrited.tychoparthenogenesis n. [Gr. tyche, change; parthenos, virgin;genesis, beginning] Unfertilized eggs that can occasionally,or accidentally, develop through parthenogenesis.tylasters n. [Gr. tylos, knob; aster, star] (PORIF) A starshapedspicule with a small center and knobbed rays.tylenchoid bursa see bursatylenchoid esophagus (NEMATA: Secernentea) An esophaguswith a narrow procorpus, a strongly formed median bulb(metacorpus), followed by a narrow typical isthmus andterminating with a glandular basal bulb.

924Maggenti and Gardnertyloid n.; pl. tyloides [Gr. tylos, knob] (ARTHRO: Insecta) InTrigonalidae and Ichneumonidae, any large indented, flattenedor raised sensory area on the antennae.tylosis n.; pl. -es [Gr. tylos, knob] A hardening or thickening;a callous.tylostyle a. [Gr. tylos, knob; stylos, column] (PORIF) Amonactinal monaxon knobbed at the broad end and pointedat the other. see subtylostyle.tylote n. [Gr. tylos, knob] (PORIF) A diactional monaxon inwhich both broad ends are knobbed.tylus n.; pl. tyli [Gr. tylos, knob] (ARTHRO: Insecta) The distalpart of the clypeal region of the head.tymbal n. [F. timbale, kettledrum] (ARTHRO: Insecta) InHemiptera (Cicadidae), an area of thin cuticle supported bya cuticular rim and a series of dorso-ventral strengtheningribs; involved in sound production. see Pearman's organ.tympanal air chamber (ARTHRO: Insecta) An air-sac or space,usually posterior to the tympanal organ into which outsideair is admitted by a spiracle allowing the tympanum to vibratefreely.tympanal bullae see tympanal hoodtympanal fossa (ARTHRO: Insecta) In Diptera, a largely membranousarea between the suprasquamal ridge and thelower margin of the postalar wall.tympanal frame (ARTHRO: Insecta) The supporting frameworkof the tympanal membrane.tympanal hood (ARTHRO: Insecta) In some Lepidoptera, oneof a pair of tubercles or rounded prominences on the dorsalsurface at the base of the first abdominal segment.tympanal organs (ARTHRO: Insecta) Specialized chordotonalorgans that occur on prothoracic legs, mesothorax,metathorax, or abdomen; the auditory organ or eardrum.tympanal pockets (ARTHRO: Insecta) In Lepidoptera, pocketsin the tympanal frame, usually 4 in number.tympanal ridge (ARTHRO: Insecta) In some Diptera, a rib-likesclerite forked anteriorly, forming a single or double Y thatencloses the tympanic pit.

Online Dictionary of Invertebrate Zoology 925tympanic pit (ARTHRO: Insecta) In Diptera, a membranousarea opening toward the base of the wing, enclosed by thetwo lowermost arms of the tympanal ridge.tympanum n.; pl. -ana [Gr. tympanon, drum] (ARTHRO: Insecta)A vibrating membrane involved in hearing; typanicmembrane; an auditory membrane.Tyndall colors or scattering (ARTHRO: Insecta) Color of certaininsects resulting from interference of light reflected bygranules cast upon an absorbing layer of dark pigment beneatha more or less transparent cuticle; producing blue,green or white, depending upon the size of granules.type n. [Gr. typos, type] A zoological object that serves as thebase for the name of a taxon.type by absolute tautonomy see type by original designationtype by elimination A type designated when some of theoriginal species of a genus have been transferred to othergenera, the type of the genus selected from among theoriginal species that remain in the genus. ICZNtype by original designation A species designated as type inthe original publication of a genus. a. If in the original publicationof a genus, typicus or typus is used for any of thespecies. b. The species in a proposed new genus (monotypicalgenus). c. In a genus containing a number of species,one original species has the generic name as its specificor subspecific name, whether a valid name or asynonym (type by absolute tautonomy). ICZNtype by virtual tautonomy An original species of a genus thathas a specific or subspecific name, either as a valid nameor a synonym, is virtually the same as the generic name, orof the same origin or meaning. ICZNtype genus In families, the specific genus on which the familyis founded, not necessarily the first one described.type host A designated organism from which a type specimenhas been collected.type locality The area from which a holotype, lectotype, orneotype was collected.

926Maggenti and Gardnertype method The method by which the name for a taxon isunquestionably associated with a definite zoological objectbelong to the taxon.type species The species which was used by the author of agenus to designate as type of a nominal genus.typhlosole n. [Gr. typhlos, blind; solen, channel] A longitudinalinfolding of the dorsal intestinal wall into the intestinallumen.typologist n. [Gr. typos, type; logos, discourse] One who disregardsvariation and who considers the members of apopulation as replicas of the type.typolysis n. [Gr. typos, type; lysis, loosing] Phylogerontic;stage that precedes extinction of a type organism or group.typostasis n. [Gr. typos, type; stasis, standing] A static phasein evolution.

Uuliginose, uliginous a. [L. uliginosus, swampy] Of or pertainingto mud; swampy.ultradextral a. [L. ultra, beyond; dexter, right] (MOLL: Gastropoda)Having a shell appearing to be sinistral but soft partsorganized dextrally; hyperstrophic.ultrasinistral a. [L. ultra, beyond; sinister, left] (MOLL: Gastropoda)Having a shell appearing to be dextral but softparts organized sinistrally; hyperstrophic.ultrasonic a. [L. ultra, beyond; sonus, sound] High frequencysounds inaudible to the human ear.ultrastructure n. [L. ultra, beyond; struere, to construct] Thefine structure of cells seen with an ultramicroscope or anelectron microscope.umbel n. [L. umbella, a sunshade] 1. An arrangement in whicha number of processes, nearly equal in length, spread froma common center. 2. (CNID: Anthozoa) In Umbellulidae,polyps coming from a common center, forming a cluster, asin the anthocodia of Umbellula . 3. (PORIF) Processes extendingfrom the clavules.umbilical suture (MOLL: Gastropoda) In phaneromphaloustype shells, a continuous line separating successive whorls.umbilicus n.; pl. -lici [L. umbilicus, navel] 1. A navel, or navel-likedepression 2. (MOLL: Gastropoda) A cavity formedaround the shell axis between the faces of the adaxial wallof the whorls where these do not coalesce to form a solidcolumella. a. In conispiral shells opening at the base of theshell, excepting hyperstrophic type. b. Involute shells mayhave two umbilici, an upper or adapical and lower or abapicalin asymmetrical types, and left and right in isostrophictypes. umbilicate a.umbo n.; pl. umbones, umbos [L. umbo, knob or boss] 1.(ARTHRO: Crustacea) a. In Cirripedia, a portion of the platefrom which successive growth increments extend. b. In bi-

928Maggenti and Gardnervalves, apical portion of either valve. see beak. 2. (AR-THRO: Insecta) In Coleoptera, an elevated knob on the humeralangle of the elytra. 3. (BRACHIO) Apical portion ofeither valve containing the beak. 4. (BRYO: Gymnolaemata)In Cheilostomates, a blunt knob on the front wall of theovicell. 5. (MOLL: Bivalvia) That region of the valve surroundingthe point of maximum curvature of the longitudinaldorsal profile; when not coinciding with the beak, extendingto its base. umbonal a.umbonal angle (MOLL: Bivalvia) In pectinoid shells, the angleof divergence of the umbonal folds; in other shells the divergenceof the posterodorsal and anterodorsal parts of thelongitudinal profile.umbonal cavity (MOLL: Bivalvia) 1. Part of the valve interiorwhich lies within the umbo and under the hinge plate. 2. Inoysters, that part of the left valve interior lying in the umbonalregion beneath the ligamental area.umbonal depression (MOLL: Bivalvia) A depression at theumbo tip.umbonal fold (MOLL: Bivalvia) In pectinoid shells, a ridgeoriginating at the umbo and setting the auricle off from theshell body.umbonal pole (MOLL: Bivalvia) The point of maximum curvatureof the longitudinal profile of the dorsal valve.umbonal reflection (MOLL: Bivalvia) The reflection of the dorsalmargin of the valves anterior to and usually over theumbos.umbonal region (MOLL: Bivalvia) The region of the umbo.umbonal spine (ARTHRO: Crustacea) In Conchostraca, a hollow,curved, looped or nodular spinose projection of variablesize, sometimes covering the entire umbo.umbone see umboumboniform a. [L. umbo, knob or boss; forma, shape] 1. Likeor shaped like an umbo. 2. (MOLL: Gastropoda) Having alow blunt or rounded spire, nearly lenticular in shape. seerotelliform.umbonuloid a. [L. umbo, knob or boss; Gr. eidos, like] (BRYO:

Online Dictionary of Invertebrate Zoology 929Gymnolaemata) In cheilostomates, autozooids havingfrontal shields formed by calcification of the basal side ofthe epifrontal fold.umbo-veliger (MOLLL:Bivalvia) In oysters, the last larvalstage.umbraculate, umbraculiferous a. [L. umbraculum, sunshade]Bearing an umbrella-like structure or organ.umbrella n. [L. dim. umbra, shade] 1. Any umbrella-shapedstructure. 2. The ectodermal cells located anterior to thepreoral band of cilia in the development of a trochophorelarva. 3. (CNID: Scyphozoa) The deep to shallow bowl likebody of a medusa or jellyfish; the bell. see exumbrella,subumbrella. 4. (MOLL: Cephalopoda) The velum or interbrachialweb interconnecting the head and arms of the finnedoctopods.umbrella organ see sensillum campaniformiumunarmed a. [A.S. un-, not; L. arma, arms] Without armatureof any kind, i.e., shield, spurs, spines, plates, teeth, etc.unarticulate a. [A.S. un-, not; L. articulare, to divide] Notjointed or segmented.uncate a. [L. uncus, hook] Hooked; hamate.unci pl. uncusunciform a. [L. uncus, hook; forma, shape] Hook-shaped.uncinal plate see radulauncinal seta (ANN: Polychaeta) Setae modified into hooks,functioning in feeding or gripping.uncinate a. [L. uncinus, hook] 1. Hooked or barbed at the end;unciniform. 2. (PORIF) Pertaining to megascleres, a fusiformoxea with thornlike spines.uncinate mastax (ROTIF) A mastax with fulcrum and manubriagreatly reduced, stout rami, and large subunci; specializedfor food laceration.uncini n.pl; sing. uncinus [L. uncinus, hook] 1. (ANN: Polychaeta)Deeply embedded seta with only its multidentatehead showing above the cuticle. 2. (MOLL: Gastropoda)Numerous small teeth- or hook-like structures on the

930Maggenti and Gardnerradula of plant-eating gastropods.uncus n.; pl. unci [L. uncus hook] 1. (ARTHRO: Insecta) a. Insome larvae, a hooked process on the distal inner marginof the maxillary mala, possibly a reminant of the lacinia. b.In Lepidoptera, a process of the 10th abdominal tergumoverhanging the anus. 2. (ROTIF) One of a pair of the sevenmain pieces of the mastax.undate a. [L. unda, wave] Wavy, undulating.underbridge n. [A.S. under, below; bricg, bridge] (NEMATA:Secernentea) In Heterodera cysts, a structure extendingacross the vulval cone below and parallel to the vulvalbridge.undifferentiated a. [A.S. un-, not; L. differens, dissimiler] 1.Immature or embryonic form; unspecialized; capable ofdifferentiation into more specialized form. 2. With cells,meaning an embryonic cell that can develop into othertypes of cells.undose a. [L. unda, wave] Undulating; nearly parallel depressionsblending more or less into each other.undulate a. [L. unda, wave] Having a wavy surface or margin.ungual a. [L. unguis, claw] Pertaining to the ungues or claws.unguiculus n.; pl. unguiculi [L. dim. unguis, claw] 1. A smallterminal claw or nail-like process. 2. (ARTHRO: Insecta) Thesmaller of the toothed tarsal claws of Collembola. unguiculatea. see unguis.unguifer n. [L. unguis, claw; ferre, to bear] (ARTHRO: Insecta)A median process of the last tarsomere, articulating withthe pretarsal claws.unguiferate a. [L. unguis, claw; ferre, to bear] (PORIF) Pertainingto a type of chelate microsclere with short and discreteteeth, often more than three at each end of the shaft.unguiflexor n. [L. unguis, claw; flectere, to bend] (ARTHRO:Insecta) Muscles responsible for moving or extending theungues.unguiform a. [L. unguis, claw; forma, shape] Shaped like aclaw.unguis n.; pl. ungues [L. unguis, claw] (ARTHRO) 1. The lat-

Online Dictionary of Invertebrate Zoology 931eral claw of the pretarsus of several groups. 2. The largerof the toothed tarsal claws of Collembola. ungual a. seeuguiculus, homodactyl.unguitractor n. [L. unguis, claw; tract, to pull] (ARTHRO: Insecta)A ventral sclerotized plate of the pretarsus fromwhich arises the retractor muscles of the ungues or claws;also called unguitractor plate.unguitractor tendon (ARTHRO: Insecta) The tendon servingfor attachment of the unguitractor to the pretarsal depressormuscle; apodeme.ungula see unguisuniauriculate a. [L. unus, one; auricula, outer ear] Having asingle ear-like process.unibranchiate a. [L. unus, one; branchia, gill] Having one gill.unicameral a. [L. unus, one; camera, chamber] Having onechamber.unicapsular a. [L. unus, one; capsula, little box] Having only asingle capsule.unicarinate a. [L. unus, one; carina, keel] Having a singleridge or keel.unicellular a. [L. unus, one; cellula, small chamber] Consistingof only one cell.uniciliate a. [L. unus, one; cilium, eyelash] Having a singlecilium or flagellum.unicolonial a. [L. unus, one; colere, to dwell] (ARTHRO: Insecta)A population of social insects not recognizing nestboundaries; multicolonial.unicolorate a. [L. unus, one; color, tint] Having one colorthroughout.unicornous a. [L. unus, one; cornu, horn] Having only onehorn.unicuspid a. [L. unus, one; cuspis, point of spear] Having asingle tapering point; one tooth.unidentate a. [L. unus, one; dens, tooth] Having only onetooth.unidiverticulate a. [L. unus, one; diverticulum, bypath] Hav-

932Maggenti and Gardnering one diverticulum.uniflagellate a. [L. unus, one; flagellum, whip] With one flagellum;monociliated.unifollicular a. [L. unus, one; folliculus, small bag] Having onefollicle.unigeminal a. [L. unus, one; geminus, twin-born] 1. With onepair. 2. (ECHINOD: Echinoidea) Pertaining to one row ofpore pairs.unilabiate a. [L. unus, one; labium, lip] Having one lip.unilaminate colony (BRYO) A colony consisting of a singlelayer of zooids opening in approximately the same direction.unilateral a. [L. unus, one; latus, side] On one side only.unilocular a. [L. unus, one; loculus, small place] Having onecell or cavity.uniloculate a. [L. unus, one; loculus, small place] (ANN) Havingonly one seminal chamber, such as the spermathecaldiverticulum.unimucronate a. [L. unus, one; mucro, sharp point] Having asingle sharp tip.uninominal a. [L. unus, one; nomen, name] Having only onename; monominal.uninominal nomenclature The designation of a taxon abovespecies rank by a scientific name consisting of a singleword.uniordinal crochets (ARTHRO: Insecta) In larvae, crochetsarranged in a single row of uniform length or somewhatshorter towards the ends of the row. see ordinal.uniparous a. [L. unus, one; parere, to beget] Producing oneegg or young at a time.uniplicate a. [L. unus, one; plicare, to fold] Having a singlefold or line of folding.unipolar a. [L. unus, one; polus, pole] Having one pole only.unipolar cell A nerve cell with one fiber issuing from it.uniradiate a. [L. unus, one; radius, wheel spoke] One-rayed.

Online Dictionary of Invertebrate Zoology 933uniramous a. [L. unus, one; ramus, branch] Having onebranch only.uniramous appendage (ARTHRO) An unbranched appendage.uniramous parapodium (ANN: Polychaeta) A parapodium thathas only one part.uniseptate a. [L. unus, one; septum, partition] Having onepartition.uniserial a. [L. unus, one; series, row] Arranged in one row orserial.uniserial circle (ARTHRO: Insecta) Referring to crochets of larvaearranged in a single row or series with bases in a continuousline. see serial crochets.uniserrate a. [L. unus, one; serra, saw] One row of serrations.unisexual a. [L. unus, one; sexus, male or female sex] Individualshaving separate sexes (dioecious, gonochoric) andproducing only one kind (male or female) of gamates,therefore, being dimorphis.unispire a. [L. unus, one; spira, coil] A single turn of a spiral.unit character A trait behaving as a unit in heredity, inheritableindependently of other traits.univalent a. [L. unus, one; valens, strong] One member of apair of homologous chromosomes.univalve a. [L. unus, one; valva, leaf of a folding door] (MOLL:Bivalvia) Having a shell composed of one piece.univariate analysis A biometric analysis of one character.univoltine a. [L. unus, one; It. volta, time] Having one generationa year; monovoltine.unjointed seta (ANN: Polychaeta) A seta without a joint; asimple seta.unmyelinated a. [A.S. un, not; Gr. myelos, marrow] Nervesnot covered with a myelin sheath.unspecialized a. [A.S. un, not; L. species, a particular kind]Lacking modifications for any special function or purpose.unsuitable host An immune or resistant animal or plant.upcurved growth line (ARTHRO: Crustacea) In Conchostraca,

934Maggenti and Gardneran upwardly bent growth line covering a tear in the shellmargin at the site of an injury.upper latus (ARTHRO: Crustacea) In Lepadomorph barnacles,the plate in the upper whorl between the scutum and tergumor carina.upper lip see labrumupsilon see furcauranidin see pterineurate a. [Gr. ouron, urine] A salt of uric acid.urate cells (ARTHRO: Insecta) Special cells of the fat-body or inthe epidermis or elsewhere that segregate the uric acid,when not excreted through the Malpighian tubules.urceolus n. [L. dim. urceus, pitcher] A pitcher- or urn-shapedstructure.urea n. [Gr. ouron, urine] A simple organic compound, CO(NH2 ) 2 , a major nitrogenous waste product.ureter n. [Gr. ureter] 1. (ARTHRO: Insecta) A discharging ductof aggregate Malphigian tubules. 2. (MOLL: Gastropoda) Aduct connecting the kidney with the mantle cavity.uric acid A nitrogenous waste product, more complex and usuallyformed in smaller amounts than urea.uricotelic a. [Gr. ouron, urine; telos, end] The excretion of nitrogenas uric acid.urinary vessels see Malphigian tubulesurine n. [L. urina, urine] A solution of various waste products.urite see cirrusurn bodies 1. (MESO: Rhombozoa) An urn-like sac on the ventralsurface of infusoriform larvae of a dicyemid that containsfour germinal cells. 2. (SIPUN) Vase-shaped, multicellularstructures in the coelom.urocardiac ossicle (ARTHRO: Crustacea) In a decapodan gastricmill, a T-shaped plate running backwards and downwards,sometimes bearing a U- or V-shaped median tooth.urogastric groove (ARTHRO: Crustacea) A short transversegroove in the median or submedian region of a decapod

Online Dictionary of Invertebrate Zoology 935carapace posterior to the postcervical groove, sometimesjoining the upper part of the postcervical groove.urogastric lobe or area (ARTHRO: Crustacea) In Decapoda, aposterior division of the gastric region of a brachyurancarapace; genital region.urogenital a. [L. urina, urine; gignere, to beget] Of or pertainingto the urinary and genital system.urogenital opening (MOLL: Bivalvia) Opening through whichthe gonadal products and excretory products are releasedinto the cloacal passage of the exhalant mantle chamber.urogomphi n.pl.; sing. urogomphus [Gr. oura, tail; gomphos,club] (ARTHRO: Insecta) In Coleoptera larvae, a pair of outgrowthsof the tergum of segment 9 in the form of shortspines or multiarticulate processes; pseudocerci; corniculi.uromere n. [Gr. oura, tail; meros, part] (ARTHRO) An abdominalsegment.uropatagium n.; pl. uropatagia [Gr. oura, tail; patagium,border] (ARTHRO: Insecta) One of the paraprocts located oneither side of the anus.uropod(ite) n. [Gr. oura, tail; pous, foot] (ARTHRO: Crustacea)1. In Malacostraca, an appendage of the 6th abdominalsomite, fanlike or reduced or modified. 2. In Amphipoda,the last 3 pairs of abdominal appendages.uropolar cells (MESO: Rhombozoa) In Dicyemida, somatodermcells at the posterior end of the trunk.uropore n. [Gr. ouron, urine; poros, passage] (ARTHRO: Chelicerata)In Prostigmata and Tarsonemida, an externalopening of the excretory duct in groups that have an incompletegut. see anus.urosome, urosoma n. [Gr. oura, tail; soma, body] 1. (AR-THRO) The abdomen. 2. (ARTHRO: Crustacea) That part ofthe body posterior to the major articulation, usually includinglast 3 abdominal somites, bearing modified appendages.urosternite n. [Gr. oura, tail; sternon, chest] (ARTHRO) Thesternal or ventral part of the uromeres.urotergite n. [Gr. oura, tail; L. tergum, back] (ARTHRO) An

936Maggenti and Gardnerabdominal tergite.urstigmata n.pl.; sing. urstigma [Ger. ur, primitive; Gr.stigma, mark] (ARTHRO: Chelicerata) In Acari, sense organsbetween the coxae of the first and second pairs of legs;thought to be humidity receptors; Claparede organs.urticate v. [L. urtica, nettle] To sting or burn. urtication n. seenematocyst.urticating hairs (ARTHRO: Insecta) In some caterpillars andadults, bristles with minute lateral points producing markedirritation upon contact, whether due to mechanical actionalone or presence of poisonous secretion.urticator n. [L. uritica, nettle] (CNID) Cnidocytes; a nettle orsting cell.urzellen see prohemocyteU-shaped notal ridge see scutoscutellar sutureustulate a. [L. ustulatus, scorch or burn] Having the appearanceof being scorched or burned; brownish.uterine bell (ACANTHO) A bell-like or tubular structure of somefemales, that moves eggs from the pseudocoel to theuterus.uterine vagina see vagina uterinauterus n. [L. uterus, womb] An enlargement of the lower endof the oviduct, in which eggs are retained temporarily or inwhich the embryo develops. uterine a.utricle n. [L. dim. uter, bag] A small bag or bladder.utriculus n. [L. dim. uter, bag] (ARTHRO: Insecta) In Lepidoptera,the larger lobe of the spermatheca; may be fused intoone organ. see lagena.uvette n. [L. dim. uva, grape] (NEMATA: Adenophorea) Theglandular region where the efferent tubes of the Demanianvessels meet before passing on to one or more exit poresin the body wall.

Vvacuole n. [L. vacuus, empty] A minute cavity within a cell,usually filled with a liquid product of protoplasmic activity.vacuolar a.vagile a. [L. vagus, wandering] Freely wandering; motile.vagility n. see sessile.vagina n. [L. vagina, sheath] The terminal portion of the femalereproductive tract, that opens to the outside. vaginala.vaginate a. [L. vagina, sheath] Enclosed by a sheath.vagina uterina (NEMATA) An inward extension of the vagina,uniting with the distal part of the uterus, that histologicallyresembles the vagina, but lacks cuticular lining.vagina vera (NEMATA) The outermost part of the vagina, linedwith cuticle.vaginipennate a. [L. vagina, sheath; penna, wing] (ARTHRO:Insecta) To ensheath a wing; having wings covered with ahard sheath.vaginula n. [L. dim. vagina, sheath] (ARTHRO: Insecta) Thecovering of the terebra.vagus see stomogastric nervous systemvalency n. [L. valentia, strength] Power; important; value.valid name An available name for a taxon that is not preoccupiedby a valid senior synonym or homonym.valva n.; pl. valvae [L. valva, leaf of a folding door] (ARTHRO:Insecta) In Lepidoptera, a valve in the external male genitalia;the coxite and the stylus. see harpagones.valvate a. [L. valva, leaf of a folding door] 1. Furnished withvalves. 2. Hinged only at the margin. 3. Of or pertaining toa valve.valve n. [L. valva, leaf of a folding door] 1. Any structure thatlimits or closes an opening. 2. One of the discrete shells orplates of a mollusk, brachiopod or crustacean. 3. (ARTHRO:

938Maggenti and GardnerInsecta) Certain external genitalia.valve coverage (MOLL: Polyplacophora) 1. Complete coverageTwo contiguous valves with the rear edge of one coveringthe whole front edge of the one posterior to it. 2. Partialcoverage A small part of the front edge of the next valvethat is overlapped. 3. Jugal coverage With only the apicalpart of a valve overlapping the next one.valvelet n. [L. dim. valva, leaf of a folding door] A small valveor fold.valvifers n.pl. [L. valva, leaf of a folding door; ferre, to bear](ARTHRO: Insecta) The basal plates of the ovipositor, derivedfrom the basal segment of the gonopods; also knownas the first and second gonocoxae.valvula n.; pl. valvulae [L. dim. valva, leaf of a folding door]1. Any small valve-like process. 2. (ARTHRO: Insecta) InHymenoptera, processes from the valvifers forming thebody of the ovipositor and the ovipositor sheath.valvular a. [L. dim. valva, leaf of a folding door] Of or pertainingto a small valve or valvula.valvular process see stylevannal fold (ARTHRO: Insecta) A radial line of folding of awing, commonly between the cubital field and the firstvannal vein; sometimes variable.vannal lobe (ARTHRO: Insecta) A lobe in the anal area of awing, immediately distad of the jugal lobe (when present).vannal region (ARTHRO: Insecta) That part of the wing comprisingthe vannal veins, or veins directly associated withthe third axillary; vannus.vannal veins (ARTHRO: Insecta) The veins of a wing in thevannal region, with basal association with the third axillarysclerite.vannus see vannal regionvariance n. [L. variare, to change] A sampling statistic relatingto deviations from the mean.variate n. [L. variare, to change] A variable quantity or character.

Online Dictionary of Invertebrate Zoology 939variation n. [L. variare, to change] Differences resulting fromnongenetic responses of the phenotype to immediate environmentalconditions; ecophenotype.varicellate a. [L. varix, dilation] Having small or indistinctvarices.varices pl. of varixvaricose a. [L. varix, dilation] Bearing a varix or varices.variegated a. [L. variegatus, of different sorts] Marked by differentshades or colors.variety n. [L. variare, to change] An ambiguous taxonomicterm for a heterogeneous group of phenomena includingnongenetic variations of the phenotype, morphs, domesticbreeds, and geographic races.variole n. [F. variole, smallpox] A pock-like mark; fovea;fossa. variolate a.varix n.; pl. varices [L. varix, dilation] (MOLL: Gastropoda)Transverse elevations that occur on the outer shell surface;more prominent than the costa and generally spaced morewidely; result of growth halt in which a thickened outer lipdeveloped.vas n.; pl. vasa [L. vas, vessel] A small tubular vessel, duct orcanal, especially leading from the testis.vascula n.pl.; sing. -um [L. dim. vas, vessel] (BRACHIO)Branches of the mantle canal system.vascular a. [L. dim. vas, vessel] Pertaining to vessels adaptedfor transmission or circulation of fluids.vascular markings (BRACHIO) Impressions of the mantle canalson the inside of the shell; pallial markings.vas deferens sing.; pl. vasa deferentia 1. A sperm ductleading away from a testis. 2. (ANN: Oligochaeta) A ductcarrying sperm from the male funnel to the male pore.vas efferens sing.; pl. vasa efferentia Tubule leading fromthe testis to the vas deferens.vasiform a. [L. vas, vessel; forma, shape] Vessel-shaped.vector n. [L. vehere, to carry] 1. Any carrier, particularly ananimal that transmits a disease organism from one host to

940Maggenti and Gardneranother. 2. In helminthic disease, an intermediate host thatseeks out the definitive host; as a mosquito.vegetal pole In an early embryo, a region with large cells withmuch yolk; portion of egg or zygote with more yolk thanopposite end.vegetative functions All natural functions of living organismsthat maintain life.vegetative reproduction The development of a new individualfrom a group of cells in the absence of any sexual process.veinlets n.pl. [L. dim. vena, vein] Small veins.veins n.pl. [L. vena, vein] 1. Vessels conducting blood towardthe heart. 2. (ARTHRO: Insecta) The heavily sclerotizedportion of wings that usually enclose small central tracheae.velarium n. [L. velarium, awning] (CNID) A velum-like structurehaving canals lined with endoderm; flaps on the edgeof the bell.veliconch n. [L. velum, curtain; concha, shell] (MOLL: Bivalvia)The shell of the veliger larva; prodissoconch.veliger n. [L. velum, curtain; gerere, to bear] (MOLL) A larvalstage with a ciliated swimming membrane or membranes;a free-swimming young bearing a velum.velum n.; pl. vela [L. velum, curtain] 1. A thin membranouscovering. 2. (ANN: Hirudinoidea) A membrane separatingthe buccal cavity from the cavity of the oral opening. 3.(ARTHRO: Crustacea) In Ostracoda, a ventral ridge, flange,or frill that may extend around part or all of the anteriorand posterior ends. 4. (ARTHRO: Insecta) The membraneforming part of the apical and marginal areas of a paramere.5. (CNID) A shelf of tissue extending inward nearthe margin of the bell of medusae. 6. (MOLL) a. In Bivalvia,the large, ciliated swimming disc of larval oysters. b. InGastropoda, the swimming membrane consisting of twolarge semicircular folds bearing cilia. 7. (NEMATA) The ventralmembranous winglike extensions on the spicule ofsome male nematodes. 8. (PLATY: Cestoda) The membranousposterior margin of a proglottid overlapping the anteriorof the following one.

Online Dictionary of Invertebrate Zoology 941velutinous a. [NL. vellutum, velvet] Clothed with very dense,upright short hairs.venation n. [L. vena, vein] The complete system of veins.venom n. [L. venenum, poison] The secretion of the accessoryvenom, or poison gland. venomous a.venom apparatus 1. (ARTHRO: Insecta) The sting apparatus oraccessory glands. 2. (ANN: Polychaeta) The seta or venomousjaws.venom gland 1. A gland secreting an irritating or lethal substance.2. (ARTHRO: Chelicerata) In true spiders, a pair ofglands situated in the cephalothorax; in others, on the cheliceraewith ducts traversing each claw with an oval slitopening near the tip. 3. (ARTHRO: Insecta) In Hymenoptera,the largest sting gland situated between the rectumand vagina and ending in the aculeus. see apid venomgland, braconid venom gland, vespid venom gland.venose a. [L. vena, vein] Having veins or lines that branch likeveins.venous a. [L. venosus, full of veins] Having numerous veins.vent n. [L. findere, to split] The anus.venter n. [L. venter, belly] The ventral side; the entire undersurface of an animal.ventilation tracheae (ARTHRO: Insecta) Tracheae, that aresubject to collapse, that respond to varying surroundingpressure. see diffusion tracheae.ventrad adv. [L. venter, belly; -ad, toward] Toward the venter,or underside of the body. see dorsad.ventral a. [L. venter, belly] 1. The lower or underside of thebody. 2. (MOLL: Bivalvia) The edge remote from the hinge;opposite the umbones.ventral brush (ARTHRO: Insecta) In culicid larvae, a linear seriesof irregularly paired setae, often divided into twogroups, posteroventrally on the midline of abdominal segment10.ventral cardo (ARTHRO: Crustacea) In Ostracoda, that portionof the peniferum that serves as a hinge by which it articulateswith the zygum.

942Maggenti and Gardnerventral cirrus see neurocirrusventral comb (ARTHRO: Crustacea) In Cephalocarida, a row ofsetae or bristles on the posteroventral margin of the lastabdominal somite.ventral cup (ARTHRO: Crustacea) An element of the naupliuseye.ventral diaphragm (ARTHRO: Insecta) A horizontal septumabove the nerve cord separating the perineural sinus fromthe main perivisceral sinus.ventral frontal organ (ARTHRO: Crustacea) Paired sensorystructures associated with the nauplius eye.ventral gland see prothoracic glandventral groove (ARTHRO: Insecta) In Collembola, a cuticularchannel down the middle ventral line of the body from thelabium to the anterior part of the ventral tube; thought tofunction in osmoregulation.ventralia n. [L. venter, belly] (GNATHO) Paired sensory bristlesfound ventrally on the head of jaw worms.ventral membrane (ARTHRO: Insecta) In Diptera, skin-like tissueconnecting the tergites and the sternites along thesides of the abdomen.ventral muscles (ARTHRO: Insecta) Tergal and sternal longitudinalabdominal muscles running between the intersegmentalfolds or on the antecostae of successive sterna.ventral nerve cord The primary nerve cord of all invertebrates,except those of the Hemichordata and Chordataphyla.ventral pharyngeal gland see pharyngeal gland, ventralventral plate (ARTHRO: Insecta) 1. In embryology, a layer ofcolumnar cells of the blastoderm on the ventral side of theegg. 2. In Diptera, the floor of the cibarium.ventral process see sternal coxal processventral prolegs (ARTHRO: Insecta) Prolegs occurring ventrallyon the abdominal segments of larvae, except the last segmentthat are called anal prolegs.ventral scale (ARTHRO: Insecta) In Diaspinae, the ventral part

Online Dictionary of Invertebrate Zoology 943of the scale, composed of a thin layer of wax and the ventralexuviae that are interposed between the insect and theplant.ventral setae (ARTHRO: Insecta) In Culicidae, four small peglikecibarial setae located at the posterior margin of thecibarium.ventral sinus (ARTHRO: Insecta) The space of the body cavitybelow the ventral diaphragm, containing the nerve cord;the perineural sinus.ventral stylet (ARTHRO: Insecta) In Siphunculata, the lower of3 stylets (labium), toothed at the base for piercing.ventral sympathetic nervous system (ARTHRO: Insecta) Apair of transverse nerves associated with the ganglia of theventral nerve cord in each segment, passing to the spiraclesof their segment; may be connected to the perisympatheticsystem.ventral thickening (ARTHRO: Insecta) In soft scales, twosclerotic, dorsal, internal processes that support the analplates.ventral tube (ARTHRO: Insecta) In all Collembola, a basal columncontaining a pair of protrusible vesicles (shallow sacsor long and tubular), on the ventral aspect of the first segment;functioning in respiration, water absorption and/oradhesive organ for mobility over smooth or steep surfaces.see ventral groove.ventral vessel (ANN: Oligochaeta) A major blood vessel foundin the mesentery ventral to the alimentary canal.ventricle n. [L. dim. venter, belly] A cavity or chamber of anorgan, especially of the heart; receives blood from theauricles. see heart chamber.ventricose a. [L. dim. venter, belly] 1. Distended, inflated towardthe middle. 2. (MOLL: Gastropoda) In Harpidae, havingthe whorls or valves swollen or strongly convex; inflatedin the middle or on one side.ventricular valve 1. (ARTHRO: Insecta) see auricular valve.2. (NEMATA) A valve between the esophagus and the mesenteronproper; esophagointestinal valve.

944Maggenti and Gardnerventriculus n. [L. dim. venter, belly] (NEMATA) Anterior part ofthe intestine if cellularly different from the rest of the intestine;sometimes corrupted to mean glandular portion ofthe esophagus. ventricular a. see ventricular valve.ventrite n. [L. venter, belly] A ventral segment; ventral aspectof annular rings.ventrodorsal a. [L. venter, belly; dorsum, back] Extendingfrom ventral to dorsal.ventrolateral a. [L. venter, belly; latus, side] Of or pertainingto the area ventrally and to the side.ventromedially adv. [L. venter, belly; medius, median] Of orpertaining to the median ventral line.venulose a. [L. dim. vena, vein] Having many small veins.verge n. [F. verge, rod] (MOLL: Gastropoda) In Prosobranchia,the penis.Vermes n. [L. vermis, worm] An obsolete term for animals thatincluded all worm-like phyla.vermian a. [L. vermis, worm] Worm-like.vermicide n. [L. vermis, worm; caedere, to kill] Any of varioustherapeutic agents producing the death of a helminth;anthelmintic. see vermifuge.vermiculate a. [L. dim. of vermis, worm] Resembling a worm,or having tracery simulating the tracks of a worm. vermiculationn.vermiform a. [L. vermis, worm; forma, shape] Worm-shaped.vermiform cells see plasmatocytevermiform embryos (MESO: Rhombozoa) In Dicyemida, theyoung produced within the axial cell of adults.vermiform larva (ARTHRO: Insecta) A legless worm-like larva,lacking a well developed head. see pronymph.vermifuge n. [L. vermis, worm; fugare, to drive away] Atherapeutic agent causing expulsion of a helminth, thatmay or may not cause its death; anthelmintic. see vermicide.vernacular name The colloquial designation of a taxon. seescientific name.

Online Dictionary of Invertebrate Zoology 945vernal a. [L. vers, spring] Appearing or occurring in spring.vernicose a. [NL. vernicosus, varnished] Appearing as thoughvarnished or brilliantly polished.verricule n. [L. verriculum, net] A dense tuft of nearly parallelupright hairs. verriculate a.Verrill's organ see funnel organverruca n.; pl. verrucae [L. verruca, wart] 1. A wart or wartlikeprominence. 2. (ARTHRO: Chelicerata) In certain Acari,a genital papilla, sternal prominence, or the genital capsule.3. (ARTHRO: Insecta) In Lepidoptera larvae, a tuberclebearing tufts of setae. 4. (CNID: Anthozoa) a. In Alcyonaria,a protuberance surrounding the base of polyps. b. In Actiniaria,wart-like prominences on the body wall.verruciform cells (MESO) Somatic cells enlarged by lipoproteinbodies.verrucose a. [L. verruca, wart] Covered with minute warts ortubercles. see papillate.versatile a. [L. versatilis, mobile, changeable] Moving freely.versicolor a. [L. versicolor, to change color] Having many colors;changeable in color.Versonian glands see Verson's glandsVerson's cells see apical cellVerson's glands (ARTHRO: Insecta) In Lepidoptera larvae,large paired, segmental epidermal glands that secrete a"cement layer" over the wax layer; dermal glands.vertebra n.; pl. -ae [L. vertebra, turning joint] (ECHINO) 1. InAsteroidea, the fused pair of opposite ambulacrals, articulatingwith adjacent vertebrae by ball-and-socket joints. 2.In Ophiuroidea, enclosed by a ventral arm plate and skin ora dorsal arm plate.vertex n. [L. vertex, top] 1. The top; apex; summit; the highestor principal point. 2. (ARTHRO: Crustacea) The top pointof the head or cephalon. 3. (ARTHRO: Insecta) The top ofthe head, between the eyes and anterior to the occipitalsuture; the crown of the head.vertical a. [L. vertex, top] 1. Of or pertaining to the vertex;

946Maggenti and Gardnerhighest point. 2. (ARTHRO: Insecta) A wing vein when bothends are equally distant from the wing base.vertical bristles (ARTHRO: Insecta) In Diptera, two pair ofbristles, "inner and outer" behind the upper and inner cornersof the eyes; vertical cephalic bristles.vertical classification Classification focusing on common descent,tending to unite ancestral and descendant groups ofa phyletic line into a single higher taxon, thereby separatingthem from contemporaneous taxa having reached asimilar grade of evolutionary change. see horizontal classification.vertical triangle see ocellar triangleverticillate a. [L. verticillus, small whorl] Whorled; providedwith whorls of fine hairs; having spines arranged in nodesor whorls.verticillate antenna (ARTHRO: Insecta) Antenna with whorls ofhair at the joints or segments.vertition n. [L. vertere, to turn] An idionymous organ observedunilaterally among specimens of the same species andstage that has evolutionary significance.vesica see preputial sacvesicating a. [L. vesica, blister, bladder] Blister-like.vesicle, vesicula n. [L. dim. vesica, bladder, blister] 1. A sac,bladder, or cyst, frequently extensible. 2. (ANN: Oligochaeta)The anteriorly or posteriorly directed pockets ofa septum in which male germ cells mature; the reproductivesystem. vesiculate a.vesicular a. [L. dim. vesica, bladder, blister] Containing smallcavities or vesicles.vesicular cell (BRYO) A cell enclosing a large vesicle; found inperitoneal network and funicular strands.vesicula seminalis see seminal vesiclevesparium n. [L. vespa, wasp; -arium, place for] (ARTHRO: Insecta)In Hymenoptera, a natural or artificial colonial nestof vespine wasps.vespid venom gland (ARTHRO: Insecta) In Hymenoptera, a

Online Dictionary of Invertebrate Zoology 947type of venom gland in which two tubes end in a distinctspherically formed reservoir whose wall has a strong muscularlayer, but no glandular elements.vespoid a. [L. vespa, wasp; -oid, like] Wasp-like.vessel n. [L. dim. vas, vase] A tubular structure that conveysfluid.vestibular organs (CHAETO) A transverse row of papillae, orpapillae on a ridge, just behind the teeth.vestibular pit (CHAETO) A glandular depression behind thevestibular organs.vestibular wall (BRYO) The body wall surrounding the vestibuleand connecting the tentacle sheath to the wall of theorifice.vestibule, vestibulum n.; pl. -bula [L. vestibulum, entrancehall] 1. A cavity forming an entryway to another cavity orpassageway. 2. (ANN) Containing a penis or male porophoreand pore fissure. 3. (ARTHRO: Crustacea) In Ostracoda,a space between the duplicature and outer lamella.4. (BRYO) The area through which the lophophore passes.5. (ROTIF;CHAETO) An opening leading to the mouth. 6.(NEMATA) see stoma, cheilostome. vestibulate a.vestige n. [L. vestigium, footprint] A degenerate or imperfectremaining ancestral organ.vestigial a. [L. vestigium, footprint] Pertaining to a small, degenerate,nonfunctional organ that was ancestrally morefully developed or functional.vestiture n. [L. vestis, garment] The body covering, as scalesor hairs.vexillum n.; -illa [L. vexillum, flag] (ARTHRO: Insecta) In fossorialHymenoptera, an expansion on the tip of the tarsi.viable a. [L. vita, life] Capable of living; the ability to grow anddevelop.vibraculum n.; pl. vibracula [L. dim. vibrare, to vibrate](BRYO: Gymnolaemata) A heterozooid with the operculumin the form of a long bristle or seta between pivots, supposedlyused to sweep away detritus and settling larvae.vibrissa n.; pl. -sae [L. vibrissa, whisker] 1. Stiff hairs or bris-

948Maggenti and Gardnertles. 2. (ARTHRO: Insecta) For Diptera, see oral vibrissae.vibrissal ridge (ARTHRO: Insecta) In Diptera, a ridge arising oneach side of the face, inside the arms of the frontal suture;limited distally by the epistoma and the vibrissal angles;facial ridge.vibrotaxis n. [L. vibrare, to vibrate; Gr. taxis, arrangement]An organism's response to mechanical vibrations.vicarious a. [L. vicarius, deputy] 1. Taking the place of. 2.Closely related taxa in corresponding but separate environments.vicarious polymorph (BRYO: Gymnolaemata) A polymorph ina budding series that communicates with several zooids.vicinal a. [L. vicinus, neighbor] Neighboring; nearby.vicinism n. [L. vicinus, neighbor] The propensity to variationdue to proximity of related organisms.villi pl. of villusvillose a. [L. villus, tuft of hair] Covered with villi.villus n.; pl. villi [L. villus, tuft of hair] Soft flexible hairs. seemicrovillus.vinculum n.; pl. -la [L. vinculum, anything used for binding] 1.Anything used to bond structures together. 2. (ARTHRO: Insecta)In male Lepidoptera, an U-shaped genital plate, dorsallyarticulating with the pedunculus and midventrallyforming a saccus. 3. (MOLL: Bivalvia) A shelly material betweenthe basic dental structures of the shell.vinous a. [L. vinum, wine] Wine-colored; vinaceous.violaceous a. [L. viola, violet] Having a violet hue.virescent a. [L. virescere, to grow green] Greenish or turninggreen.virga n. [L. virga, rod] (ARTHRO: Insecta) In Dermaptera, athreadlike, sclerotized extension of the ejaculatory ductthat guides the passage of the spermatophore into thespermatheca of the femalevirgalium n.; pl. -lia [L. virga, rod] (ECHINOD: Asteroidea) Ossicleslateral to and symmetrically placed on each side ofthe ambulacral ossicles.

Online Dictionary of Invertebrate Zoology 949virgate a. [L. virga, rod] Rod-shaped.virgate mastax (ROTIF) With fulcrum and manubrium in theshape of elongate rods; rami are triangular plates.virgula organ (PLATY: Trematoda) Two pyriform sacs fused inthe median line with forward pointed ends and placed nearthe posterior margin of the oral sucker.virgulate cercaria (PLATY: Trematoda) A Xiphidiocercariagroup with a ventral sucker smaller than the oral, tail withouta fin and a virgula organ near the posterior margin ofthe oral sucker.viridis a. [L. viridis, green] Green; greenish; viridescent.virion n. [L. virus, poison] The mature virus.virology n. [L. virus, poison; Gr. logos, discourse] The study ofviruses.virulence n. [L. virulentus, fr. virus, poison] The state of beingpathogenic.virus n. [L. virus, poison] An intracellular obligate, infectiousparasitic agent visible only under the electron microscope,causing many diseases in man, animals and plants. viral a.viscera n.pl. [L. viscera, entrails, flesh inside the body] Internalorgans. visceral a.visceral ganglion 1. (MOLL: Bivalvia) Ganglion found near theposterior adductor muscle in the posterior viscera. 2.(MOLL: Gastropoda) Unpaired, median ganglion lying posteriorlyand ventrally to the gut; may be fused with otherganglia in advanced forms.visceral hump or mass (MOLL) The main metabolic region ofthe body; contains the body organs; the visceropallium.visceral nervous system see stomogastric nervous systemor sympathetic systemvisceral pouch (MOLL: Bivalvia) A small extension of the visceralmass on the anterior side of the adductor muscle inoysters.visceral segments (ARTHRO: Insecta) All abdominal segmentsanterior to the genital segments; only the anterior visceralsegments are variously modified.

950Maggenti and Gardnervisceral sinus (ARTHRO: Insecta) A central cavity between thedorsal and ventral sinuses, containing the main internal organs.visceral trachea (ARTHRO: Insecta) The median segmentaltrachea beginning at a spiracle and branching to the alimentarycanal, fat tissue, and reproductive organs.visceral tracheal trunk (ARTHRO: Insecta) A longitudinaltrunk associated with the walls of the alimentary canal.visceropallium see visceral hump or massviscid a. [L. viscidus, sticky] Having a thick or sticky consistency;adhesive.viscosity n. [L. viscidus, sticky] The resistance of a fluid toflow due to adherence of particles of one to another. viscousa.vital staining Staining of living cells and tissues by relativelynon-toxic dyes; intravital staining. see intra vitam.vitellaria larva (ECHINOD: Holothuroidea, Crinoidea, Ophiuroidea)A nonfeeding, barrel-shaped larva possessing ciliatedbands with no arms.vitellarium n.; pl. -ia [L. vitellus, yolk; -arium, place for] 1. Ayolk gland; a zone of growth. 2. (ARTHRO: Insecta) Thatpart of an ovariole that contains the developing eggs. 3.(PLATY) Glands which produce yolk material and possiblythe eggshell.vitelligenous a. [L. vitellus, yolk; gignere, to produce] Producingyolk; sometimes applied to certain cells in the ovaries.vitelline a. [L. vitellus, yolk] Yellow like the yolk of an egg.vitelline body see yolk nucleusvitelline duct (PLATY: Turbellaria) One of paired ducts connectingthe vitelline glands to the common vitelline duct.vitelline membrane A membrane enclosing eggs of invertebrateslocated within an egg shell.vitellogenesis n. [L. vitellus, yolk; Gr. genesis, beginning] Theproduction of yolk.vitellophages, vitellophags n.pl. [L. vitellus, yolk; Gr.

Online Dictionary of Invertebrate Zoology 951phagein, to eat] Cells involved with the breakdown of theyolk at all stages of development. vitellophagic a.vitellus n. [L. vitellus, yolk] The yolk of an egg.vitreous a. [L. vitrum, glass] Glassy; transparent.vitreous body see crystalline conevitreous humor (MOLL: Cephalopoda) A jelly-like substancefilling the posterior chamber of the eye.vitta n.; pl. -tae [L. vitta, band] A broad stripe or band. seefascia, frontal vitta. vittate a.vitta frontalis see frontal stripeviviparous a. [L. vivere, to live; parere, to beget] Bringingforth living young. viviparity n. see oviparous, ovoviviparous.volant a. [L. volare, to fly] Capable of flying.volatile a. [L. volare, to fly] Passing away by evaporation.volsella n.; pl. -ae [L. volsella, pincers] (ARTHRO: Insecta) InHymenoptera, the inner basal process of the gonocoxite.-voltine suff. [It. volta, time] Used with a prefix to denote thenumber of broods in a year; i.e., multivoltine.voluntary muscle Striated muscle capable of rapid contractionand relaxation; found in arthropods and other groups ofanimals.volute n. [L. volvere, to roll] (MOLL) A whorl or turn of a spiralshell.volution n. [L. volvere, to roll] (MOLL: Gastropoda) A completecoil of a helicocone. see whorl.volvent see desmonemevomer n. [L. vomer, plowshare] (ARTHRO: Insecta) In the infraorderPhasmatidea or suborder Anareolatae, a movablesclerotized process that functions during copulation; vomersubanal.vulva n. [L. vulva, womb] The external opening of the femalereproductive system.vulva cone (NEMATA: Secernentea) In some Heterodera cysts,the posterior protuberance on the posterior portion.

952Maggenti and Gardnervulva fenestra (NEMATA: Secernentea) In some Heterodera, athin transparent zone in the body wall of a white femaleand the cyst wall; encircling or at the sides of the vulva.vulval bridge (NEMATA: Secernentea) In some Heteroderacysts, a narrow connection across the fenestra of the vulvalcone, forming two semifenestrae.vulval flap/membrane see epiptygmavulvar lamina (ARTHRO: Insecta) In Odonata, a subgenitalplate of the 8th abdominal sternite.

WWagener's larva (MESO: Rhombozoa) In Mycrocymea , a freeswimming larval stage that attaches to the host kidney tissueand transforms into a nematogen.waggle dance (ARTHRO: Insecta) A dance performed by honeybeesindicating source and location of a good source.walking leg see pereopodwall n. [L. vallus, a palisade] The encumbering sides of an organor structure.warm-blooded see homoiothermalwarning coloration Conspicuous colors of invertebratescausing predators to ignore them as food, either becausethey are poisonous or distasteful or because they are mimickingorganisms possessing disagreeable qualities. seesematic, aposematic, pseudaposematic.wart see verruca, tuberclewater pore see hydroporeWaterston's organ (ARTHRO: Insecta) In Hymenoptera Ceraphronidae,a medial patch of reticulum on the 5th gastrictergite; function unknown.water vascular system (ECHINOD) A unique system comprisedof tube-like body wall appendages (tube-feet), and asystem of canals derived from the coelom.wax n. [A.S. weax, wax] (ARTHRO: Insecta) A substance secretedby various insects consisting of a complex mixtureof lipids, varying from species to species.wax gland Any gland in various parts of the body that secretea waxy product in the form of a scale, string or powder.wax layer (ARTHRO: Insecta) Wax secreted by oenocytes at ornear the surface or incorporated into the inner layers of thecuticle; responsible for waterproofing the cuticle.

954Maggenti and Gardnerwax-plate (ARTHRO: Insecta) A plate where the secretions ofthe wax glands are deposited.wax scale (ARTHRO: Insecta) In Apis, thin plates of wax secretedfrom the intersternal pockets of younger workerbees.web n. [A.S. webb] (ARTHRO) A network of threads spun byspiders, mites and some insects.weighting n. [A.S. gewiht, weight] An evaluation of phyleticcontent of a character and the evaluation of its probablecontribution to a sound classification.Weismann's ring see ring glandwheel organ (ROTIF: Bdelloidea) Ciliated trochal discs, raisedon pedestals, functioning in locomotion and in the productionof food currents; corona.white body see Hensen's glandwhite cuticle (ARTHRO: Insecta) The inner thick, tough, laminatedendocuticle of an egg membrane secreted by theserosa, and containing chitin. see yellow cuticle.wholemount An intact specimen prepared for examination.whorl n. [A.S. hweorfan, to turn] (MOLL: Gastropoda) 1. Anycomplete coil of a helicocone. 2. The exposed surface ofany complete coil of a helicocone.width n. [A.S. wid, broad] (MOLL) The maximum dimensionmeasured at right angles to the length or height of a shell.wild type A strain, organism, or gene of the type predominatingin nature; natural.wing n. [ME. winge, wing] 1. (ARTHRO) One of paired, thin,membranous reticulated organs of flight. 2. (MOLL) A projection,flattened, expansion, or earlike extension of ahinge line; auricle. see ala.winter egg Resting egg; where applicable, a type of egg with athick shell that protects the egg over winter; opsiblastic.see summer egg.With's organs (ARTHRO: Chelicerata) In Acari, paralabial hypertrophiedsetae mediad from the rutella.workers n.pl. [A.S. worc, work] (ARTHRO) 1. An individual of

Online Dictionary of Invertebrate Zoology 955the semisocial and eusocial Hymenoptera, nonreproductive,laboring caste. 2. In Isoptera, individuals which lack wingsand possess reduced pterothorax, eyes and genital apparatus.3. In Formicidae, the ordinary sterile female, bearingreduced ovarioles and simplified thorax; includes both minorworkers and soldiers in species with two subcastes.worker jelly (ARTHRO: Insecta) In Apis, food given to larvaethat causes them to become workers; bee milk.

Xxanthic a. [Gr. xanthos, yellow] Yellowish in color.xanthophyll n. [Gr. xanthos, yellow; phyllon, leaf] An oxidisedderivative of carotene found in the blood of some planteating insects.xanthopterin, xanthopterine (ARTHRO: Insecta) A yellowpteridine pigment of some insects.X-chromosomes In most dioecious diploid organisms, sexchromosomes of which there are a pair in the female, butonly one in the male.xenagones n.pl. [Gr. xenos, guest; agein, to lead] Substancesproduced by parasites that act upon the host.xenic a. [Gr. xenos, guest] The rearing of individuals of onespecies together with an unknown number of species ofother organisms. see axenic, polyxenic, synxenic, trixenic.xenobiosis n. [Gr. xenos, guest; bios, life] (ARTHRO: Insecta)A form of relation in which one species lives in and amongthe nests of another species, obtaining food from them byregurgitation or other means, but keeping their own broodseparate.xenoecic a. [Gr. xenos, guest; oikos, house] Living in anabandoned shell of an unrelated species.xenogamy see cross-fertilizationxenogenesis see heterogenesisxenomone see allelochemicxenomorphism n. [Gr. xenos, stranger; morphe, form] (MOLL:Bivalvia) Sculpture in the umbonal region of the unattachedvalve that resembles the substratum on which the attachedvalve was fixed. xenomorphic a.xenoparasite n. [Gr. xenos, guest; para, beside; sitos, sit] Anecosite that becomes pathogenic due to a weakened resistanceon the part of its host.

Online Dictionary of Invertebrate Zoology 957xerarch succession A series of community changes from bareland to climax.xeric a. [Gr. xeros, dry] Arid; lacking in moisture; adaptationto dryness.xerophilous a. [Gr. xeros, dry; philos, loving] Living in dryplaces.xerophobous a. [Gr. xeros, dry; phobos, fear] Intolerant ofarid conditions.xerosere n. [Gr. xeros, dry; L. serere, to join] A sere arisingunder dry conditions. see lithosere, hydrosere.xerothermic fauna Animals found in warm, dry conditions.xiphidiocercaria n. [Gr. xiphos, sword; kerkos, tail] (PLATY:Trematoda) Cercaria with a long tail and a stylet in theanterior rim of the oral sucker. see microcotylate cercaria,microcercous cercaria.xiphiform a. [Gr. xiphos, sword; L. forma, shape] Swordshaped.x-organ 1. (ARTHRO: Crustacea) In Decapoda, a neuro-secretoryorgan situated in the eye stalk, and the cephalon ofsessile-eyed crustaceans; frontal organs in Anostraca. seeorgan of Bellonci, frontal eye complex, frontal organ.2. (KINOR) In female chaetonotoids that lack an oviduct, asac-like structure through which the eggs pass to the surfaceof the body.xylanase n. [Gr. xylon, wood; -ase, enzyme] (ARTHRO: Insecta)In wood ingesting Cerambycidae, an enzyme thathydrolizes xylosan to xylose.xyloid a. [Gr. xylon, wood; eidos, like] Like or resemblingwood; ligneous.xylophagous a. [Gr. xylon, wood; phagein, to eat] Wood-eating.xylotomous a. [Gr. xylotomous, wood-cutting] The ability tocut or bore into wood.xyphus n. [Gr. xiphos, sword] (ARTHRO: Insecta) In Heteroptera,a posteriorly directed triangular process of themesosternum.

YY-chromosomes A chromosome in the male, which pairs withthe X-chromsome at synapsis.yellow body (ARTHRO: Insecta) An amorphous mass formed byshed larval epithelium of the midgut occurring in the lumenat pupation.yellow cells see chlorogogen cellsyellow cuticle (ARTHRO: Insecta) A thin epicuticle of the eggmembrane secreted by the serosa, that is highly impermeableto water and lacks chitin. see white cuticle.yolk n. [A.S. geoloca, yolk] Stored food substances in the eggcell.yolk cells Primary yolk cells that take no part in the blastodermformation.yolk duct see vitelline ductyolk gland see vitellariumyolk nucleus Intensely osmiophilic body located near the nucleus;vitelline body; Balbiani's body.Y-organs (ARTHRO: Crustacea) In Decapoda, paired nonneuralglands in the antennary or maxillary segments that secretethe molting hormone ecdysone.Y-vein (ARTHRO: Insecta) Two adjacent veins fused distallyforming a Y shape.

ZZ-band, disc, line [Ger. zwischenscheibe, intermediate] Thezone of actin interaction between sarcomeres; the boundarybetween muscle sarcomeres; Krause's membrane.Z-chromosome A sex chromosome present in both sexes infemale heterogametic reproduction.zeitgeber see synchronizerZenker's organs (ARTHRO: Crustacea) In Ostracoda, anejaculatory duct.zeugobranchiate a. [Gr. zeugos, a pair; branchia, gills](MOLL: Gastropoda) In Prosobranchia, pertains to pairedsymmetrical conditions of some structures of the pallialcomplex.zigzag n. [F. zigzag, alternately changing direction by sharpangles] 1. A series of short, sharp turns or angles. 2. Zizzagevolution; anorthogenesis.zoaea see zoeazoanthella n. [Gr. zoon, animal; dim. anthos, flower] (CNID:Anthozoa) An elongate larval form of Zoanthinaria with aventral band of very long cilia. see zoanthina, Semper'slarva.zoanthina n. [Gr. zoon, animal; dim. anthos, flower] (CNID:Anthozoa) An oval larval form of Zoanthinaria with a girdleof long cilia near the oral pole. see zoanthella, Semper'slarva.zoarium n. [Gr. zoon, animal; -arium, belonging to] (BRYO) Acolony.zoea, zooea, zoaea n. [Gr. zoe, life] A larval stage in the developmentof higher Crustacea. zoea I First zoeal stagewith paired compound eyes that are sessile. zoea II Secondaryzoeal stage with stalked compound eyes. zoea IIIThird zoeal stage that features the first appearance of uropods.see mysis, phyllosoma, protozoea, schizopodlarva.

960Maggenti and Gardnerzoecium see zooeciumzonate a. [L. zona, a belt] Marked with zones or concentricbands of color; ringed; belted.zone n. [L. zona, a belt] 1. An area having similar fauna andflora. 2. A region of a body. 3. Area of the earth havingsimilar climate; temperate zone; tropical zone.zone of growth see vitellariumzonite, zoonite n. [Gr. zoon, animal] A body segment or somaticdivison of Kinorhyncha and Diplopoda, equivalent toarthromere or somite in Insecta.zonociliate a. [L. zona, a belt; cilium, eyelash] Banded withcilia.zooanthroponosis n. [Gr. zoon, animal; anthropos, man;nosos, disease] Any disease in man acquired from a loweranimal, including invertebrates; zoonosis. see anthropozoonosis.zoobiotic a. [Gr. zoon, animal; bios, life] Pertaining to an organismthat lives as a parasite on an another animal.zoocenose n. [Gr. zoon, animal; koinos, common] An animalcommunity.zoochlorellae n.pl. [Gr. zoon, animal; dim. chloros, green] Asymbiotic intracellular algae on Cnidaria that are usuallyendodermal, from which cnidarians derive nutritive benefitfrom the algal photosynthate.zoochromes n.pl. [Gr. zoon, animal; chromos, color] (ARTHRO:Insecta) Biochromes acquired in the food that are metabolicallyhandled and often modified.zooea see zoeazooecial compartment (BRYO) The body cavity of a zooid.zooecial lining (BRYO) The inner lining of a zooidal chamber.zooecial wall (BRYO) The skeletal wall of a zooid.zooeciules n.pl. [Gr. zoon, animal; dim. oikos, house] (BRYO)Small to minute zooids; function unknown.zooecium n.; pl. zooecia [Gr. zoon, animal; oikos, house](BRYO: Stenolaemata;Gymnolaemata) 1. The skeleton of azooid, comprised of calcareous layers of zooidal walls and

Online Dictionary of Invertebrate Zoology 961connected zooidal structures. 2. In Phylactolaemata, comprisedof any nonliving secreted parts of the body.zoogamy n. [Gr. zoon, animal; gamos, marriage] Sexual reproduction.zoogenic a. [Gr. zoon, animal; genesis, origin] Pertaining tochanges caused by animals or their activities; zoogenous.zoogeography n. [Gr. zoon, animal; ge, earth; graphein, towrite] 1. The science of geographical distribution of animals.2. The environmental relationships that cause thedistribution.zooid n. [Gr. zoon, animal; eidos, like] 1. Any of the individualanimals of a colonial or compound organism produced byasexual means. 2. (BRYO) A single member of a colonyconsisting of polypide and zooecium. zooidal a.zoology n. [Gr. zoon, animal; logos, discourse] The study ofanimals.zoonite see zonitezoonosis n.; pl. -ses [Gr. zoon, animal; nosos, disease] A diseasein man acquired from one of the lower animals.zoonotic a.zooparasite n. [Gr. zoon, animal; para, beside; sitos, food] 1.A parasite of animals. 2. Any parasitic animal.zoophagous a. [Gr. zoon, animal; phagein, to eat] Feeding onanimals.zoophilous a. [Gr. zoon, animal; philos, loving] Animal loving.zoophyte n. [Gr. zoon, animal; phyton, plant] 1. A bryozoan.2. Any non-motile plant-like animal.zooplankton n. [Gr. zoon, animal; plankton, wandering] Animalplankton.zoosemiotics n.pl. [Gr. zoon, animal; semeion, signal] Theanalysis of animal communication.zoosuccivorous n. [Gr. zoon, animal; L. succus, juice; vorare,to devour] Any animal that sucks blood or other body-fluids.zootomy n. [Gr. zoon, animal; temnein, to cut] 1. The dissectionof animals. 2. The anatomy of animals.

962Maggenti and Gardnerzootoxin n. [Gr. zoon, animal; toxikon, poison] A toxic substanceproduced by animals.zooxanthellae n.pl. [Gr. zoon, animal; dim. xanthos, yellow]Symbiotic intracellular algae that are usually endodermal,from which cnidarians derive nutritive benefit from the algalphotosynthate. see zoochlorellae.z-organ (NEMATA: Adenophorea) In Xiphinema an undefinedstructure located between the oviduct and uterus.zwitter n. [Ger. zwitter, halfbreed] (NEMATA) Nematode intersexes,sometimes mistakenly used as synonym of hermaphrodite.see gynadromorph.zygocardiac ossicles (ARTHRO: Crustacea) In Decapoda, triangularplates projecting into the cavity of the cardiacstomach from each side usually bearing denticles; part ofthe gastric mill.zygogamy see isogamyzygogenetic, zygogenic a. [Gr. zygon, yoke; genesis, origin]Product of fertilization. see parthenogenic.zygolobous a. [Gr. zygon, yoke; lobos, lobe] (ANN: Oligochaeta)A prostomium lacking demarcation from the firstsegment.zygolophous a. [Gr. zygon, yoke; lophos, crest] (BRACHIO) Alophophore with brachium consisting of straight or crescenticside arm bearing 2 rows of paired filamentary appendages.zygolophus n.zygomorphic a. [Gr. zygon, yoke; morphos, shape] Bilaterallysymmetrical.zygonema n. [Gr. zygon, yoke; nema, thread] The chromosomesynapses of the 2nd stage of prophase I of meiosis;sometimes used as a synonym of zygotene.zygoneure n. [Gr. zygon, yoke; neurone, nerve] A nerve cellconnecting other neurons.zygoneury n. [Gr. zygon, yoke; neuron, nerve] (MOLL: Gastropoda)A connection between the main mantle nerve andthe intestinal ganglial nerves and pallial nerves from thepleural ganglia, usually on the left side, but may be on theright. see dialyneury.

Online Dictionary of Invertebrate Zoology 963zygophase see diplophasezygosis n. [Gr. zygosis, a joining] 1. Conjugation. 2. (ARTHRO:Insecta) In coccids, the median lobes of the pygidium thatare united basally by internal sclerotization. 3. (MOLL: Gastropoda)A neural connection between the supraintestinalganglion and the pleural ganglion on the left side or betweenthe subintestinal ganglion and the pleural ganglionon the right side. see orthoneury.zygote n. [Gr. zygosis, a joining] A fertilized egg or egg nucleus.zygotene n. [Gr. zygon, yoke; tainia, ribbon] The 2nd stage inmeiosis during prophase I, following the leptotene stage;homologous chromosomes (zygonema) begin to pair andcoil about one another. see zygonema.zygum n.; pl. zyga [Gr. zygon, yoke] 1. (ARTHRO: Crustacea)In Ostracoda, a chitinous process of the male copulatoryapparatus suspended in the posterior shell region by asystem of chitinous rods, about which the peniferum arcs.2. (ARTHRO: Insecta) In Scarabaeoidea larva, a convexcross bar forming the anterior margin of the haptomerum.zymogen n. [Gr. zyme, leaven; genesis, origin] Formerly asubstance able to be transformed into an enzyme.

Online Dictionary of Invertebrate Zoology: Complete Work - Best Text

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?