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E g cell sperm Stock Photos and Images
RM2AJFGAF–The cell in development and inheritance . in the neighbourhood of the sperm-nucleus, and this in a large number of cases gives rise or is definitely-related to the cleavage-amphiaster (coelente-rates, flat-worms, echi-noderms, nematodes,annelids, arthropods,mollusks, tunicates, ver-tebrates). In many ofthese cases the sperm-aster, which by divi-sion gives rise to theamphiaster, has beenfound to arise in inti-mate relation with themiddle-piece of thespermatozoon; e.g. inechinoderms(Flemming,Hertwig, Boveri, Wil-son, Mathews,Hill, etc.),in the axolotl(Fick) andsalamander (Michaelis),in the tunic
RMPG41TE–. Essentials of botany. Botany; Botany. Pig. 123. Germination of Pollen Grain of an Angiosperm. (Much magnified and somewhat dia^ grammatic.) Pig. 122. Pollen Grains producing ^' ™*'^« S^ain, with germination con- siderably advanced. B, tip of pollen tube at a much later stage, after the tube nucleus has disappeared: g, the generative cell beginning to enter the tube;, t, the tube nucleus; s, sperm Tubes, on Stigma of a Lily. (Much magnified.) g, pollen grains; t, pollen tubes; p, papillse of stigma; e, canal or passage running toward ovary. cells formed from the generative cell. which contain
RMMA7HFD–. The eggs of mammals . The events occurring at fertilization in the fallopian tubes have been subject to detailed examination chiefly in poly- ovular mammals, e.g., the rabbit, rat, mouse, ferret, etc. In all cases the sperm surround the ova embedded in the mass of follicle cells, and penetrate to the ova causing the follicle cells to fall away at the same time. That the sperm swarm present in the tubes is actively responsible for the fall- ing away of the follicle cell mass is abundantly evident from numerous recent observations of fertilization in the rabbit (Pincus, 1930; Yamane, 1930, 193
RM2AJFDW9–The cell in development and inheritance . t thefourth cleavage. Such embryos develop as far as the blastula stage,but never form a gastrula.^ In cases where several spermatozoanormally enter the Q^g (physiological polyspermy), only one of thesperm-nuclei normally unites with the egg-nucleus, the supernumer-ary sperm-nuclei either degenerating, or in rare cases — e.g. in elas-mobranchs and reptiles — living for a time and even dividing to form 1 For an account of the internal changes, see p. 355. UNION OF THE GERM-CELLS 199 merocytes or accessory nuclei. The fate of the latter is still indoubt;
RMPG3PEM–. A manual of zoology. ntc. Fig. 45.—Hydra. A vertical section of entire animal; E, portion of transverse section, highly magnified ; C, two large ectoderm cells ; D, endoderm cell of H. inridis ; E, large nematocyst; F, small nematocyst; G, sperm; a, ingested diatom; bd.1, bd.2, buds; chr, chromatophores; cub/, cnidoblast; enc, cnidocil; ect, ectoderm; cud, endoderm; cut. cav, enteric cavity; ent. cav1, its prolonga- tion into the tentacles; J7, flagellum; hyp, hypostome or manubrium; int. c, in- terstitial cells; m.ftr, muscle processes; mtli, mouth; wsg!, mesoglcea; ?ict, large, and ate1, s
RM2AXD61G–Plants and their ways in South Africa . bryo sac; a,antipodal cells ; b, two polarnuclei which unite to form thecentral or definitive nucleus ; e,G.gg apparatus with sperm cellapplied to the egg cell, d; s,seed coat; c, nuclei dischargedby the pollen tube ; /, funicle ;/, pollen tube which has enteredthrough the micropyle. Classification of Plants 237 developed the pollen tube mentioned on p. 159. When thepollen tube reaches its destination in an angiospermous ovule(Fig. 210) it discharges two nuclei which it has brought theentire journey. One serves as a sperm nucleus. For a longtime the fate
RM2AX0W3H–The structure & development of the mosses and ferns (Archegoniatae) . Fig. 5.—A-F, Development of the antheridium of K. glauca, seen in longitudinal section ; G, cross-section of a young antheridium of the same ; H, antheridium of R. hirta ; I, sperm cells of R.g-lauca. Figs. E, F, X 150; I, x6oo, the others X300. ordinary growth of the dorsal part of the thallus, and thespace about the archegonium is the direct equivalent of theordinary air-spaces. The first division in the primary antheridial cell is thesame as in the archegonium, but the later divisions differ muchand dp not show such absol
RM2AFNCHY–. The animans and man; an elementary textbook of zoology and human physiology. c n. s.n. FIG. 235. Diagram of section of pistil and ovary of a flower, showing thedescent of the pollen tube and its entrance into the ovule, p. g., pollen-grain; p. /., pollen-tube; e. s., embryo sac; e. c., egg-cell; s. n., spermnucleus. Left-hand figure (1) shows the pollen-tube grown down,around and up into the ovary with the sperm-nucleus just entering theovule; right-hand figure (2) shows the fusion of the sperm-nucleus.(After Stevens.) animals; a germ- (sperm-) cell from one individual (male orhermaphrodite)
RMRJBC6A–. The cell in development and inheritance. Cells. PKELIMINARV GENERAL SKETCH 187 aster or amphiaster) is developed in the neighbourhood of the sperm- nucleus, and this in a large number of cases gives rise or is definitely related to the cleavage- amphiaster (coelente- rates, flat-worms, echi- noderms, nematodes, annelids, arthropods, mollusks, tunicates, ver- tebrates). In many of these cases the sperm- aster, which by divi- sion gives rise to the amphiaster, has been found to arise in inti- mate relation with the middle - piece of the spermatozoon; e.g. in echinoderms(Flemming, Hertwig, Bove
RMRJD3HG–. The cell in development and inheritance. Cells. PRELIMINARY GENERAL SKETCH 187 A B aster or amphiaster) is developed in the neighbourhood of the sperm- nucleus, and this in a large number of cases gives rise or is definitely related to the cleavage- amphiaster (coelente- rates, flat-worms, echi- noderms, nematodes, annelids, arthropods, mollusks, tunicates, ver- tebrates). In many of these cases the sperm- aster, which by divi- sion gives rise to the amphiaster, has been found to arise in inti- mate relation with the middle-piece of the spermatozoon; e.g. in echinoderms( Flemming, Hertwig,
RMRDDBWY–. The eggs of mammals. Ovum; Embryology -- Mammals; Mammals -- physiology; Ovum. CHAPTER VII FERTILIZATION AND CLEAVAGE. The events occurring at fertilization in the fallopian tubes have been subject to detailed examination chiefly in poly- ovular mammals, e.g., the rabbit, rat, mouse, ferret, etc. In all cases the sperm surround the ova embedded in the mass of follicle cells, and penetrate to the ova causing the follicle cells to fall away at the same time. That the sperm swarm present in the tubes is actively responsible for the fall- ing away of the follicle cell mass is abundantly evident
RMRJBC32–. The cell in development and inheritance. Cells. UNION OF THE GERM-CELLS 203 the ^%g at any point, the sperm-nucleus first moves rapidly inward along an entrance-path that shows no constant relation to the position of the egg-nucleus and is approximately but never exactly radial, i.e. toward a point near the centre of the ^g^. After penetrating a. Fig. 103. — Diagrams showing the paths of the germ-nuclei in four different eggs of the sea- urchin, Toxopneustes. From camera drawings of the transparent livmg eggs. In all the figures the original position of the egg-nucleus (reticulated) is shown
RMRH6PYA–. The breeding of animals. Livestock. 14 THE BREEDING OF ANIMALS somes of the egg-cell unite with those of the sperm-cell and a new nucleus is thus formed which becomes the active center of the new daughter cell. 16. The spermatozoon.—The male germ-cell or sper- matozoon is exceedingly minute and its investigation cor-. FiG. 4. — Human spermatozoa (greatly magnified), a, acrosome; h, nucleus; c, end knob; d, middle piece; e, tail; /, end piece; g, axial filament. respondingly difficult. Although early discovered, its significance was not clearly determined until 1865 when Schweigger-Seidel and
RMRE0C2M–. The germ-cell cycle in animals . Cells. Fig. 73. — Rhabditis nigrovenosa. Stages in maturation, fertilization, and cleavage. A. Oogonium with twelve chromosomes. B. Sec- ond miaturation division. Pronucleus and second polar body each with six chromosomes. C. Primary spermatocj'te. D. Division of primary spermatocyte. E. Second spermatocyte division; one chromosome delayed. F. Two spermatozoa each with six chromo- somes. G. Cleavage spindle of egg showing two groups of chromo- somes ; one with six contributed by the egg, the other with five contributed by the sperm. {After Schleip, 1911.). Pl
RMRH6RBG–. The breeding of animals. Horses; Livestock. 14 THE BREEDING OF ANIMALS somes of the egg-cell unite with those of the sperm-cell and a new nucleus is thus formed which becomes the active center of the new daughter cell. 16. The spermatozoon.—The male germ-cell or sper- matozoon is exceedingly minute and its investigation cor-. FiG. 4. — Human spermatozoa (greatly magnified), a, acrosome; b, nucleus; c, end knob; d, middle piece; e, tail; /, end piece; g, axial filament. respondingly difficult. Although early discovered, its significance was not clearly determined until 1865 when Schweigger-Se
![. The cell in development and inheritance. Cells. Fig. 92. — Maturation and fertilization of the egg of the mouse. [SOBOTTA.] A. The ovarian egg still surrounded by the follicle-cells and the membrane {p.p. zona pel- lucida) ; the polar spindle formed. B. Egg immediately after entrance of the spermatozoon (sperm-nucleus at cf). C. The two germ-nuclei {g, 9) still unequal; polar bodies above. D. Germ-nuclei approaching, of equal size. E. The chromosomes forming. F. The minute cleavage-spindle in the centre ; on either side the paternal and maternal groups of chromosomes. as in the ordinary mito Stock Photo](https://c8.alamy.com/comp/RJCTPW/the-cell-in-development-and-inheritance-cells-fig-92-maturation-and-fertilization-of-the-egg-of-the-mouse-sobotta-a-the-ovarian-egg-still-surrounded-by-the-follicle-cells-and-the-membrane-pp-zona-pel-lucida-the-polar-spindle-formed-b-egg-immediately-after-entrance-of-the-spermatozoon-sperm-nucleus-at-cf-c-the-two-germ-nuclei-g-9-still-unequal-polar-bodies-above-d-germ-nuclei-approaching-of-equal-size-e-the-chromosomes-forming-f-the-minute-cleavage-spindle-in-the-centre-on-either-side-the-paternal-and-maternal-groups-of-chromosomes-as-in-the-ordinary-mito-RJCTPW.jpg ". The cell in development and inheritance. Cells. Fig. 92. — Maturation and fertilization of the egg of the mouse. [SOBOTTA.] A. The ovarian egg still surrounded by the follicle-cells and the membrane {p.p. zona pel- lucida) ; the polar spindle formed. B. Egg immediately after entrance of the spermatozoon (sperm-nucleus at cf). C. The two germ-nuclei {g, 9) still unequal; polar bodies above. D. Germ-nuclei approaching, of equal size. E. The chromosomes forming. F. The minute cleavage-spindle in the centre ; on either side the paternal and maternal groups of chromosomes. as in the ordinary mito Stock Photo")
RMRJCTPW–. The cell in development and inheritance. Cells. Fig. 92. — Maturation and fertilization of the egg of the mouse. [SOBOTTA.] A. The ovarian egg still surrounded by the follicle-cells and the membrane {p.p. zona pel- lucida) ; the polar spindle formed. B. Egg immediately after entrance of the spermatozoon (sperm-nucleus at cf). C. The two germ-nuclei {g, 9) still unequal; polar bodies above. D. Germ-nuclei approaching, of equal size. E. The chromosomes forming. F. The minute cleavage-spindle in the centre ; on either side the paternal and maternal groups of chromosomes. as in the ordinary mito
RMRJBD2J–. The cell in development and inheritance. Cells. UNION OF THE GERM-CELLS 203 the Q.gg at any point, the sperm-nucleus first moves rapidly inward along an entrance-path that shows no constant relation to the position of the egg-nucleus and is approximately but never exactly radial, i.e. toward a point near the centre of the Q.^^g. After penetrating a. Fig. 103. — Diagrams showing the paths of the germ-nuclei in four different eggs of the sea- urchin, Toxopneustes. From camera drawings of the transparent living eggs. In all the figures the original position of the egg-nucleus (reticulated) is s
RMRDHG4W–. Essentials of botany. Botany; Botany. Pig. 123. Germination of Pollen Grain of an Angiosperm. (Much magnified and somewhat dia^ grammatic.) Pig. 122. Pollen Grains producing ^' ™*'^« S^ain, with germination con- siderably advanced. B, tip of pollen tube at a much later stage, after the tube nucleus has disappeared: g, the generative cell beginning to enter the tube;, t, the tube nucleus; s, sperm Tubes, on Stigma of a Lily. (Much magnified.) g, pollen grains; t, pollen tubes; p, papillse of stigma; e, canal or passage running toward ovary. cells formed from the generative cell. which contain
![. The cell in development and inheritance. Cells. ^vl^'^C^^.i! V I// A//. Fig. 99. — Fertilization in an annelid (armed Gephyrean), Thalassema. [GRIFFIN.] A. Second polar body forming; sperm-nucleus and centrosome below. B. Approach of the egg-nucleus and sperm-nucleus, the latter accompanied by the sperm-amphiaster. C. Union of the nuclei. D. Later stage of last. E. Prophase of cleavage-spindle. F. Anaphase of the same ; centrosome divided. G. H. I. Successive stages in the nuclear reconstitution and formation of the daughter-amphiasters for the second cleavage. J. Two-cell stage. in the t Stock Photo](https://c8.alamy.com/comp/RJD3GJ/the-cell-in-development-and-inheritance-cells-vlci!-v-i-a-fig-99-fertilization-in-an-annelid-armed-gephyrean-thalassema-griffin-a-second-polar-body-forming-sperm-nucleus-and-centrosome-below-b-approach-of-the-egg-nucleus-and-sperm-nucleus-the-latter-accompanied-by-the-sperm-amphiaster-c-union-of-the-nuclei-d-later-stage-of-last-e-prophase-of-cleavage-spindle-f-anaphase-of-the-same-centrosome-divided-g-h-i-successive-stages-in-the-nuclear-reconstitution-and-formation-of-the-daughter-amphiasters-for-the-second-cleavage-j-two-cell-stage-in-the-t-RJD3GJ.jpg ". The cell in development and inheritance. Cells. ^vl^'^C^^.i! V I// A//. Fig. 99. — Fertilization in an annelid (armed Gephyrean), Thalassema. [GRIFFIN.] A. Second polar body forming; sperm-nucleus and centrosome below. B. Approach of the egg-nucleus and sperm-nucleus, the latter accompanied by the sperm-amphiaster. C. Union of the nuclei. D. Later stage of last. E. Prophase of cleavage-spindle. F. Anaphase of the same ; centrosome divided. G. H. I. Successive stages in the nuclear reconstitution and formation of the daughter-amphiasters for the second cleavage. J. Two-cell stage. in the t Stock Photo")
RMRJD3GJ–. The cell in development and inheritance. Cells. ^vl^'^C^^.i! V I// A//. Fig. 99. — Fertilization in an annelid (armed Gephyrean), Thalassema. [GRIFFIN.] A. Second polar body forming; sperm-nucleus and centrosome below. B. Approach of the egg-nucleus and sperm-nucleus, the latter accompanied by the sperm-amphiaster. C. Union of the nuclei. D. Later stage of last. E. Prophase of cleavage-spindle. F. Anaphase of the same ; centrosome divided. G. H. I. Successive stages in the nuclear reconstitution and formation of the daughter-amphiasters for the second cleavage. J. Two-cell stage. in the t
![. The cell in development and inheritance. Cells. Fig. 100. — Entrance of th^spermatozoon into the egg. A-G. In the sea-urchin, Toxopneustes. H. In the medusa, Alitrocoma. [Metschxikoff.] /. In the star-fish Asterias. [FOL.] A. Spermatozoon of Toxopneustes, X 2000; a. the apical body, n. nucleus, w. middle-piece, /. flagellum. B. Contact with the egg-periphery. C. D. Entrance of the head, formation of the entrance-cone and of the vitelline membrane (z/), leaving the tail outside. E. F. Later stages. G. Appearance of the sperm-aster (j) about 3-5 minutes after first contact; entrance-cone break Stock Photo](https://c8.alamy.com/comp/RJBC43/the-cell-in-development-and-inheritance-cells-fig-100-entrance-of-thspermatozoon-into-the-egg-a-g-in-the-sea-urchin-toxopneustes-h-in-the-medusa-alitrocoma-metschxikoff-in-the-star-fish-asterias-fol-a-spermatozoon-of-toxopneustes-x-2000-a-the-apical-body-n-nucleus-w-middle-piece-flagellum-b-contact-with-the-egg-periphery-c-d-entrance-of-the-head-formation-of-the-entrance-cone-and-of-the-vitelline-membrane-z-leaving-the-tail-outside-e-f-later-stages-g-appearance-of-the-sperm-aster-j-about-3-5-minutes-after-first-contact-entrance-cone-break-RJBC43.jpg ". The cell in development and inheritance. Cells. Fig. 100. — Entrance of th^spermatozoon into the egg. A-G. In the sea-urchin, Toxopneustes. H. In the medusa, Alitrocoma. [Metschxikoff.] /. In the star-fish Asterias. [FOL.] A. Spermatozoon of Toxopneustes, X 2000; a. the apical body, n. nucleus, w. middle-piece, /. flagellum. B. Contact with the egg-periphery. C. D. Entrance of the head, formation of the entrance-cone and of the vitelline membrane (z/), leaving the tail outside. E. F. Later stages. G. Appearance of the sperm-aster (j) about 3-5 minutes after first contact; entrance-cone break Stock Photo")
RMRJBC43–. The cell in development and inheritance. Cells. Fig. 100. — Entrance of th^spermatozoon into the egg. A-G. In the sea-urchin, Toxopneustes. H. In the medusa, Alitrocoma. [Metschxikoff.] /. In the star-fish Asterias. [FOL.] A. Spermatozoon of Toxopneustes, X 2000; a. the apical body, n. nucleus, w. middle-piece, /. flagellum. B. Contact with the egg-periphery. C. D. Entrance of the head, formation of the entrance-cone and of the vitelline membrane (z/), leaving the tail outside. E. F. Later stages. G. Appearance of the sperm-aster (j) about 3-5 minutes after first contact; entrance-cone break
![. The classification of lower organisms. Biology. 170] The Classification of Lower Organisms. Fig. 32.—Hypermastigina : a-d, Trichonympha Campanula after Kofoid & Swezy (1919); a, cell x 250; b, division of centroblcpharoplast and formation of paradesmose, and c and d, earlier and later stages of mitosis x 500. e, f, g, Sperm, egg, and fertilization of Trichonympha sp. from the roach Cryptocercus after Cleve- land (1948). h, Hoplonympha Natator x 250 after Light (1926). i, Staurojoenina assimilis x 250 after Kirby (1926). j, Tcratonympha mirabilis after Koidzumi (1921).. Please note that t Stock Photo](https://c8.alamy.com/comp/REK8N6/the-classification-of-lower-organisms-biology-170-the-classification-of-lower-organisms-fig-32hypermastigina-a-d-trichonympha-campanula-after-kofoid-amp-swezy-1919-a-cell-x-250-b-division-of-centroblcpharoplast-and-formation-of-paradesmose-and-c-and-d-earlier-and-later-stages-of-mitosis-x-500-e-f-g-sperm-egg-and-fertilization-of-trichonympha-sp-from-the-roach-cryptocercus-after-cleve-land-1948-h-hoplonympha-natator-x-250-after-light-1926-i-staurojoenina-assimilis-x-250-after-kirby-1926-j-tcratonympha-mirabilis-after-koidzumi-1921-please-note-that-t-REK8N6.jpg ". The classification of lower organisms. Biology. 170] The Classification of Lower Organisms. Fig. 32.—Hypermastigina : a-d, Trichonympha Campanula after Kofoid & Swezy (1919); a, cell x 250; b, division of centroblcpharoplast and formation of paradesmose, and c and d, earlier and later stages of mitosis x 500. e, f, g, Sperm, egg, and fertilization of Trichonympha sp. from the roach Cryptocercus after Cleve- land (1948). h, Hoplonympha Natator x 250 after Light (1926). i, Staurojoenina assimilis x 250 after Kirby (1926). j, Tcratonympha mirabilis after Koidzumi (1921).. Please note that t Stock Photo")
RMREK8N6–. The classification of lower organisms. Biology. 170] The Classification of Lower Organisms. Fig. 32.—Hypermastigina : a-d, Trichonympha Campanula after Kofoid & Swezy (1919); a, cell x 250; b, division of centroblcpharoplast and formation of paradesmose, and c and d, earlier and later stages of mitosis x 500. e, f, g, Sperm, egg, and fertilization of Trichonympha sp. from the roach Cryptocercus after Cleve- land (1948). h, Hoplonympha Natator x 250 after Light (1926). i, Staurojoenina assimilis x 250 after Kirby (1926). j, Tcratonympha mirabilis after Koidzumi (1921).. Please note that t
![. The cell in development and inheritance. Cells. Fig. 100. — Entrance of the spermatozoon into the egg. A-G. In the sea-urchin, Toxopncusfes. H. In the medusa, Mitrocotna. [MeTSCHNIKOFF.] /. In the star-fish Asterias. [FOL.] A. Spermatozoon of Toxopneustes, X 2000; a. the apical body, n. nucleus, m. middle-piece, f. flagellum. B. Contact with the egg-periphery. C. D. Entrance of the head, formation of the entrance-cone and of the vitelline membrane (v), leaving the tail outside. E. F. Later stages. G. Appearance of the sperm-asler {s) about 3-5 minutes after first contact; entrance-cone break Stock Photo](https://c8.alamy.com/comp/RJD3GA/the-cell-in-development-and-inheritance-cells-fig-100-entrance-of-the-spermatozoon-into-the-egg-a-g-in-the-sea-urchin-toxopncusfes-h-in-the-medusa-mitrocotna-metschnikoff-in-the-star-fish-asterias-fol-a-spermatozoon-of-toxopneustes-x-2000-a-the-apical-body-n-nucleus-m-middle-piece-f-flagellum-b-contact-with-the-egg-periphery-c-d-entrance-of-the-head-formation-of-the-entrance-cone-and-of-the-vitelline-membrane-v-leaving-the-tail-outside-e-f-later-stages-g-appearance-of-the-sperm-asler-s-about-3-5-minutes-after-first-contact-entrance-cone-break-RJD3GA.jpg ". The cell in development and inheritance. Cells. Fig. 100. — Entrance of the spermatozoon into the egg. A-G. In the sea-urchin, Toxopncusfes. H. In the medusa, Mitrocotna. [MeTSCHNIKOFF.] /. In the star-fish Asterias. [FOL.] A. Spermatozoon of Toxopneustes, X 2000; a. the apical body, n. nucleus, m. middle-piece, f. flagellum. B. Contact with the egg-periphery. C. D. Entrance of the head, formation of the entrance-cone and of the vitelline membrane (v), leaving the tail outside. E. F. Later stages. G. Appearance of the sperm-asler {s) about 3-5 minutes after first contact; entrance-cone break Stock Photo")
RMRJD3GA–. The cell in development and inheritance. Cells. Fig. 100. — Entrance of the spermatozoon into the egg. A-G. In the sea-urchin, Toxopncusfes. H. In the medusa, Mitrocotna. [MeTSCHNIKOFF.] /. In the star-fish Asterias. [FOL.] A. Spermatozoon of Toxopneustes, X 2000; a. the apical body, n. nucleus, m. middle-piece, f. flagellum. B. Contact with the egg-periphery. C. D. Entrance of the head, formation of the entrance-cone and of the vitelline membrane (v), leaving the tail outside. E. F. Later stages. G. Appearance of the sperm-asler {s) about 3-5 minutes after first contact; entrance-cone break
RMRN5GEX–. Animal biology. Biology; Zoology; Physiology. ec.en.gc Cell Division (Embryological development) Zygote (z) produces ani- mal contain- ing germ cells (g.c.) and two layers of spe- cialized somatic cells, the ectoderm (ec.) and endoderm (en.). Budding (Asexual re- production) Part of animal separates from parent and leads separate existence. Cell Division (Gamete for- mation) Certain germ cells produce eggs (e); others produce sperm (sp.). Permanent Conjuga- tion (Fertilization) one sperm unites with one egg, form- ing a zygote (z). Cell Division (Embryological development) Zygote (z) produce
![. The cell in development and inheritance. Cells; Cells. Fig. 74. — Entrance of the spermatozoon into the egg. A.-G. In the sea-urchin ToA-f^j^wf^/jfef. H. In the medusa Mitrocoma. [METSCHNIKOFF.] /. In the star-fish Asterias. [FOL.] A. Spermatozoon of Toxop7ieustes, X 2000; a, the apical body, n, nucleus, m, middle-piece, f, flagellum. B. Contact with the egg-periphery. C. D. Entrance of the head, formation of the entfrince-cone and of the vitelline membrane (ti), leaving the tail outside. E.F. Later stages. G. Appearance of the sperm-aster {s) about 3-5 minutes after first contact; entrance- Stock Photo](https://c8.alamy.com/comp/RJBDR6/the-cell-in-development-and-inheritance-cells-cells-fig-74-entrance-of-the-spermatozoon-into-the-egg-a-g-in-the-sea-urchin-toa-fjwfjfef-h-in-the-medusa-mitrocoma-metschnikoff-in-the-star-fish-asterias-fol-a-spermatozoon-of-toxop7ieustes-x-2000-a-the-apical-body-n-nucleus-m-middle-piece-f-flagellum-b-contact-with-the-egg-periphery-c-d-entrance-of-the-head-formation-of-the-entfrince-cone-and-of-the-vitelline-membrane-ti-leaving-the-tail-outside-ef-later-stages-g-appearance-of-the-sperm-aster-s-about-3-5-minutes-after-first-contact-entrance-RJBDR6.jpg ". The cell in development and inheritance. Cells; Cells. Fig. 74. — Entrance of the spermatozoon into the egg. A.-G. In the sea-urchin ToA-f^j^wf^/jfef. H. In the medusa Mitrocoma. [METSCHNIKOFF.] /. In the star-fish Asterias. [FOL.] A. Spermatozoon of Toxop7ieustes, X 2000; a, the apical body, n, nucleus, m, middle-piece, f, flagellum. B. Contact with the egg-periphery. C. D. Entrance of the head, formation of the entfrince-cone and of the vitelline membrane (ti), leaving the tail outside. E.F. Later stages. G. Appearance of the sperm-aster {s) about 3-5 minutes after first contact; entrance- Stock Photo")
RMRJBDR6–. The cell in development and inheritance. Cells; Cells. Fig. 74. — Entrance of the spermatozoon into the egg. A.-G. In the sea-urchin ToA-f^j^wf^/jfef. H. In the medusa Mitrocoma. [METSCHNIKOFF.] /. In the star-fish Asterias. [FOL.] A. Spermatozoon of Toxop7ieustes, X 2000; a, the apical body, n, nucleus, m, middle-piece, f, flagellum. B. Contact with the egg-periphery. C. D. Entrance of the head, formation of the entfrince-cone and of the vitelline membrane (ti), leaving the tail outside. E.F. Later stages. G. Appearance of the sperm-aster {s) about 3-5 minutes after first contact; entrance-
RMRJBC63–. The cell in development and inheritance. Cells. Fig. 94. — Entiance and rotation of the sperm-head and formation of the sperm-aster in the sea-urchin, Toxopneustes {A-F. X 1600; G, //, X 800). A. Sperm-head before entrance; n. nucleus; m. mid- dle-piece and part of the flagellum. B. C. Immediately after entrance, showing entrance-cone. D. Rotation of ihe sperm-head, formation of the sperm-aster about the middle- piece. E. Casting off of middle-piece; centrosome at focus of the rays {cf. Fig. 12). The changes figured occupy about eight minutes. F. G. Approach of the germ-nuclei; growth of the
![. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. FIG. 3. FIG. 4. FIG. 5. FIG. 6. Central bodies in sperm-asters of To.vopncustes (Wilson, 'oo). Figs. 3 to 6 are reproduced from Wilson, 'oo, Figs. 94^ to 946. For discussion see pp. 106 and 120. there a minute, period-like centriole. These figures are similar to those of the present study (Figs, n to 18). They have been reproduced in text-books only occasionally, e.g., Doncaster ('20, Plate 12). In the first edition of " The Cell " ('96, p. 138) Wilson reproduces the same illustrations but in the discussion he poin Stock Photo](https://c8.alamy.com/comp/RHP7FW/the-biological-bulletin-biology-zoology-biology-marine-biology-fig-3-fig-4-fig-5-fig-6-central-bodies-in-sperm-asters-of-tovopncustes-wilson-oo-figs-3-to-6-are-reproduced-from-wilson-oo-figs-94-to-946-for-discussion-see-pp-106-and-120-there-a-minute-period-like-centriole-these-figures-are-similar-to-those-of-the-present-study-figs-n-to-18-they-have-been-reproduced-in-text-books-only-occasionally-eg-doncaster-20-plate-12-in-the-first-edition-of-quot-the-cell-quot-96-p-138-wilson-reproduces-the-same-illustrations-but-in-the-discussion-he-poin-RHP7FW.jpg ". The Biological bulletin. Biology; Zoology; Biology; Marine Biology. FIG. 3. FIG. 4. FIG. 5. FIG. 6. Central bodies in sperm-asters of To.vopncustes (Wilson, 'oo). Figs. 3 to 6 are reproduced from Wilson, 'oo, Figs. 94^ to 946. For discussion see pp. 106 and 120. there a minute, period-like centriole. These figures are similar to those of the present study (Figs, n to 18). They have been reproduced in text-books only occasionally, e.g., Doncaster ('20, Plate 12). In the first edition of " The Cell " ('96, p. 138) Wilson reproduces the same illustrations but in the discussion he poin Stock Photo")
RMRHP7FW–. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. FIG. 3. FIG. 4. FIG. 5. FIG. 6. Central bodies in sperm-asters of To.vopncustes (Wilson, 'oo). Figs. 3 to 6 are reproduced from Wilson, 'oo, Figs. 94^ to 946. For discussion see pp. 106 and 120. there a minute, period-like centriole. These figures are similar to those of the present study (Figs, n to 18). They have been reproduced in text-books only occasionally, e.g., Doncaster ('20, Plate 12). In the first edition of " The Cell " ('96, p. 138) Wilson reproduces the same illustrations but in the discussion he poin
RMRN5GFJ–. Animal biology. Biology; Zoology; Physiology. THE CONTINUITY OF LIFE 231 C. Hydra.. ec.en.gc Cell Division (Embryological development) Zygote (z) produces ani- mal contain- ing germ cells (g.c.) and two layers of spe- cialized somatic cells, the ectoderm (ec.) and endoderm (en.). Budding (Asexual re- production) Part of animal separates from parent and leads separate existence. Cell Division (Gamete for- mation) Certain germ cells produce eggs (e); others produce sperm (sp.). Permanent Conjuga- tion (Fertilization) one sperm unites with one egg, form- ing a zygote (z). Cell Division (Embryol
RMRDYWK9–. Principles of modern biology. Biology. Cell Division in Relation to Reproduction - 53 r — H A P L 0 I D S T A G E S (. SPERMATOCYTES IN TESTIS MITOTIC MULTIPLICATION MEIOSIS STARTING. ANAPHASE 2nd MEIOTIC DIVISION 2nd MEIOTIC DIVISION SPERMATIDS METAMORPHOSIS, NUCLEAR CONDENSATION MATURE SPERM Fig. 3-10. Diagram of meiosis as observed in a testis during the production of sperm. Note that the prophase of the first meiotic division differs in several ways from the prophase of an ordinary mitotic division: (1) it en- dures much longer; (2) it is accompanied by considerable cell growth; and (3)
RMRE2NAK–. Elementary botany. Botany. Fig. 163. Chlamydomonas pulvisculus (Mull.) Ehrb, A, an old motile individual; M, nucleus; p, pyrenoid; s, red eye spot; v, contractile vacuole; B, motile indi- vidual has drawn in its cilia and divided into two; C, mother plant has drawn in its cilia and divided into four non-muJ;ile cells; D, pamella stage; E, female gamete —egg; F, male gamete —sperm; G, early stage of conjugation; H, zygo- spore with conjugating tube and empty male cell attached. (After Wille.) jugate as in G and //, the protoplasm of the smaller one passing over into the larger one, and a zygo
RMRH6R2B–. Breeding of farm animals. Livestock. REPRODUCTIVE ORGANS AND GERM CELLS 17 is very minute, many thousand times less than the bulk of the latter. The sperm cell resembles a minute, elon- gated tadpole, swimming very actively about by the vibrations of a long slender tail. This locomotion is. Fig. 6—Diagram of the Germ Cells 1. Egg cell. 2. Sperm cell size to compare with egg cell. 3. Sperm cell enlarged to show parts. A. Apical body. B. Nucleus. C. End knob. D. Middle piece. E. Envelope of tail. F. Tail piece. G. End piece. L. Nucleolus or germinal spot. M. Nucleus or germinal vesicle contain
RMRJ4XJW–. Chordate morphology. Morphology (Animals); Chordata. pineal nasal pit neural cavity I EMBRYO OF 10 SOMITES. Rathke's pouch J EMBRYO OF ABOUT 35 SOMITES Figure 7-6. Stages of the lamprey {Lampetra). A, upper end of egg shov/ing micropyle for entrance of sperm and perivitelline space which forms after fertilization; B, 8-cell stage; C, section of early cleavage stage; D, section of early blastula; E, sagittal section of early gastrula, anterior end to left; F, sagittal section of early neurulo; G, cross section of early neurulo; H, sagittal section of embryo with three somites; I, sagittal sec
![. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. CELL BIOLOGY 205. Figure 1. Microtubules in varnnis model cell types visuali:ctl b /•/'; i. c'I: Limulus amehocvies (</, </'): [»;</ hlnuj urk cnthrocvtes (e, e'). Sen urchin rK"te initnlic apparatus (Lytechinus pictus; / /'; fertilization membrane removed h Ni/e filtration) and sea urchin sperm jltiijcllu I Arbacia punctulata; g, g') are also readilv labeled. (g inset): a DAPI-staineJ sperm nucleus. Also, tin unkiiomi tvpe "I spider i rub hemot te e./nhils distinct MB labeling III. /;'). The thiomh Stock Photo](https://c8.alamy.com/comp/RHG8W7/the-biological-bulletin-biology-zoology-biology-marine-biology-cell-biology-205-figure-1-microtubules-in-varnnis-model-cell-types-visualictl-b-i-ci-limulus-amehocvies-lt-lt-lt-hlnuj-urk-cnthrocvtes-e-e-sen-urchin-rkquotte-initnlic-apparatus-lytechinus-pictus-fertilization-membrane-removed-h-nie-filtration-and-sea-urchin-sperm-jltiijcllu-i-arbacia-punctulata-g-g-are-also-readilv-labeled-g-inset-a-dapi-stainej-sperm-nucleus-also-tin-unkiiomi-tvpe-quoti-spider-i-rub-hemot-te-enhils-distinct-mb-labeling-iii-the-thiomh-RHG8W7.jpg ". The Biological bulletin. Biology; Zoology; Biology; Marine Biology. CELL BIOLOGY 205. Figure 1. Microtubules in varnnis model cell types visuali:ctl b /•/'; i. c'I: Limulus amehocvies (</, </'): [»;</ hlnuj urk cnthrocvtes (e, e'). Sen urchin rK"te initnlic apparatus (Lytechinus pictus; / /'; fertilization membrane removed h Ni/e filtration) and sea urchin sperm jltiijcllu I Arbacia punctulata; g, g') are also readilv labeled. (g inset): a DAPI-staineJ sperm nucleus. Also, tin unkiiomi tvpe "I spider i rub hemot te e./nhils distinct MB labeling III. /;'). The thiomh Stock Photo")
RMRHG8W7–. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. CELL BIOLOGY 205. Figure 1. Microtubules in varnnis model cell types visuali:ctl b /•/'; i. c'I: Limulus amehocvies (</, </'): [»;</ hlnuj urk cnthrocvtes (e, e'). Sen urchin rK"te initnlic apparatus (Lytechinus pictus; / /'; fertilization membrane removed h Ni/e filtration) and sea urchin sperm jltiijcllu I Arbacia punctulata; g, g') are also readilv labeled. (g inset): a DAPI-staineJ sperm nucleus. Also, tin unkiiomi tvpe "I spider i rub hemot te e./nhils distinct MB labeling III. /;'). The thiomh
RMRDHDBE–. A manual of zoology. ntc. Fig. 45.—Hydra. A vertical section of entire animal; E, portion of transverse section, highly magnified ; C, two large ectoderm cells ; D, endoderm cell of H. inridis ; E, large nematocyst; F, small nematocyst; G, sperm; a, ingested diatom; bd.1, bd.2, buds; chr, chromatophores; cub/, cnidoblast; enc, cnidocil; ect, ectoderm; cud, endoderm; cut. cav, enteric cavity; ent. cav1, its prolonga- tion into the tentacles; J7, flagellum; hyp, hypostome or manubrium; int. c, in- terstitial cells; m.ftr, muscle processes; mtli, mouth; wsg!, mesoglcea; ?ict, large, and ate1, s
RMRHN6Y8–. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. EGG-LAYING IN SAGITTA 249. FIGURE 1. A—maturing egg; B—mature egg; C to F—stages in migration of egg to duct; G—ovary with mature unmigrated eggs showing contractions of ovary walls; H—eggs in duct immediately prior to laying. Figures A-C and H are from sections, D-G from live material; width of body approximately 0.5 mm ; a—accessory fertilization cells; b—body wall; d—duct; e—maturing egg; ei—mature unmigrated egg; 62—migrating egg; e3—migrated egg; cw—egg cell wall; g—germinal epithelium; go—gonopore ; gu—gut; s—sperm.. P
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