. The Cambridge natural history. Zoology. EPICARIDA LIFE-HISTORY OF DANALIA 131. Fig. 86.—Inachus mauritanicus, 9, xl, carrying two SaccuUna negUda {a, b), and a Bcmalia curvata (c), the latter bearing two dwarf males. which is itself parasitic on the spider-crab, Inachus mauritanicus, at Naples. The adult Danalia is a mere curved bag full of eggs or developing embryos, and without any other recognisable organs except two pairs of sper- mathecae upon the ventral surface where the sper- matozoa derived from the larval males are stored. In Fig. 86 is repre- sented a female of Inachus mauritanicu

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. The Cambridge natural history. Zoology. EPICARIDA LIFE-HISTORY OF DANALIA 131. Fig. 86.—Inachus mauritanicus, 9, xl, carrying two SaccuUna negUda {a, b), and a Bcmalia curvata (c), the latter bearing two dwarf males. which is itself parasitic on the spider-crab, Inachus mauritanicus, at Naples. The adult Danalia is a mere curved bag full of eggs or developing embryos, and without any other recognisable organs except two pairs of sper- mathecae upon the ventral surface where the sper- matozoa derived from the larval males are stored. In Fig. 86 is repre- sented a female of Inachus mauritanicus which carried upon it two Sacculinae and a Danalia curvata, and upon the latter are seen two minute larval males in the act of fertilising the adult Danalia. The eggs develop into the Epicaridian stage, after which the larva passes into the Cryptoniscus stage (Fig. 87). In this larval form the segments are clearly delimited ; the only mouth-parts present are the mandibles, but there are seven pairs of thoracic limbs and the full number of pleopods. This Cryptoniscus stage is found in all the Epicarida, and only differs in detail in the various families. In the Cryptoniscina the Cryptoniscus larva is the male, and at this stage possesses a pair of large testes in the thorax. The ovaries are also present at this stage as very small bodies applied to the anterior ends of the testes. The larval males in this state seek out adult fixed Danaliae and fertilise them; and, when this is accomplished, they themselves become fixed to the host and begin to develop into the adult Fig. 87.—Ventral view female condition. The limbs are all lost, and of Cryptoniscus q^j; gf ^j^g niQuth grows a long proboscis (Fig. larva of Danalia ° ° -^ i- i cwrmto, (5, X 25. 88, P), which penetrates the tissues 01 the host. The ovaries begin to grow, and a re- markable process of absorption in the testes takes place. These organs, when fixation occurs, are never empty of spermatozoa, and are frequently