. Elements of Comparative Anatomy. GENEEATIVE ORGANS OF AETHEOPODA. 293 partly formed from tlie appendages (Crustacea), or by tliem and whole metanieres (Insecta). The appendages have further many other relations to the generative apparatus, for they serve as organs for seizing and holding the female, and are modified accordingly. The generative system is here seen to be so correlated with other parts, as to be of great importance in determining the form of the whole organism. § Fig. 153. Gut and male generative appa- ratus of Pleuroma. Side view, oe Fore- gut. V Mid-gut. /i Unpaired cse
. Elements of Comparative Anatomy. GENEEATIVE ORGANS OF AETHEOPODA. 293 partly formed from tlie appendages (Crustacea), or by tliem and whole metanieres (Insecta). The appendages have further many other relations to the generative apparatus, for they serve as organs for seizing and holding the female, and are modified accordingly. The generative system is here seen to be so correlated with other parts, as to be of great importance in determining the form of the whole organism. § Fig. 153. Gut and male generative appa- ratus of Pleuroma. Side view, oe Fore- gut. V Mid-gut. /i Unpaired csecal-sac. i Hind-gut. c Heart, t Testis, vd Coiled vas deferens (after Glaus). Among the Crustacea we meet with hermaphroditism in some of the Cirripedia. The testes and ovaries are greatly ramified tubes, which can only be distinguished externally by their position in the body. In the Lepadida3 the ovaries are placed in the stalk formed by a diverticulum of the mantle; they give off an oviduct to the mantle-cavity on either side. In the Balanidne they are em- bedded in the mantle. In both families the male reproductive o-lands are disposed around the intestinal tract, and unite at each side into a vas deferens, which runs alongside the hind-gut, and opens with its fellow of the other side at the end of the postabdomen. In the other, or dioecious Crustacea, the organs of both sexes are arranged in very much the same manner. There are two different forms of the generative apparatus accord- ing as the germ-gland is paired or unpaired. But these are connected with one another by forms in which the two germ-glands are united into an organ which is externally single. We meet with unpaired germ-glands in the free-living Copepoda. The ovary or testis (Fig. 153, t) lies in the middleliue above the mid-gut {v). The ovary gives off an oviduct on either side, which either takes a simple course backwards, or forms in its terminal portion several coils, which function as a uterus (parasitic
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