THE OSTRACODA 795 



stomach-like intestine (Fig. 1244). The intestine opens at the 

 origin of the furcal appendages. 



Propagation. — The male sexual organs are usually large, of 

 complex structure, and may consist of a whorled sack or spiny 

 cylinder, the ejaculatory duct (Fig. 12466), connecting with the 

 testes and vas deferens, which may lead to a more or less chitinous 

 plate or penis (Fig. 1 246 a) . The testes usually consist of glands 

 which are partly extended within the shell proper and the shell 

 membrane, and may show through the shell as three or four gran- 

 ular bands (Fig. 12 71 6), as in Candona and Cypris. The arrange- 

 ment of these testes may constitute a good generic character, as 

 in Spirocypris (Fig. 1267), where the testes originate in the ante- 

 rior part of the shell in parts of circles or circles. 



The ovaries may show through the shell in its posterodorsal 

 part, and are arranged somewhat as the testes (Fig. 1244). They 

 usually lead to a chitinous plate by a vaginal canal or oviduct, 

 which retains the semen and undeveloped eggs as with Cypris, and 

 commonly lie between the two lamellae of either valve, and extend 

 diagonally to the posterior extremity, where they curve up to form 

 a nearly semicircular band. Here the true germinal layer is found, 

 which forms the ovicells. These ovicells are poured from the 

 ovary into the body cavity, where they generally accumulate in 

 its posterior part on either side of the intestine. Here they 

 attain their full development and are fertilized, after which they 

 are laid. 



The inner genital organs of the male are more complicated 

 (Fig. 1246). As the ovaries, they are situated between the lameUae 

 of the valves, and commonly consist of a number of narrow and 

 elongate bands on either side, which are generally to be found 

 filled with numerous fine, thread-like bodies (Fig. 1246 J), the sper- 

 matozoa, which may occasionally be curled up in spiral groups. In 

 addition there are present a number of large nuclear cells (Fig. 

 1246 g). These are the germinal cells, or spermatocysts, from 

 which the spermatozoa develop. 



The efferent or ejaculatory apparatus (Fig. 1 246 h) consists of 

 the spiny cylinder already mentioned. It seems to be composed of 

 an inner tube (Fig. 1246 c), supported by a complicated chitinous, 



