252 



THE ANATOMY OF INVERTEBRATED ANIMALS. 



but, in Cypridina, Conchoecia, and Halocryptis there is, ac- 

 cording to Claus, a short saccular heart with one anterior and 

 two lateral apertures. The nervous system is difficult to make 

 out ; but, in Cythere lutea, the same observer found a large cer- 

 ebral ganglion in front of the mouth, whence filaments passed 

 to an ophthalmic ganglionic mass, and to the antennary or- 

 gans. A double ganglion, behind the mouth, supplies the 

 gnathites ; three ganglia, situated in the thorax, send fila- 

 ments to its appendages, and a terminal ganglion supplies the 

 caudal appendage and genitalia. In the female, the ovaries 

 lie in the valves of the carapace, and terminate in oviducts 

 which open by distinct apertures in front of the caudal ap- 

 pendage. Immediately anterior to them are the openings of 



Fig. 66.— A. Cypris. — A. I. n. Antennules and Antennre. M. i. n . in. Mandibles 



and maxillae. P. i. ir. Thoracic members ; c, caudal extremity ; b, mandibular 



palp ; o, eye. B. Maxillary appendage. 

 B. Cythere. — o, eye; a, antennule; b, antenna; c, mandible; d, first maxilla; 



e, e, <?, second maxilla and two thoracic members ; /, caudal extremity. (Alter 



Zenker.) ' 



two horny canals, called vaginae by Zenker, each of which is 

 continued into a long convoluted transparent tube, and event- 

 ually terminates in a large vesicle, the spermatheca, into 

 which the spermatozoa of the male are received. 



In the males, the antennae, the second maxillae or some of 

 the thoracic limbs, are modified in such a manner as to enable 

 them to seize and hold the females. The testes are elongated 

 caeca in Cypris, globular vesicles in Cythere, and communi- 

 cate with a long vas deferens, which opens into the copula- 

 tory apparatus. In Cypris, a very singular cylindrical mu- 

 cous gland is connected with the vas deferens ; but perhaps 

 the most remarkable peculiarity about the genital apparatus 

 in the male consists in the size of the spermatozoa, which in 

 Cypris ovwn are, according to Zenker, more than three times 

 as long as the body. They possess a spirally-wound coat, and 

 are totally deprived of mobility. 



1 " Monographic der Ostracoden." (" Archiv fur Naturgeschichto," 1854.) 



