NO. 2063. NORTH AMERICAN PARASITIC C0PEP0D8— WILSON. 589 



runs diagonally to the sides of the maxilli-pedal and maxillary glands. 

 At the posterior corner of the ganglion a slender nerve extends back- 

 ward along the ventral walls of the stomach and close to its fellow from 

 the other side. These nerves show no ganglionic swelUngs and no 

 ganglion cells. The nervous system is thus practically concentrated 

 in the infra-esophageal ganglion. 



THE REPRODUCTIVE ORGANS. 



The reproductive system in the female consists of paired ovaries 

 and oviducts, an unpau-ed sperm receptacle, and paired cement 

 glands. In the male it consists of paired testes and vasa deferentia, 

 and paired spermatophore receptacles. 



The ovaries and testes lie in what may be termed the small of the 

 back, between the stomach and the dorsal body wall. From the 

 posterior ends are given off the oviducts and vasa deferentia which run 

 around the stomach to the ventral surface, and then backward to the 

 openings in the sides of the genital segment. 



In both sexes these ducts become so convoluted and swollen at 

 maturity that they fill the entire cavity on either side of the digestive 

 tract, which is flattened laterally into a mere slit. 



The sperm receptacle in the female Hes in the posterior portion of 

 the trunk, sometimes dorsal and sometimes ventral to the intestine. 

 In those genera (AcWheres, etc.) which have an abdomen the recep- 

 tacle is dorsal and consists of a bag nearly twice as long as wide, placed 

 transversely in the trunk and flattened dorso-ventrally. Each end 

 of the bag is prolonged at the anterior corner into a slender tube 

 which runs outward to the oviduct and opens into the latter just 

 inside of its external opening; at the posterior corner into a canal, the 

 vagina, which leads diagonally backward and inward to the posterior 

 margin of the abdomen, where it opens to the exterior alongside the 

 midline. In those genera (CUvella, etc.) which have no abdomen the 

 sperm receptacle is ventral to the intestine, is not as long as in AcTi- 

 tJieres, and the vaginae are usually more or less fused. They run back 

 through the genital process and open at its tip, either closely side by 

 side or, if fused, in one common opening. 



Wlien the spermatophores are fastened by the male upon the 

 abdomen or genital process of the female their tubes enter these 

 external openings (vulvae) . And the spermatozoa which they contain 

 are discharged through the vulvae and vaginae into the receptacle. In 

 the present family there is no crossing of the tubes of the spermato- 

 phores, as in the CaUgidae, but each spermatophore empties into the 

 vagina on its own side of the body (fig. 8, p. 586). Even in those 

 genera where the vaginae are fused and have a common vulva the 

 spermatophore tubes are stiU uncrossed. 



