COPEPODA 



337 



In Herpyllobius, parasitic on annelids, the female is reduced to a 

 mere sac, drawing nourishment from the host by rootlets and bearing 

 minute males which are also sac-like. 



Xenocoeloma^ also parasitic on annelids, is represented in the host's 

 body only by the gonads, which are hermaphrodite, and some 

 muscles, enclosed in a cylindrical outgrowth of the host's epithelium 

 which forms a body for the vestiges of the parasite and contains a 

 gut-Hke prolongation of the host's coelom. 



Appendix to the Copepoda 



BRANCHIURA 



Crustacea, temporarily parasitic on fishes ; which possess compound 

 eyes; carapace-like lateral expansions of a cephalothorax which is 

 formed by the fusion of the head with two thoracic somites ; and five 



Fig. 243. Argulus. A, A ventral view of a female of A. americanus. From 

 Caiman, after Wilson. B, The second left swimming limb of A. foliaceus. 

 After Hansen, an.' antennule; an." antenna; e. paired eye; ex. exopodite; 

 mx." maxilla; mxp. maxilliped; ram. ramus of caudal furca; sip. siphon, or 

 suctorial proboscis; sp. poison spine. 



pairs of thoracic limbs, of which the first is uniramous and the rest 

 biramous, with usually a proximal extension of the exopodite. 

 The members of this group resemble in many respects the Cope- 



