No. 2194. NORTH AMERICAN PARASITIC C0PEP0D8— WILSON. 79 



segment and armed with small branched chitin horns. The neck is 

 joined to the trunk on the dorsal surface of the latter and consid- 

 erably away from the midline. 



Trunk ellipsoidal, the anterior end bluntly rounded, the posterior 

 end with lobed processes over the bases of the egg strings. Abdomen 

 as long as the trunk, flattened dorso-ventrally, and bent sidewise at 

 right angles to the trunk axis. Egg strings coiled in tight spirals, 

 eggs uniseriate. 



Two pairs of antennae, second pair chelate; one pair of maxillae; 

 four pairs of swimming legs, first two pairs close together and bira- 

 mose, third and fourth pairs separated a short distance and unira- 

 mose, all the rami two-jointed. 



Internal generic characters of female. — Bilateral symmetry com- 

 pletely distorted; esophagus inclined to the head axis, Avith a tri- 

 partite eye buried in the tissues at its base; stomach not sending out 

 lateral lobes nor convoluted; intestine looped once in the trunk; 

 rectum short and straight; an anal lamina, destitute of setae on 

 either side of the anus. 



Ovaries at the extreme posterior end of the trunk on the dorsal 

 surface, each a flattened sphere inclined to the trunk axis; oviducts 

 separated by the neck, then coming together again, running forward 

 diagonally to the anterior end of the trunk, then backward on the 

 ventral surface to the vulvae. Cement glands also separated by the 

 neck, then closing together again ; they start between the ovaries at 

 the posterior end and run diagonally forward the whole length of the 

 dorsal surface, then backward on the opposite diagonal on the ventral 

 surface, with no differentiation between the glandular portion and 

 the ducts. 



Chitinogen layer of the body wall thickest in the posterior lobes 

 of the trunk and in the abdomen, elsewhere very thin. 



Genus habitat. — This genus, like Ilaemohaphes^ burrows from the 

 bases of the gill arches into the throat and buries its head and the 

 four anterior thorax segments in the bulbus arteriosus of its host. 

 The abdomen is bent outward, away from the fish's throat, on which- 

 ever side the parasite may be attached, and the egg strings project 

 through the gill opening. 



Tyjw of the genus. — Collipravus parvus., new species, monotypic. 



{Collipravus, coUum^ neck and pravus^ irregular, misplaced.) 



COLLIPRAVUS PARVUS, new «pecies. 



Plate 11, figs. 89-07. 



Host and record of specimens. — Five females were obtnined from 

 the gill arches of Jenkinsia stoUfera at Nassau, in the Bahamas, by 

 the Bureau of Fisheries steamer Albatross in 188G. One of these is 

 made the type of the new species with Cat. No. 47810, U.S.N.M. ; 



