NO. 2063. NORTH AMERICAN PARASITIC COPEPODS— WILSON . 605 



The head is covered by a minute, but distinct, dorsal carapace. 

 The second antennae are biramose, the exopod two-jointed, the en- 

 dopod one-jointed. The first maxillae are bipartite and have no palp. 

 The egg strings are attached, not at the proximal ends, but on one 

 side, and to the trunk (genital segment) in front of the abdomen. 

 The covering of the egg strings is a thin membrane, wliich is prob- 

 ably elastic, but is not "muscular." 



The strange structm-es outside of and behind the maxillipeds seem 

 at first sight anomalous, but Hesse describes and figures them in cyg- 

 niformis as occurring on the second joint of the maxillipeds. 



In comparison with the other species it is doubtful whether they 

 actually do occur on the maxillipeds ; but however that may be, they 

 are certainly closely connected with those organs and may possibly 

 represent palps. They do not show the structure of sucking disks, 

 as most of the authoi-s would have us believe, either in surface view 

 or in sections, and it is extremely doubtful if they ever function in 

 that manner. The modified second maxillae are universally desig- 

 nated as "muscle bands," but when examined in sections they are 

 found to be epithelial and cartilaginous rather than muscular. The 

 muscles are in the form of three bundles of fibers running lengthwise 

 of the bands, which probably represent the ordinary longitudinal 

 muscles of the second maxillae. How this attachment apparatus is 

 formed in the copepodid larva and how it is thrown around the gill 

 filament of the host can not be determined until we obtain the devel- 

 opment history of the larva. 



Genus CAULOXENUS Cope. 



Generic characters of female. — Cephalo thorax stout, separated from 

 the trunk by a deep constriction, like the waist of a wasp; trunk a 

 stout, sacklike, unsegmented ovoid; no posterior processes, genital 

 process, abdomen, or anal laminae; egg strings ovoid, shorter than 

 the trunk; second maxillae elongate, fused through their entire 

 length, tapering toward the distal end, where they are furnished 

 with a broad, disklike bulla; these maxillae are attached at about 

 the center of the cephalothorax and are folded back against the head. 

 Male, unknown. 



Type. — Cauloxenus stygius Cope. 



{Cauloxenus, kocuXoc, a stem, and ^tvbc, a guest.) 



RemarTcs. — This genus contains but a single species which is para- 

 sitic on the blind fish, Amhylopsis spelaeus De Kay. Both the host 

 and the parasite were obtained by Professor Cope from Wyandotte 

 Cave. The parasite was fastened to the inner edge of the upper lip 

 of the fish, where it had to hold its body rigidly, by means of its pow- 

 erful second maxillae, at an angle with the fish's lip in order to keep 

 itself from being eaten. Professor Cope has given in the American 



