44 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.60 



were captured in the pound net at Beaufort, and upon one of them, 

 only 2 inches in length, were found two young female parasites of 

 the present species and one male. This extreme inequality of the 

 sexes is the more remarkable in view of the fact that other species 

 of this same genus, obtained from fish caught at the same time, were 

 about evenly divided. From these facts we may infer that the males 

 of some species can be found only upon fish which are quite im- 

 mature, and even the youngest fish are not to be overlooked as sources 

 of desirable specimens. 



Specific characters of male. — General body form short and stocky ; 

 cephalothorax as wide and almost as long as the body, with smoothly 

 convex margins, the antennal area projecting anteriorly. Eye double 

 and distinctly visible about one-third the distance from the anterior 

 margin, just behind the antennal area. Body obovate, one-fifth 

 longer than wide, bluntly pointed posteriorly. Genital segment con- 

 siderably narrower than the free thorax, but long and containing 

 large spermatophore receptacles. Abdomen much narrower than the 

 genital segment ; anal laminae short and very narrow. 



First antennae like those of the female ; second pair enlarged, with 

 a very stout basal joint and a curved terminal claw. The bases of 

 the basal joints are fused on the midline; on the inner margin above 

 the fusion is a pointed process or peg against which the tip of the 

 claw shuts when closed. Each mandible has a slender basal portion 

 and an enlarged tip, which is toothed along its inner margin, the 

 margins of the two mandibles being parallel. The first maxillae ex- 

 tend outward on either side from about the center of the base of the 

 proboscis and at right angles to its long axis. Each consists of a 

 small joint next to the proboscis, corresponding to the chewing 

 blade and armed with a single stout spine, and a larger swollen 

 joint, outside of the chewing blade, covered with hairs and tipped 

 with two spines of unequal size. 



The second maxillae are removed some distance behind the pro- 

 boscis; their basal joint is moderately swollen, their terminal joint 

 is long and slender, and is tipped with a short conical claw. The tip 

 of the terminal joint and the outer margin of the claw are armed 

 with minute spines. 



The maxillipeds consist of a very stout basal joint furnished with 

 powerful muscles, and a large terminal claw bent into a half circle. 



The first swimming legs are seen in figure 55 and are almost ex- 

 actly like those of the female, the only difference being that here the 

 two rami are about the same size, while in the female the exopod is 

 much larger than the endopod. The third and fourth legs are 

 uniramose, thick cylinders bluntly rounded at their tips, the third 

 pair about half the length of the fourth, and the latter one-fourth 

 longer than the body behind the cephalothorax. 



