NO. 1404. PARASITIC COPEPODS—CALIGID.E— WILSON. 577 



Claw of the second niaxilliped less than half the lonotli of the hasal 

 joint, slender, and strongly curved at the tip. 



First thoracic legs tipped with the usual three claws but lacking 

 the seta at the inner distal corner between the three terminal claws 

 and the three posterior setfv. The claws are short and stout, all of 

 the same length, and all fringed on either side from the l)ase nearly 

 to the tip with a lamina or wing which is sharply serrate (tig. 109). 

 Second legs ordinary, save that the large spines upon the exopod are 

 each fringed with a serrate wing like those on the claws of the first 

 legs. Rami of the third legs ([uite widely separated; claw on the 

 exopod very large, nearly straight, and with a wide, nonserrate wing- 

 along either side, giving it a broadly spatulate outline. 



Fourth legs large, reaching al)out to the posterior margin of the 

 genital segment, four-jointed, with the usual five spines; but the 

 spines upon the second and third joints are much larger and longer 

 than usual, and, together with the three curved terminal spines, are 

 fringed with a wide serrate wing along either side from the tip nearly 

 to the base. There is in addition a peculiar appendage upon the outer 

 distal margin of the basal joint. This consists of a thread-like or 

 whip-like projection longer than the second joint, very pliable, and 

 apparently muscular rather than chitinoiis. It is tipped with a long- 

 plumose seta and is evidently tactile, but what other function it ma}" 

 serve is a question. The lifth legs are situated just ventral to the 

 l)ases of the egg cases, are very small, and do not project bej^ond the 

 posterior border of the genital segment. 



Total length 7 mm. Length of carapace 4 mm.; width of same 3.3 

 mm.; length of genital segment 1..5 mm.; width of same 1.7 mm.; 

 length of abdomen 1.23 nun. Egg strings broken so that their 

 length can not be determined. 



Unfortunately there is but a single specimen — a female — as the expo- 

 nent of this species. This specimen was taken at the surface under 

 the attraction of an electric light. The label is one of the United 

 States Bureau ot" Fisheries steamer Albatross labels, but no localit}" is 

 given. But the specimen differs in so many particulars from other 

 species of Caligus as to leave no doubt of its validity. There is only 

 one other species of Caligus known, C co7'y2)hcena'^ in which the abdo- 

 men has four joints, and in that species the size and proportions of the 

 free and genital segment are entirely different. The winged margins 

 on the claws and spines is another distinctive feature, and is the one 

 which has suggested the specific name. 



{alluncus — ala, a wing, and tmcus, a claw.) 



