562 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. xxviii. 



First maxillipeds with a rather stout basal joint and the usual slender 

 terminal joint, the two joints in this species being about the same 

 length. The two terminal claws are fringed with hairs and look more 

 like plumose seta? than like claws, and there is also a small protuber- 

 ance on the inner margin near the tip which carries a tuft of hairs. 

 The second maxillipeds have a stout basal joint, but a very weak 

 terminal claw, the tip of which is abruptly narrowed at the junction of 

 the accessory spine on the inner margin. Furca peculiar; branches 

 about the same length at the base, both increasing in width from the 

 center, giving the whole structure somewhat the outline of an hour- 

 glass. Branches flattened dorso-veutrally, as wide at the tip as at the 

 base, and considerably divergent; lumen broad, triangular. First legs 

 with three weak terminal claws, a long and slender plumose seta at the 

 posterior corner, and the usual three plumose setae along the posterior 

 border of the terminal joint. Second and third legs large and stout; 

 the spine on the last joint of the exopod of the second legs is notice- 

 ably slender and weak, while that upon the basal joint of the exopod 

 of the third legs is stout and as wide at the tip as at the base. Rami 

 of the third legs well separated, large and prominent. Fourth legs 

 small and weak, not reaching the posterior margin of the genital 

 segment; three-jointed with five spines, the terminal ones graded in 

 length from without inward, the inner one three times as long as the 

 outer. Fifth legs very rudimentary, scarcety visible in ventral view. 

 \ Male. — Carapace the same shape as in the female, but relatively 

 much larger. Free thoracic segment much more distinctly separated 

 from the genital segment and nearly as wide as the latter (fig. 52). 



Genital segment very much smaller than in the female, being onty 

 a quarter the length of the carapace; fifth legs showing plainly on the 

 lateral margins about one-third the distance from the posterior end. 

 Abdomen little more than half the width of the genital segment and 

 about one-fifth longer; two-jointed, the basal joint less than half the 

 length of the terminal. Anal laminae much larger than those of the 

 female and armed with longer seta?. The chief differences in the 

 appendages are found in the second antenna?, the ffrst maxilla?, the 

 second maxillipeds, the furca, and the third and fourth swimming legs. 



The second antenna? are larger and stouter than those of the female 

 and are branched as is usual in the males of this genus. 



The first maxilla? are fully twice as long as in the female, and are 

 strongly curved, evidently serving as secondary clasping organs. The 

 second maxillipeds are much, enlarged in both the basal and terminal 

 joints. In the center of the basal joint on the inner margin, opposite 

 the base of the accessory spine, there is a large swelling capped b} T a 

 small hemispherical plate with a roughened surface. This aids in the 

 prevention of slipping, and shows that these maxillipeds with the sec- 

 ond antenna? are manifestly the chief organs of prehension (fig. 57). 



