278 BULUETIN 15 8, UNITED STATES NATIONAL MUSEUM 



the metasome ; rostrum short and 3-lobed at its tip the middle lobe 

 with a short seta on either side at its base. Urosome five-ninths as 

 long as the metasome; genital segment divided into equal portions; 

 anal segment much shorter than penultimate segment, anal oper- 

 culum triangular and acuminate posteriorly; caudal rami stout, 

 slightly divergent and as long as the last two abdominal segments 

 combined, apical setae as long as the urosome; two setae close to- 

 gether at the center of the outer margin of each ramus. 



First antennae short, 6-segmented, and exceptionally stout for this 

 genus, the four basal segments widened, the second segment with a 

 row of five stout setae across its dorsal surface. The aesthetask on the 

 fourth segment is slender and much elongated ; the sixth segment is 

 three times as long as the fifth and heavily armed with setae. The 

 two endopod segments of the second antennae are about the same 

 length but the distal one is much narrower than the basal, with five 

 apical setae, of which the four outer ones are geniculate, and a row 

 of spinules along the inner margin. The exopod is attached to the 

 side of the basal endopod segment, and is very weak, 1-segmented 

 with one terminal and one lateral seta. The maxillipeds are rather 

 stout, the terminal claw the same length as the second segment, and 

 without an accessory bristle. 



The exopod of the first leg is 3-segmented, the end segment with 

 two apical geniculate setae and two outer spines ; the basal segment of 

 the endopod is five times as long as the distal segment, with scattered 

 hairs on its inner margin and a slender fingerlike process on the 

 anterior surface near the distal end; the terminal claw is short and 

 very slender and bent abruptly near its tip. The second basipod of 

 this leg has a blunt ciliated spine on its outer margin, another spine 

 on its anterior surface opposite the base of the endopod, and a longi- 

 tudinal row of stout spinules running from this second spine back to 

 the base of the segment. The rami of the second, third, and fourth 

 legs are widened, and the endopod segments are fringed with long 

 hairs on both margins, while the exopod segments have an outer 

 fringe of coarse spinules. In the second and third legs the two 

 basipod and the proximal exopod segments have also longitudinal 

 rows of coarse hairs just inside the outer margin on the surface of the 

 segments. The outer spine of these proximal exopod segments is 

 blunt and pectinate on both margins, and the outer seta of the second 

 basipod segments is set on the tip of a hairy process. The end seg- 

 ment of the second endopod has one apical, one outer, and two inner 

 setae ; the end segment of the third endopod has two apical, one outer, 

 and three inner setae; the end segment of the fourth endopod has 

 three setae — one apical, one outer, and one inner. The basal seg- 

 ment of the fifth legs is broadly diamond-shaped, its pointed end 



