270 BULLETIN" 15 8, UNITED STATES NATIONAL MUSEUM 



ment considerably narrower than the genital segment ; anal segment 

 longer than the penultimate segment, with a wide posterior sinus; 

 caudal rami two and one-half times as long as wide, apical seta three- 

 fifths of the body length. 



Rostrum wider than long, well defined at its base, evenly rounded 

 anteriorly and tipped with two setae some distance apart and a row 

 of six stout bristles between their bases. First antennae 7-segmented, 

 the four basal segments more than twice as long as the three terminal 

 ones, the third, fourth, and seventh segments densely setose. The 

 third segment has a transverse row of six large setae across the mid- 

 dle of the dorsal surface; the fourth segment has a bunch of large 

 setae at the center of the anterior margin and a stout aesthetask at 

 its distal end, whose basal half is much widened. 



The endopod of the second antenna is distinctly 3-segmented; its 

 end segment is longer and narrower than the second segment, with 

 a row of spines along its inner margin, increasing in length out- 

 wardly and three apical setae, the two inner ones geniculate. The 

 exopod is 2-segmented, the distal segment much longer than the basal 

 and armed with two apical and two inner setae, all of equal length. 

 The maxilliped is made up of three distinct segments and a terminal 

 claw, the third segment very short, the second segment with a fringe 

 of short inner hairs, the claw the same length as the second segment. 



The endopod of the first legs is twice the length of the exopod, 

 and both rami are very slender and 2-segmented. The basal endo- 

 pod segment is five times as long as the distal segment and fringed 

 with hairs on its inner margin ; the distal exopod segment is longer 

 than the basal segment, with two apical geniculate setae and three 

 outer spines. The fourth endopod reaches the middle of the second 

 exopod segment; its end segment has one apical, one outer, and one 

 inner setae. The second endopod reaches beyond the tip of the sec- 

 ond exopod segment; its end segment has two apical and two inner 

 setae. The middle exopod segment of the second, third, and fourth 

 legs carries an inner seta. The distal segment of the fifth legs pro- 

 jects but little beyond the basal expansion, is narrowed at its base, 

 and 3-lobed at its apex, and each lobe is tipped with a seta, the inner 

 one the longest. The basal expansion is broadly rounded, with three 

 setae, the outer one the longest; the outer process of this basal seg- 

 ment is long and fingerlike, with a rather stout seta. Total length, 

 0.65-0.65 mm. 



Male. — Considerably smaller than the female, but having the same 

 general proportions. First antennae rather densely setose, the fourth 

 segment greatly swollen posteriorly and produced at its base an- 

 teriorly into a hooklike process. The fifth segment is also swollen 

 and produced laterally into coarse overlapping processes; the end 

 segment is narrow and curved like the letter S. 



