COPEPODS OF THE WOODS HOLE REGION 243 



First antennae 8-segmented, longer than the cephalic segment, the 

 aesthetask on the fourth segment longer than the entire antenna. 

 The four terminal segments are less than half as long as the four 

 basal; the fourth and eighth segments are well armed with setae, 

 the others sparsely setose. The second antenna is tipped with six 

 setae, five of which are geniculate, the basal segment is not divided 

 and the 1-segmented exopod is attached to its side nearer the base 

 and carries three apical setae. The maxillipeds are rather small 

 and weak, the second segment fringed with minute hairs on its inner 

 margin. 



The first endopod is much longer than the exopod, its terminal 

 segment is narrow and more than twice as long as the second seg- 

 ment ; the spine on the second basipod over the base of the endopod 

 is long, narrow, and acuminate. The three following pairs of legs 

 are chiefly noticeable for the length of the apical setae at the tips of 

 their rami, and the rudimentary condition of the other setae. The 

 basal expansion of the fifth legs does not reach the center of the distal 

 segment, is narrowed at its tip, and carries two apical and three 

 inner setae, the inner apical seta more than twice the length of the 

 others. 



The distal segment is twice as long as wide and swollen through 

 its center ; it carries five apical setae and one on the outer margin at 

 the center, and five or six spinules on the inner margin; the second 

 inner apical seta is twice the length of any of the others. Total 

 length, 0.45-0.55 mm. 



Male. — Smaller than the female but with the same general propor- 

 tions. First antennae stouter and 9-segmented; the second segment 

 has a transverse row of setae across its dorsal surface near the distal 

 end. The aesthetask on the fourth segment is fully as wide as the 

 terminal segments and nearly as long as the whole antenna. As a 

 result under low magnification the antenna appears bifurcate at the 

 fourth segment. The first legs are stouter than those of the female ; 

 the two terminal segments of the endopod are about equal in length, 

 and the two apical setae are geniculate. The spine on the second 

 basipod over the base of the endopod is transformed into a stout 

 club-shaped process, with a well-defined chela at its tip. This is 

 evidently used as a prehensile organ and is more or less character- 

 istic of the genus, corresponding spines of a different pattern being 

 found in the species Mhemica and S'hnplex. The basal expansion 

 of the fifth legs is shorter than in the female and is armed with five 

 setae all about the same length ; the distal segment has two subequal 

 apical setae, two on the inner and two on the outer margin. Total 

 length, 0.-^0.45 mm. 



