372 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.39. 



margin, while the terminal joint has five. The arrangement of the 

 spines and setae on the other legs is as follows: Second exopod, I-O 

 I-l; II-l; II-4: endopod, 0-1; 0-2; 0-3: third exopod, I-O; I-l 

 I-l; II-4: endopod, 0-1; I-l; II-2: fourth exopod, I-O; I-l; I-l 

 II-4: endopod, 0-1 ; 0-1 ; 1-2. The fifth leg is two-jointed, the basal 

 joint triangular, with a small spine on the outer distal corner; the 

 terminal joint carries a spine at the center of the outer margin and 

 three at the tip, the central one longer than the others. 



Color, a uniform light cinnamon brown, deepening in preservatives. 



Total length, 1.80 mm. Cephalothorax, 0.65 mm. long, 0.9 mm. 



wide. Length of free segments, 0.55 mm. Length of anal seta?, 0.5 



mm. Length of egg cases, 0.85 mm. Width of genital segment, 0.3 



mm. 



Male. — General body form much longer and narrower than that 



of the female; cephalothorax nearly circular in outline, a little wider 



than long, with evenly rounded lateral and anterior margins, and a 



nearly squarely truncated posterior margin. 



Second, third, and fourth segments about the same length and 

 diminishing regularly in width, but with the bases of the swimming 

 legs projecting at the sides, and so making them appear nearly as 

 wide as the carapace. Fifth segment very short and hidden between 

 the fourth and genital segments. The latter is the same width as the 

 fourth segment, oblong, widened posteriorly, with straight sides and 

 truncated corners. 



Abdomen three-jointed, basal joint much shorter than the other 

 two, the three about the same width; anal laminae as long as the last 

 joint, twice as long as wide, evenly rounded posteriorly, and each 

 armed with five nonplumose setee, three short ones on the outer 

 margin and two longer ones at the tip, the inner one of the latter 

 being over half the entire length of the animal, the outer one a third 

 as long. 



First antennae similar to those of the female, but the basal portion 

 is not as heavily armed with setce and the tactile hairs are shorter. 

 The third joint of the second antennae is considerably more swollen 

 than in the female, and there is a similar tuft of clav/s and setae at 

 the tip of the last joint. The maxillipeds are in normal position 

 behind the other mouth parts; each consists of a fairly stout basal 

 joint with three or four short spines on its ventral surface, a very much 

 stouter second joint furnished with powerful muscles, and a long 

 slender terminal claw slightly curved and armed with fine sawteeth 

 along its inner margin. 



The swimming legs are similar to those of the female, except the 

 first and fifth pairs; in the former a stout and flattened plumose seta, 

 fully as long as either ramus, is attached to the outer margin of the 

 basal joint; in the latter each leg has but a single slender joint, tipped 

 with two non^jiumose setae. Color the same as that of the female. 



