534 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 94 



and wide as the genital segment; caudal rami very short, each tipped 

 with three setae. The abdomen is on a level with the dorsal surface of 

 the genital segment and is much thinner than the latter. ^ 



First antennae long and slender, the end segment tipped with 

 three setae of equal length. Second antenna 3-segmented and tipped 

 with a long claw, bent at right angles near its tip, which is very 

 acuminate. First maxilla in the form of a simple, straight, and slen- 

 der spine with an acuminate, not a bipartite, tip. Maxilliped with 

 a long and slender basal segment, which is twice the length of the 

 terminal claw. The latter is rather weak but well curved with an 

 accessory spine on the concave margin near its center. The basipod 

 of the first leg carries the rudiment of an endopod at the distal pos- 

 terior corner, which is club-shaped and covered with short hairs. 

 The fourth leg is 4-segmented, the basal segment swollen but little, the 

 three terminal segments combined about as long as the basal segment, 

 each with a long slender spine at its outer distal corner and the end 

 segment with two other longer terminal spines and a very short one 

 at the inner corner. There are rudimentary fifth legs on the ventral 

 surface of the genital segment in front of the bases of the egg strings. 

 Each consists of a small semicircular knob tipped with 3 setae and a 

 short distance outside the knob on the ventral surface of the genital 

 segment is another single seta. Total length, 3.50 mm. Carapace, 

 1.60 mm. long and wide. Egg strings, 1.80 mm. 



^/rt/^._Carapace a little more than half the entire length, which 

 is much less than in the female and as long as wide. The lobes and 

 dorsal markings are like those of the female except that the lateral 

 lobes are relatively wider. The free segment is a fifth as long and 

 wide as the carapace and the genital segment is barrel-shaped, nearly 

 half as long as the carapace, the anterior end narrowed more than the 

 posterior, the sides strongly convex. There are two pairs of leg rudi- 

 ments, one just behind the center of the segment and the other at the 

 posterior corners. The abdomen is l-segmented, two-fifths as long, 

 half as wide, and fully as thick as the genital segment. The caudal 

 rami are small, well separated and divergent, each with three setae. 



The antennae, mouth parts, and swimming legs are like those of the 

 female except that the claw on the second antenna is very much stouter 

 with a strongly swollen base and three blunt coarse spines on the con- 

 cave margin. The first three pairs of legs are like those of the female, 

 but the fourth pair are relatively longer and nearly reach the posterior 

 margin of the genital segment. Total length, 2.50 mm. Carapace, 1.30 

 mm. long and wide. 



Remarks. — This new species can be readily distinguished by the gen- 

 eral proportion of the body regions, the peculiar grooving of the dorsal 

 surface of the carapace, and the conspicuous testes in the male. 



