2 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 9I 



The female. — Carapace ovate, considerably less than half the entire 

 length and strongly narrowed anteriorly, with convex lateral margins 

 and broadly rounded posterior lobes. Frontal margin with a shallow 

 median depression but no incision, the two frontal plates combined 

 less than half the width of the carapace. Lunules large, nearly circu- 

 lar, comparatively close together and scarcely projecting beyond the 

 frontal margin. Posterior sinuses narrow, median lobe less than half 

 the entire width and projecting but little behind the lateral lobes. 

 Free thorax segment small, two-thirds as wide as the median lobe of 

 the carapace, its lateral margins projecting for the attachment of the 

 fourth legs. Genital segment ovate, one-third longer than wide, nar- 

 rowed anteriorly and widest considerably behind the center, with 

 strongly convex lateral margins and broadly rounded posterior lobes, 

 which reach beyond the center of the basal abdominal segment. Abdo- 

 men two-segmented, two-thirds as long as the genital segment, the 

 two segments about the same length and width, with straight and 

 parallel sides. Caudal rami small, parallel, slightly widened at their 

 distal end, each armed with five short setae. 



First antennae with a stout basal segment and a short and slender 

 terminal segment. Second antennae rather stout, the strong terminal 

 claw bent into a half circle and armed with a large spine on its inner 

 surface near the base (fig. 3). First maxilla of the usual pattern; 

 second maxilla long and slender, the proximal segment enlarged at 

 its base, the distal segment with a knifelike process on its inner margin 

 beyond the center, and tipped with two unequal curved claws. Maxil- 

 liped stout, the basal segment with a tiny spine on its inner surface, 

 the terminal claw curved into a semicircle and sharply pointed (fig. 5). 



First legs with a rudimentary two-segmented endopod on the pos- 

 terior margin of the basipod (fig. 8) ; the exopod is two-segmented, 

 the terminal segment without the usual setae on its posterior margin. 

 The furca has an elongated U-shape, the prongs nearly parallel and 

 about as long as the basal portion. Second and third legs of the 

 customary pattern, but with exceptionally long setae ; fourth legs 

 three-segmented, the basal segment longer than the other two com- 

 bined, the middle segment the shortest. The basal and second seg- 

 ments each carry a spine at the outer distal corner, the terminal seg- 

 ment has three spines on its outer margin and one at the tip. Each 

 of these spines has at its base a small semicircular lamina fringed 

 with hairs. No rudimentary fifth legs can be detected anywhere on 

 the genital segment. Total length 4.50 to 4.75 mm. Length of carapace 

 2 mm, width 1.90 mm. Length of genital segment 1.65 mm. Length 

 of abdomen 1.16 mm. 



