112 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 121 



proximately one-seventh the total length) with almost parallel sides, 

 region with indistinct evidence of division from rest of abdomen. 

 Posterior end of abdomen with concave lateral surfaces, irregularly 

 U-shaped median region, at anal opening. Caudal rami (fig. 40i) 

 subrectangular, inner margin plumose distally, distal surface with 

 3 plumose setae medially, fourth plumose seta laterally; 2 plumose 

 setules also present, one on either side of setae. 



Cephalothorax of male (fig. 406) similar to that of female. Free 

 fourth pedigerous segment of similar shape although division between 

 segment and genital segment distinct, segment bearing ridgelike 

 area of heavy sclerotization posteriorly, extending from posterior 

 end of foiu-th leg attachment surface. Genital segment (fig. 40e) 

 barrel shaped, constricted slightly anteriorly. Fifth legs (fig. 40^) 

 situated in posterior half of ventral lateral surface, consisting of 3 

 lightly plumose setules. Sixth legs (fig. 40A) situated on posterior- 

 lateral ventral siu*face, consisting of pair of lightly plumose setules 

 arising from nodule. Abdomen 2-segmented, distinct from genital 

 segment. Second segment slightly less than 1% times the length of 

 first, first subrectangular; second segment narrower anteriorly than 

 posteriorly, lateral margins flatly convex, posterior surface as in 

 female. Caudal rami as in female. 



Female antennules (fig. 416) 2-segmented, attached to lobate pro- 

 jection of lateral anterior-ventral surface of cephalothorax. First 

 segment slightly less than 1% times the length of second, broad proxi- 

 mally, tapered to narrow distal surface; distal half of anterior and 

 anterior ventral surface bearing approximately 26 lightly plumose 

 setules and setae. Second segment rod shaped, distal region with 

 approximately 12 naked setules. Male antennule similar to that of 

 female except second segment (fig. 41c) longer. Female antenna 

 (fig. 41c^) 3-segmented, situated posterior and slightly medial to anten- 

 nule base. First segment stubby, irregular, base subtriangular, 

 bearing small, heavUy sclerotized, subconical projection from outer 

 posterior surface. Second segment well developed, broader proxi- 

 mally than distally. Third segment indistinctly separable from 

 clawlike terminal process, bearing setide-like accessory process from 

 distal lateral surface and small, lappet-like process from proximal 

 posterior siuface. Male antenna (fig. 41e) 3-segmented, first segment 

 short, subovate, concave distally. Second segment club shaped, 

 narrow end distalmost, with small adhesion surface on proximal 

 anterior surface and second, ridge-shaped adhesion surface on distal 

 half of inner surface. Third segment short, indistinctly separable 

 from trifid terminal process, bearing setule-like accessory process from 

 anterior distal surface. Tines of trifid terminal process short, sit- 

 uated at distal end of process. 



