134 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 121 



distinct concavity. Posterior sinus (fig. 49c) narrow, bearing fine 

 membrane along outer siu-face. Posterior median cephalothoracic 

 region broadly convex, projecting posteriorly well past posterior lat- 

 eral cephalothoracic region, overlapping anterior end of free fourth 

 pedigerous segment. Major dorsal cephalothoracic grooves forming 

 irregular H; dorsal surface with several spinules. Ocular region 

 distinct, pigmented cups contiguous on median longitudinal axis in 

 anterior third of cephalothorax. 



Female free fourth pedigerous segment wedge shaped, irregular 

 posteriorly, indistinctly separable from genital segment. Genital 

 segment (fig. 49(/) narrower anteriorly than posteriorly, lateral margins 

 flatly convex, posterior flatly concave. Fifth legs (fig. 49/) situated 

 on ventral-posterior lateral surface, consisting of pair of knobs, ante- 

 riormost with single pkimose setule, posterior with 2 plumose setules. 



Female abdomen indistinctly separable from genital segment, con- 

 sisting of 1 or 2 segments. Indication of 2-segmented condition given 

 by constriction anteriorly although indication superficial. Posterior 

 two-thirds of abdomen subrectangular, posterior end tapered at junc- 

 tion with caudal rami, indented at anal opening. Caudal rami (fig. 49i) 

 short, division between abdomen and rami incomplete. Lateral mar- 

 gins of rami essentially parallel, distal surface irregular, with 3 large 

 plumose setae medially, 2 plumose setules on outer surface and 1 

 on inner surface; inner lateral margin of rami lightly plumose distally. 



Male cephalothorax (fig. 49b) and free fourth pedigerous segment 

 as in female although fourth pedigerous segment of figured male 

 retracted under median posterior region of cephalothorax more than 

 in female. Genital segment (fig. 49e) barrel shaped, distinct from 

 both fourth pedigerous segment and abdomen. Fifth legs (fig. 49g) 

 situated on posterior half of lateral surface, consisting of 3 plumose 

 setules grouped as in female but without knobs. Sixth legs (fig. 49^) 

 on sHght ventral swelling posterior and medial to fifth legs, consisting 

 of 2 plumose setules. Abdomen distinctly 2-segmented, first segment 

 short, slightly more than half the length of second, second as in pos- 

 terior two-thirds of female abdomen. Caudal rami as in female. 



Female and male antennule (fig. 506) 2-segmented, attached to 

 lateral-anterior ventral surface of cephalothorax and lateral-posterior 

 ventral surface of frontal region. First segment approximately Iji 

 times the length of second, broad medially, narrower proximafly and 

 distally, distal two-thirds of anterior and anterior ventral surface 

 bearing approximately 26 lightly plumose setae and setules, including 

 1 long, anteriorly projecting seta. Second segment club shaped, 

 bearing approximately 12 naked setae and setules distally, including 

 5 long setae (length slightly shorter than length of segment). Female 

 antenna (fig. 50c) 3-segmented, situated posterior and medial to anten- 



