120 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 121 



ules. Abdomen 1-segmented, elongate, indistinctly separable from 

 genital segment; with small concavity in anterior- ventral lateral 

 surface, concavity giving 2-segmented appearance but no complete 

 division indicated, either by cuticle or musculature. Posterior half 

 of abdomen broader than anterior, posterior margin angled laterally, 

 with anal concavity medially. Caudal rami (fig. 45A) width approxi- 

 mately nine-tenths the length, narrower proximally than distally, 

 distal half of inner margin plumose. Distal surface bearing 3 large 

 plumose setae medially, smaller plumose seta laterally and 2 plumose 

 setules, 1 on either side of setae. 



Male cephalothorax (fig. 436) similar to that of female although 

 slightly larger. Free fourth pedigerous segment with small, plate- 

 like lateral extensions of tergal region, attached anteriorly to place of 

 fourth leg attachment. Genital segment (fig. 43e) distinct from fourth 

 pedigerous segment, barrel shaped, posterior surface slightly irregular, 

 ventral surface with padlike swelling posteriorly. Fifth leg (fig. 43^) 

 situated on lateral ventral surface in posterior half of segment, simi- 

 lar to that of female ; sixth leg (fig. 43A) situated on posterior ventral 

 surface, consisting of nodule bearing 2 plumose setules. Abdomen 

 2-segmented, distinct from genital segment dorsally, indistinctly 

 separable ventrally. First segment approximately five-ninths the 

 length of second, subrectangular; second segment slightly narrower 

 anteriorly than posteriorly, posterior end similar to that of female. 

 Caudal rami as in female. 



Female and male antennule (fig. 446) 2-segmented, attached to 

 lateral-anterior ventral cephalothoracic surface. First segment ap- 

 proximately IK times the length of second, broad proximally, distal 

 half of anterior surface angled to narrow distal surface, bearing 

 approximately 25 plumose setae and setules. Second segment rod 

 shaped, rounded distally, distal surface bearing approximately 12 

 naked setae and setules. Female antenna (fig. 44c) 3-segmented, 

 situated medial and posterior to antennule base. First segment 

 short, squat, almost completely fused with cephalothorax, with 

 spikelike posterior projection. Second segment broad proximally, 

 narrower distally; third segment fused with clawlike terminal process, 

 bearing setule-like accessory process proximally. Male antenna (fig. 

 44(Z) 3-segmented; first segment of each antenna in close proximity, 

 structurally similar to female first segment although spinelike pro- 

 jection smaller. Second segment elongate, with adhesion surface 

 extending as band in median third of segment, segment also bearing 

 spike-shaped projection from distal third of inner surface, projection 

 with adhesion surface. Third segment indistinctly separable from 

 clawlike terminal process, with setule-like accessoiy process proximally. 



Female and male mandible (fig. 44c) 4-parted, distal part curved 



