174 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 115 



visible as very fine groove extending from junction of segments 

 medially, on each side, for about one-fourth width of region; no evi- 

 dence of division present in middle of segment. 



Genital segment swollen, lateral margins almost parallel; posterior 

 lateral regions of segment protruding as irregular lobes; lobes extending 

 to posterior lateral corners of abdomen. Median posterior surface 

 depressed. Fifth legs visible dorsally as three small, plumose setae 

 projecting from posterior lateral margin, single seta from small nodule, 

 two setae from second nodule just posterior to first (fig. 106). 



Abdomen one-segmented, width approximately equal to length; 

 widest at posterior lateral corners, margins curving medially both 

 anteriorly and posteriorly, anteriorly in convex curve to region of 

 fusion of abdomen and genital segment, posteriorly in concave curve 

 to slightly projecting anal region (fig. 106). 



Antennule two-segmented, excluding frontal plate, attached to 

 frontal region under free surface of lunule, at junction of frontal region 

 and cephalothorax. Greatest length of first segment slightly more 

 than that of second. First segment wider in proximal region 

 than at either end, tapering abruptly to proximal end, gradually to 

 distal; distal end irregular. Anterior surface with about 23 plumose 

 setae. Second segment slender, slightly wider in middle than at 

 either end. Second segment with naked seta on distal region of pos- 

 terior margin, nine naked setae from distal surface (fig. lOd). 



Second antenna three-segmented, attached posterior and slightly 

 medial to base of antennule. First segment short, forming articular 

 surface for second segment. Distal surface of first segment con- 

 cave, posterior surface protruding posteriorly as blunt-tipped, spine- 

 like projection. Second segment wider proximally than distally, 

 lateral margins convex. Greatest width of second segment slightly 

 less than greatest length. Distal margin of segment irregular, inner 

 portion with concave depression; several points of articulation present 

 as heavily chitinized regions. Third segment and terminal process 

 elongate, longer than greatest length of second segment, with two 

 accessory processes, spinelilve process on posterior sm*face of distal 

 end of segment and two-parted, sharp-tipped process on anterior 

 proximal surface of segment. Base of third segment heavily chitin- 

 ized, protruding slightly proxunally as small, rounded articular sur- 

 face. Terminal process curving sharply in distal region, distal end 

 bluntly pointed (fig. lOe). 



Mandible four-parted. Fu*st part wider proximally than distally, 

 with even taper to junction of second part. Second part short, 

 approximately one-fifth length of first part, tapered slightly to junction 

 of third part. Thkd part shghtly shorter than first part, expanded 

 slightly distally. Fourth part short, half length of first part, width 



