18 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 122 



from hub slightly forward and below center of valve; posterior ribs 

 terminating in knob with 2 small lateral pits; anterior and ventral 

 ribs not reaching outer margin of valves; shell broadest at hub of 

 radial ribs, highest near middle; valve siu-face with scattered short 

 hairs; valve margins with row^s of long hairs faintly annulated proxi- 

 mally; long hairs in row between ventral edge of valve and ventral 

 flange; false radial pore canals numerous, true radial pore canals 

 sparse; normal canals sparsely distributed over valve sm-face. 



Duplicature with 1 small bare bristle below rostrum (fig. 7a) ; 3 

 small bare bristles and 2 hu'sute bristles dorsal to caudal process 

 (fig. 1h) ; 1 short bare bristle and cluster of 3 bare bristles anterior 

 to caudal process (fig. 7c), and 2-3 medial bristles on caudal process; 

 lamellar prolongation extending outward from selvage in area of 

 caudal process (fig. 7c). 



Dimensions of adult males are as follows: 



First antenna: first joint bare; 2nd joint with 1 spinous dorsal 

 bristle and 2 groups of spines along dorsal margin; 3rd joint -with 1 

 dorsal bristle and mthout suture separating it from 4th joint (fig. 7g); 

 4th joint with 1 dorsal bristle with a few marginal hairs and 2 short 

 ventral bristles; 5th joint triangular, inserted ventrally between 4th 

 and 6th joints; sensory bristle of 5th joint \\dth about 6 filaments 

 distally and numerous filaments fringing "cup" at base; 6th joint 

 with 1 short medial bristle with marginal spines (fig. 7d)', 7th joint 

 with short bare a-bristle, medium length b-bristle with a few distal 

 filaments, and long c-bristle with distal filaments; 8th joint A\dth long 

 slender, bare d- and e-bristles and long stout f- and g-bristles, each 

 with a few filaments distally; d- and e-bristles about the same length 

 as f-bristle. The 2 ventral bristles of the 4th joint were not observed 

 on all appendages examined. Some variation occurs in the spinosity 

 of the bristles on the 2nd-6th joints. 



Second antenna: exopodite Anth 9 joints decreasing in width dis- 

 tally; 1st joint mth short, recurved medial bristle on temiinal margin; 

 2nd-9th jomts each with 1 long, stout bristle with marginal hairs; 

 9th joint with 1 medimn and 1 long bristle, each udth marginal hairs; 

 2nd-5th joints with comb of short spines along terminal margin. 

 Endopodite 3-jointed (figs. 7c, f); 1st joint with 2 annulate spinous 



