6 PROCEEDESTGS OF THE NATIONAL MUSEUM vol. 121 



Hairs with either pointed or blunt ends distributed on rostral surface 

 (fig. 16), some forming row near margin of shell; slender haii-s with 

 pointed ends on posterior surface of shell, some forming row near pos- 

 terior margin (fig. Id); a long tapered hair projecting from base 

 immediately behind posterior hinge element of each valve (figs. 

 2c-e); all hairs coming through normal pore canals; radial pore 

 canals not observed. 



Dimensions: Lectotype (specimen B) greatest length 1.12 mm, 

 greatest height 0.63 mm; paralectotype (specimen C) greatest length 

 1,12 mm, greatest height 0.63 mm. Graf (1931, p. 38) gives length 

 of this species as 1.05 mm and height 0.60 mm. 



First antenna (fig. 2/): First joint with faint clusters of short 

 hairs on medial surface. Second joint with clusters of long hairs on 

 medial surface, and distally, a dorsal, ventral, and lateral bristle; 

 all bristles bare or with short hairs, none with wreaths of long hairs. 

 Third joint with a few clusters of short hairs on medial surface, and 1 

 ventral and 2 dorsal bristles, the longer dorsal bristle provided with 

 wreaths of long hairs near middle and short hairs distally; 

 other dorsal bristle and ventral bristle with short hairs. Fourth 

 joint with 2 dorsal bristles, each with wreaths of long hau-s and the 

 more proximal bristle with short hairs distally, and 4 long ventral 

 bristles sub terminally, latter bristles bare or with short hairs distally. 

 Fifth joint, inferred to be inserted ventrally between 4th and 6th 

 joints, bearing sensory bristle with broad base and provided with 

 numerous filaments. Sixth joint with single bristle on 1 limb 

 and without bristle on other limb (bristle may have been broken off 

 during dissection). End joints with 5 slender bristles and 2 long 

 stout c- and f -bristles. 



Second antenna (figs. 2g-i): Protopodite triangular with trans- 

 parent rim (fig. 2i). Exopodite (fig. 2g): 1st joint elongate; 2nd 

 joint about K length of 1st; 3rd joint about same length as 1st; distal 

 margins of joints 2-8 with comb of short spines (not shown on fig. 2g); 

 basal spines not observed. Bristle of 2nd joint about K length of 

 3rd joint, bearing short marginal spines. Bristles of joints 3-8 

 bearing natatory hairs, without marginal spines. End joint with 4 

 stout bristles with natatory hairs and 2 short slender bristles. Endop- 

 odite 3-jointed (figs. 2h,i); 1st joint with 5 bare short bristles and 

 1 long distal bristle with wreaths of long hairs near middle and short 

 spines distally; 2nd joint elongate, with 2 subterminal bristles pro- 

 vided with short spines; 3rd joint elongate, broad proximally, with 

 1 short proximal bristle and 2 longer subterminal bristles; tip with 

 short spine and about 5 serrate ridges. 



Mandible (figs. 2j-l, 3a, b) : No coxale endite observed. Basale 

 (fig. 36): ventral margin with 3 short slender spinous bristles, and 2 



