274 Journal of the Asiatic Society of Bengal. [July, 1906. 
situated near the anterior extremity. The dorsal margin is 
short and straight and ends posteriorly in a sharp angle: the 
anterior, ventral and posterior margins form an . curve. 
Seen dorsally, the shell is narrow, the greatest width in front, on 
a level with the umbones. The valves are thin and rather trans- 
few lines of growth posteriorly. In all the specimens these hairs 
The dorsal edge of the tail is armed with a series of short 
rea regularly diminishing in size from in front backwards (Fig. 
: the last seven segments and 
leaving each Segment armed dorsally with a short strong spine and 
] 
Size of Shell. 
Length, Height. 
Male: 3:°0—3-25 mm. 1:85—2:0 mm. 
Female: 3°25—3-75 mm. 2-0—2'25 mm. 
Locality— 
Mandapam, Pamben Passage, South India. 
Collected by Dr. Annandale in a small rain-pool in sand, 
devoid of vegetation. The pool had been filled a week before by ® 
shower of rain. 
he species differs considerably fi ies of 
he sp y from any of the species 0 
see hitherto described from India. In the outline of the 
Shell it has some resemblance to Bstheria boysi, Baird, but the 
