210 Memoirs oj the Indian Museum. [Vol. V, 



are enlarged, again breaking the evenness of the contour. The posterior margin is 

 convex in the female; in large males it is tridentate owing to the enlargement of the 

 tubercles in the centre and at the outer angles. The infero-lateral margin of the 

 carapac(! is defined by a beaded ridge immediate^ above the bases of the legs and 

 this beading extends posteriorly from side to side across the carapace close to the 

 insertion of the first abdominal somite. There are thus, at the posterior end of the 

 carapace, two transverse rows of beading, the uppermost, which is the continuation 

 of the iDostero-lateral margins, being tridentate in the male. 



The most conspicuous feature of the dorsal surface of the carapace is a promi- 

 nent ridge, much elevated above the general surface and covered with large close-set 

 tubercles, which roughly takes the form of a " broad-arrow " with the point directed 

 forwards The point is formed by a tuberculate eminence situated in the median line 

 of the carapace a little in front of its middle point. The haft of the arrow extends 

 directly backwards in the mid-dorsal line and ends on the intestinal region before 

 reaching the po.sterior margin ; the wings reach obliquely outwards and backwards on 

 the branchial region and terminate in a sharp prominence in the anterior third of the 

 postero-lateral margin. The tuberculate elevations on the branchial and intestinal 

 regions are separated by narrow grooves from the central cardiac area. 



There is usually a .short row of large tubercles extending forwards from the 

 cardiac region on either side of the gastric area, continued with or without a brief 

 interruption as a narrow row of smaller tubercles which reaches the front near the 

 inner limit of each orbit, a short branch diverging on the outer side to the back of 

 the orbit itself. There is also a cluster of large tubercles, more conspicuous in the 

 male than in the female, in the vicinity of the first angulation on the antero-lateral 

 margin of the carapace and short row of four or five large tubercles extending trans- 

 versely outwards on either side from the granular patch on the intestinal region. The 

 areas between the granular patches are sunken and quite smooth ; among the granules 

 themselves a few sparse hairs are to be found. 



In females, especially in young individuals, the tuberculation of the carapace is 

 much stronger than in males (c/. text-fig. la and pi. xii, fig. i). 



The eyes are .small and the cornea is exposed in dorsal view ; the orbit is in open 

 communication with the antennular fossae and there is a well-marked space between 

 the edge of the floor of the orbit and the free edge of the buccal cavern. The anten- 

 nae are small but distinct. 



The buccal cavern is a little broader than long. In the external maxillipedes 

 the merus, which is pointed distally, is nearly as long as the ischium and the exopod 

 does not reach so far as the merus of the endopod and is expanded with a convex 

 external margin. 



The chelipedes are slightly longer than the carapace in the male, slightly shorter 

 in the female. The merus is more or less cylindrical, covered with vesiculous gra- 

 nules beneath and, dorsally, with granules arranged in parallel rows, a median 

 longitudinal area being left quite naked. The outer edges of the carpus and propodus 

 are very finely granulate and numerous scattered granules are to be seen on the 



