I9I5-] 



Faiiihi of tlic Cliilka Lake : Cntstacca Dccapoda. 



22' 



while another groove, faint but distinct, runs transversely close to the posterior 

 margin (pi. xii, fig. 4). 



The central triangular region of the carapace, delimited by the two oblique grooves 

 mentioned above, is rather obscurely divided by shallow depressions into post-gastric 

 and cardio-intestinal areolas. The first of these is bluntly elevated anteriorly and 

 the lateral portions of both bear a few coarse and ill-defined tubercles. There is 

 no median longitudinal groove on the anterior part of the post-gastric region. The 

 elevated portions of the carapace behind the orbit also bear tubercles, while those 

 which surround the Y"Shaped lateral grooves are fineh^ granulate and set with coarse, 

 stiff setae. 



The orbital margin is sinuous and its outer angle, owing to a deep emargina- 

 tion immediately behind it, is prominent and acute in dorsal view. The trough in 

 which the eye lies is continuous beneath this point with a groove which extends along 

 the upper limit of the side-walls of the carapace. The apex of the front is narrowly 



a. 



h. 



Fig. 7. — Dolilla pertinax, sp. nov. 



a. Outer maxillipede. 



b. Chela of male. 



c. Propodus and dactylus of last leg. 



d. Abdomen of male. 



rounded and the subhepatic and pterygostomian regions are finely granular, set with 

 coarse setae, and show the characteristic convolute sulci. 



In the external maxillipedes the merus is very much larger than the ischium and 

 is deeply sulcate as shown in text-fig. ja ; the grooves cover the greater part of the 

 segment and are not restricted to its outer half as in D. hlanfordi, D. intermedia and 

 D. wichmanni. The surface is minutely granulate and bears very short stiff setae. 



Measured round the curve, the length of the chelipedes in males that appear to be 

 adult is less than twice the length of the carapace. The spine or tubercle found on 

 the under surface of the merus in D. sulcata is absent. The outer surface of the carpus 

 and chela is closely covered with large vesiculous granules (text-fig. yb) which, in 

 some specimens, also invest the inner surface of the palm. On the dorsal edge of the 

 palm the granules are often a little elongated, forming an obscurely defined double 

 ridge ; this feature, however, frequently cannot be detected. From the apex of the 

 fixed finger, on its outer side, a granular ridge extends backwards on to the palm, 



