224 Memoirs of the Indian Museum. [Vol,. V, 



where it merges with the other granules ; the palm is rounded inferiorly and does not 

 bear the fine carinae found in D. clepsydrodactylus or D. malabarica. The cutting 

 edge of the fixed finger is serrated in its proximal half, but is without teeth. The dac- 

 tylus, which is about twice the length of the upper border of the palm, bears several 

 rows of granules and its cutting edge, in large males, is produced in the middle to 

 form an angular blade furnished with a few small serrations. When the claw is closed 

 this blade and the extreme tip are the only points in contact with the fixed finger. 

 In females the blade is entirely absent and it is relatively feebly developed in young 

 males. 



There is a small ( ' tympanum " on the outer surface of the merus of the chelipedes 

 and a large one on both upper and lower surfaces of this segment in all the walking 

 legs. The merus of the first three walking legs is expanded and the propodus, which 

 is ornamented with longitudinal rows of granules, is scarcely shorter than the dacty- 

 lus. The dactyli of all the walking legs are conspicuously grooved dorsally, that of 

 the last pair is about one-third longer than the propodus in adults (text-fig. yc), a 

 little longer proportionately in young specimens. 



The sternal plates corresponding to the chelipedes are transversely ridged at their 

 posterior end L , the remainder are smooth except for fine scattered granules. There 

 are no sternal f ' tympana." 



The distal end of the fourth abdominal segment is deeply emarginate and bears 

 the usual tuft of thick bristles overhanging the succeeding segment (text-fig. yd). 

 The abdomen of the female is closely similar to that of the male; it is scarcely 

 broader and has the same emarginate fourth segment and the same tuft of bristles. 

 It affords no protection to the eggs, which extrude on either side of it like bunches of 

 grapes. The abdomen of fully adult and ovigerous females consists of seven separate 

 segments, thus differing from de Haan' s account of Doto {=Dohlla) sulcata' 1 . 



The carapace of a large male is 5'0 mm. long, 6*4 mm. broad and 4-0 mm. deep. 

 In ovigerous females the breadth of the carapace is only 4-9 mm. 



In Alcock's key to the Indian species of Dotilla 1 , D. pertinax would take its 

 place alongside D clepsydrodactylus , Alcock, a species which was also found during 

 the survey of the Chilka Lake. From this form it may readily be distinguished by 

 several well-marked characters. In D. clepsydrodactylus there is a longitudinal mid- 

 dorsal groove on the carapace and four distinct tubercle-like elevations on the post- 

 gastric region, while the deep groove parallel with the lateral margins is simple and 

 not Y-shaped. There is a large tooth in fully adult males in the middle of the fixed 

 finger and on the lower edge of the chela, which is mueh more finely granulate exter- 

 nally, there is, even in very small individuals, a well-marked double serrated carina. 

 In the legs of the last pair, also, the propodus is much stouter and the dactylus pro- 

 portionately longer. 



] Not in the middle as in D. clepsydrodactylus. 



% De Haan, in Siebold's Fauna Japonica Crust., p. 24 (1833). 



3 Alcock, Journ. Asiat. Soc. Bengal, L,XIX, p 364. 



