334 



Records of the I ndiaii M useitin. 



[Vol. XVI, 



Genus Dotillopsis, 



nov. 



Text-fig. ii.— Dotillopsis hre^'. 

 farsis (de Man). 



Endopod of second maxilliped. 



This genus, which is established for Dotilla brevitarsis, de Man 

 and D. p}ofuga, Nobili, may be recognised b3' tlie following com- 

 bination of characters : — 



The carapace is cuboidal rather than globose and deeply 

 grooved above. The side- walls possess the deep convolute sculpture 



seen in Dotilla. The penultimate 

 segment of the second maxilliped 

 is but little expanded and the ulti- 

 mate segment is terminal in posi- 

 tion. The merus of the outer 

 maxilliped is longer than the ischi- 

 um and IS gyrous-sulcate. The 

 meral segments of the legs bear 

 ill-defined tympana. In the first 

 three pairs of walking legs the me- 

 rus, carpus and propodus are dense- 

 ly tomentose inferiorly. The ab- 

 domen consists of seven distinct 

 segments ; the fourth segment does 

 not overlap the fifth and does not 

 bear a brush of hairs at its distal 

 end. In the male the fifth, sixth and seventh segments are 

 narrow, the fifth not deeply constricted ; the fourth segment is 

 greatly expanded and produced on either side, its breadth being 

 nearly three times that of the fifth. In the female the abdomen 

 is broadly oval. 



Type. — Dotilla brevitarsis, de Man. 



The genus is in some respects intermediate between Dotilla 

 and Tympanomerus : it agrees with the former in the deep sculpture 

 of the upper surface and lateral walls of the carapace and with the 

 latter in the structure of the ultimate segments of the second 

 maxilliped. The abdomen differs altogether from the very 

 characteristic type found in Dotilla ; in the male it shows signs of 

 considerable specialization and has little resemblance to that found 

 in any other genus of the subfamily. 



The presence of a dense tomentum on the first three walking 

 legs, a character also found in a few species of Tympanomerus , is 

 almost certainly an adaptation to environment ; the species of 

 Dotilla are in my experience always found burrowing in clean firm 

 sand, whereas Dotillopsis brevitarsis lives in the softest mud. 

 Nobili's D. profuga, which I have not seen, probably also lives 

 in mud, being described from the Upper Sadong River in Borneo. 

 The two species of the genus may be distinguished thus ; — 



Sculpture of carapace .sharp ; frontal groove continued 

 almost to posterior margin ; palm with conspicuous 

 longitudinal carinae on its lower and inner aspects 



Sculpture of carapace indistinct ; frontal groove reaching 

 only to gastric region ; palm without longitudinal 



1. 



II 



/). brevitarsis. 



D. profiign. 



