62 



concave from side to side ; it is rather closely covered -witli a very fine short fur, 

 beneath which the surface may be granular or nearly smooth, but the margins 

 are always granular. The regions are all well defined and are slightly tumid : 

 the gastric region is divided into 3 gently tumid subregions, the branchio-hepatic 

 regions are subdivided transversely into three areas, and the fronto-orbital 

 margin is also marked off. 



The antero-lateral border is thin and sharp and is cut into four sharp finely 

 granular teeth, the first of which runs by a long nearly transverse margin into 

 the (undefined) angle of the orbit. The front is laminar and projects beyond 

 the supra-orbital margin ; it is squai'e-cut and is slightly notched in the middle 

 line, so as to form two broad shallow lobes. The eyes are small and are to a 

 variable extent deficient in pigment. 



The chelipeds are unequal — very much more so in the male than in the 

 female : the arm to a variable extent, the entire surface of the wrist, and the 

 upper border of the hand are scabrous and more or less hairy ; the other surfaces 

 of the hand may be smooth and polished, or the outer surface may be to a 

 variable extent granular : the fingers are large, compressed and pointed. 



In the male the larger cheliped is about 2^ times the length of the carapace 

 (the hand and fingers forming slightly more than half the length) and nearly 

 half the arm projects beyond the carapace in repose. 



The legs are long slender and finely and sparsely hairy : the upper edge of 

 the meropodites is scabrous or closely spinulate. 



Colours in spirit ; chestnut brown, with blackish fingers. Length of carapace 

 (average) 11 millim., breadth 1-5 to 16 millim. 



In the Indian Museum are 29 specimens from the Bay of Bengal, 

 105-350 fms. 



Platypiltjmnus, Wood-Mason. 



PZa(ypi7umniis, Wood-Mason MS., Alcock, Ann. Mag. Nat. Hist. May, 1891, p. 401; Aloook, J. A. S. B. 

 Vol. LXVII. pt. 2, 1898, p. 232. 



Carapace hexagonal — the prominent bilaminar horizontally-projecting front 

 forming the shortest side of the hexagon — thin, depressed, perfectly flat, with 

 the regions and subregions very faintly impressed : the antero-lateral borders 

 are spinate, the postero-lateral are slightly convergent, and the posterior border 

 is long. 



Front about a third the greatest breadth of the carapace. Upper margin 

 of orbit spinate, the inner angle of the lower margin acutely spiniform. 



The antennules fold transversely. The basal antenna-joint, though of fair 

 length, does not reach the front ; the next joint lies loosely in the wide orbital 

 hiatus ; the antennary flagellum is long; about twice the major diameter of the 

 orbit. 



