348 A. Alcock — Carcinological Fauna of India. [No. 3> 



45. Ocypoda platytarsis, Edw. 

 Ocypoda platytarsis, Milne Edwards, Ann. Sci. Nat. Zool. (3) XVIII. 1852, 

 p. 141 : Kingsley, Troc. Ac. Nat. Sci. Philad. 1880, p. 180 : Miers, Ann. Mag. Nat. 

 Hist. (5) X. 1882, pp. 378, 383: Ortmann, Zool. Jahrb , Syst., X. 1897-98, pp. 359, 

 363 (ubi synon.). 



This species may be distinguished from 0. ceratopJithalma, which it 

 closely resembles, by the following characters : — 



(1) the carapace is very distinctly broader, its length being about 

 four-fifths of its breadth, and the orbits are hardly at all oblique : 



(2) the surface of the ischium of the external maxillipeds is often 

 quite smooth : 



(3) the stridulating ridge is not, or hardly at all, hairy and consists 

 entirely of granules or small mamillated tubercles ; and though the 

 upper edge of the inner surface of the ischium of the larger cheliped is 

 raised and rough, there is no special process against which the stridulat- 

 ing-ridge of the palm can be scraped : 



(4) the dactyli of the legs, though fluted as in the other species, are 

 distinctly compressed dorso-ventrally and broadened : 



(5) there are no brushes of hairs along the anterior surface of the 

 propodites of any of the legs. 



It is a somewhat larger species, the carapace in full-sized adults 

 being 40 millim. long and 54 millim. broad. 



In the Indian Museum there are 42 specimens from both coasts of 

 the peninsula and from Ceylon. 



46. Ocypoda rotundata, Miers. 

 Ocypoda rotundata, Miers, Ann. Mag. Nat. Hist. (5) X. 1882, pp. 378, 382 : 

 Ortmann, Zool. Jalirb., Syst., X. 1897-98, pp. 360, 364. 



This species differs from 0. ceratophthalma in the following impor- 

 tant particulars : — 



The carapace is less distinctly quadrilateral, owing to the fact that 

 the antero-lateral borders are arched, instead of forming an angle with 

 the upper border of the orbit. These borders sometimes form an un- 

 broken curve with the upper border of the orbit, but sometimes the 

 junction between the two is marked by a notch. The length of the 

 carapace is about five-sixths its greatest breadth, which, owing to the 

 curvature of the antero-lateral borders, is some distance behind the 

 orbits. 



There is a notch in the middle of the lower border of the orbit, and 

 a gap at the outer angle, between the upper and lower borders. 



The deflexed tip of the front is swollen. 



The spines or serrations at the inner angle of the wrist are more 

 numerous, and at the outer angle are better marked. 



