1900.] A. Alcock — Oareinological Fauna of India. 405 



but the H-shapod mark in the middle is always plainly visible, the 

 whole surface is closely and finely punctate : there are no post-frontal 

 tubercles, but on the posterior part of either epibranchial region there 

 is a fine line running obliquely-parallel with the postero-lateral borders. 



Front prominent, laminar, slightly sinuous, its extent is two-fifths 

 the greatest breadth of the carapace. 



The antero-lateral borders are cut into 3 not very acute or distinct 

 lobes (including the outer orbital angle), of which the first is much the 

 largest, and the last much the smallest. 



Upper border of the orbit slightly sinuous : the antennules fold 

 very obliquely. The anterior border of the buccal cavern is granular 

 and a little concave. 



The exognath is long and elliptical; its breadth in the female, is 

 nearly twice that of the ischiognath. 



The chelipeds in the female (male unknown) are about as long as 

 the carapace, and their outer surface is very finely reticulate-granular : 

 inner angle of wrist pronounced, but not spiniform : palm without hair, 

 but there is a characteristic brush of stiffish hair at the tip of the fixed 

 finger on its outer surface. The fingers have broad tips, especially the 

 fixed finger, which is stouter and more strongly toothed than the dactylus : 

 the dactylus is about twice as long as the upper border of the palm : 

 the outer surface of the palm and fixed finger is traversed, near the 

 lower border, by a fine raised granular line. 



The legs have not much tomentum on the basal joints, but the 

 anterior border of the meropodites is rather thickly fringed: the subter- 

 minal denticle on the anterior border of the meropodites is small, blunt, 

 inconspicuous, or obsolescent. The 2nd and 3rd pair of legs, which are 

 the longest, are about 1| times, the 1st pair are not 1 J times, and the 4th 

 pair are little more than once, the length of the carapace. 



In the Indian Museum are two young females from a freshwater 

 stream at the base of Saddle Hill in North Andaman Island. Their 

 colour is dark mottled green. The carapace is a little over 13 millim. 

 long and about 14 millim. broad. 



93. Ptychognathus pusilla, Heller. 



Ptychognathus pusillus, Heller, Novara Crust, p. 60 : Kingsley, Proc. Ac. Nat. 

 Sci. Philad. 1880. p. 204: de Man, Notes Leyden Mns. V. 1883, p. 161, and Zool. 

 Jahrb. Syst. IV. 1888-89, p. 440, and in Weber's, Zool. Ergebn Niederl. Ost- 

 Ind. U. p. 325, and Zool. Jahrb. Syst. IX. 1895, p. 99, and X. 1898, pi. xxviii. fig. 22 : 

 Ortmann, Zool. Jahrb., Syst. VII. 1893-94, p. 712. 



This species, which was first found in the Nicobar Islands, is not 

 represented in the Museum collection and I have never seen it. 



