1899.] A. Alcock — Carcinological Fauna of India. 53 



In spirit the gastric region is purplish brown with a large yellow 

 cross. 



Size large : good specimens in the Indian Museum have the carapace 

 65 millim. in extreme length and 95 millim. in extreme breadth. 



29. Charyhdis (Goniosoma) Rivers- Andersoni, n. sp. 



Very closely related to C. crucifera^ from which it only differs in 

 coloration, in having the epibranchial regions most remarkably swollen 

 abovfe the general dorsal surface of the carapace, in having the frontal 

 teeth very acute, the first tooth of the antero-lateral border not emavgi- 

 nate, and the transverse ridges of the carapace even more obscure. 



Carapace perfectly free from pubescence, smooth and polished ; its 

 length is a little more than two-thirds its breadth ; the gastric region 

 is slightly tumid and the epibranchial regions are very strongly tumid 

 above the rest of its surface. A fine and very faint strongly-arched line 

 crosses the carapace between the last spine of either antero-lateral 

 border, and a still fainter one crosses the gastric region anteriorly : 

 these are the only lines on the carapace and are as faint in the joung 

 as in the adult. 



Front cut into 8 acute teeth — including the inner supra-orbital 

 angles — arranged in four distinct pairs, the outer pair ou either side 

 being almost spine-like. 



Antero-lateral borders quite like those of C. crucifera, except that 

 the first tooth is obliquely truncated with the inner angle very acute. 



Posterior border curved as in C. crucifera. 



Inner angle of lower border acutely dentiform : the orbits otherwise 

 as in G. crucifera. 



Chelipeds exactly as in 0. crucifera except that the hands are 

 less inclined to be tumid. 



Last pair of legs as in 0. crucifera except that the merus is hardly 

 two-thirds as broad as long. 



Abdomen in both sexes as in G. crucifera. 



Colours in spirit : salmon-red, the frontal and antero-lateral borders 

 and the boundary between the branchial and hepatic regions with 

 numerous large creamy spots ; four similar spots in a square on the 

 gastric region and a very large one on either branchial region near the 

 middle of the postero-lateral border ; fingers blood-red in their distal 

 half, the extreme tips milk-white. 



In the Indian Museum are 9 specimens from off the Konkan coast, 

 56-58 fms., on a bottom of fine sand. The carapace of the largest 

 specimen is 50 millim. in length and 78 millim. in extreme breadth. 



