48 A. Alcock — Carcinological Fauna of India. [No. 1, 



Chelipeds massive, longer than any of the leofs, usually a little 

 unequal : arm with spines ; the inner angle of the wrist strongly 

 spiniform, the outer angle usually armed with spinules ; palm prismatic 

 or tumid, generally with costse and some definitely placed spines ; 

 fingers strong, usually about as long as palm, strongly toothed. 



Legs compressed : in the last pair the merus and carpus are 

 shortened and broadened (the merus usually having a spine at the far 

 end of the posterior border) and the propodite and dactylus typically 

 foliaceous for swimming. 



The abdomen is as in Neptunus. 



Although the name Gharybdis has the priority, and although I 

 cannot admit that anything short of absolute identity — letter for letter — 

 justifies any charge of " preoccupation," I regret to discard a name that, 

 like Goniosoma, has been in use without any shadow of misunderstand- 

 ing, for nearly 40 years. 



I do so only because I believe that Goniosoma, if the name be 

 accepted, might with perfect propriety be merged again in Thalamita, 

 and because, in any case, the name Goniosoma may couvenieutly be used 

 for a subgenus. 



I agree with Ortmann that Thalamonyx may quite reasonably 

 be regarded as a subgenus of Gharybdis, but for mere convenience T should 

 prefer to subdivide the latter genus into three sections, or subgenera, 

 characterized as follows : — 



I. The lobale at the external angle of the basal antenna- 

 joint joins the front and completely excludes the 

 flagellum from the orbital hiatus. The posterior angles 

 of the carapace may be accented or not, but the line 

 that bounds the dorsum of the carapace posteriorly 

 forms a curve with the postero- lateral borders. The 

 fonr median teeth of the front are not very dissimilar 

 from the two outermost on either side. No spine on 



the posterior border of the arm Goniosoma, 



II. The lobule at the external angle of the basal antenna- 

 joint is as in Goniosoma ; but the posterior border of 

 the dorsum of the carapace is straight and forms a 

 well-marked dog's-eared angle of junction with the 

 postero-lateral borders. The four median frontal teeth 

 are broad and truncated. A spine at the end of the 



posterior border of the arm Goniohellenus, 



III. The lobule at the external angle of the basal antenna- 

 joint does not nearly touch the front, so that the 

 flagellum stands in the upper part of the orbital hiatus. 

 The posterior border of the dorsum of the carapace is 

 straight and forms either an angular junction, or a 

 curve, with the postero-lateral borders. The four 



