Oarcinologtcal l^anna of India. 317 



The buccal cavern is square and is well separated from the pro- 

 minent epistorae : the efferent branchial channels ai-e not well defined. 

 The external maxillipeds completely close the buccal cavern : their 

 merus is square and carries the flagellum at the antero- internal ano-le. 



Chelipeds in both sexes much more massive, and in the male very 

 much longer, than the legs, which are long and slender. 



The abdomen in both sexes consists of 7 separate segments : in the 

 male the 3rd segment nearly but not quite covers the sternum between 

 the last pair of legs. 



Distribution: North-Eastern Atlantic coasts, Mediterranean basin • 

 Persian Gulf ; East Indian Archipelago. 



In the Indian Museum there is a young female, lately received by 

 myself from the Persian Gulf, of a species of Gonoplax. Apart from 

 the shortness of the chelipeds it differs from G. angnlala, of whicli we 

 have several good specimens from Europe, only in wanting the terminal 

 spine to the upper border of the meropodites of the legs. 



Subfamilies iii. & iv. RhizopiNjE & Hex.vpodin^. 



Keij to the Indian Genera. 



A. Four pairs of legs, besides the cheb'peds {Rhizopinss) : — 

 I. The antennulary flagella can be completely retracted 

 within the antennulary fossae : — 



1. The epistome is of good length fore and aft, it 



is not in any way confused with the palate but 



is commonly pi'ominent and almost verticRl : — 



i. Eyes well formed, rarely deficient in 



pigment : — 



a. Eyes in all respects perfect : front 

 straight, entire, from two- fifths 

 to half the greatest breadth' of 

 the carapace : merus of the exter- 

 nal maxillipeds nearly square Notonyx. 



h. Eyes either quite perfect or defi- 

 cient in pigment : front slightly 

 curved and notched in the middle, 

 about a third the greatest breadth 

 of the carapace : antero-external 

 angle of the morns of the exter- 

 nal maxillipeds much produced... CKRATOPtAX. 

 ii. Eyes obsolete or nearly so : — 



a. Carapace much broader than 

 long, the postero-lateral borders 



parallel TYrntocARciNus. 



h. Carapace a little bx-oader than 

 long, the postero-lateral borders 

 anteriorly-convergent XENOPHTHALMODFg, 



659 



