1896.] A. Alcock — Carcinological Fauna of India. 141 



II. Extreme length of the carapace about two- 



thirds of its extreme breadth : free mar- 

 gin of clypeiform expansions strongly 

 laciniate : — 



1. Carapace, in the adult, nearly smooth : 



clypeiform expansions well-developed. 



[Inhabitants of shallow water] : — 

 i. Anterior border of endostomial sep- 

 tum deeply concave : no spine in 

 the middle line, on the posterior 

 border ... ... ... C. lophos. 



ii. Anterior border of endostomial sep- 

 tum strongly convex : a spine in 

 the middle line, on the posterior 

 border ... ... ... 0. philargius. 



2. Carapace, in the adult, more or less 



covered -with pustular tubercles : clyp- 

 eiform expansions little developed. 

 [Habitat deep water] ... ... C. exanthematosa. 



III. Extreme length of the carapace very much 



less than two-thirds of its extreme 

 breadth : free margin of clypeiform ex- 

 pansions either smooth throughout, or 

 broadly dentate : — 



1. Extreme length of carapace rather more 



than half its extreme breadth : surface 

 of carapace with numerous sharpish 

 tubercles : antero-lateral border of clyp- 

 eiform expansions with broad teeth 

 the points of which are either acute 

 or have the form of up-curved spines : — 

 i. Antero-lateral border of carapace 



coarsely serrate ... ... C. hepatica. 



ii. Antero-lateral border of carapace, 

 and of clypeiform expansions, with 

 strongly up-curved spines ... G. spinosissima. 



2. Extreme length of carapace rather less 



than half its extreme breadth : surface 

 of carapace with wavy beaded lines 

 only : free edge of clypeiform expan- 

 sions smoothly moulded and entire ... C. fornicata. 



