66 



Records of the Indian Muse-um. 



[Vol. IX, 



G. Iri'juga. 



G. indopeninsiilaris. 



The following key should make it possible to distinguish the 

 Indian and Burmese species of the genus formed b}^ joining together 

 Gcoemyda {s.s.), Nicoria and Chaibassia. 



I. Species with flattened feet and dis- 

 tinctly webbed fingers and to&s. 



1. Carapace tricarinate.' Posterior or- 



bital process elongate and slender. 

 (Anterior margin of shell smooth), 



A. Second vertebral shield con- 



siderably more than half as 

 wide as first costal shield ; 

 quadrato-jugal ossified 



B. Second vertebral shield a little 



more than half as wide as first 

 costal shield; quadrato-jugal 

 absent 



2. Carapace with a single median 



carina. No temporal arch. 



A. Anterior margin of shell ser- 



rated ; second vertebral shield 

 much broader than long, at 

 least as broad as second cos- 

 tal shield 



B. Anterior margin of shell smooth ; 



second vertebral shield not 

 much broader than long, not 

 k as broad as second costal. 



a. Vertebral region arched or 

 tectiform in cross-section 

 in the adult; the w^hole 

 carapace flattaned in the 

 young 

 h Vertebral region flattened . . 

 II. Digital webs vestigial, hind feet more 

 or less club-shaped. (Carapace tri- 

 carinate). 



1. Upper jaw distinctly hooked; cara- 



pace flattened as a whole 



2. Upper jaw distinctly notched ; cara- 



pace domed 



G. spinosa. 



G. grandis. 

 G. depressa. 



G. sylvatica. 



G. tricarinata. 



As can be seen from the key, the Indian and Burmese species 

 fall readily into three groups, which perhaps may be ultimately 

 recognized as subgenera. 



I. Amphibious species with a tricarinate carapace, fully 

 webbed digits and a temporal arch, which, however, may 

 be incomplete, =iV4con<3!, Gray. 



1 In the carapace oi aged specimens the three keels maybe almost completely 

 obliterated. 



