16 TRIONYCHID^. 



tuberculate. Epiplastra small and widely separated ; entoplastron 

 forming a right or an acute angle ; plastral callosities largely 

 developed. Head moderate ; snout very short and broad ; pro- 

 boscis very short ; interorbiral space broader than the greatest 

 diameter o£ the orbit ; mandible narrowest at the symphysis. 

 Olive above, uniform or spotted with darker ; lips and throat of 

 young olive, speckled with whitish ; plastron whitish. 



Lengtli of dorsal disk 2 feet. 



Hah. Ganges, Burma, Malay Peninsula, Borneo, Philippines. 



Genus CHITRA, 

 Gray, Cat. Tort. p. 49, 1844. 



Outer extremities of the nuchal plate overlying the second 

 dorsal rib ; neural plates well developed. Limbs completely 

 exposed. Hyoplastron distinct from hypoplastron ; not more 

 thaa five plastral callosities. Bony choanae behind the orbits, 

 which are situated quite at the anterior extremity of the skull ; 

 jaws weak ; postorbital arch at least twice as broad as the diameter 

 of the orbit ; posterior border of pterygoids free, without ascending 

 process. 



A single species. 



12. CMtra indica. 



Trionyx iiidicus, Gray, Syn. Bept. p. 47. 



Trionyx asgyptiamis, var. iodicus, Gray, III. huh Zool. i, pi. Ixxx. 

 Ch'itra iudica, part., Gilnth. Ilept. B. I. p. oO. 



Chitra indica, Gray, P. Z. S. 18G4, p. (Jl, figs. ; Theoh. Cat. p. 27 ; 

 Bouleng. Cat. Chel. Sfc, p. 264. 



Costal plates eight pairs, the last well developed and forming a 

 median suture ; a single neural between the first pair of costals ; 

 plates coarsely pitted and vermiculate. Epiplastra \^idely sepa- 

 rated ; entoplastron forming an acute augle ; plastral callosities 

 largely developed. Head small, with extremely short snout ; 

 iuterorbital space considerably narrower than the greatest diameter 

 of the orbit. Olive or green above, whitish inferiorly ; dorsal disVi 

 of young with dark verraiculations ; head and neck with dark 

 longitudinal lines. 



Length of dorsal disk 2 feet. 



Hah. Ganges and Irrawaddy ; Indus ? 



Genus EMYDA, 

 Gray, 8yii. Kept. p. 49, 1831. 



Nuchal notclied at each outer end, which underlies the first 

 costal plate ; carapace large, with a series of bony plates in the 

 posterior cutaneous border and a praeuuchal marginal bony plate ; 

 neural plates well developed, seven or eight iu number, forming a 



