1853.] Notices and Descriptions of various Reptiles. 613 



and all the vertebrals are about equally broad. Colour dull yellow 

 throughout. Presented to the museum by Dr. Allan "Webb. 



Of the numerous true Terrapins (Emts) of the Gangetic rivers, 

 only three species are common in the vicinity of Calcutta ; and adults 

 of all are rarely met with. These are — E. thurgii, Gray, which 

 attains to a much larger size than has hitherto been described, adults 

 measuring 20 to 22 in. (straight) in length of carapax ; E. tectum, 

 Gray, the adults of which measure similarly 6 in. ; and E. Hamil- 

 tonii, Gray, the adults of which measure similarly 5£ in. The only 

 other species we have yet met with from this vicinity is E. tentoria, 

 Gray, one young specimen only. This Mr. Gray describes from 

 the Bombay Dukhun, where procured by Col. Sykes; and Sir 

 Alexander Burnes obtained an adult from the Indus, which is 

 now in the Society's museum. These two specimens differ in some 

 respects from each other, also from Mr. Gray's description, and 

 from Buchanan Hamilton's coloured figure, the two latter again 

 presenting certain discrepancies one from the other. The species 

 is nearly affined to E. tectum, Bell, but at all ages has the median 

 keels to the first three vertebral plates much less developed, and the 

 form of the whole carapax is conspicuously flatter and broader. A 

 peculiarity of both species consists in the peculiar decanter-shaped 

 form of the fourth vertebral plate. Comparing the adult of E« 

 tentoria from the Indus (length of carapax, measured straight, 

 6f in.,) with an adult of E. tectum from the Hughly (carapax, 

 similarly measured, 6 in.), the first vertebral plate is proportionally 

 much broader in the former, pentagonal, narrower to the front, with 

 a broad straight transverse base posteriorly, and the keel little 

 developed ; whereas the first vertebral plate of E. tectum is penta- 

 gonal, broader to the front, with a rounded posterior base, and much 

 more developed keel. In the former, the first vertebral is considerably 

 larger and somewhat broader than the second, whereas in the latter 

 it is sub-equal or even rather smaller than the second : in adult E. 

 tentoria the second vertebral plate is hexagonal but almost square, 

 and rather broader than long, with the keel nearly obsolete; in 

 E. tectum somewhat pear-shaped, truncate to the front and narrow- 

 ing and curving off posteriorly, with the keel strongly marked : the 

 third vertebral plate of adult tentoria is quadrangular, longer by 



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