382 FAUNA ANTIQUA SIVALENSIS. 



XXI. ON A FOSSIL SPECIES OF EMYS FROM THE 

 SEWALIK HILLS, EEFEEABLE TO THE 

 EXISTING EMTS TECTA (BELL).i 



The almost constant distinctness of species between forms 

 observed in the trne fossil state and recent ones, in the 

 mammalia and reptilia, requires that every apparent excep- 

 tional case should be rigidly examined, and have the strongest 

 evidence to sustain it. The land and fresh-water Tortoises, 

 when weU preserved in the fossil state, supply the required 

 character, for determining a case of this kind, imder much 

 more favourable circumstances, and in greater abundance, 

 than any other tribe of the reptilia or the mammalia. For, 

 with the latter, the evidence is almost invariably limited to 

 the bony skeleton : while, in the Tortoises we have, in addi- 

 tion, the characters presented by the dermal integmnent or 

 homy scutes which leave weU-marked impressions indicating 

 their form and extent, these scutes furnishing to naturalists 

 the best marks for the distinction of species in the living 

 state. 



The small Lidian species of Emys, well known under the 

 name of E. teda,^ is readily distinguished from every other in 

 the genus by the peculiar form of its carapace, which, in- 

 stead of being vaulted, as is usual in the tribe, slopes down 

 on either side from the ridge of the back, with a pitch nearly 

 equal to a right angle, resemblmg somewhat the roof of a 

 house. In addition, the three anterior vertebral scutes are 

 elevated each mto an obtuse point of which the posterior one 

 is the most prominent, so as to form an uninterrupted tri-tuber- 

 cular keel. The plastron is slightly curved leng-thwise with 

 a well-marked keel at either side, and throws off its alee in- 

 clined at a considerable angle upwards. The JE. Bellii is 

 the only other species that has anythmg of a 'tectiform' 

 carapace — but in a much slighter degree — and it is further 



' This essay was -written in 1844, but i Dinkel. Among the Sewalik specimens 



is now for tlie first time published. The 

 specimen described in it is now in the 

 British Museum, and from it the drawings 

 in Plate xxxii. have been made by Mr. 



in the British Museum there are likewise 

 specimens of other species of Emi/s as 

 well as of Trionyx and Testudo. — [Ed.] 

 2 Emys tectum in MS.— [Ed.] 



