COLOSSOCHELYS ATLAS. 359 



XX. ON THE COLOSSOCHELYS ATLAS, A GIGANTIC 

 TORTOISE FROM THE SEWALIK HILLS.' 



I. — Olf SOME Remains op the Megalochelts Sivalensis, 

 A GIGANTIC Tortoise from the Tertiaet Strata 

 OP THE Sewalik Hills. ^ 



BY H. FALCONER, M.D. 



The class of Reptilia has been prolific in colossal and surpris- 

 ing forms, beyond all others ; nor are its wonders at an end. 

 Year after year has continuously added something new, till 

 air, land, and sea have alike vindicated by their representa- 

 tives the pre-eminence of Saurians above all other monsters. 

 The Iguanodon of Europe had not ceased to create astonish- 

 ment by the vastness of its dimensions, when the Basilo- 

 saurus of America comes forth to claim a higher rank, and ex- 

 hibit a reptile still more enormous ; and, when the fossiliferous 

 deposits of the tropics shall have unfolded their contents, 

 something still more may be produced. 



The analogy of nature would a priori lead to the presump- 

 tion that gigantic types of the Chelonian reptiles must have 

 formerly existed, as well as Saurian ones. We see the 

 existing species extending through the same range of habit 

 and organization, some carnivorous and some herbivorous, 

 some marine or fluviatile and others terrestrial. The same 

 analogy would lead us to infer that the largest types would be 

 found among the terrestrial and herbivorous groups, as this 

 holds among the Saurians. But, so far as we know, no very 

 immense Testudinata have hitherto been discovered, although 

 such might have been expected to be associated with the 

 Iguanodon and Megalosaurus. So much is it the reverse, 

 that the Emydes and Trionyches of the strata which have 



' Unfortunately no complete memoir 

 on the Colosscochelys was ever published, 

 and there are no drawings of this re- 

 markable fossil in the ' Fauna Antiqua 

 Sivalensis.' The documents, however, 

 now brought together remedy in a great 

 measure this defect. The remains of 

 this gigantic tortoise are preserved in 

 the British Museum, where there is also 

 a restoration of the shell. The illus- 

 trations in Plates xsx. and xxxi. have 

 been di-awn by Mr. Dinkel, from the 



specimens in the British Museum. — • 

 [Ed.] 



^ This memoir was commenced about 

 1 837, but was never finished. The fossil, 

 however, was referred to under the 

 designation Megalochelys Sivalensis, in 

 Journ. Asiat. Soc. vi. 358, 1837. The 

 name was afterwards clianged to Co- 

 lossocheli/s Atlas, 'as the term "Mega- 

 lochelys " was thought not to convey a 

 sufficiently expressive idea of the size.' 

 [Ed.] 



