174 Proceedings of the Asiatic Society. [No. 2. 



" The plastron or sternal portion of the shell affords the chief distinctive 

 character. The episternal portion in the adult is six and a half inches 

 thick, and contracted into a diameter of eight inches, bifid at the apex, 

 and supplied with a thick cuneiform keel on its inferior side : this keel 

 constitutes one of the principal features in the fossil. The entosternal 

 portion exhibits exactly the form of Testudo, the same being the case with 

 the xiphiosternal or posterior portion. The plastron in the adult animal 

 was estimated to be nine feet four inches long. 



" The carapace or buckler of the shell coincides exactly with the general 

 form of the large land-tortoises, of which it exhibits only a magnified 

 representation, flattened at the top and vertical at the sides, with the 

 same outline and recurved margin. The shell was estimated to have 

 been twelve feet three inches long, eight feet in diameter, and six 

 feet high. 



" The extremities were described as constructed exactly as in the 

 land-tortoises, in which the form of the femur and humerus is marked by 

 peculiar characters. These bones in the fossil were of a huge size, 

 corresponding to the dimensions of the shell. The ungueal bones indi- 

 cated a foot as large as that of the largest Rhinoceros. The humerus was 

 more curved, and the articulating head more globular and deeper in the 

 fossil, from which it was inferred that it had a stronger articulation, 

 greater rotation, and that the Colossochelys was enabled to bring its 

 anterior extremities more under its weight than is the case with 

 existing tortoises. 



" The affinities with Testudo shown in the shell and extremities were 

 found to hold equally good in the construction of the head, of which 

 a comparatively small-sized specimen, inferred to have belonged to a 

 young or half-grown Colossochelys, was exhibited. The head of the 

 adult to correspond with the dimensions of the shell, and according to the 

 proportions furnished by a large Testudo Indica, was deduced to have 

 been two feet long. 



" There were no ascertained cervical vertebrae to afford direct evidence 

 as to the length of the neck, which was constructed in the diagram 

 relatively to the proportions of Testudo Indica. The entire length of the 

 Colossochelys Atlas was inferred to have been about eighteen feet, and 

 that it stood upwards of seven feet high. 



" The generic name given by the discoverers has reference to the 

 colossal size of the fossil (KoAocrabs et x € ' Au s)> and the specific one to its 

 fitting representation of the mythological tortoise that sustained the 

 world, according to the systems of Indiau cosmogony. 



