374 FAUNA ANTIQUA SIVALENSIS. 



chelys was then described. The epistemal, or anterior por- 

 tion of the plastron, is 6^ inches thick, contracted into a 

 diameter of 8 inches, bifid at the apex, and supplied on its 

 inferior surface with a thick cuneiform keel. This keel 

 constitutes one of the principal features in the fossil. The 

 entosternal portion presents exactly the same character as in 

 the ordinary forms of Testudo, the Hke being the case in 

 regard to the xipliostemal or posterior pieces, of which there 

 was a magnificent specimen exhibited on the table. The 

 ^ Ijlastron' or breast-plate in the adult animal was estimated 

 to have been 9 feet 4 inches long. The ^carapace'' or buckler 

 portion of the shell was described as coinciding in every 

 leading character with the general form of the land-tortoises, 

 of which in fact it exhibits but a hugely magnified repre- 

 sentation. The same resemblance was found to hold good 

 in regard to the dermal covering or scutes. The shell was 

 estimated to have been about 12 feet 3 inches long measured 

 along the chord, and 15 feet 9 inches measured along the 

 curve of the back, 8 feet in transverse diameter, and about 

 6 feet high. 



The extremities were then described, and shown to follow 

 the same line of affinities as was indicated by the shell : viz., 

 to be constructed precisely as in the land-tortoises, m which 

 the form of the femur and humerus is marked by peculiar 

 characters. These bones in the fossil are of a prodigious 

 size, corresponding to the dimensions of the shell. A 

 specimen comprising the upper part of the humerus was 

 exhibited, exceeding in size the same portion of the corres- 

 ponding bone of the Indian Rhinoceros, yet so like the 

 humerus of an existing Tortoise that the outline of the fossil 

 could pass for a magnified representation of the small recent 

 bone, done by means of the pantograph. The same was 

 found to hold good in regard to the construction of the feet, 

 which are formed exactly on the plan of Testudo : viz., with 

 columnar legs and truncated club-shaped hoofs, as in the 

 proboscidean Pachydermata. The ungual phalanges or bones 

 which support the nails were shown from specimens to equal 

 the size of those of the largest Elephant. 



Dr. Falconer then described the form of the head, which, 

 like the rest of the skeleton, was closely ahied to the ordinary 

 forms of Testudo. The collection did not contain an adult 

 specimen of the head, but from the proportions of a half- 

 grown perfect specimen, the head was deduced to have been 

 2 feet long (see Plate XXXI.). The entire length of the Colos- 

 sochelys Atlas, from the tip of the head to the extremity of 

 the tail, was inferred to have been close upon 20 feet, and 

 the animal was said to have stood upwards of 7 feet high. 



