380 FAUNA ANTIQUA SIVALENSIS. 



attaclied to the buckler. Tn Turtles, the soft Tortoises, and 

 the Terrapins, the bodies of the dorsal vertebrae are connected 

 with the vertebral plates by a bony lamella on either side 

 forming a continuous osseous canal upon the upper surfaces 

 of the bodies in which the spinal marrow is lodged. The 

 bodies of the vertebrse are consequently attached with con- 

 siderable strength to the buckler, and do not separate readily 

 when the soft parts decompose. But in the Land Tortoises the 

 only connection between the vertebral plates and the shafts 

 of the bodies is established by means of a membranous 

 lamella, there being no osseous canal for the spinal marrow, 

 which is lodged in a cavity formed by a duplicature of this 

 membranous lameUa and a groove on the ui^jDer surface of 

 the bodies. The only osseous connection is established by 

 m^eans of a thin slender splint-shaped process, given off on 

 either side from the vertebral plates to the common point of 

 union between the bodies of two vertebrae. The bodies are 

 consequently but feebly attached, their principal strength 

 arising from their bemg arranged ui an arch, and they 

 generally fall off when the soft parts decompose. The line 

 of attachment of the membrane is indicated by a ridge along 

 the axis of the plates. In all the vertebral fragments of the 

 fossil we observe precisely the same arrangement ; there is a 

 well-marked keeled ridge along the axis, indicating the line 

 of attachment of the membrane, and no indication of any 

 bony canal — nothing besides the thin sj)lint-shaped processes, 

 or new apophyses, indicating, as in the rest of the skeleton, 

 the strictly Testudo affinities of the fossil. 



The same leading resemblances are found in the sacral 

 vertebrae, which show the surfaces for the attachment of the 

 posterior and upper angles of the ilium exactly as in Testudo. 



Wliile on the vertebrae of the trunk, I may mention that 

 there are no caudal vertebrae in the collection, and that, as 

 the number of these vary iia the Chelonians from 18 to 26, the 

 restoration in the drawing has been assumed from the type 

 of the Land Tortoises, in which the tail is thick and the higher 

 number prevails. Li certain species of this genus whose 

 habits have been well observed, the tail has been noticed to 

 be used as a pivot or fifth leg to sustain them, especially 

 during the act of defaecation ; and, from the huge size of 

 the fossil, and the weight which its limbs had to sustain, 

 it is at least highly probable that natm-e gifted it with a 

 similar aid in its tail, although we have no direct evidence on 

 the point. 



We shall now pass to the special organs of progression, 

 and see how the extremities of the fossil were constructed. 

 In regard to the anterior member, no remains have yet been 



