§ 22. REPTILES OF THE PERMIAN. 567 



Mr. Stutchbury, by whom they were first made known.* 

 The teeth are pointed, compressed laterally, trenchant, and 

 finely serrated on the edges. These reptiles, in their theco- 

 dont type of dentition, biconcave vertebrae, double-headed 

 ribs, and proportionate size of the bones of the extremities, 

 are nearly related to the Teleosaurus of the Oolite (ante, 

 p. 531) ; but combine a lacertian form of tooth, and struc- 

 ture of the pectoral arch, with these crocodilian characters : 

 and the bodies of the vertebrae have a series of ventricoso 

 excavations for the spinal chord, instead of a cylindrical 

 canal. | The reptile found in the Zechstein, and termed the 

 Thuringian monitor (Protorosaurus), appears to be related 

 to the thecodont saurians of Bristol. The spinous pro- 

 cesses of the dorsal vertebrae are described as remarkably 

 high, and the caudal vertebrae are characterized by double 

 diverging spinous processes.^ 



Rhojxilodon. — A fragment of a jaw with teeth, and a few 

 detached teeth, of a thecodont reptile, apparently related to 

 the Bristol saurians, are, I believe, the only reptilian remains 

 hitherto obtained from the Permian deposits of Russia. 

 They are figured and described by M. Fischer under the 

 name of Rhopalodon.§ 



From what has been advanced respecting the fossils 

 hitherto found in the Permian formation, it appears, that 

 while specifically the organic remains are distinct from 

 those of the contiguous upper and lower systems, yet they 

 present a closer relation to the ancient types, than to the 

 forms which predominate in the upper and newer deposits. 



23. Reptiles. — As with the Permian deposits, the 

 multitude of reptilian forms with which we have been 

 surrounded in our progress through the faunas of the 



* Geological Transactions, vol. v. 



f Ibid. vol. v. pi. xxix. figs. 6, 7. X Professor Owen. 



§ Sur le Ehopalodon, genre de Saurien Fossile, du Yersant Occi- 

 dental de l'Oural; par G. Fischer de Waldheim. Moscou, 1841. 



