210 Mr. Owen on some Ophidiolites from the London Clay at Sheppey. 



height. The ridge continued from the lower anterior to the lower posterior oblique 

 processes on each side is less developed in the fossil Ophidian. The oblique pro- 

 cesses themselves do not extend so far outwards ; and the spinous process is nar- 

 rower in its antero-posterior extent, but longer. 



In the first two of the above-mentioned differences the fossil agrees with the 

 Linnsean genus Coluber and its subgenera, but differs from the Crotalus ; in the re- 

 maining points it differs from Crotalus, Coluber, Najia, and Trigonocephalus. The 

 long and comparatively narrow spine, the outward and backward prolongation of 

 the upper angle of the posterior oblique processes, the uniform convexity of the 

 costal protuberance, the uneven or finely-wrinkled external surface of the superior 

 arch of the vertebra, are characters which distinguish the present Ophidian vertebrse 

 from those of any other genus of the order with which I have been able to compare 

 them ; and I therefore propose to designate the species provisionally by the name 

 of Palfsophis toliapicus. 



The ribs, as in all land-serpents, are hollow. 



In some respects, as the configuration of the under surface of the body of the 

 vertebrae and in the anterior tubercle upon this surface, the fossils agree with the 

 BocB and Pythons more nearly than with the Colubri, in which the under surface 

 of the abdominal vertebrse are traversed by a median longitudinal ridge ; and in 

 none of the differences above noted can there be inferred any obstacle to the prac- 

 tice of the same arts of entrapping and modes of destroying a living and strug- 

 ghng prey. 



The largest of these Ophidiolites in Mr. Bowerbank's collection exhibits a por- 

 tion of the vertebral column suddenly bent upon itself, and indicating the usual 

 lateral flexibility of the spine. 



If we may suppose the species to have had the same number of vertebrse as the 

 existing Boas, it must have exceeded eleven feet in length, and such dimensions 

 would indicate that the species was not provided with poison-fangs. Serpents, of 

 these dimensions, exist in the present day only in warm or tropical regions, and 

 their food is by no means restricted to animals of the cold-blooded classes. The 

 remains of Birds and Mammalia are those which are most commonly found in the 

 alimentary canal of such as are brought to this country dead ; and living birds or 

 quadrupeds also constitute the favourite food of the Pythons and Boas, of similar 

 dimensions, which are exhibited in our menageries. If, therefore, there had not 

 been obtained direct evidence of both Birds and Mammals in the London clay, I 

 should have felt persuaded that they must have coexisted with Serpents of such 

 dimensions as the species of which the dorsal vertebrse and ribs are here described. 



