333 Proceedings of the British Association. 



Wight, and with those preserved in the slab containing the Maid- 

 stone Iguanodon, Prof. O. stated it to be his opinion, that the 

 animal did not possess the pecuharity of having the fore legs pro- 

 vided with compressed, and the hind legs with depressed claws, 

 but that the narrow compressed curved claws occasionally found 

 in the Wealden, belonged to another extinct reptile. This sec- 

 tion of the Report concluded with a notice of all the British 

 localities, and the strata in which those remains had been discov- 

 ered. The anatomical peculiarities of the Hylseosaurus, another 

 large extinct reptile of the Wealden clay, discovered by Dr. Man- 

 tell, were next described ; and an account of the microscopical 

 structure of the dermal bones was given. This remarkable rep- 

 tile combines the sub-biconcave structure of the vertebrae, with 

 crocodilian scutee, and a plesiosauroid form of the scapular arch. 

 The teeth not uncommonly found in the Wealden strata, for- 

 merly supposed to belong to the Phytosaurns cylitidricodon of 

 Jaeger, and more recently to the genus Rhopalodon of Fischer 

 de Waldheim, Mr. O. showed to be quite distinct from both, and 

 stated that if they were not the teeth of the Hylceosaur, they 

 must belong to some unknown genus of Lacertine Saurian. The 

 remains of the genera Thecodon and PalcBosaur, from the mag- 

 nesian conglomerates near Bristol, and of the genus Cladeiodon 

 from the Keuper sandstone of Warwickshire, were next described. 

 These were the most ancient of the Saurians yet discovered in 

 Great Britain, and although they differ from modern Lacertians 

 in the implantation of their teeth in distinct sockets, agreed with 

 them in the form and structure of the teeth. The last genus of 

 Saurians described, [Rhynchosaurus, O.) is new to science, and 

 the remarkable peculiarities of its cranial anatomy, together with 

 its vertebral characters, and the structure of the ribs, and some of 

 the long bones, were given in detail. Characters of the croco- 

 dile, lizard and tortoise were combined in the forms and connex- 

 ions of the bones of the skull, a nearly entire specimen of which 

 had been transmitted by Dr. O. Ward, of Shrewsbury, to Prof. 

 Owen from the Grinsiil quarries of the new red sandstone, where 

 the foot prints of a reptile agreeing in size with the Rhynchosau- 

 rus were not uncommon. Reasons were adduced showing the 

 high probability that they were the foot prints of the Rhyn- 

 chosaurus: they differ in shape from those of the Chirotherium, 

 which were shown, in the concluding part of the Report, to be- 



