CRETACEOUS DINOSAURS. 263 



above the neural canal, expanding where it coalesces with its fellow, and developing out- 

 wards a broad and strong platform, n n, which sui-jDasses the base of the neurapophysis 

 both in length and breadth. The platform is chiefly supported by a buttress-like ridge, 

 which rises nearly vertically from the hinder and outer angle, n, of the base of the 

 neurapophysis, and gradually expands as it ascends, inclining a little forwards to blend 

 with the under part of the overhanging platform. The rudiment of a transverse 

 process, p, answering to the lower one or '' jmrapophT/sis,'' in the vertebra of the 

 Crocodile, (' Crocodilian PI. 1 d, fig. 3, jo,) extends from the side of the neurapophysis 

 anterior to the buttress ; its base presenting the form of an oval with the long axis 

 vertical, and the small end upwards, from which a smooth, convex prominence extends 

 upwards and forwards, and subsides on the base of the anterior zygapophysis, which is 

 developed from, or terminates, the fore-part of the neural platform. This transverse 

 process is very short, and afforded an articular surface for the head of the rib. The 

 second transverse process, answering to the upper one or " diapophysis" in the 

 vertebra of the Crocodile (lb., fig., 3 d,) which has been broken away in this specimen, 

 is better preserved in the vertebra nearest the upper border of the slab in the 

 'Dinosauria,' PI. 1, and in a few other detached vertebree. The anterior zyga- 

 pophyses scarcely project as distinct processes from the neural platform, but seem 

 to form the natural anterior boundary of that part; their thickness gradually diminishes 

 to an edge anteriorly, and their flat oval articular surfaces look obliquely upwards 

 and inwards. The posterior articular surfaces are developed from the under and 

 back part of the neural platform, and look downwards and outwards, over-hanging 

 the hinder surface of the centrum. This part of the neural arch has been somewhat 

 crushed and depressed in the vertebra which best shows its characters amongst 

 those in Mr. Bensted's specimen ; but one may see that the plane from which the 

 neural spine rises has sloped from behind downwards and forwards. The base of 

 the neural spine is coextensive with the neural platform ; from the middle line of which 

 it rises, but it contracts as it ascends, and inclines backwards ; its height is shown to 

 equal that of the> rest of the vertebra in one that lies between the humerus and femur ; 

 although it has there suffered fracture ; in the other specimens the broken summits of 

 the spines have not been preserved. 



In the characters above defined we may plainly recognise a vertebra differing from 

 any of those that have been previously described ; from those of the Crocodiles and 

 Gavials (' Crocodilian Pis. 1 D, 3, 3 A, 3 b,) in the flattened articular ends of the centrum ; 

 and by the same character from those of the Ophidian, {'Ophidian Pis. 2 and 3,) and 

 Lacertian {'Lacertia,' Pis. 1, 2, 8 and 9,) reptiles, which we have hitherto met with in the 

 Tertiary and Cretaceous deposits ; it is equally distinct from the biconical and short ver- 

 tebrae of the Ichthyosaurus, {' Enaliosauria,' PI. 7.) Were the centrum of the Iguanodon's 

 vertebra {' Di/iosaifria," PI. 3,) to be found detached from the neural arch, it might not be 

 so easy to distinguish it from that of a dorsal vertebra of a Pksiosaurus, which is similarly 



