4 FOSSIL REPTILIA OF THE 



with the original series of Megalosaurian remains, have sufficed for the determination 

 of subsequently discovered and better-preserved specimens of detached vertebrae of 

 the Megalosaurus from other localities. 



Dorsal vertebra. 



The Megalosaurus departs, perhaps even more than does the Iguanodon, from the 

 existing Crocodiles, Monitors and Lizards, in its vertebral characters. The articulating 

 surfaces of the vertebral bodies are very slightly concave, indeed almost flat, presenting 

 in that respect the type of the Amphiccelian Crocodiles : the non-articular surface is 

 remarkably smooth and polished. The centrum is much contracted in the middle, 

 presenting a deep concave outline of the under surface : the margins of the expanded 

 articular extremities are thick and rounded off. The almost cylindrical section of the 

 middle part of the vertebra arises from its being nipped in, as it were, by a more or 

 less deep longitudinal fossa on each side, just below the base of the neural arch; the 

 centrum, however, slightly expanding above the fossa to support the arch. 



The length of the base of the neurapophysis is nearly equal to that of the centrum ; 

 the suture is persistent, as in Crocodiles ; its course is undulating, and it rises in the 

 middle of the centrum. The neurapophysis ascends and inclines outwards, to form, at a 

 height above the centrum equal to three fourths its vertical diameter, the margin of a 

 broad platform of bone, from the sides of which the upper transverse processes (diapo- 

 physes) are developed, and from the middle of the upper surface the spinous process. 

 A recent discovery has shown the extraordinary development of the latter 

 apophysis in some of the anterior dorsal vertebrae. 



In the Wealden deposits at Battle, Sussex, a large nodule of the ferruginous clay 

 had been formed and consolidated around a portion of the skeleton of a Megalosaurus 

 consisting of some anterior thoracic vertebrae. In the state in which this 

 nodule was submitted to my examination, three almost entire and consecutive 

 vertebrae, wanting the ribs, were preserved in natural juxtaposition. A figure 

 of this unique specimen, discovered by S. H. Beccles, Esq., f.g.s., was, with 

 his kind permission, given in a preceding Monograph.* In a second portion 

 of the same nodule two almost entire and consecutive ribs of the right side were 

 preserved : a smaller fragment contained the bodies and neural arches of two con- 

 secutive vertebrae in natural junction from a more anterior part of the chest than the 

 series of the three vertebrae {ioc. cit., pi. xix). Two detached vertebrae, wanting the 

 spinous process, from a hinder portion of the trunk, had been obtained either from, or 

 near to, the above-described large nodule. 



* ' Palseontographical Society,' 1855, t. 19. 



