ROOM III. VERTEBRA OF PELOROSAURUS CONYBEAREI. 331 



rally referred to that stupendous creature ; for it was not 

 supposed that the remains of several genera of gigantic reptiles 

 were entombed in those previously unproductive deposits. 



These vertebrae are distinguished by their great size and 

 extreme shortness ; the antero-posterior diameter of the body 

 being but little more than three inches, and the transverse di- 

 ameter of the articular face upwards of seven inches. They are 

 doubly concave ; the anterior face being the most depressed. 

 They were ascribed by Professor Owen, ("Brit. Assoc. Reports," 

 1841, p. 101,) to a genus of marine saurians, whose vertebrae 

 and other parts of the skeleton occur in the Oolitic deposits ; 

 and which, from the presumed general 

 resemblance to the cetaceans in the short, 

 doubly concave vertebrae, and the solid 

 bones and natatory character of the extre- 

 mities, has been named Cetiosaurus : the 

 present vertebrae being described as a new 

 species, Cetiosaurus brevis. 



Referring the scientific inquirer to 

 "Philos. Trans." 1849, for the considera- 

 tions which led Dr. Melville and myself 

 to question the correctness of this deter- 

 mination, it will only be necessary to state 

 that these vertebrae are remarkably distin- 

 guished by the entire absence of projecting 

 posterior articular processes, or zygapo- 

 physes. The base of the neural spine has on the posterior 

 part a deep depression on each side, and the anterior processes 

 extend over the body of the vertebra, and are articulated to 

 the corresponding surfaces of the spinous process of the con- 

 tiguous bone. 



The following are the dimensions of the largest vertebra : 



OTHE PE . 

 tmus CONTBEAREI. 



Antero-posterior diameter of the body 



Transverse diameter 



Vertical diameter of the anterior face . 



posterior . 



Height to the top of the spinous process 

 Diameter of the neural canal . . . . 



3 inches. 



e! 



6 



13 

 2 



The general resemblance of these caudals to two vertebrae 

 found at Honfleur, struck me when I first discovered them ; 

 but the latter appear to be generically distinct; they are figured 



