48 



ME. E. LYDEKKER ON DINOSATJES OF THE WEALDEN 



known, is one of the few marine beds found in that series. The best- 

 preserved of the two specimens is represented in fig. 5 ; and it will 

 be seen therefrom that both the ribs and the neural arch were not 

 anchylosed to the centrum, from which we may probably infer that 

 the specimens belong to an individual which had not attained full 

 maturity. Apart from the fractures which they have sustained in 



rig. 5. — Anterior, right lateral, and ventral aspects of the Centrum of 

 a Dorsal Vertebra of Cimoliosaurus portlandicus ; from the Pur- 

 beck of the Isle of Portland. (|.) 



CO, costal facet. 



the process of extraction from their bed, these specimens are beauti- 

 fully preserved, and are thereby in marked contrast to the posterior 

 cervicals from the Portlandian in the collection of the British 

 Museum, all of which have suffered by rolling. The extreme pro- 

 minence of the carina on the haemal surface at once shows that 

 these specimens agree with the cervical figured by Phillips* as 

 Plesiosaurus carinatus. They are, indeed, of somewhat larger dimen- 

 sions, as is shown by the following table : — 



Phillips's Present 



specimen. specimen. 



Length 1'63 in. 1*9 in. 



Height 1-60 in. 1-9 in. 



Width 1-95 in. 2-4 in. 



* Geology of Oxford, p. 375. 



