BRITISH FOSSIL REPTILES. 7" 



In the museum of Viscount Cole, at Florence Court, there 

 are some detached vertebral centres, which, from their remark- 

 able compression in the antero-posterior direction, resemble 

 those of the Ichthyosaurus, but which combine the peculiar 

 Plesiosaurian structure with this character. 



The articular surfaces for the contiguous vertebrae are very 

 slightly concave, with a small round depression, but no convex 

 rising at the centre. The sides and under part of the body are 

 concave : the surface is tolerably smooth, and the two usual 

 vascular perforations are present at the lower part of the body. 

 I have figured one of these vertebrae from the posterior part of 

 the cervical series, where the costal articular surface is continu- 

 ous with the neurapophysial one, but has not wholly risen above 

 the centrum. 



The costal surface stands out a short way from the level of the 

 lateral surface of the vertebra in the form of a compressed ver- 

 tically elongated transverse process. 



The neurapophysial depression is shallow, occupies the whole 

 breadth of the vertebra, and presents a convex edge next the 

 spinal canal. 



The part of this canal due to the centrum is in the form of a 

 cojicave depression widened at both ends, but more so posteriorly. 



Localities. — The vertebrae here described were from the Kim- 

 meridge clay, Heddington Pits, near Oxford. 



There are similar vertebrae in the collection of the Philoso- 

 phical Society of Bristol, from the Kimmeridge clay near Wey- 

 mouth. These appear to be the vertebrae figured by Mr. Cony- 

 beare in PI. XXII. vol. i. Second Series of the Geol. Trans., 

 also from the Kimmeridge clay near Weymouth, belonging to the 

 same species. They present the same compressed form and cen- 

 tral pit on the anterior and posterior articular surfaces, and pro- 

 minent costal articular surfaces. These figures are referred to by 

 Cuvier and V. Meyer as the type of the Flesiosaurus recentior 

 of Conybeare. They are alluded to by Mr. Conybeare in a 

 subsequent memoir as belonging to the same species as the 

 gigantic fragments obtained by Professor Buckland at Market 

 Raisen, and which are provisionally indicated under the name of 

 giganteus. The most striking peculiarity of this species is, that 

 the anterior cervical vertebrae are even more compressed in the 

 antero-posterior direction than the posterior cervical vertebra 

 above described, while the vertebrae in the dorsal region regain 

 more of the ordinary Plesiosaurian proportions, although still 

 narrower in the antero-posterior direction than in any of the 

 previously described species ; hence we may conclude that the 

 neck was shorter in the PI. hracht/sjmiulyhis than in the other 



