rLESIOSATTRlD^:. 26^ 



23812. The imperfect crown of a very similar tooth, in matrix ; 

 from the Bhaetic near Bristol. Purchased, 1842. 



23353. The imperfect crown of a tooth of similar type, in matrix ; 

 from the Bhaetic near Bristol. Purchased, 1842. 



44832. The centrum of an anterior or middle caudal vertebra of a 

 comparatively large species ; from the Bhaetic of Aust 

 Cliff, near Bristol. The terminal faces are somewhat 

 polygonal ; the chevron-facets being confined to the pos- 

 terior border. Presented by B. Bright, 2&g'.,JL873. 



R. 72. The centrum of a smaller and relatively shorter caudal ver- 

 tebra ; from Aust Cliff. 

 Transferred from the Museum of Practical Geology, 1881. 



48041. A bone of the paddle which is probably either an ulnare or 

 fibulare ; from the Bhaetic of Aust Cliff. 



Presented by Sir B. Owen, K.C.B., 1860. 



Plesiosaurus bitractensis, Sauvage 1 . 



An imperfectly known form of considerable size. The centra of 

 the cervical vertebra? are comparatively short, with the terminal 

 faces deeply cupped, and the haemal surface devoid of any ridge or 

 pits, and its two foramina very minute and widely separated ; the 

 external surface is nearly smooth. 



This species was founded upon a cervical and a dorsal vertebra 

 from the Bhaetic of Autun (Saone-et-Loire), France. The dimen- 

 sions of the centrum of the former are : — length 0,042 (1*65 inches ), 

 height 0,072 (2-85 inches), width 0,080 (3-15 inches). 



Hab. Europe (France and [?] England). 



40117. Two vertebrae belonging either to the " pectoral" or lumbar 

 region of a Plcsiosaur either identical with or closely allied 

 to the present species; from the Bhaetic (Upper Triassic) 

 of " Old Passage," near Bristol. These two specimens aro 

 joined together by matrix ; the dimensions of the larger, 

 centrum being : — length 0,042 (1*65 inches), height 0,054 

 (2-12 inches), width 0,068 (2-67 inches). The costal arti- 

 culations are single and placed partly on the arch and partly 

 on the centrum. These vertebra* present all the genera] 

 characters of thecervicals of /'. bitractensis, but if belonging 

 t<> the i; pectoral " region indicate ;i small individual. 



Purchased^ L866 



Ai, ti. Soi. Qeol. v.. | iiv, art, •".. p. 20 | L8£ 



