ROOM III. VERTEBRAE OF MOSASAURUS. 197 



of the premandibular part of the lower jaw, with fifteen 

 teeth, seven of which have the enamelled crowns perfect. 

 Near it there is a fragment of another jaw with three mature 

 teeth, and the germs of as many successional ones. These 

 valuable fossils were presented to the British Museum by the 

 distinguished Dr. Peter Camper in 1784. 



Vertebrce of Mosasaurus. The only other parts of the 

 skeleton of the Maestricht reptile in the collection, are a few 

 vertebrae placed in the recess above the Geosaurus (ante 

 p. 153), which exemplify the general character of the spinal 

 column; they present the ordinary structure of the vertebrae in 

 the existing lizards and crocodiles, the body being concave in 

 front and convex behind, and the neural arch united to the 

 centrum by suture. 



The entire vertebral column appears to have consisted of 

 131 vertebrae, of which 97 belonged to the tail. The struc- 

 ture of these elements of the spine is minutely described, 

 and their homologies considered, in the classic work on the 

 fossil vertebrata, to which the collector who may obtain any 

 specimens of this kind should refer. 1 



The peculiar character of the posterior caudal vertebrae 

 requires, however, a brief notice, in consequence of the 

 interesting discovery which I had the good fortune to make 

 in 1820, of the occurrence of remains of this genus in 

 another division of the cretaceous 

 formation, and far from the only 

 locality previously known. The 

 posterior caudal vertebrae of the Mo- 

 sasaurus differ from the anterior by 

 the want of transverse processes; 

 these form a large proportion of 

 the tail. Their faces are elliptical, 

 at first transverse, and then more m L l?5:_ 44 : 



and more compressed at the sides. 

 A great number are destitute of CHALK, LEWM. 



chevron bones, and in many this 



apophysis is not articulated to the body, but soldered to it, 

 so as to form a part of the bone itself; and it is attached, 



1 " Ossemens Fossiles" tome v. pp. 326334. 



