THE PEOTOEOSAURIA. 227 



rate size. The tail is long and slender, and the limbs well 

 developed, as in tlie existing Monitors. Notwithstanding 

 the length of the neck, it contained not more than nine, 

 possibly not more than seven, vertebrae, which, except the 

 atlas, are remarkably stont and strong. There are about 

 eighteen or nineteen dorsal, two (or not more than three) 

 sacral, and more than thirty caudal vertebrae. In all these 

 vertebrae the neurocentral suture is completely obliterated, 

 and the centra ai-e slightly concave at each end. The side 

 of each cei-vical vertebra, after the atlas, presents, near its 

 anterior edge, a small tubercle, with which the head of a 

 slender stylifoitn rib articulates. The transverse processes 

 of the dorsal vertebrae are very short, antero-posteriorly 

 flattened, plates, and the strong ribs are articulated with 

 them by undivided heads. The sternum has not been 

 preserved. In the abdominal region of some specimens, 

 numerous short and filiform bones appear to represent, 

 and correspond with, the abdominal ribs of Plesiosauria 

 and Crocodilia. 



The spinous processes of the caudal vertebrae, up to near 

 the middle of the tail, have the ordinary structure ; but 

 beyond this point they bifurcate, so that each vertebra 

 seems to have two spinous processes, a peculiarity unknown 

 in other Lacertilia. 



The large chevi-on bones are articulated between the 

 bodies of the caudal vertebrae, as in the Crocodilia, but also 

 as in some Lacertilia, such as the Geckos. The skull is 

 presei-ved in one specimen only, and in that it is in such an 

 imperfect condition that the details of its structure cannot 

 be made out. The teeth, however, are nearly straight, 

 conical, and sharply pointed, and seem to have been im- 

 planted in distinct sockets, thoiigh there may be some doubt 

 upon this point. 



The pectoral and pelvic arches are large and strong. The 

 fore limbs are shorter than the hind limbs, and each limb 

 bears five digits. The manus contains certainly eight, pos- 

 sibly nine, carpal bones, five of which correspiond with the 

 metacarpals. The number of phalanges is exactly the same 



