ROOM III. VERTEBILE OF THE HYL.EOSAURUS. 317 



" the anterior part of the body is rounded, the tubercle for the 

 attachment of the rib well marked, and the transverse pro- 

 cess short and strong : its rib is near it, and shows the deep 

 bifurcation of the head, as in the Crocodiles. 



The second, third, fourth and fifth dorsals succeed, and 

 differ but little from each other; except that the third is 

 more carinated ; the fifth, which is 2^ inches long, has its left 

 rib near it ; and the latter, unlike the four other ribs, has no 

 strongly marked bifurcation, but its process sinks into a single 

 head, as in the corresponding rib of the crocodile ; and it 

 is this character which, in the absence of other evidence, has 

 been taken to determine the respective situations in the 

 column to which the vertebrae belonged. 



The second, third, fourth, fifth and sixth Ribs are seen on 

 the left side of the vertebrae ; on the right, the first, second 

 and fourth only remain ; the face of the sixth dorsal vertebra 

 is shown beneath the sternal margin of the left coracoid, and 

 one of its transverse processes appears near the fourth rib. 

 The seventh, eighth, and ninth dorsals are displaced, and lie 

 in a hollow formed by the extremities of the left ribs and the 

 corresponding Coracoid. Another vertebra of the back, 2-8 

 inches long, (perhaps the tenth,) is thrown to the left side of 

 the stone, and rests on portions of two ribs ; the body is 

 smooth and rounded, slightly arched, and its extremities, which 

 are flat, are nearly circular, and two inches in diameter. 



It is scarcely necessary to observe, that the ribs and verte- 

 brae above described are decidedly of the fossil crocodilian 

 structure ; the union of the annular part by suture occurring, 

 as M. Cuvier observes, in the living reptiles, in the crocodiles 

 and turtles only ; and if these bones were the only data from 

 which to form an opinion of the nature of the original animal, 

 we could not hesitate to assign it to some one of the fossil 

 crocodiles mentioned in a former part of this Memoir. But 

 the bones we have next to describe incontrovertibly prove that 

 the animal could not have belonged even to the same family ; 

 and they afford another striking example of that union and 

 blending, as it were, of different generic characters, which 

 geology is constantly presenting to the comparative anatomist. 



In the Crocodile, the sternum consists of a long, slender, 

 flat bone, pointed both before and behind ; and this is sup- 

 ported on each side of the middle of its lateral edges by 



