370 FOSSIL REPTILES. 



Mr. Conybeare, after his first researches, had calculated 

 that there might have been, in the neck and back, a total of 

 forty-six, and even this much surpasses the number in all 

 known saurians, and even in the ichthyosaurus. 



The skeleton of Lyme exhibits in their places, thirty-five 

 evidently cervical, and supporting only small ribs articulated 

 by two tubercles, and terminating in a hatchet-form, like those 

 of the crocodile, in the same part. Then come six, whose 

 little ribs are elongated, and assume by degrees the form of 

 the dorsal ribs. The dorsal and lumbar vertebrai are a little 

 in disorder, so that it is impossible to say if their number be 

 complete or not. One-and-twenty have been counted. 



Then come twenty-three caudal vertebrae, and three appear 

 wanting towards the end, which would make them twenty-six. 

 This makes eighty-eight vertebrae in all, and Mr. Conybeare 

 adding two sacral vertebrae, makes ninety. 



In front of this series of vertebrae, is, in this skeleton, a 

 head, so small, that taking it as unity, the neck is five times 

 its length, the trunk four times, and the tail three times. 

 Thus the head does not make a thirteenth of the whole 

 length. On examining, too, the state of this trunk, and the 

 length which the vertebrae belonging to it ought to occupy, if 

 they were in line, there is reason to believe that the shoulder 

 and pelvis have been more approximated than in nature, and 

 the ribs a little mixed up, so that the trunk must have been 

 rather longer than it appears. 



It is, however, quite certain that, in the living state, the 

 plesiosaurus must have exhibited the true neck of a serpent 

 attached to a trunk whose proportions differed little from 

 those of a common quadruped. The tail from its shortness 

 has little analogy with that of reptiles, and the form of this 

 animal must have been the more extraordinary, inasmuch as 

 its extremities, like those of the ichthyosaurus, were true fins 

 or paddles similar to those of the cetacea. 



In the back, or in most part of it, the ribs have but one 



