287 



The teeth are of the same number at all ages, and are 

 never solid in the centre. They are pointed and enamelled ; 

 their surface is striated longitudinally, and they have a 

 cutting edge on the fore and back part. It appears that 

 they are frequently shed, since they are never found much 

 worn, in very old, or even in fossil animals. The renewal 

 of the teeth appears to be effected in this manner : the germ, 

 at the bottom of the socket, gradually enlarging on the 

 inside of the existing tooth, occasions in it a depression, and 

 then, penetrating and splitting its substance, causes it to be 

 shed. The first and the fourth teeth below, and the third 

 above, are the longest and thickest ; and then, in the cro- 

 codiles and the alligators, the eleventh below, and the eighth 

 and ninth above, are the next in size. In the gavials, the 

 rest after the fourth are nearly of the same size. The fourth 

 tooth below, it is observed by Cuvier, may bear the name of 

 the canine tooth, as it answers to the suture of the inter- 

 maxillary and maxillary bones of the upper jaw. The five 

 or six last teeth of each side are more obtuse and more com- 

 pressed than the others, and the crown is distinguished from 

 the tooth by an evident contraction ; this, however, takes 

 place only in the crocodiles and alligators ; it is not ob- 

 servable in the gavials. 



The vertebrae are sixty : seven cervicals, twelve dorsals, 

 five lumbar, two sacral, and thirty-four caudals. All the 

 vertebrae have the anterior surfaces concave and the posterior 

 convex, and both circular : and the annular part is joined to 

 the body by a suture peculiar to this genus and to the tortoise. 



The atlas is formed of six pieces, which are distinct, 

 being united only by cartilage. The axis is formed of five 

 pieces. The annular part is joined to the body of the ver- 

 tebrae by suture ; and the odontoidal apophysis is united to 

 the anterior surface by a cartilage. 



From the other cervical vertebrae proceed those little 

 false ribs or processes, which, by their pressure against each 



