TEETH OF CROCODILES. 



255 



in the existing creation, is peculiar to certain members of 

 the highest organized warm-blooded animals. 



In the other reptilia, recent or extinct, which most 

 nearly approach the mammalia in the structure of their 

 teeth, the difference characteristic of the inferior and 

 cold-blooded class is manifested in the shape, and in the 

 system of shedding and succession of the teeth; the base 

 of the implanted teeth seldom becomes consolidated, 

 never contracted to a point, as in the fangs of the simple 

 teeth of mammalia, and at all periods of growth one or 

 more genus of teeth are formed within or near the base 

 of the tooth in use, prepared to succeed it, and progressing 

 towards its displacement. The dental armature of the 

 jaws is kept in serviceable order by uninterrupted change 

 and succession ; but the forming organ of the individual 

 tooth is soon exhausted, and the life of the tooth itself 

 may be said to be comparatively short. 



If one of the conical, sharp-pointed, and two edged 

 teeth of the Gangetic crocodile, called "garrhial," by the 

 Hindoos, be extracted, its base will be found hollow, and 



Fig. 65. 



TOOTH, WITH GERMS OP SUCCESSORS, OF THE GARRHIAL [Gavialis gangeticus). 



