188 GIGANTIC TERRESTRIAL SAURIANS. 



bone upon the nose, (PI. 24, Fig. 14.) The concurrence of 

 pecuharities so remarkable- as the union of this nasal horn 

 with a mode of dentition of which there is no example, ex- 

 cept in the Iguanas, aflords one of the many proofs of the 

 universality of tlie laws of co-cxistcncc, which prevailed 

 no less constantly thronghoiit the extinct genera and species 

 of the fossil world, than they do among the living members 

 of the animal kingdom. 



Teeth. 



As the teeth arc the most characteristic and important' 

 parts of the animal, I shall endeavour to extract from them 

 evidence of design, both in their construction and mode of 

 renewal, and also in their adaptation to the office of con- 

 suming vegetables, in a manner peculiar to themselves. 

 They are not lodged in distinct sockets, like the teeth of 

 Crocodiles, but fixed, as in Lizards, along the internal face 

 of the dental bone, to which they adhere by one side of the 

 bony substance of their root. (PI. 24, Fig. 1.3.) 



The tooth of most herbivorous quadrupeds, (exclusively 

 of the defensive tusks,) are divided into two classes of dis- 

 tinct oliicc, viz. incisors and molars; the former destined to 

 collect and sever vegetable substances from the ground, or 

 from the i)aront plant; the latter to grind and masticate 

 them on their way towards the stomach. The living Igua- 

 nas, which are in great part herbivorous, afford a striking 

 exception to this economy: as their teeth are little fitted for 

 grinding, thov transmit tlicir f)od very slightly comminuted 

 into tho stomacJi. 



Our giunt Ignanodon, also, bad tooth resembling those of 

 the Iguana, and of so herbivorous a character, that at first 

 sight they were su))posed by Cuvier to be the teeth of a 

 Rhinoceros. 



The examination of these teeth will lead us to the disr 



