THE IGUANODON. 



195 



and seventy feet, which is double that of the largest living crocodile. 

 But the great peculiarity of the iguanodon is the fonn of its teeth, 

 which bear a striking resemblance to the grinders of herbivorous 

 mammalia, being evidently intended for mastication, in which respect 

 it differs from all living animals of the lizard family. The herbivo- 

 rous amphibia gnaw off the vegetable productions on which they 

 feed, but do not chew them. — " Since the vegetable remains," says 

 Mr. Mantell, " with which theteetb of the iguanodon are associated, 

 consist principally of those tribes of plants that are furnished with 

 rough thick stems, and which were probably the principal food of 

 the original animal, we may be permitted to remark, that this pecu- 

 liar structure of the teeth seems to have been required, to enable 

 the animal to accommodate itself to the condition in which it was 

 placed." — The iguanodon appears also to have possessed a horn, 

 equal in size to that of the rhinoceros, and not very different from 

 it, in form : in this respect, it resembles a living species of iguana, 

 a native of St. Domingo. 



d c b 



a. h. c. represent the teeth of the iguanodon of the natural size ; 

 a is the front view of the perfect tooth of a young animal ; b is the 

 front view of a full grown tooth, with the points worn down ; c, the 

 back view of the tooth ; c?, represents a highly magnified tooth of the 

 living iguana. The reader may be surprised at the smallness of the 

 teeth of the iguanodon ; but the same proportion takes place in the 

 teeth of all reptiles. A living iguana, five feet in lengili, has teeth 

 not larger than those of a mouse, e, is a reduced drawing of the horn. 



One of the thigh bones of ihe iguanodon, in Mr. Mantell's muse- 

 um, is twenty three inches in circumference. The condyle, or joint 

 of another bone which I measured, was thirty four inches in circum- 



