§ <$<• THE IGUANODON. 423 



the West Indies, I proposed the name of Iguanodon (signi- 

 fying an animal with teeth like the Iguana), for the extinct 

 reptile to which they belonged.* 



The numerous bones and teeth subsequently exhumed 

 from the strata of Tilgate Forest, Horsham, Battle, Hast- 

 ings, and other places in Sussex, and in the Isle of Wight ;f 

 and of a considerable portion of the skeleton of an indi- 

 vidual discovered in the greensand of Kent, have supplied 

 the data upon which our present knowledge of the characters 

 of the original is based. But unfortunately the form and 

 structure of the skull are still unknow r n ; and of the jaws, 

 a fragment retaining the fangs of a few teeth, is the only 

 recognizable relic. 



38. Teeth of the Iguanodon. ;[;— The first specimen 

 which arrested my attention was a portion of a large tooth 

 which, from the flat surface of the crown, had evidently 

 belonged to a herbivorous animal ; for it possessed the 

 prismatic form of a worn incisor of one of the large pachy- 



dile, spring up in the centre of the cavities of the old, and push 

 through them, but arise from near the inner part of the base, and by 

 pressure occasion the absorption of a portion of the fang of the old 

 tooth, which they ultimately displace, by destroying the adhesion to 

 the dental parapet. The teeth of the Iguana closely resemble the 

 perfect fossil tooth, (Lign. 102, fig. 2,) in form, but not in structure or 

 size ; those of the recent lizard scarcely exceeding in magnitude the 

 teeth of the common mouse. In the Iguana the crown of the tooth 

 never presents a flat surface ; it is broken or chipped off by use, but 

 not ground smooth as in the herbivora. The reason is obvious ; none 

 of the existing reptiles are furnished with cheeks or moveable cover- 

 ings to their jaws, and therefore cannot perform mastication ; their 

 food or prey is seized by the teeth and tongue, and swallowed 

 whole. 



* See my memoir " On the teeth of the Iguanodon, a newly dis- 

 covered fossil herbivorous reptile, from the strata of Tilgate Forest." 

 Philos. Trans, for 1825. 



f Geology of the Isle of Wight, p. 312. 



X Medals of Creation, vol. ii. p. 742. 



