248 IGUANODON. 



proved highly satisfactory, for in an Iguana which Mr. Stutchbury had 

 prepared to present to the College, we discovered teeth possessing the 

 form and structure of the fossil specimens. 



" Like the teeth of the recent Iguana, the crown of the tooth is 

 acuminated ; the edges are strongly serrated or dentated ; the outer 

 surface is ridged, and the inner smooth and convex ; and, as in that 

 animal, the secondary teeth appear to have been formed in a hollow 

 in the base of the primary ones which they expelled as they increased 

 in size. 



** From the appearance of the fangs in such fossil teeth as are 

 in a good state of preservation, it seems probable that they adhered to 

 the inner side of the maxillae, as in the Iguanse, and were not placed 

 in separate alveoli, as in the crocodile. The teeth appear to have 

 been hollow in the young animals, and to have become solid in the 

 adult. The curved teeth probably occupied the front of the jaw ; and 

 those which are nearly straight the posterior part." (1) 



A subsequent discovery by Dr. Mantell(2) of a portion of the 

 lower jaw of the Iguanodon confirmed the previous inference as to 

 the mode of attachment of the teeth, and approximates the extinct 

 gigantic species to the Pleurodont section of Iguanians ; whence it 

 may also be inferred that the teeth were all of nearly uniform size 

 and shape, at least not divisible into laniaries and molars as in the 

 Acrodont Iguanians. 



Theportion of jaw alluded to, w^hich is now in the British Museum 

 with the rest of the Mantellian Collection, shows that the Iguanodon 

 differed from the Crocodile not only in the lateral adhesion of the 

 teeth to an alveolar wall, but in their arrangement in a close- set 

 series. 



Besides the opportunity of studying this unique fossil and the 

 extensive series of detached teeth in the British Museum, I have 

 availed myself of the kindness of Dr. Mantell and Mr. Dixon of 

 Worthing to examine the specimens in their private collections, and 

 I have been favoured by both these gentlemen with Iguanodon 's teeth 

 from which I have had sections prepared for microscopical examination. 



(1) Philos. Trans. 1825, Mr. Mantell, Notice on the Iguanodon. 



(2) Wonders of Geology, vol. 1, p. 393. 



