ROOM III. MATURE LOWER TOOTH OF IGUANODON. 



237 



nodon being of a coarser and softer texture than that of other 

 reptiles. 



In a series of specimens, the abrasion of the coronal summit 

 by mastication may be traced in every stage, from the 

 slightest wearing away of the apex, and the more decided 



LIGN. 51. TOOTH OF AN IGCAKODON, WITH THE APEX SLIGHTLY WORN. 

 TILGATE FOREST, (natural size.) 



1. Front aspect, showing the longitudinal ridges, and denticulated lateral 



margins of the crown. 

 2. View of the back, or inner surface of the tooth. 



a. The denticulated margins. 



b. The apex of the crown, worn by use; 6. fig. 2, shows the obb'que smooth 



surface produced by mastication. 



c. A transverse fracture of the fang, showing a section of the pulp cavity 



occupied by the ossified remains of the pulp. 



d. Marks the inferior limit of the denticulated margin ; if a line were 



carried horizontally from d, across the tooth, the under figure would 

 represent a tooth worn down below the denticulations, and deprived of 

 its peculiar dental characters, as in Lign. 48 ; it is in this state that 

 the tooth somewhat resembles an incisor of a Rhinoceros. 



degradation observable in Lign. 51, to the tooth represented 

 in Lign. 48, and which has acquired a classical interest from 

 having been mistaken for the incisor of a Rhinoceros, in 

 which the lateral denticulations are entirely effaced, down to 

 the deciduous molar, Lign. 52, in which the crown is worn 



