DR. MANTELL ON THE IGUANODON. 
193 
“ The teeth never become anchylosed to the sockets ; the great transverse diameter 
of the dentary element of the jaw above appears to have allowed of the outward 
curvature of the elongating fang, while the inner surface was maintained nearly ver- 
tical. By the same provision the germ attained a considerable size before it pressed 
upon and excavated the root of the tooth, which it was destined ultimately to displace. 
The wedge-shaped crown and the anterior serrated recurved trenchant edge, must 
have rendered the teeth in this early stage very efficient instruments, in the absence 
of incisors, for cutting vegetable food. 
Xylograph, No. 3. 
Outer aspect. 
Xylograph, No. 4. 
Anterior 
marginal 
angle. 
Outer aspect. 
Upper molars 
of the ri^ht 
side of the jaw. 
Lower tooth ot 
the right side. 
Inner aspect. 
Successional 
coronal germ, 
Inner aspect. 
The arrangement of the upper and lower molars, and the situation of a lower 
successional germ, are shown in the above figures. In the wood-cut No. 3, two 
upper molars of the right side are represented on their external or enamelled aspect, 
and a corresponding lower molar beneath them ; in No. 4, are ,.seen the opposite or 
internal aspect, and the position of the successional germ in the fang of the lower 
tooth. 
