IGUANODON. 
245 
Teeth, 
As the teeth are the most characteristic and 
important parts of the animal, I shall endeavour 
to extract from them evidence of design, both 
in their construction and mode of renewal, and 
also in their adaptation to the office of consum- 
ing vegetables, in a manner peculiar to them- 
selves. They are not lodged in distinct sockets, 
like the teeth of Crocodiles, but fixed, as in 
Lizards, along the internal face of the dental 
bone, to which they adhere by one side of the 
liony substance of their root. (PI. 24, Fig. 13.) 
The teeth of most herbivorous quadrupeds, 
(exclusively of the defensive tusks), are divided 
into two classes of distinct office, viz. incisors 
and molars ; the former destined to collect and 
sever vegetable substances from the ground, or 
from the parent plant ; the latter to grind and 
masticate them on their way towards the sto- 
mach. The living Iguanas, which are in 
great part herbivorous, afford a striking excep- 
tion to this economy: as their teeth are little 
fiUed for grinding, they transmit their food very 
slightly comminuted into the stomach. 
Our giant Iguanodon, also, had teeth resem- 
ling those of the Iguana, and of so herbivorous a 
eharacter, that at first sight they were supposed 
liy Cuvier to be the teeth of a Rhinoceros. 
