IGUANODON. 243 
As the modern Iguana is found only in the 
warmest regions of the present earth, we may 
reasonably infer that a similar, if not a still 
warmer climate, prevailed at the time when so 
huge a Lizard as the Iguanodon inhabited what 
are now the temperate regions of the southern 
coasts of England. We know from the frag- 
ment of a femur, in the collection of Mr. 
Mantell, that the thigh-bone of this reptile 
much exceeded in bulk that of the largest 
Elephant : this fragment presents a circumfe- 
rence of twenty-two inches in its smallest part, 
and the entire length must have been between 
four and five feet. Comparing the proportions of 
this monstrous bone with those of the fossil teeth 
with which it is associated, it appears that they 
bear to one another nearly the same ratio that 
the femur of the Iguana bears to the similarly 
constructed and peculiar teeth of that animal.* 
other kinds of animal food, until happening to be near some 
kidney-bean plants that were in the house for forcing, it began 
to eat of their leaves, and was from that time forth supplied from 
these plants." In 1828, Captain Belcher found, in the island of 
Isabella, swarms of Iguanas, that appeared omnivorous; they 
fed voraciously on the eggs of birds, and the intestines of fowls 
and insects. 
* From a careful comparison of the bones of the Iguanodon 
with those of the Iguana, made by taking an average from the 
proportions of different bones from eight separate parts of the 
respective skeletons, Mr. Mantell has arrived at these dimensions 
as being the proportionate measures of the following parts of this 
extraordinary reptile : 
