49 
are distinguished by their feet being compressed 
and fin shaped; they live principally on fuci 
and sea weeds. It is this kind of Tortoise which 
is most commonly used as food; and great 
quantities of one of the species {Test, Midas ) 
are brought to this country for that purpose. 
The horny plates of the Imbricated Turtle 
{Test, Imbricata) afford the best sort of tortoise 
shell. 
The Alligators, which are peculiar to Ame¬ 
rica, are distinguished from the Crocodiles, 
which are found in both the old and the New 
World, by their feet having the toes free, that 
is, without webs, and by the canine tooth of the 
lower jaw being received in a pit in that 
jaw, while in the Crocodiles, they are received 
in a notch on its margin. The Gavials agree 
with the Crocodiles in their teeth, but differ in 
their muzzle being very long and slender. Spe¬ 
cimens of all the three genera are in the Col¬ 
lection. The upper jaw of these animals is 
generally said to be moveable, but this is an 
error, arising from the lower jaw being much 
produced posteriorly. 
Case 2 contains those Saurian Reptiles which 
have the tongue long and deeply forked ; 
namely, the Monitors of the Old World and its 
islands. Among these are the Two Banded 
Monitor {Mon, bivittatus') from India; the 
Laced Monitor {Mon, varius ) from New Hol- 
e land; 
room x 
