CROCODILES AND ALLIGATORS 
153 
clusively fish-eating propensities. !' 
Full-grown examples of the gavial 
may attain to a length of 20 feet. 
The Tvnc.AL or Mississippi 
Alligator is, as its name denotes, 
a North American form, having 
the modified dental and other 
structural details previously re- 
ferred to, but otherwise in size and 
its aggressively destructive habits 
nearly corresponding with the 
Oriental crocodile. A second 
species of alligator is found in 
China. 
In the tropical South American 
rivers the place of the alligator 
is occupied by the C.\IM.\NS, some 
of which attain to huge pro- 
portions, and are distinguished 
from the former by the greater 
development of the bony armature 
of both their back and under- 
surface, and by certain essential, 
but to the lay reader obscure, 
modifications of the skull. An ex- 
ample of the Great Caiman once 
did duty as a riding-horse to the 
naturalist Waterton, as all those 
familiar with his book of travels 
will remember. 
The habits of the caiman 
differ somewhat locally. From the main stream of the Lower Amazon they are in the habit 
of migrating in the dry season to the inland pools and flooded forests. In the middle districts 
of the same river, where the drought is e.xcessive and protracted, the caimans are addicted to 
burying themselves in the mud till the rains return ; while in the upper reaches of the 
¥hoto hy Scholastic Photo. Co» 
MISSISSIPPI AND CHINESE ALLIGATORS 
T/ie Chinees ipecies, which is the smaller of the two, feeds mainly upon fish 
Amazon, where the droughts are not prolonged, the caimans are perennially present, 
eggs of these reptiles are much esteemed for food by the natives of Dutch Guiana. 
The 
CHAPTER II 
TORTOISES AND TURTLES 
T he order of the Chelonians, including the Tortoises, Turtles, and Terrapins, with their 
allies, constitutes one of the most distinct and readily defined groups of the Reptile 
Class. The more or less complete bony shell, or carapace, which encases the body, and 
into which both head and limbs can in many cases be completely retracted, separates these 
reptiles very widely from the other orders. In some respects certain details of the skull- 
structure assimilate them to the Crocodiles; but here again there is an entire absence of the 
rows of formidable teeth, the upper and lower jaws being sharply pointed, covered with horn, 
and thus converted into a trenchant beak. The two leading groups of the Tortoises and the 
Turtles are distinctly separated, by the respective conformation of their limbs, for a terrestrial 
or aquatic existence. The Tortoises have normal walking-legs, with toes and, in most instances, 
claws, fitting them for walking on the land or burrowing into the earth. In the True Turtles 
