198 
ZOOLOGY. 
Order 5. Crocodilia. — The crocodile, caiman, gavial, and 
alligator are the examples of this well-known group. They 
present a decided step in advance of other reptiles, the 
heart approaching that of birds, in having the ventricle 
completely divided by a partition into two chambers; the 
venous and arterial blood mingle outside of the heart, not 
in it, as in the foregoing orders. The brain is also more 
like that of birds. The nostrils are capable of closing, so 
that crocodiles and alligators dtaw their prey under the 
water and hold them there until they are drowned; Dut they 
are obliged to dra^ them ashore in order to eat them. The 
Fig. 240.— Head of the Florida Crocodile. 
skin is covered with large bony, epidermal scales. The 
conical teeth are lodged in sockets in the jaws. The feet 
are partly webbed. The crocodiles and gavials lay from 
twenty to thirty cylindrical eggs in the sand on river banks. 
The crocodiles are distributed throughout the tropics, even 
Australia; the gavials are mostly confined to India and 
Malaysia, and also Australia. The group is represented in 
the Southern States by the alligator [A. Mississippieyisis). 
It is nearly two metres (10-12 feet) long; while the Florida 
crocodile ((7. acutus, Pig. 240) in which the jaws are much 
narrower, is over two and a half metres (14 feet) long. It 
inhabits the rivers of Florida, where it is very rare, and also 
the West Indies and South America. The cayman of 
Guiana belongs to a distinct genus, Caman, and is char- 
acteristic of the rivers of tropical South America, 
