The Biology of the Crocodilia ay 
They are said by some writers to be extremely 
abundant in the waters of the upper Amazon, 
migrating to the flooded forests during the rainy 
season and returning to the streams on the approach 
of the dry season. According to Ditmars there 
are five species of caiman of which the spectacled 
caiman, C. sclerops, and the black caiman, C. niger, 
are the most striking. The former is so named 
because of the spectacled appearance due to the 
swollen and wrinkled upper eyelids; it reaches a 
length of eight feet and is said to be of a treacherous 
disposition. The latter has a blunt snout like 
the alligator and is the largest of the New World 
crocodilians. 
THE AMERICAN CROCODILE 
Of about a dozen existing species of crocodile, 
but one, the American crocodile, C. america- 
nus, is found in the United States, and it is 
limited to the swamps and coast of southern Flor- 
ida below Lake Worth; its greater sensitiveness 
to cold is doubtless the cause of its not being 
found so far north as the alligator. Its range 
extends south through Mexico and Central Am- 
erica into South America. It was first found 
in Florida by Dr. Hornaday in 1875. It sometimes 
reaches a length of fourteen feet. 
As has already been noted there is, besides cer- 
tain structural differences, a marked difference in 
