Beside the American form, _Alligator mississippiensis_, the only other species of alligator is found in China, along the Yang-tse-Kiang River; it is _Alligator sinensis_. It reaches a length of six feet and externally resembles its American relative; it is greenish black above speckled with yellow; grayish below. THE CAIMAN This is the nearest relative of the alligator and is found in Central America and tropical South America. As seen by the table on page 2, it is usually a small animal, though one species, the black caiman, is said to reach a length of twenty feet (Fig. 10). The nasal bones do not form a bony septum as in the alligator and the ventral armor consists of overlapping bony scutes. The canine teeth of the lower jaw fit into a pit in the upper jaw, as in the alligator. 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. americanus_, is found in the United States, and it is limited to the swamps and coast of southern Florida 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 America into South America. It was first found in Florida by Dr. Hornaday in 1875. It sometimes reaches a length of fourteen feet.