Fig. 37.—Emydes Caspica.
Fig. 38.—Chelys matamata.
The Emydes are divided into four considerable groups, namely, the European group, of which [Fig. 37], E. Caspica, is typical; the American group, containing twelve or fourteen species; the African Emys; and the Oriental group of twelve species.
The Pleuroderes have the neck retractile on one side of the carapace, without their having the power of drawing it between their fore feet, and under the buckler and plastron, like the Cryptoderes. Chelys matamata ([Fig. 38]) belongs to this division. This species lives in stagnant water, and is altogether remarkable for its singular appearance—for its depressed, wide, and triangular nostrils, prolonged into a proboscis; its wide gape, rounded jaws, and the cutaneous appendages to the chin. This is sometimes called the Bearded Tortoise.
Potamians, or River Tortoises.
The River Tortoises live constantly in the water, only coming to land occasionally; they swim with much ease below and on the surface. The carapace is very broad and flat; the toes united up to the claws by broad flexible membranes. These membranes change the feet into true paddles, which perform the office of oars. They seem to attain a considerable size, one kept by Pennant for three months weighing twenty pounds, its buckler not reckoned; the neck measuring twenty inches in length. The upper parts of their bodies vary in tint from brown to grey, with irregularly marbled, dotted, or ocellated spots; the underpart is a pale white, rosy, or purple tint. Sinuous brown, black, or yellow lines are symmetrically disposed on the right and left, principally on the neck and on the limbs.
During the night, when they think themselves safe, the River Tortoises seek repose on the rocks and islets, or on timber floating in the rivers, from which they plunge into the water on the slightest noise. These Tortoises, which accommodate themselves so perfectly to the medium that they inhabit, are continually at war with the fishes, reptiles, mollusks, and other denizens of the rivers. They are voracious and active, and are relentless enemies to the young of fishes, and especially of Crocodiles.
The carapace of the River Tortoise, Trionyx, is soft, covered with a flexible cartilaginous skin resting on a greatly-depressed osseous disk; its upper surface is covered with shrivelled sinuosities. As they are destitute of scales these Tortoises are said to be soft; their flesh is much esteemed, and they are angled for with hook and line, baited with small fishes or living worms and mollusks, or with dead bait, to which the sportsman gives motion and apparent life, for they are said never to approach dead prey. When they seize their victim, or defend themselves, they dart out their head and long neck with great rapidity, biting sharply with their trenchant beak, and holding on till they have bitten out the piece. From this peculiarity they are commonly known in the United States as the Snapping Turtle. Persons wading have been known to lose toes from their bite.
