to the same author, it remains concealed, night being its feeding time and season of activity: and he also says, that its food consists of the herbage which grows on the borders of the rivers and lakes it frequents; adding, that the individual described by Bruguière was kept upon bread and vegetable substances. The Matamata, however, is not herbivorous, as this writer states, but carnivorous; it inhabits freshwater ponds and rivers, and conceals itself under the leaves of aquatic plants, with only the extremity of its nose, which is like a small proboscis, above the surface: in this position it awaits the approach of young birds, fishes, and small aquatic animals, which it seizes as they pass near it. It swims with rapidity, and darts eagerly on its prey.

In the character of the jaws, in the proboscis-like elongation of the nose, and in the soft and almost flexible condition of the carapace, this Tortoise evinces an affinity to the succeeding family, and may be regarded as an intermediate form between the marsh and river Tortoises.

The head is greatly depressed, and of a triangular figure, the nostrils being elongated into a sort of double tube, or proboscis; the mouth is extremely wide; the jaws are not covered with skin only, as has been supposed, but are protected by a thin sheath of horn. The eyes are small; the limbs are strong; the nails robust; the tail is short. Above the tympanum, or ear, is placed on each side a somewhat triangular membrane, and behind this, on the same line, along the neck, are four or five cutaneous appendages, with fringed edges: two pendant membraneous excrescences are immediately under the chin, and four of a larger size are placed across the throat, from the lower border of one tympanum to the other. The carapace is depressed, with a longitudinal keel down the centre, and a furrow along each side of it. The general colour of the carapace is dusky brown. When full grown, the Matamata is about two feet, six inches in total length, of which the carapace measures about fifteen or sixteen inches.

RIVER, OR FLUVIATILE TORTOISES.

THOUGH this family of the Tortoises includes but few species, forming two genera, still it is distinct and well characterized.

Like the marine Tortoises, or Turtles, the species of this group are obliged, by their structure, to live continually in the water, where they swim with great facility, by the aid of the extended and almost flat surface of the carapace, and especially by means of their feet. These are flattened and extensively webbed, being, in fact, paddles not destined for progression on the ground, but for rowing the body through the water. The toes, however, as in the marsh Tortoises, are distinguishable, and are armed with claws; and here they differ from the Turtles, which have the feet fashioned into long, compressed oars.

The river Tortoises are, then, exclusively aquatic: they seldom come on the shore, or banks of the large rivers which they inhabit, and in which they pursue their prey. In the Turtles the neck is generally short; in these animals, on the contrary, it is extremely long, and capable not only of being retracted and extended with great rapidity, but of performing lateral undulatory movements, as we see in serpents. The head is narrow, and pointed before, the jaws have sharp cutting edges, but are covered with fleshy skin resembling lips. The nasal canal is prolonged into a short flexible tube or proboscis. In the Turtles the jaws are sheathed with strong horny beaks, and they feed mostly on vegetable productions, whereas the river Tortoises are carnivorous, feeding on fish, reptiles, and mollusca.

Not less marked are the differences between the river and the marsh Tortoises, though there is a gradual transition from the latter to the former, which cannot be overlooked. In none of the marsh Tortoises, however, is the carapace entirely destitute of horny scales, as in these animals; nor have any of them lips or folds of skin covering the cutting edge of the jaws. Still these two

families closely resemble each other in habits and manners; for some genera, especially among the Pleurodera, reside almost constantly in the water, and feed upon living prey, which they pursue with cruel pertinacity. The Matamata, as already stated, is the immediate link between them: its manners and habits are the same, its carapace is broad and thin, its scales are flexible, its nostrils are tubular, the head is depressed, and the neck flattened. The essential characters of the river Tortoises are thus summed up by Messrs. Dumeril and Bibron: "Tortoises with a soft carapace, a flexible and cartilaginous expansion forming the circumference of a centre of bone, by which it is supported; the surface of this bone, which is nearly flat, is marked with inequalities, and is rough. The ribs are free at their ends, the head is narrow and elongated, and the nose terminates in a flexible proboscis; the jaws are cutting, and furnished externally with folds of skin resembling lips; the eyes are prominent, placed near together, and directed obliquely upwards. The plastron has its hinder portion short,

but is advanced anteriorly, so as to come under the neck. It is not entirely osseous, even in the centre, (see above engraving,) and it is united to the carapace by cartilage.

The tail is short and thick, the limbs robust, with large webbed feet of the toes, three on each foot only are provided with nails, which are nearly straight, and channelled underneath."

Hitherto no species of the present tribe has been found in the rivers of Europe; all those which are known to naturalists, and of which the country is ascertained, are tenants of the rivers or large fresh-water lakes of the hotter regions of the globe; the Nile and the Niger in Africa, the Euphrates and the Ganges in Asia, and the Mississippi and Ohio in America.

It would appear, that some species of the river Tortoises attain to very great dimensions. Pennant speaks of individuals weighing seventy pounds: one which he kept for three months weighed twenty pounds; its carapace was twenty inches in length. As these animals swim at the surface, or float on the water, with the carapace exposed to the sun, and the plastron shielded from the direct rays of light, a marked difference exists between the colouring of the one and the other. The carapace is generally dark-coloured, and variegated with brown, black, or yellow; but the plastron, and all the under parts are pale. In this point they resemble the sole, the turbot, or the plaice, and other flat fishes.

We have said, that river Tortoises seldom come upon the land; they never search for food there; but the females seek the shore, in order to deposit their eggs; and it may be added, that during sultry nights, when all is still, and even during the day, if no danger is perceived, these animals assemble on small islets, on trunks of floating trees, or rocks jutting above the water, and there take repose; but they are very watchful, and at the sight of man, or upon the least alarm, they plunge into the water.

Their voracity is equalled by their activity. They pursue reptiles and fishes, and make great havoc among them; but being themselves highly esteemed by man as food, they themselves fall a prey to him. The usual way of taking them is by means of a line or hook, baited either