it. Hence, when the mouth of the Crocodile is opened, it appears as if there were no farther passage; as if, indeed, its posterior part were completely walled up, there being neither windpipe nor gullet visible. Walled up it really is, by this firm, elastic, moveable portion, which consists of a large cartilaginous expansion, (covered with skin,) of the os hyoïdes.

Anterior to it, and between the branches of the lower jaw, stretches forward a muscular space, covered with a yellowish skin, having numerous pores over its surface, whence exudes a viscid saliva: this part is analagous to the tongue, and is usually considered to be such, though it is incapable of being protruded. By its action, however, against the palate, the food is propelled along.

still

Now, as already stated, the nostrils open at the end of an elongated snout, and their internal orifices are behind the depending portion of the palate, and just over the opening of the windpipe; so that, provided the end of the snout be just above the water, the Crocodile may lie submerged all day in the water, with its mouth wide open, without the slightest inconvenience, and breathing all the while at ease. But, were the animal to lie with its closed mouth below the level of the water, the nostrils being just above, as it often does for days together, would this valve be required; for it must not be forgotten, that these creatures have no lips round their jaws, by the compression of which the entrance of water into the mouth may be prevented; on the contrary, the teeth are all exposed in terrible array; and there is plenty of room in various small, irregular spaces between the jaws, even when closed, to admit the gradual ingress of the fluid, so that this valvular apparatus is in perpetual requisition.

What an express and admirable provision, then, is this gular valve for the Crocodile; a tiger-like reptile, which snaps up its prey in the water, which seizes waterfowl as they swim on the surface, or pursues fishes through the depth of the lagoon, or river; or which,

having grasped in its jaws a large animal, as a pig or a dog, on the bank, plunges beneath the water, in order to drown its victim! How fitted this contrivance to the habits of a ferocious animal, which lurks for days together submerged, with the exception of the nostrils, beneath the oozy fluid of weed-grown morasses, in order to spring upon the first animal that may come within its reach!

From what we have said, it will be easy to understand, that the process of breathing has, here, nothing to do with the mouth; but, it may be asked, how, with the back of the mouth thus closed, is the act of swallowing accomplished? As the Crocodile bolts its food in large pieces, or whole, the gullet being extremely capacious and dilatable, the act of swallowing is momentary. At this instant, the elastic valve is drawn down by the action of the muscles of deglutition, so as to leave, for the time, a free passage for the food to pass over it; which done, it returns to its former place.

In this respect, its action is analogous to that of the epiglottis in man and Mammalia. The epiglottis is a valve, which protects the orifice of the windpipe, over which orifice our food has to pass when we swallow it. Under ordinary circumstances, this valve, or epiglottis, is raised, and the orifice of the windpipe is open, in order that breathing may go on; but when we swallow, this valve closes over it, and thus, while it allows the food to pass, prevents any particle from entering the windpipe, and producing suffocation; an accident, which, as we know, occasionally occurs. In this case, however, the valve is ordinarily open; in the Crocodile it is ordinarily closed.

As the nostrils are valvular, so, for the same reason, is the external orifice of the ear defended by a valve. In all terrestrial Mammalia* the orifice of the ears is open; in Lizards generally, the membrane of the tympanum,

* In seals, the hippotamus, and a few others, the orifice of the ear is capable of being expanded or contracted, as necessity may require.

or ear-drum, is on a level with the scaly integument of the head, appearing like a thin horny plate. In the Crocodile, however, which has to endure the pressure of water, sometimes at a considerable depth, the orifice of the ear is guarded by a firm, moveable lid, capable of being raised or shut down at pleasure. Thus, while basking among the herbage of the bank, or floating on the surface of the water, the Crocodile may open the ear-valves, and listen for the footsteps of its prey; when beneath the surface, the valves will be closed.

In the stomach of the Crocodile, there are usually, or not unfrequently, found several stones of various sizes, which have been swallowed, as some suppose, to form a sort of ballast. Such an opinion is erroneous. The fact is, that the stomach of the Crocodile bears a close resemblance, both in its form and structure, to the gizzard of birds; and they, as is well known, swallow stones to titurate the food, and assist digestion; and, in the case of the Crocodile, a similar consequence may be the result. We have several times dissected young Crocodiles, which have been kept for a considerable period in confinement; and we have, more than once, found a quantity of Indian corn, (this having been within their reach,) unaltered in the stomach, doubtless swallowed in lieu of stones, which they could not obtain.

The Crocodiles are essentially carnivorous; they are tyrants by necessity; they are the scourge of the lakes and rivers in which they dwell: what the eagle is among birds, what the tiger or lion among Mammalia, such are they among the Sauria. Their principal food consists of fishes, aquatic birds, and such Mammalia as they can seize on the borders of the water: they employ both force and cunning in their warfare, or rather in the supply of their wants. Like all carnivorous animals, which have often to endure the long deprivation of food, their prey being scarce, these aquatic reptiles can fast for weeks, and even months without inconvenience;

but when opportunity serves, they glut themselves, and become indolent and half torpid.

It is when excited by hunger that the Crocodile displays its force and activity. Where a river enters a lake, or where a lake discharges its superfluous waters, there does the animal lurk, watching for fish; on which, as they pass, it darts with wonderful velocity. It conceals itself near the spot where animals come to drink, and suddenly rushes from its ambuscade upon them; in the same way it seizes water-birds, and often, also, catches them by swimming quietly under them, and then pulling them down by their legs. The prey, which is too large to be swallowed at once, it takes to its usual haunt; and it is said, that the Crocodile thus keeps a sort of larder, in which the game acquires that degree of putrescence which it relishes. Hence, floating carrion, and even the bodies of human beings, especially in the Ganges, where such are too common, are eagerly devoured.

Although sometimes carried inland by floods, the Crocodile seldom advances far on shore in pursuit of prey. On land it is by no means difficult to escape its attack, for the legs of the animal are ill-formed for running; and the vertebræ of the neck are so constructed, and fitted together, as to render a lateral motion difficult, and the turning out of a straight line not to be accomplished, without describing a considerable compass. Instances, however, sometimes occur, in which men are seized, being surprised before they have time to retreat. Mr. Watterton relates a melancholy account of a man being carried off by one of the Alligators of the Orinoko. The monster came upon the public walk, or almæda, rushed upon him, and bore him to the bottom of the river, before any assistance could be given. The same writer states, as a proof of the innate ferocity of these animals, that young ones, only a foot long, would furiously bite the arrows with which they were wounded; and snap at the archers with malignant fury.

It is in the month of April, or May, that the female deposits her eggs, the number varying from twenty to sixty. For this purpose she comes on the bank, or borders of the water, and chooses a sandy place, exposed to the sun; scraping a cavity for their reception, lining it with dry leaves, and carefully covering them with leaves and sand. The eggs are about as large as those of a swan, and covered with a parchment-like membrane. In about forty days the young are hatched, and are then about five or six inches in length. The female, who watches her eggs, conducts the young to the water, and supplies them with half-digested food, attending to them till they are able to capture their own prey. male takes no part in the care of the young.

The

The Crocodiles are strangers to Europe, and hitherto no species has been found in Australia; they are all limited to the warmer latitudes of Asia, Africa, and America

M. Bibron divides the Crocodiles into Caïmans, (Alligator;) Crocodiles proper, (Crocodilus ;) and Gavials, (Gavialis.) The Caïmans, of which M. Bibron reckons five species, are all peculiar to America. The Crocodiles are divided between Asia, Africa, and America; two being natives of the latter. Only one Gavial is known, and this is peculiar to the river Ganges.

GENUS ALLIGATOR.

This genus is characterized as follows:-The head is broad; the muzzle short; the teeth are of unequal length; the fourth tooth of the lower jaw (counting from the fore point of the jaw) is the longest, and is received into a cavity of the upper jaw when the mouth is closed, so that it is concealed. The hinder limbs are rounded, and destitute of ridged scales; the webs between the toes are short.

The principal species belonging to this genus, Alligator, are the CAIMAN WITH BONY EYELIDS, (Alligator palpelrosus;) the PIKE-NOSED CAIMAN, (Alligator lucius;) and the SPECTACLED CAIMAN, (Alligator sclerops.)