CROCODILES AND ALLIGATORS.

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the shore except for this purpose. So admirable an account of the manner in which the Turtle behaves when laying her eggs is written by Audubon, that the description must be given in his own words.

"On nearing the shore, and mostly on fine calm moonlight nights, the Turtle raises her head above the water, being still distant thirty or forty yards from the beach, looks around her, and attentively examines the objects on shore. Should she observe nothing likely to disturb her intended operations, she emits a loud hissing sound, by which such of her enemies as are unaccustomed to it are startled, and apt to remove to another place, although unseen by her.

Should she hear any more noise, or perceive any indication of danger, she instantly sinks and goes off to a distance; but should everything be quiet, she advances slowly towards the beach, crawls over it, her head raised to the full stretch of her neck, and when she has reached a place fitted for her purpose, she gazes all around in silence. Finding all well, she proceeds to form a hole in the sand, which she effects by removing it from under her body with her hind flappers, scooping it out with so much dexterity, that the sides seldom, if ever, fall in. The sand is raised alternately with each flapper as with a ladle, until it has accumulated behind her, when, supporting herself with her head and fore-part on the ground, she, with a spring from each flapper, sends the sand around her, scattering it to the distance of several feet.

In this manner the hole is dug to the depth of eighteen inches or sometimes more than two feet. This labour I have seen performed in the short space of nine minutes. The eggs are then dropped one by one and disposed in regular layers to the number of one hundred and fifty, or sometimes nearly two hundred. The whole time spent in this operation may be about twenty minutes. She now scrapes the loose sand back over the eggs, and so levels and smooths the surface, that few persons on seeing the spot would imagine that anything had been done to it. This accomplished to her mind, she retreats to the water with all possible despatch, leaving the hatching of the eggs to the heat of the sand.

When a Turtle, a loggerhead for example, is in the act of dropping her eggs, she will not move, although one should go up to her, or even seat himself on her back; but the moment it is finished, off she starts, nor would it be possible for one, unless he were as strong as Hercules, to turn her over and secure her."

CROCODILES AND ALLIGATORS.

ACCORDING to the arrangement of the national collection in the British Museum, the link next to the tortoise tribe is formed of an important group of reptiles, containing the largest of the reptilian order, larger indeed than most present inhabitants of the earth, if we except one or two African and Indian animals, and some members of the cetaceous tribe. As is the case with nearly all reptiles, they are carnivorous, and owing to their great size, strength of muscle, voracity of appetite and the terrible armature of sharp teeth with which their jaws are supplied, they are the dread of the countries which they inhabit, ruling the rivers with a sway as despotic as is exercised by the lion and tiger on land, the eagle in the air, or the shark in the seas.

On account of the peculiar manner in which their bodies are covered with square, keeled, bony plates embedded in the skin, and protecting the body with an armour that effectually guards its upper and more exposed portions from any ordinary weapon, they are separated from the true lizards and scientifically termed EMYDOSAURI, or Tortoiselizards, the bony plates being considered to have a certain analogy with those of the shielded reptiles. By some zoological authors these animals are termed LORICATA or Mailed Reptiles, from the Latin word lorica which signifies a coat of mail or cuirass.

Although these creatures are capable of walking upon land, for which purpose they are furnished with four legs, they are more fitted for the water than its shores, and are swift and graceful in the one, as they are stiff, awkward, and clumsy on the other Through the water they urge their course with extraordinary speed, their long, flattened, flexible tail answering the double purpose of an oar and a rudder, but on land their bodies are so heavy and their legs are so weak, that they can hardly be said to walk, a term which seems to imply that the body is wholly supported by the legs, but to push or drag themselves along the ground, on which rests a considerable portion of their weight.

The head of these creatures is always rather elongated, and in some species is lengthened into a narrow and prolonged snout. Each jaw is furnished with a row of sharply pointed and rather conical teeth. These teeth are hollow, mostly grooved on the surface, and are replaced when they fall by new teeth that grow behind them, and in process of time push the old ones out of their sockets.

The nostrils are placed at the very extremity of the skull and upon a slightly raised prominence, so that the animal is able to breathe by merely exposing an inch or so above the water, and thus can conceal itself from almost any foe, or make an unsuspected approach upon its prey. There is yet another more important use for the position of the nostrils. The Crocodiles feed on fishes and various water-loving creatures, but also are in the habit of lurking by the river-bank, and suddenly seizing upon any unfortunate animal that may come to drink. Suppose, for example, that a calf or a dog is thus dragged into the water, the reptile grasps it across the body, and sinks below the surface so as to keep the head of the victim below water while itself can breathe by means of the elevated nostrils.

But as during this process the mouth is held widely open, it might be rationally presumed that considerable inconvenience would be caused by the water running down the throat. Such would indeed be the case, were not this difficulty provided for by a simple yet very wonderful contrivance. At the back of the throat, a pair of thin cartilaginous plates are so arranged, that when the animal opens its mouth the pressure of the water rushing into the mouth immediately closes one upon the other, and effectually prevents the passage of a single drop, the closure being in exact proportion to the volume of water. The structure indeed is very like that of the valves of the heart. The channels which lead from the nostrils run very far back through the skull, and open behind the throat valves, so that respiration is in no way impeded. They cannot, however, swallow their prey while under water, but are obliged to bring it on shore for that purpose. tongue is small, and fastened down to the lower jaw throughout its length, so that it was formerly thought that the Crocodiles were destitute of that organ.

The

There is rather a curious structure in the vertebræ of the neck. These bones are furnished with short transverse processes like false ribs, which have the effect of preventing the animal from turning its head from side to side. On land therefore, where its feeble limbs are so inadequate to the support of the long and heavy body, it can easily be avoided by any one of ordinary agility. The eyes are large, and set rather far back upon the head. The ears are carefully guarded from the ingress of water by a pair of tightly closing valves. Below the throat are a pair of glands which secrete a substance having a strong musky scent which is very disagreeable, and in old individuals taint the whole flesh with its rank odour and render it uneatable to ordinary palates.

The young of these reptiles are hatched from eggs, which are strangely small in proportion to the large dimensions of the adult animal, the newly hatched offspring being so small as hardly to be recognised as belonging to the same species as their parents, especially as there are certain differences of shape hereafter to be mentioned.

These great reptiles are divided, or rather fall naturally, into two families, namely, the Crocodiles and the Alligators. All the members of these families can be easily distinguished by the shape of their jaws and teeth, the lower canine teeth of the Crocodiles fitting into a notch in the edge of the upper jaw, and those of the Alligators fitting into a pit in the upper jaw. This peculiarity causes an obvious difference in the outline of the head, the muzzle of the Crocodiles being narrowed behind the nostrils, while that of the Alligators forms an unbroken line to the extremity. A glance therefore at the head will suffice to

settle the family to which any species belongs. In the Crocodiles, moreover, the hind legs are fringed behind with a series of compressed scales.

OUR first example of the Crocodiles is the very remarkable GAVIAL, or GANGETIC CROCODILE, Sometimes known by the name of NAKOO.

This curious reptile is one of the largest, if not the very largest of its order, sometimes reaching a length of twenty-five feet. As its popular name imports, it is a native of India, and swarms in many of the Indian rivers, the Ganges being greatly infested with its presence. It is a striking animal, the extraordinary length of its muzzle giving it a most singular and rather grotesque aspect.

This prolongation of the head varies considerably according to the age and sex of the individual. In the young Gavial, for example, just hatched from the egg, the head is short and blunt, and only attains its full development when the creature has reached adult age. The males can be distinguished from the other sex by the shape of the muzzle, which is much smaller at the extremity. There are many teeth, the full complement being about one hundred and twenty. They are similar in appearance, and about equal in length.

The colour of this species is dark olive-brown, spotted with black. Several species of African Gavials are known to zoologists, besides the Asiatic animal, but on account of the different formation of the head, such as the absence of a swollen muzzle in the male, and some important variations in the plates of the neck and back, they are placed in another genus, and termed False Gavials. In the British Museum examples may be found, among which may be named BENNETT'S GAVIAL (Mecistops Bennettii), an inhabitant of Western Africa, and the False Gavial (Mecistops cataphractus). Some naturalists, however, think that these animals are only varieties of the same species.

WE now arrive at the true Crocodiles, in which the jaws are moderately lengthened, wide, flat, tapering, and rather dilated at the extremities. The most peculiar of these reptiles is the long-celebrated CROCODILE of Northern Africa.

This terrible creature is found chiefly in the Nile, where it absolutely swarms, and though a most destructive and greatly dreaded animal, is without doubt as valuable in the water as the hyæna and vulture upon the land. Living exclusively on animal food, and rather preferring tainted or even putrefying to fresh meat, it is of great service in devouring the dead animals that would otherwise pollute the waters and surrounding atmosphere.

It also feeds on fish, which it can catch by means of its great swiftness in the water, and is a dangerous foe to cattle or other beasts that come to the river-side for drink. Some persons relate that when its intended victim does not come sufficiently near to be snapped up, the Crocodile crawls to the banks, and with a sweep of its long and powerful tail strikes the poor creature into the water, where it is immediately seized in the Crocodile's ready jaws.

Human beings have a great dread of this terrible reptile. Many instances are known where men have been surprised near the water's edge, or captured when they have fallen into the river. There is, it is said, only one way of escape from the jaws of the Crocodile, and that is to turn boldly upon the scaly foe, and press the thumbs into his eyes, so as to force him to relax his hold, or relinquish the pursuit. Mr. Petherick relates a curious instance, where a man was drawing water, and was chased by a Crocodile into the recess in the earth in which he was standing while working the lever of the "shadoof." The man crouched as far back as he could squeeze himself, and the Crocodile tried to follow him, but got itself so firmly wedged in the narrow channel through which it was endeavouring to force its way, that it could neither reach the man, whose trembling breast was within a span of the reptile's terrible teeth, nor retreat from the strange position into which it had forced itself. After spending some time in terror, the poor man contrived to give the alarm to his comrades, who came running to his assistance, and despatched the Crocodile as it lay helplessly fixed in the crevice.

The plates which cover the skin of the Crocodile are of exceeding hardness, so hard, indeed, that they are employed as armour by some ingenious warriors. A coat of natural scale armour formed from the Crocodile skin may be seen in the British Museum. Even a rifle ball may be turned by these horny plates, provided that it strikes rather obliquely; and they are impervious to ordinary steel weapons. Modern rifles, however, especially if the ball is hardened with solder or tin, make little account of the plates, but cut their way through them without difficulty.

As this reptile is so dangerous and costly a neighbour to the inhabitant of the river banks, many means have been adopted for its destruction. One such method, where