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ORDER II. LORICATA.
Table of Contents (Crocodiles.)
The appellation by which this Order is distinguished, derived from the word lorica, signifying a coat of mail, expresses the most obvious peculiarity by which its members may be known, the ridged and bony armour in which they are invested. "The Crocodiles and Alligators of both worlds, and the Gavials of India, which constitute this order, are distinguished," observes Mr. Bell, "from the true Saurians or Lizard tribe, by several important characters. Of these the most tangible and obvious is that upon which the name of the Order is founded; the covering of the whole of the back part of the neck, body, and tail, with distinct series of bones, of modederate size, imbedded, as it were, in the substance of the skin, and covered externally with a thick cuticle. These dermal bones are usually furnished with a crest, which renders them exceedingly strong, and they altogether form a panoply of defence which can resist the attacks of the most powerful enemies of whatever kind."[1]
The general form of the Loricata agrees with that of the Lizards; but besides the important difference already mentioned, the bony plates run down the body in longitudinal lines, the structure of the skull is much more solid, and the posterior orifice of the body is longitudinal. The tail is ?flattened at the sides; there are five toes before and four behind, of which the innermost three on each foot are armed with claws; the toes are connected by intervening membranes, varying in extent. There is a single row of pointed teeth in each jaw; the tongue is fleshy, flat, and free only at the extreme edge; whence the Crocodile was vulgarly reputed to be without a tongue. The back and tail, as already intimated, are covered by large and strong scales of square form, elevated into a ridge in the middle; the tail is surmounted by a deeply notched or saw-like crest, which is double at the base; the scales of the belly are delicate and smooth. The nostrils are situated at the end of the muzzle, and open by small crescent-form slits, closed by valves; they lead through a long and straight canal pierced in the bones of the palate, to the back of the mouth. The lower jaw is prolonged behind the skull, and this structure causes the upper jaw to seem moveable; but this is simply an illusion. The external ear is closed at pleasure by means of two fleshy lips; the eye is furnished with three lids: two small glandular orifices are placed beneath the throat, whence exudes a musky secretion, the odour of which strongly marks these animals even for years after their dried skins have been preserved in a museum.
The Reptiles of this Order are of large size and great strength; and as they are exclusively carnivorous and predaceous, and very ferocious, they are dreaded, not without reason, in the tropical countries which they chiefly inhabit. Yet these creatures, feared and hated as they are, were not created in vain. "In the grand policy ?of Nature," observes Prof. Jones, "the scavengers are by no means the least important agents. In hot climates, especially, where putrefaction advances with so much rapidity, were there not efficient and active officers continually employed in speedily removing all dead carcases and carrion, the air would be perpetually contaminated with pestilential effluvia, and entire regions rendered uninhabitable by the accumulation of putrefying flesh. Perhaps, however, no localities could be pointed out more obnoxious to such a frightful cause of pestilence, than the banks of tropical rivers-those gigantic streams, which, pouring their waters from realm to realm, daily roll down towards the sea the bloated remains of thousands of creatures which taint the atmosphere by their decomposition."[2]
Here, then, is the appointed dwelling-place of the Loricata. Lurking in the dense reeds, or tangled herbage that grows rank and teeming at the edges of rivers in hot climates, or under the mangroves that interweave their myriad roots in arches above the water, or concealed among the bleaching trunks and branches of trees that have fallen into the stream, these huge reptiles watch for the approach of a living prey, or feed at leisure on the putrid carcases with which the waters daily supply them. It is even affirmed that they prefer a condition of putrescence in their prey, and that their practice, when not pressed by immediate hunger, is, on seizing a living prey, to plunge into the stream in order to drown it, after which, it is dragged away to some hole, and stored until decomposition has commenced.
?The subjects which compose this Order are few in number, and are all comprised in a single Family, which we shall presently describe more in detail. They are natives of both hemispheres, but are confined to the warmer regions of both, neither Europe nor Australia possessing any known species: they all inhabit fresh waters.
Family I. Crocodilidæ.
Table of Contents (Crocodiles.)
Messrs, Duméril and Bibron enumerate the following characters as proper to this family. The body is depressed, lengthened, protected on the back with solid and keeled scutcheons, or shields;
TOOTH OF CROCODILE. the tail is longer than the trunk, compressed, the plates here set in rings, and rising into a ridge of pointed crests; the limbs are four in number, short; the toes of the hind feet united by a swimming membrane; three claws only on each foot; the head is flattened, lengthened into a muzzle, in the front of which are the nostrils, not far apart, upon a fleshy tubercle, furnished with moveable suckers; the gape opens beyond the base of the skull; the tongue is fleshy, entire, adherent, not protractile; the teeth are conical, simple, hollowed towards the root, unequal in length, but placed in a single row. The cavity at the root of each tooth serves as a case or sheath for the germ of the tooth destined to replace it, which is to be of greater bulk; ?and each being thus gradually pushed out from below by a successor ready to supply its place, the jaws of the Crocodiles present, at all ages, their formidable array of pointed teeth in undiminished number.
The Crocodiles, as we have said, are fierce and voracious, and prove destructive, not only to quadrupeds, (and those of large size), but also to man himself. Cuvier states that they are unable to swallow in the water, but this seems to be unconfirmed. They do, however, commonly resort to the shore for the purpose of devouring those animals which they have seized and drowned, dragging them out again after they have begun to decay. On land their motions are stiff, ungainly, and embarrassed, and a peculiar structure of the vertebræ precludes them from being able to turn themselves with facility. Yet they are able to bound forward with considerable agility, springing to a distance which would scarcely be expected from creatures so unwieldy.
In the water they swim with swiftness both upon and beneath the surface; here they know themselves to be at home, and usually leap into the water with precipitation if surprised on land by even the distant appearance of a man.
These are not only the largest of all reptiles, but are among the most gigantic of animals. Some are reported to have attained a length of twenty-five feet, and it seems probable that they are long-lived, and that their bulk continues to increase with years. The mouth is enormous; and the numerous pointed teeth, thirty or more on each side of each jaw, are so disposed as to fit into the interstices of each other. As the lips are ?altogether wanting, the teeth are visible when the mouth is closed; hence the animal, even when tranquil, seems grinning with rage. A similar expression is communicated to the visage from the eyes, which are placed obliquely near each other, and have a peculiarly fiery glare.
The compressed and dentelated tail, though from its length and weight it impedes the motions of these animals on the land, is yet an organ of the utmost importance to them in the water, where it is a most powerful instrument of progression, and influences their aquatic habits much more than their webbed hind feet. The latter are indeed used, when the animal is paddling with a slow and gentle action; but in sudden and swift motion, as in escaping from an object of alarm, or in energetic pursuit of prey, alternate strokes with the tail upon the element give the powerful impulse. On land, also, the Crocodile is said to use this organ as an efficient weapon of offence, dashing it from side to side with swift contortions, when its weight, its hard rough surface, and especially its saw-like crests, render its strokes eminently formidable. Like the Turtles, the Crocodiles lay their eggs in the sand, and leave them to be hatched by the heat of the sun. The general number is from eighty to a hundred: their size is about that of a goose's egg, but their form is more oblong.
When we consider the vast bulk of the adult animal, we may affirm that no creature exhibits so great a disproportion between its youth and age. The eggs are covered with a hard calcareous shell, like that of birds' eggs, but more shining, harder, and more brittle.
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Genus Alligator. (Cuv.)
Table of Contents A broad obtuse muzzle, with uneven teeth, marks the genus before us; the fourth tooth on each side of the lower jaw...
