own bodies. The vertebræ of the great Boa are more numerous than those of other serpents, which gives them a greater power of surrounding and strangling their prey with their dreadful voluminous folds, of crushing it, and, with the help of their saliva, rendering it fit for deglutition. With their tail, likewise, they can lay strong hold of a tree, so as to use it as a fulcrum, by which their powers of compression are increased and rendered more available where they have to contend with the struggles of powerful animals.

Order 4.-The connexion of the Saurians, or the animals forming the next Order with the Ophidians, is very intimate. Cuvier says that many serpents under the skin have the vestige of a posterior limb, which in some shows its extremity externally, in the form of a little claw. Amongst the lizards is one that has only two fore-legs, and another that has only two hind ones;* and a third, in which the legs are so short and so distant, and the body so slender and serpentiform, that they resemble a snake with four legs rather than a lizard.

This Order is divided into numerous genera and sub-genera. One of the most celebrated is the Chameleon. I have already noticed some of its peculiarities, and its mode of catching the insects that form its food. The ancients were of opinion that it lived upon air, led by the power it has of swelling itself to twice its natural size, by inflating its vast lungs, when its body becomes transparent. Cuvier is of opinion that it is the size of the lungs of these animals that enables them to change their colour, not in order to assume that of the bodies on which they happen to be, but to express their wants and passions. He supposes that the blood, being constrained to approach the skin, more or less, assumes different shades, according to the degree of transparency. The Rev. L. Guilding, however, mentions another genus, the species of which, when in search of prey, adapt their colour to the green tree or dark brown rock on which they lie in ambush. As these animals have the power of inflation, at least partially, by assuming a degree of transparency, they may appear of the colour of the substance they are standing upon, a remark which may also apply to the Chameleon. The object of this may be to conceal themselves from their enemies, as well as from their prey.

The Guanas, also, are said to change their colour; they are remarkable, as well as the Anolis, for the kind of goitre in their throat, which when irritated or excited they can inflate to a large size. These animals, though their flesh is said to be unwholesome, in the countries they frequent are highly prized for the table, and are often hunted with dogs. Their eggs also are in request.

The Monitors, or safeguards, as the French call some of them, deserve notice, because one species is said to assist in the diminution of the crocodile, since, like the ichneumon, it devours its eggs, and even the young ones, on which account it is supposed to be sculptured on the monuments of the ancient Egyptians. This name was given them because they were believed to warn people, by hissing, of the approach of the crocodile, or venomous Reptiles.

But the most celebrated of the Saurians, from the earliest ages, is the Crocodile: its history, however, is so well known that I shall only mention a few circumstances, of less notoriety, connected with it. There has been some difference of opinion as to whether the crocodile can move the upper or lower jaw. Aristotle observes, all animals move the lower jaw, except the crocodile of the river, for this animal only moves the upper. Denon says the same. Lacepede, on the contrary, affirms that the lower jaw is the only moveable one." I was assured by Mr. Cross, when looking at two aligators in his menagerie, then at Charing-cross, that they moved both their jaws; and my friend, Mr. Martin has observed the same thing in India. M. Geoffroy St. Hilaire and Baron Cuvier nearly reconcile the two opinions. The head, says the former, moves on the lower jaw like the lid of a snuff-box, that opens by a hinge. By this mechanism they can elevate their nostrils above the water, which they do with great rapidity for cencealment:" and the latter observes, that the upper jaw moves only with the whole head. So that the fact seems to be that the lower jaw alone has motion independent of the head, and the upper one can only move with it: but when we consider that the lower one extends beyond the skull, a condyle of which acts in an acetabulum of that jaw, we can easily comprehend that the upper jaw and head forming one piece, may be elevated at any angle, according to the will of the ani

mal; and thus the upper one acquires additional power of action in attacking its prey in the water and securing it.

The nostrils of this animal are at the end of the muzzle, and this structure enables it, by causing the upper jaw to emerge a little, which, as the crocodile cannot remain under water more than ten minutes, enables it to breathe without exposing itself to observation. When on shore it turns itself to the point from which the wind blows, keeping its mouth open. Adanson relates that he once saw in the Senegal more than two hundred of these river monsters swimming together, with their heads only emerging, and resembling so many trees. Were it not for the number of their enemies, great and small, their increase would be so rapid that they would drive man from the vicinity of the great rivers of the torrid zone. The River-horse,' attacks them and destroys many-Behemoth against Leviathan,-for though the Leviathan of the Psalmist is clearly a marine animal or monster, that of Job is as clearly the crocodile, and they are stated to destroy many of them; even the feline race, in some countries, contrive to make them their prey. Though the scales that cover their back are impervious to a musket ball, those on the belly are softer and more easily penetrated; and here the saw-fish and other voracious fishes, find them vulnerable, and so destroy them. The Trionyx, also, a kind of tortoise, devours them as soon as hatched. Their eggs are the prey not only of the ichneumon and the lizard, before mentioned, but of many kinds of apes; and aquatic birds also devour them, as well as man himself.

The crocodile has no lips, so that when he walks or swims with great calmness, he shows his teeth as if he was in a rage. When extreme hunger presses him, he will swallow stones. and pieces of wood to keep his stomach distended. The heron and the pelican are said to take advantage of the terror which the sight of the crocodile produces amongst the fishes-causing them to flee on all sides-to seize and devour them: therefore they are frequently seen in his vicinity.

Order 5.-The Chelonians, as far as at present known, seem far removed from the Saurians. The turtles indeed, in their paddles, exhibit an organ which is common to them, and some of the fossil Saurians, as the Icthyosaurus and Plesiosaurus. Cuvier places the Trionyx next above the crocodiles; but it

1 Hippopotamus. 3 Chap. xli.

2

Psl. civ. 26. 4 See above, p. 16.

agrees with them only in its fierceness and voracity, and the number of its claws.

The importance of the highest tribe of this Order to seamen in long voyages, is universally known and acknowledged, but otherwise there is nothing particularly interesting in their history, or that of the tortoises.

A singular circumstance distinguishes the animals of this Class, very few of them have teeth formed for mastication. The guana is almost the only one amongst the existing tribes that has them. The Chelonians, which seem almost capable of living without food, have none. The teeth of the predaceous tribes are fitted to retain or lacerate their prey, but not to masticate it; so that the function of the great majority appears to be the same with that of the Ophidians before mentioned, the complete deglutition of the animals their instinct compels them to devour. Insects, which, of all minor animals, are the most numerous, and require most to be kept in check, form the principal part of the food of a large proportion of them. Creatures also that frequent dark and damp places, and that take shelter under stones and similar substances, seem to be particularly appropriated to them by the will of their Creator. Of this description are slugs, earth-worms, and several others: these, therefore, they have in charge to keep within due limits. And thus, in their doleful retreats and hiding-places, they fulfil each its individual function, instrumental to the general welfare.

CHAPTER XXIII.

Functions and Instincts. Birds.

We are now arrived at the highest department of the animal kingdom, the members of which are not only distinguished by a vertebral column, but also by warm red blood, and a more ample brain. This department consists of two great Classes, viz. those that are oviparous, and do not suckle their young; and those that are viviparous, which suckle their young till they are able to provide for themselves. The first of these Classes consists of the Birds, and the last of the Quadrupeds, Whales and Seals, called from the above circumstance Mammalians. Man, though physically belonging to the latter Class, metaphysically considered, is placed far above the whole animal kingdom, by being made in the image and after the likeness of his Creator, receiving from him immediately a reasonable and immortal soul; and entrusted by him with dominion over the fish of the sea, and over the fowl of the air, and over every living thing that moveth upon the earth.

Having, in a former chapter, given some account of those animals, to which the waters of this globe are assigned as their habitation and scene of action, I am now to consider those which their Creator has endowed with a power denied to man, and most of the Mammalians-that of moving to and fro in the air as the fishes do in the water, which, on that account, though they move also on the earth, are denominated, in the passage just quoted, the fowl of the air.

The animals of this great Class are rendered particularly interesting to man, not only because many of them form a portion of his domestic wealth, look to him as their master, and vary most agreeably his food; but because numbers, also, strike his senses by the eminent beauty and grace of their forms, the brilliancy or variety of the colours of their plumage, and the infinite diversity, according to their kinds, of their motions and modes of flight. But of all their endowments, none is more striking, and ministers more to his pleasure and delight, than their varied song. When the time of the singing birds is come, and the voice of the turtle is heard in our land, who can be dead