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. 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 foul 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 to the goodness which has provided for all such an unbought orchestra, tuning the soul not only to joy, but to mutual goodwill; reviving all the best and kindliest feelings of our nature, and calming, at least for a time, those that harmonize less with the scene before us. I may here offer a few observations upon the voice of animals, especially birds. A distinction is made by physiologists between a voice and a sound, and none but those that breathe by means of lungs are reckoned to utter a voice; others, whatever their respiratory organs, only emit a sound. The voice also is from the mouth alone, the sound from other parts of the body.1 The vocal animals, therefore, are confined to the three last classes of vertebrates-the Reptiles, the Birds, and the Mammalians. In most of these, also, the voice partakes, in some degree, of the character of speech; it is intended to indicate to another the wishes, emotions, or sufferings of the utterer. The great organ of the voice is the wind-pipe, or tracheal artery, as it is often called, and its parts, which by its bronchial ramifications is so intimately connected with the lungs as to form part of their substance. Birds, of all animals, are best organized with regard to their voice. Besides the upper larynx, or throat, which they have in common with Mammalians, at the base of their wind-pipe, where it divides into two branches, rendering to each lobe of the lungs, it has also another larynx, forming a second vocal apparatus. This is produced by a contraction of the organ furnished with muscular fibres, or vocal strings, which by their various tensions and relaxations, modify greatly the tones of the voice; ascending also in the tube of the wind-pipe to undergo another modification at the upper larynx, which, as it were, adds the tube of the horn to that of the reed. Thus, if the head of a duck is cut off, it can produce sounds by means of its lower throat, if I may so call it, which no quadruped could do. Besides this, birds can, more or less, shorten or lengthen the tube of their wind-pipe, so as to modify the sounds they emit. Though the upper larynx, in birds, has no vibratory vocal strings, as in the Mammalians, to modify the sounds, these modifications taking place at the lower larynx, still they can enlarge or contract it, which may affect the air in its exit, and so produce some diversity. Besides all this, whoever casts an eye over Dr. Latham's and 1 See Introd. to Ent. Lett. xxiv. Mr.Yarrel's figures of the wind-pipes of various birds,' especially wild fowl, will see that they vary greatly in their relative length and volume; that some are partially dilated, and others contracted with other peculiarities that distinguish individual species, especially in male birds. All these, no doubt, modify the voice, and, by the will of Him who formed them, cause them to utter such sounds, and speak such a language, as are required by the circumstances in which they are placed. The cawing of the rook, the croaking of the raven, the cooing of the dove, the warbling of the nightingale and the other singing birds, are all the result of their organization according to the plan and will of that Supreme Intelligence, infinite Love, Wisdom, and Power, which fabricated and fashioned them with this view as well as others, to give utterance to sounds that, mixed or contrasted, would produce a kind of universal concert, delighting the ear by its very discords. It is said by a late writer, that the song of the same individual species of birds, in different districts, is differently modified. This, I should think, must be occasioned by a difference in the temperature, and other circumstances connected with the atmosphere. Of all animals, birds are most penetrated by the element in which they move. Their whole organization is filled with air, as the sponge with water. Their lungs, their bones, their cellular tissue, their feathers-in a word, almost every individual part, admit it into their interstices. Thus giving them a degree of specific levity that no other class of animals is endowed with, which however does not render them the sport of every wind that blows, for, by means of their vigorous wings, formed to take strong hold of the air; of their muscular force, the agility of their movements, and their powers of steerage by means of the prow and rudder of their little vessel, their head and tail, they can counteract this levity; and by these also, and by their great buoyancy, they can ascend above the very clouds, as well as descend to the earth; they can glide motionless through the air, or skim the surface of the waters; they can sport, at will, in the vast atmospheric ocean; they can dart forward in a straight line, or like the butterfly, fly in a zig-zag or undulatory one, and with ease take any new direction in their flight that fear or desire may dictate. Enveloped in soft and warm plumage, they can face the cold of the highest regions of the air; and the denser clad aquatic birds can 1 Linn. Trans. iv. t. ix.—xv.; xv. t. ix.—xv.; and xvi. t. xvii.—xxi. N. D. D'Hist. Nat. xxiii. 352. 2 |