provided with the means of conveyance to another, though that may be at a considerable distance. Their wings are long and powerful, and they occasionally perform long journeys, when driven by a scarcity of food to a different part of the country. Their peculiar construction is so beautifully adapted to their wants and to their haunts, that they are enabled to climb and scramble over the trees with the greatest rapidity, and to scrutinize every twig with the same perseverance as the ruminating animals show in browsing their pastures. They associate in large flocks, and although the depredations that they commit among the buds, flowers, and fruits may be considerable, we must take into consideration the prolific tendency of nature in these climes, and may conclude that a beneficial service is also performed by these birds in keeping under the destructive exuberance of the trees, whose luxuriance might otherwise be checked by the very excess of their own fruitfulness. The propensity to gnaw wood into chips, which they do, not for the sake of food, but apparently out of mere wantonness, no doubt answers some purpose in nature, and may, it has been observed, contribute not a little to the more rapid decay of dead trees, by enlarging the holes in their trunks, and thus rain is admitted and retained, and the tree is very speedily reduced to dust.

the whole may be Among the greater

As we have before observed, said to live upon vegetable food. number this food is the kernels of fruits, and those fruits which have large seeds, enclosed in a hard shell or nut within the pericarp, appear to be the favourites

with them. They find these upon many of the palms, upon the wild almonds, and upon various other trees. In order to enable them to open the valves of these nuts, it is obvious that a peculiar mechanism must be required, as many of them are exceedingly compact and hard. This is not done by mere random force, but by an application of the powers of the bill, in a manner so perfect that the bird is enabled to break the shell and get at the kernel with a very small degree of labour. The bill is not a snapping bill, but works wholly by pressure; and its operations are assisted considerably by the short muscular tongue, which guides the substance to the most effective part of the mandibles.

The curvature of the upper mandible, and the cell at its base in some of the birds, give it somewhat the character of a rapacious beak, but it is applied to a

totally different purpose. The notch in the upper

mandible, observes Mr. Swainson, so analogous to that of a rapacious bird, is not used to tear the food, but acts as a rest for those hard nuts which are to be cracked and broken by the great muscular force of the under mandible.* When the shell or kernel is introduced into the bill, it is placed by the tongue against the hook of the upper mandible, in the very best position for the application of the lower mandible, by means of which the valves are to be separated. This is done solely by the touch of the tongue, for the bill has no sensibility, and it is impossible that the eye can be of any assistance. When the shell is broken, the tongue stlll presses the kernel against

* Classification of Birds.

the hook of the upper mandible, and thus allows the lower one to be opened, so that the fragments of the shell may be rejected.

For the accomplishment of this action in the lower mandible, it is supplied with a set of very powerful muscles, and it has a sliding or grinding motion, which differs with the degree of exertion. It is pushed a little forwards at the same time that it is raised by the muscles. The upper mandible has much less motion than the lower, but still it has more than in most birds.

To prevent any concussion which might be communicated to the brain, the upper mandible is articulated with the bones of the cranium, and not united. In consequence of this, the upper mandible is susceptible of some motion on its base; and this motion not only prevents the concussion from being propagated to the brain, but enables this organ to exert a much more powerful effect than it would have, if the upper mandible were so firmly united at its base as to be incapable of motion. The bill thus not only becomes a powerful crunching instrument, but is rendered effective likewise in taking hold with a firm gripe of small boughs, to assist the bird in its progress amongst them. To render the upper mandible more effective as a rest against the pressure of the lower one, the under side is slightly hollowed towards the hook, and roughened like a millstone, by means of angular furrows, with their apices directed towards the tip.

There are several variations in the form of the bill in this numerous family. The Paroquets have the

blll considerably smaller in proportion than the others, not exceeding one-third the length of the head, and not very broad, but it is firm in its texture, and perhaps proportionably the most powerful of any. The Parrots properly so-called, which are the most scandent, have it half the length of the head, and very thick and strong. The Cockatoos, which inhabit marshy places and live upon softer food than the others, have the bill feeble. The Maccaws, which use the wing more than any of the others, and find much of their food in the tops of forest trees, have the bill large, as long as the head, and very sharp pointed.

The tongue is likewise subject to considerable variation of structure. In most of the birds of this family it is thick, fleshy, and of uniform structure throughout; in others, it terminates in a brushlike bundle of filaments; and in a third modification, consists merely of a somewhat horny snbstance, supported by a cylindrical extensile and retractile pedicle.

An extensive modification of structure is observed in the feet of these birds in conformity with their peculiar climbing habits. Their articulations are so loose, and yet are so well supplied with muscular strength, that they have the most varied and firm powers of prehension of any of the Scansores. The toes are in pairs, but all of them are free to their bases, and the exterior hinder toe is capable of considerable lateral motion. The Parrot climbs, it is well known, by clutching with its feet, assisted by the gripe of its bill; and its pasture is among the sprays or smaller twigs of large spreading trees, which inter

twine each other at the extremities of larger boughs. The bird has to make its way through this tangled brake by means of its prehensile limbs alone, as its wings would evidently be of little service here. Consequently the organization most essential to this habit is the one which enables it to get most readily from twig to twig without the use of its wings in any other way than partially opened, to assist in keeping its balance.

The foot, to possess this property, must have the whole of its prehensile action in the toes; and the legs, instead of maintaining one invariable position in assisting the foot in holding on (as is the case with the Woodpecker), must be free to move to its utmost stretch in all directions. It is also evident that unless the Parrot could hold on by one foot, and hold on with that foot in any direction, above it, below it, or laterally, it could not make its way.*

To accomplish these purposes, the joints in the leg and foot of the Parrot have a rolling or oblique motion in all directions, particularly outwards, as that is the position most required for readily laying hold with one foot, while the other retains its grasp.

It is on account of this peculiar adaptation of the feet to the climbing habits of the bird that the gene

* Mudie's Natural History of Birds.