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ORDERS OF MAMMALIA.

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properly be said to avail itself of the advantages of society ; and the only one that, strictly speaking, educates its young. It is in consequence of these advantages, particularly that derived from association, that he has been enabled under all circumstances, to acquire and preserve a dominion over other animals, to protect himself against the severity of climates, and thus spread his species over every part of the earth. Naturally tender and defenceless, he could only exist in the most equable and temperate climates; but, aided by the inventions and discoveries of social life, he is enabled to brave the cold of the polar circle, as well as the overpow ering heat of the regions on the equator.

The second order (Quadruman'a, apes, baboons, &c.) of this class of animals forms a numerous tribe, and comprehends a great variety of species. They maintain the erect position with difficulty; it is a constrained one. Their structure evidently fits them for climbing, and their usual places of habitation are trees, on the fruits of which they feed.

The third order is subdivided into several tribes or families, accordingly as they are more or less carnivorous. The first tribe is that of the Bats, distinguished by their wings, which are formed of a thin fold of skin, extending between the two limbs of the same side. By means of this apparatus, many of them are able to fly with a force and rapidity equal to that of birds; but in others it answers only the purpose of a parachute to break their fall from lofty places, or to enable them to perform great leaps in their passage from tree to tree. The second tribe includes a number of small animals, which feed principally upon insects, and are called insec tiv'orous, as the shrew-mouse and the mole. The third tribe possesses the characteristics of carnivorous animals in the highest degree. They are endowed not only with an appetite for animal food and a structure adapted for its mastication and digestion, but with strength and courage for seizing and retaining it; as the wolf, fox, lion, panther, and others. A fourth tribe of this order comprehends the amphibious "animals, as the Seal and the Morse. They live almost entirely in the sea, but they cannot remain constantly under

water.

The fourth order (Roden'tia, gnawers) are remarkably qualified by the arrangement of their teeth for penetrating

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ORDERS OF MAMMALIA.

very solid substances; and they frequently feed upon woody fibres and the bark of roots and trees. Of this order, among others, are the beaver, the squirrel, and the various species of hare and rabbit. Beavers are aquatic animals, and, they construct themselves habitations upon waters which are sufficiently deep never to be frozen to the bottom.

The fifth order (Edenta'ta, toothless) are remarkable for a great degree of torpor, listlessness, and indisposition to motion; but some more than others. The sloth, the anteater, and the armadillo are among them, and of each of these there are several species. The three-toed sloth is an animal whose very aspect is painful and disgusting. The expression of its countenance, and its whole attitude, indeed, convey to the beholder the impression, that its very existence is a burden.

Ruminating animals form the sixth order of this class, and exaniples may be found in the camel, antelope, deer, ox, and sheep. They have been more valuable to man than any others. Their flesh furnishes a large proportion of our ani mal food. They are mild, docile, and easily domesticated.

The seventh order (Pachyder'mata, thick-skinned) embraces all the animals with hoofs which do not ruminate, as the elephant, the tapir, the horse. The Hippopotamus, or River-Horse, inhabits principally the rivers of the south of Africa. It walks with ease at the bottom of the water, though obliged, occcasionally, to rise to the surface for breath.

Animals of the whale kind, or cetaceous animals, form the eighth order. They are usually confounded with the class of fishes, which they resemble in many particulars of external appearance, as well as in the circumstance of residing always in the water. In point of structure, however, they clearly belong to the present class, since they breathe air by means of lungs, are warm-blooded, produce their young alive, and nourish them with milk.

The Marsupial animals, which form the ninth order, are distinguished from all others by the possession of a receptacle, formed by a duplicature of the skin, for the purpose of holding their young, or of receiving them on the approach of danger. Such are the Kanguroo and Opossum.

QUESTIONS.-1. By what are animals of the class Mammalia distinguished? 2. Why is man, as an object of natural history, arranged with this class? 3. From a regard to what parts of animals of this

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class have naturalists arranged them into orders? 4. Describe the first order of mammalia,-second, &c. 5. What are the orders of mammalia according to Linnæus? [NOTE. The distinctive characters of the Linnæan orders of mammalia, with the exception of the last, depend on the kind, position, and number of the teeth, and thus animals of very different habits were brought together, from a reseniblance in one comparatively unimportant particular.]

LESSON 97.

Birds.

'Ornithology, that branch of natural history which describes the structure, economy, habits, &c. of birds.

Vis'cid, glutinous, tenacious.

THE immense catalogue of the species of birds, and the variety and beauty of their external characters, have made them favourite objects of investigation with the natural historian. The extraordinary degree of instinct displayed in all their habits and economy, more especially in the construction of their nests, the care of their young, and the conduct of their migrations, have called forth the admiration of the philosopher and the lover of nature. The splendid colouring of their plumage, the powers of melody, and the liveliness and docility of many species, have given them value as objects of beauty and entertainment.

The class of birds is divided, according to their structure and habits of life, into six orders. Birds of prey, or rapacious birds (accip'itres) correspond, in many respects, with the carnivorous animals among quadrupeds. They are distinguished by their strong, hooked beaks, and their crooked and powerful talons. They are particularly remarkable for the very great distance at which they perceive their prey, and the accuracy with which they direct their flight towards it. Besides the upper and under eye-lids, all birds have a third which is semi-transparent, and serves the purpose of -protecting the eye from the contact of external bodies, or from too powerful light, whilst at the same time it does not prevent them from distinguishing the objects around them. This membrane is situated at the inner angle of the eye, and is drawn over the globe of it, like a curtain, at will. It

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is by means of this protection, that the eagle is enabled to look steadily at the sun.

Sparrows (Pas' seres) form the most extensive and numerous order, embracing a great variety of species, which differ so much among themselves, as to be hardly capable of an intelligible description, common to them all. To this order belong those species which are most celebrated for the sweetness and harmony of their notes; and in general the organ of voice in them is larger and better formed, than in any others. Among them are the robin, the swallow, the linnet, the humming-bird, and the nightingale.

The third order (Scanso'res, Climbers) includes those birds that have the external toe upon each side turned backwards, which enables them to grasp substances more firmly, and affords them a more sure support, than other birds. Among them are the woodpecker, the cuckoo, and the parrot. Woodpeckers are furnished with a long and slender tongue, covered towards its tip with spines or bristles, which are turned backwards, and coated with a thick viscid secretion. They run in every direction around the trunks and branches of trees, striking them with their beaks, and thrusting their tongues into holes and clefts, for the purpose of drawing out their food.

The Gallinaceous birds (Gallina'cea) have short and weak wings, and, of course, they are not constructed for long and continued flight. Of this order are the peacock, the turkey, the pigeon and the common fowls. The pigeons form in some particulars an exception to the general characteristics of their order. They fly very well, live in pairs, and build their nests upon trees or in the clefts of rocks. The most remarkable species among them is the crowned pigeon of the Molucca islands, which is equal in size to a turkey. Its voice is exceedingly loud and harsh, and is said to have frightened sailors who landed on the islands which it inhabits, by its resemblance to the yells of the savage natives.

The Waders (Gralla,) otherwise called shore birds are distinguished by their very long and naked legs, which permit them to wade to a considerable depth in the water without wetting their feathers. All birds with this structure are not, properly speaking, waders in their habits, though they are ranked in this order. Among them are the heron, plover, oxeye, and ostrich. The ostrich is almost incapable of

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flight, but runs with immense rapidity. Its height varies from six to eight feet; it is the most lofty of birds and the swiftest of all animals.

The toes of Web-footed birds (An'seres,) are connected together by a membrane, which fits them for being used as oars. Their whole structure is such as to adapt them for swimming; their legs are situated far back upon their bodies, their feathers are thick, smooth and oily, and their skin beneath covered with a layer of close down, which effectually protects them from the contact of water. Most of them are capable of lofty and long continued flight, as the wild goose and duck; whilst others from the shortness of their wings can scarcely raise themselves into the air, but are principally confined to the surface of the water.

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As quadrupeds cast their hair, so all birds every year obtain a new covering of feathers; this is what is termed moulting. During its continuance, they always appear sickly and disordered; no feeding can maintain their strength, for their nourishment is now consumed and absorbed in administering a supply to the growing plumage. It is worthy of observation, that of the vast number of birds which inhabit the globe, it has never been discovered that a single one is of a poisonous nature. They differ very much in being more or less salutary and palatable, as an article of diet; but none of them are pernicious. Sea-faring people and travellers eat every species of egg without the smallest hesitation.

QU.:STIONS.-1 What renders birds objects of interest to the naturalist and philosopher? 2. Describe the first order of birds. 3. Second. 4. Third. 5. Fourth. 6. Fifth 7. Sixth. 8. What is said of their moulting? 9. What is worthy of observation respecting them? 10. What are the Linnæan orders of birds? (sce Appendix.)

LESSON 98.
Reptiles and Fishes.

Icthyology, that branch of natural history which treats of fishes. REPTILES have less intelligence, fewer faculties, and less instinct, than either quadrupeds or birds. They are, in general, sluggish and indolent in their habits of life, and obtuse in their sensations. In cold countries they pass the greater

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