FIRST CLASS OF ANIMALS.

213 those that are destitute of a spine, or vertebral column. The vertebral animals are subdivided into four classes, and the invertebral into five. (See Appendix.) Each of the classes is divided into a greater or less number of orders, distinguished by some important, clear, and remarkable peculiarities of conformation and structure, which are common to all the animals included under each of them. Orders are subdivided into genera. These comprehend animals that have a general external resemblance to each other, a kind of family likeness. Genera are made up of species. Each distinct. kind of animal constitutes a species, and they are known from one another by their size, colour, form, and various other circumstances of external appearance.

Each kind of animal, then, constitutes a distinct species; a number of species taken together form a genus; those genera which have important and well defined points of resemblance in structure and conformation common to all, are placed together in an order; whilst upon a similar principle, but more extensive in its application, these orders are marshalled into separate classes.

QUESTIONS-1. What are the inducements to the study of Zoology in our own country? 2. Why is this study advantageous to the young? 3. Upon what is a classification of the animal kingdom founded? 4. What are the first two grand divisions? 5. How are these subdivided? 6. What are classes? 7. Orders? 8. Genera? 9. Species? 10. Give a general definition of species, genus, order, and class. 11. What are the nine classes of the animal kingdom? 12. How many and what are the classes according to Linnæus? [NOTE. In the exercise of reading, the words included in parentheses and italicized should be passed over. They are placed in the lessons that the attention of pupils may be particularly directed to them. Pupils should mention them in answering the questions.]

LESSON 96.

The first Class of Animals (Mammalia.)

THE animals of this class are distinguished for a more perfect bodily structure, for more varied faculties, more delicate sensations, a more elevated intelligence, and greater capability of improvement by imitation and education, than those of any other. It is to this class that man, considered

as an object of natural history, properly belongs. He is arranged with the animals of this class, because he nearly resembles them in structure and organs, though raised in reality far above them by the possession of intellectual and moral powers almost infinitely superior.

The structure of an animal is always found to correspond to its character, mode of life, and food; and those, therefore, which have a similar structure, resemble one another to the same extent in other particulars. From the formation of the anterior extremities of an animal, we may judge of the degree of address of which he is capable, and of the kind of motions he is able to perform; and from the structure of his teeth, what is the nature of his food. Thus, the fore-feet of animals may be either enveloped in hoofs, or armed with claws, or furnished with slender nails; and the perfection of the sense of touch will be in proportion to the delicacy of these organs respectively. Thus too, there are three kinds of teeth; the incisive or cutting teeth, the canine or lacerating teeth, and the molar or grinding teeth; but all animals have not each of these kinds of teeth, nor are they of the same shape and formation in all animals.

It is principally from a regard to these parts, that naturalists have proceeded in the arrangement of this class of animals. The orders thus formed are nine in number. (See Appendix.) Of the first order (Biman'a) man is the only example. In point of adroitness, skill, and address, the structure of his body and the faculties of his mind give him great advantages over other animals. In consequence of his erect position, he has the free use of his hands, and his arms have unincumbered and various motions in every direction. There are several distinct races of mankind inhabiting diffe rent portions of the earth, which differ one from another more or less in form, in features, in complexion, and in character. The cause of these varieties has never been satisfactorily pointed out. They have been attributed to climate, to situation, and to manner of life, but none of these circumstances appear sufficient to produce them, and we therefore still remain in ignorance on the subject. But notwithstanding the differences in man, he maintains every where a decided rank, far above that of any other animal. He is the only one which has the power of communicating its thoughts and feelings by articulate speech; the only one which can

ORDERS OF MAMMALIA.

215

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 overpowering 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. structure evidently fits them for climbing, and their usual places of habitation are trees, on the fruits of which they feed.

tree.

Their

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 The second tribe includes a number of small animals, which feed principally upon insects, and are called insec tivorous, 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

216

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 fo a great degree of torpor, listlessness, and indisposition to motion; but some more than others. The sloth, the ant eater, 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 examples 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 animal 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

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 resemblance 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