They crowd round vessels before and during stormy weather, partly for the sake, it is supposed, of shelter, and partly for

that of food. Sailors regard them with superstitious feelings, and have long given them the name of " Mother Carey's chickens," from some hag of the olden time, whose name would have passed into oblivion had it not been associated with those harmless little birds. Their dusky plumage, diminutive size, their habit of running upon the surface of the water, and the circumstances under which the mariner sees them, account very naturally for the feelings with which he regards them.

CLASS IV.-MAMMALIA.

QUADRUPEDS, WHALES, BATS, MONKEYS, &c.

We have now reached the highest class in the animal kingdom, that class to which man himself belongs. Here only

do we find organs for supplying to the young, during infancy, that fluid nutriment to which we give the name of milk.

Every animal that suckles its young may, from that circumstances, be referred to the present class. They all have warm blood, and breathe by lungs.

While scales form the characteristic covering of fishes, and feathers of birds, hair may be said to be that of the Mammalia. It is not invariably present, and it undergoes many modifications in its appearance. We term it wool upon the sheep; the same material becomes spines upon the Hedgehog, and quills upon the Porcupine (Fig. 205). It is converted into bony plates in the defensive covering of the Armadillo (Fig. 217); and in the weapon with which the nose of the Rhinoceros (Fig. 206) is armed, it presents the appearance of solid horn, adhering to the skin, not growing from the skull.

The greater number of the animals of this class possess four feet, which are used for the purpose of locomotion; but this structure, though general, is by no means universal. In the true Monkeys (Fig. 246) all the extremities are shaped like hands; in the Seals (Fig. 232) they are converted into paddles; and in the Bats (Fig. 240), the bones which correspond to our fingers are so long, as to form the framework of the wings.

Great difference is found to prevail with regard to the number, form, and arrangement of the teeth. Farther examination shows that the teeth vary in these particulars,

according as the food of the animal is to consist of soft flesh, or of horny-covered insects; of tender herbs, or of firm wood. And so entirely is one part of the bodily frame made to correspond with another, that it is perfectly possible, merely by an inspection of the teeth, to determine, with considerable certainty, the diet, the habits, and even the general structure of most of the Mammalia.

Hence the teeth, viewed in connection with the form of the extremities, furnish, so far as external characters are concerned, a sound basis for classification. As such they were regarded by Cuvier; and the principles he laid down have been adopted by succeeding naturalists, though some differences have existed as to some of the details.

According to the following arrangement, the inferior animals are divided into ten Orders. To these man must be added, constituting another Order of which he is the sole representative, and making eleven Orders in all.*

Each of these shall now in turn be briefly noticed, commencing with those which are lowest in the scale, and gradually ascending to man, who has been gifted with dominion "over every living thing that moveth upon the earth."

MARSUPIAL OR POUCHED ANIMALS.

MARSUPIATA.

'Deform'd, unfinish'd, sent before my time

Into this breathing world, scarce half made up."-SHAKSPEARE.

THE present Order derives its scientific name from the circumstance of the female, in most instances, being furnished with a peculiar pouch,* in which the immature young are received and nourished, and to which they retreat for safety. The Kangaroos and Opossums are familiar examples. The Kangaroos of Aus

tralia are vegetable-feeding animals, which browze upon herbage like oxen, and in some cases chew the cud as

they do. Some of them,

when in their common erect position (Fig.207), are nearly as tall as a man; others,

Fig. 207.-KANGAROO.

both in size and general appearance, resemble the com