meantime brought forward.

For the purpose now in view it will be well, perhaps, to follow the suggestion of the great naturalist, Buffon, and begin with creatures which are amongst the best known and most familiar, and thence proceed to speak of less and less familiar forms.

In this Essay assertions will be freely made as to the natural affinities which the author believes to exist between the creatures to be enumerated, but no attempt will be made to give the reasons for such assertions. The justification of such affirmations will, it is believed, become apparent later, when the organization of living beings shall have been portrayed as far as the space and the ability at the command of the writer may enable him to portray them.

As before said the object now in view is to endeavour to present a general view of living beings—of animals and plants—in the hope of fixing in the reader's memory the names of species, and of groups of species, to which names reference will have to be more or less frequently hereinafter made. At the least, such a catalogue may serve for reference whenever the reader may come upon the names of animals or plants, or of groups of animals or plants, the meanings of which names may have escaped his recollection.

The animals most familiar to us, our domestic cattle and our dogs and cats, all belong to a group of animals technically termed mammals, from the circumstance that the females have milk-glands (or mammæ), by which they nourish their young. The name "beasts" may be set apart for the brute animals belonging to this group; but they do not altogether form it, since man himself—the most individually numerous of all the large animals—is, structurally considered, also a mammal.

For various reasons, which will appear later, the domestic cat (which is a member of the genus Felis) may serve as an instructive, as it is a familiar, example of a highly-organized mammal. Allied to the cat, and formed on so completely the same model as hardly to differ, save in size and colour, are the lions, tigers, leopards, jaguars, pumas, ocelots, lynxes, and wild-cats of different kinds. What are commonly called pole-cats are not really cats, but belong to a different "family;" while civet-cats are not cats in the strict sense of that term. Civet-cats pertain to a group of beasts called Viverrines (Viverridæ), to which all ichneumons and mongouses (which appear to have been the domestic cats of the ancient Romans) as well as the bone-eating hyænas also belong.

The viverrines and the cats, however, together form one great family to which the scientific name Felidæ has been assigned. The pole-cats, together with the ermine, ferret, weasel, marten, sable, skunk, badger, the otter and the bear, raccoon, coati-mondi, with the kinkajoo, panda, &c., all belong to another family. Of this family the bears are the largest in size, and constitute a small group or "genus" called Ursus, whence the whole family bears the designation Ursidæ.

Our dogs (genus Canis) are, as every one knows, first cousins to jackals and wolves and near allies of the different species of fox, the whole forming a family—Canidæ.

The otter has been already referred to, and it may be thought that mention of the seals and sea-lions has been unintentionally omitted. But the seals and sea-lions, in spite of a certain slight resemblance to otters, due to similarity of habit, are not really near allies of the latter. They (i.e., seals and sea-lions), together with the walrus, form, indeed, a very distinct family, which is termed Phocidæ, because its type, the common seal, belongs to a subordinate group, or "genus," named Phoca.

All these families, Felidæ, Ursidæ, Canidæ, and Phocidæ form together one greater group or "order," to which, of course, these four families are subordinate. This order is called "Carnivora," because it is made up of carnivorous or flesh-eating beasts.

The other familiar beasts first referred to—our domestic cattle of all kinds—form, together with all swine, horses and all asses, deer, antelopes and camels, another great order of beasts called Ungulata, because the nails of their feet are so large and solid as to form "hoofs." This order of hoofed-beasts, or ungulates, is a very large order, and is divided into two sub-orders, and in each sub-order are various families containing more or fewer genera.

The two sub-orders are characterized by the structure of the foot. The toes of the hind foot, which are made use of in progression, are even in number in one sub-order and are odd-numbered in the other sub-order.

The sub-order of odd-toed ungulates, or Perissodactyla, includes in our day only the horses, asses, zebras, and quaggas (united together in the family Equidæ); the tapirs, the rhinoceroses, and the little hyrax—the coney of Scripture. In ancient times, however, this sub-order was a very large one, but the great majority of the forms belonging to it, which formerly lived, have now become extinct.

The sub-order of even-toed ungulates, or Artiodactyla, comprises all oxen, sheep, goats, antelopes, giraffes, deer, chevrotains,[10] llamas, and camels. All these, from their practice of "chewing the cud," are called "ruminants," and they are multitudinous in kinds. The great plains of Southern Africa are the special home of most kinds of antelope, and the giraffe is exclusively African. Deer have their head-quarters in Asia, though they exist in South America as well as throughout the Northern Hemisphere.

Besides the ruminating artiodactyles there is also an extensive group of non-ruminating artiodactyles, made up of all the various kinds of swine (including the American peccaries), together with the hippopotamus, now found nowhere but in Africa. Distinct as are the ruminating and non-ruminating artiodactyles now, they were in ancient time connected by a great number of intermediate forms which have utterly passed away.

The llamas of South America represent the camels of the Old World, where the latter are to-day exclusively found. When South America was discovered by the Spaniards, llamas were the only beasts of burthen found there, and, indeed, the only cattle of any kind then and there existing; although horses had formerly abounded and had become extinct in South America at a long anterior period.

Somewhat allied to ungulates, but distinct from them, are the elephants, which form an order (Proboscidea) by themselves—an order once rich in many species widely distributed over the earth.

Hardly less familiar than our domestic animals, are our hares, rabbits, mice, squirrels, and their allies, which together form an "order" called Rodentia from the gnawing habits of its members which nourish themselves on vegetable substances. This order of rodents is very rich in species, and consists of many genera grouped in several distinct families—such, e.g., as the family of mice and rats (Muridæ), of squirrels (Sciuridæ), of guinea-pigs and spine-bearing porcupines (Hystricidæ), &c. The largest form of rodent is the capybara (or river-hog of the Rio de la Plata),—which is preyed on by the jaguar. Though a near ally of the little guinea-pig, it is as large as a hog. Amongst the more interesting rodents may be mentioned beavers,[11] the fur-bearing chinchilla, the jerboa (Dipus), the musk-rat (Fiber), and the