ANIMALS AND PLANTS. IN the first of the present series of Essays it was pointed out that the number of kinds of living creatures is so prodigious that it would be a hopeless task for any man to attempt to grasp the leading facts of their natural history, save with the help of a well-arranged system of classification. Such a system enables the student to consider the subjects of his study collectively in masses-masses arranged in a series of groups, which are successively smaller and more and more subordinate. By "subordinate groups" are meant groups which are successively contained one within the other. As an example of such subordinate grouping we may take the group of familiar objects denoted by the word "money." This group contains within it the large subordinate groups, "paper money" and "metallic money;" the latter group again contains the more subordinate and smaller groups, " gold money,” "silver money," and "copper money," and these respectively contain still more subordinate and smaller groups. Thus, the group "silver money" contains the subordinate groups-(1) crowns, (2) half-crowns, (3) florins, (4) shillings, (5) sixpences, &c.; and any one of these (e.g., shillings) is further divisible into groups of "shillings" of the coinage of different reigns. Reversing the process we may, as another illustration, select the group of articles of furniture called "chairs," which (with other co-ordinate groups, such as "tables" and "sofas") is contained within, and is subordinate to, the larger group of objects, "wooden furniture." This latter and larger group is again classifiable (together with its co-ordinate group, "metal furniture") in the yet higher and larger group of "furniture made of hard material," to which the wooden and metal groups are both subordinate. Co-ordinate with the group of "hard material" we * CONTEMPORARY REVIEW, May, 1879, p. 261. have another group (carpets, curtains, &c.) of "furniture of soft material," and these two groups are again subordinate to the largest group of all" furniture." It was also pointed out in the introductory Essay* that there are two kinds of classification, one artificial, the other natural-the latter (the kind aimed at in this Essay) being such a system of classification as leads to the association together in groups, of creatures which are really alike and which will be found to present a greater and greater number of common characters the more thoroughly they are examined. The system of classification which zoologists and botanists adopt is a system founded upon the form, structure, number, and relations of the parts of which each living being consists. It is, therefore, a morphological system, and rests rather upon the appearances of parts and organs than upon the offices which such parts and organs fulfil. It rests, that is to say upon their forms, not upon their functions. The mode in which animals have been arranged in zoological grouping affords an exceptionally good model for classification generally, as has been noted by the late John Stuart Mill. In fact, the number of subordinate groups is very great in zoology. Thus, the kingdom of animals is subdivided into a certain number of very large groups, called sub-kingdoms. Each sub-kingdom is again divided into subordinate groups termed classes. Each class is again divided into still more subordinate groups called orders. Each order is again divisible into families; each family into genera, and each genus into species, while a zoological "species" may be provisionally defined as "a group of animals which differ only by inconstant or sexual characters." It could be wished that the reader should pursue his further inquiries into the natural history of animals and plants, with a knowledge of biological classification already acquired. But this is, unfortunately, impossible, since biological classification reposes upon anatomical facts, and cannot, therefore, be really understood until the main facts of anatomy have been already mastered. Yet something in the way of a classification, or at least of a definitely arranged catalogue, must be even now attempted for the following reason; In the second of this series of Essays we indicated the lines of inquiry which must be followed up by any reader who would become acquainted with the natural history of animals and plants. We saw that their gross and minute structure, their very varied functions, their relations to past time, and their geographical relations as well as their relations to the physical forces and to their fellow organisms, would all have to be successively considered. Obviously, however, it is impossible to * L. c. p. 262. + "A classification of any large portion of the field of Nature, in conformity to the foregoing principles, has hitherto been found practicable only in one great instance, that of animals."-Logic, third edition, 1851, vol. i., chap. viii. § 5, page 279. + CONTEMPORARY REVIEW, July, 1879, pp. 716 and 717. make known the facts of anatomy, physiology, and hexicology* without constant references to animals and plants which may be expected to be either altogether unknown, or at least very incompletely known, to persons as yet unacquainted with zoological and botanical science. References to creatures so unknown or so little known would plainly be of small profit and less interest, unless the reader was already furnished with some mental images of such creatures and groups of creatures-images calculated to sustain his attention and excite his interest in the various kinds of animals and plants, otherwise unknown, which will have to be again and again referred to. Accordingly, an attempt must now be made to set before the reader a rough and general sketch, or catalogue, of what the creatures and groups of creatures are, the names of which will have so frequently to appear in the pages which are to follow. In a word, as the preceding Essay† was devoted to explaining what are the special characters of living beings-i.e., what the phrase "animals and plants" connotes; so the present Essay is intended to explain what that phrase denotes. It is not by any means intended at present to place before the reader a definitive and complete system of classification-that task must be reserved for the conclusion of the series, as it will be the expression of all the facts and inferences which will have been in the 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 mamma), by which they nourish their young. The name "beasts" may be set * L. c. p. 717. + CONTEMPORARY REVIEW, July, 1879: "What are Living Beings?' 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 (Viverride), 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 Felide 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 Phocide, because its type, the common seal, belongs to a subordinate group, or" genus," named Phoca. All these families, Felida, Urside, Canide, and Phocide 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 Equide); the tapirs, the rhinoceroses, and the little hyraxthe 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,* 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 nonruminating 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 familiessuch, e.g., as the family of mice and rats (Muride), of squirrels (Sciuridæ), of guinea-pigs and spine-bearing porcupines (Hystricide), &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. a near ally of the little guinea-pig, it is as large as a hog. the more interesting rodents may be mentioned beavers,† the furbearing chinchilla, the jerboa (Dipus), the musk-rat (Fiber), and the ratmole (Spalax). The jerboa has very long hind legs, and a habit of jumping, so that it resembles superficially (but not really) a small kangaroo. * Very small deer, commonly called in error musk-deer. Though Amongst + The European beavers have abandoned the dam-building habit. They retained it, however, as late as the thirteenth century. |