Genekal Chakactebs.- 



-MAMMALU.- 



-Classification. 



by which means the feet are at once achuirably adapted 

 for long-continued and swift motion, and completely 

 deprived of all prehensile power. The faculty of 

 turning the fore-foot, consequently, becomes unneces- 

 sary, and we find, accordingly, that in the hoofed 

 animals, the radius is reduced to a perfectly rudi- 

 mentary condition, or amalgamated with the ulna, or 

 altogetlier suiipressed. In the hog, fig. 108, Plate 33, 

 the metacarjial bones and phalanges, of which we find 

 four series, remain distinct, but only the two middle toes 

 reach the ground; tlie others terminating in the two 

 little hoofs whicli project from the back of the foot in 

 this animal. In the sheep, fig. 103, Plate 33, the amal- 

 gamation and suppression go still further ; for here 

 we find only one metacarpal bone and two toes, each 

 covered bj' a hoof. In the horse, again, even the second 

 toe is su])pressed, and with the exception of the wrist, 

 the whole limb is essentially composed of a single series 

 of bones placed end to end. Thus, from the beautiful 

 and delicate organization of the human hand, au organ 

 capable of performing the most varied functions, down 

 to the single toe of the horse, incased in a solid horny 

 hoof, we find an uninterrupted series of steps, by trac- 

 ing which we may see clearly how the great Designer, 

 by merely modifying a single original plan, has pro- 

 duced creatures destined to play the most various parts 

 in the grand economy of nature. And although we 

 may attribute greater perfection to one form than to 

 another, it must be remembered that such expressions 

 are purely conventional, and that each creature, incom- 

 plete as the development of some of its parts may 

 appear when compared with the same parts in other 

 animals, is in reality as perfect, and as perfectly 

 adapted to the purpose for which it was created, as any 

 other; indeed, those very modifications of structure, 

 which, at the first glance, would seem to be imperfec- 

 tions, are found, liy caieful study, to constitute beauties 

 instead of blemishes in the great spectacle of nature. 



We find the same structure, and the same modifica- 

 tions of structure, in the posterior as in the anterior 

 limbs ; but in these the mode of attachment to the rest 

 of the skeleton is usually ot far greater strength and 

 solidity. The bones of tlie pelvis, which here take the 

 place of the shoulder-blades and collar-bones, are 

 immovably fixed to the sacrum; and, although in the 

 embryo, and sometimes in the young mammal, there 

 are tln-ee of these bones on each side, in the mature 

 animal these are all completely united together; in 

 most cases, also, the two sides of the pelvis are firmly 

 united in the median line below, so as to form a strong 

 but irregular ring of bone. 



Near the middle of each side of this ring is the socket 

 for the articulation of the thigh-bone or fcm^lr, U, which 

 is usually a long, cylindrical bone with a nearly glo- 

 bular head, set on it almost at a right angle. Below 

 this, at the knee-joint, are articulated the tibia and 

 fibula, or shank-bones, .j, K ; and these are followed 

 by the tarsus, h, including the heel, the mdaiarsus, M, 

 and the phalanges of the toes, N. The correspondence 

 of these bones with those of the anterior limb, will be 

 at once seen by a glance at the figures of the skeletons, 

 Plates 32, 33, 34 ; and these also show clearly that the 

 modifications already described as occurring in the fore- 



leg, are accompanied by corresponding changes in the 

 hinder extremities. The onlj' mammals in which the 

 hinder limbs are wanting are the Cetacea (whales, etc.), 

 and in these the pelvis is represented by a pair of 

 bones, united below in the form of the letter V, and 

 suspended in the muscles below the sacrum, fig. 1 d. 



The classification of the Mammalia stih generally 

 adopted, and the one which will be followed in the 

 present work, is founded, with some important modifi- 

 cations, upon that of Cuvier, which in its turn was a 

 great improvement upon the system proposed by Lin- 

 naeus. The great Swedish naturalist divided the Mam- 

 malia into seven orders, distributed in three primary 

 sections, called unyuiculala, or clawed mammals ; 

 uncjulata, or hoofed mammals ; and mutica, or maimed 

 mammals. The last section includes only the order 

 Cete, formed by the whales and allied forms, in which 

 as has already been stated, the hinder limbs are wanting. 

 The hoofed mammals form two orders — the Peuoea, 

 or cattle, including the ruminating quadrupeds, and the 

 Bellu^e, those which do not chew the cud. Of the 

 four orders of clawed mammals, the first or PiUMATE-S, 

 distinguished by having two pectoral mamma;, and by 

 certain characters of tlie teeth, includes tlie human 

 species, the monkeys and their allies, and the bats ; tlie 

 second, Bruta, in which the incisor teeth are wanting, 

 is formed by the sloths, ant-eaters, and allied species ; 

 the third, FekvE, includes the carnivorous mammals ; 

 and the fourth, Glikes, those which, like the rat and 

 the rabbit, have two chisel-like incisors in each jaw. 



Cuvier, following the general arrangement of Lin- 

 naeus, also adopts the same indications of a division of 

 the class Mammalia into three primary groups. But 

 in the Cuvierian system we find no order Primates ; 

 and the species of which this Linnscan group is com- 

 posed are distributed into three orders. Man, as the 

 highest type of organization, is placed in a distinct 

 order, called Bimana, or "two-handed ;" the monkeys 

 and their aUies form a second order, that of the Quad- 

 RUMANA, " four-handed ;" and the bats are associated 

 with the greater part of the Linnajan FercE, to form 

 Cuvier's order of Carnassicrs or Carnivora. Another 

 portion of the Fcra: of the great Swede were, however, 

 separated by Cuvier, on account of certain singularities 

 in their organization and mode of reproduction, to form 

 the order of Marsvpiaux or Marsupialia, so called 

 from the females having an abdominal pouch in which 

 the young are protected for some time after their birth. 

 Two other unguioidate orders are admitted by Cuvier. 

 These are called Rongeurs, Kodentia (gnawers), and 

 Edciiies or Edektata (toothless mammals), by the 

 French naturalist, and correspond with the Glires anil 

 Bruta of Linnaeus. Cuvier's two orders of hoofed 

 quadrupeds, the Pachydermcs or Pac'IIYder.mata, 

 and the Ruminants or Ruminantia, correspond with 

 the Linnaean groups Bdlum and Pccora, and both 

 systems are closed by the whales, etc., which form 

 Cuvier's order of Ce'tacis or Cetacea. 



The most important new feature in Cuvier's classifi- 

 cation of the Maram.alia consists in the establishment 

 of the order Marsupialia. These singular animals wlncli, 

 with the exception of the American opossums, are con- 

 fined to Australia and the adjacent countries, are dis- 



