General Characters. MAMMALIA. Classification. 
6 
by which means the feet are at once admirably 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 
altogether suppressed. In the hog, fig, 108, Plate 33, 
the metacarpal bones and phalanges, of which we find 
four series, remain distinct, but only the two middle toes 
reach the ground ; the others terminating in the two 
little hoofs which 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 by a hoof. In the horse, again, even the second 
toe is suppressed, and with the exception of the wrist, 
the whole limb is essentiall}" composed of a single series 
of bones placed end to end. Thus, from the beautiful 
and delicate organization of the human hand, an 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, by careful 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 the 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 three 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 femur ^ ii, 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, l, including the heel, the metatarsus, 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 only 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 belo.w in the form of the letter V, and 
suspended in the muscles below the sacrum, fig. 1 D. 
The classification of the Mammalia still 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 unguiculata, or clawed mammals ; 
ungulata, 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 Pecora, 
or cattle, including the ruminating quadrupeds, and the 
Bellu^, those which do not chew the cud. Of the 
four orders of clawed mammals, the first or Primates, 
distinguished by having two pectoral mammae, and by 
certain characters of the teeth, includes the human 
species, the monkeys and their allies, and the bats ; the 
second, Bruta, in which the incisor teeth are wanting, 
is formed by the sloths, ant-eaters, and allied species ; 
the third, Fer.®:, includes the carnivorous mammals ; 
and the fourth, Glires, 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 Linnsean 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 allies form a second order, that of the Quad- 
RUMANA, “ four-handed and the bats are associated 
with the greater part of the Linnsean Ferae, to form 
Cuvier’s order of Carnassiers or Carnivora. Another 
portion of the Ferce 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 Marsupiaux 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 unguiculate orders are admitted by Cuvier. 
These are called Rongeurs, Kodentia (gnawers), and 
Edentes or Edentata (toothless mammals), by the 
French naturalist, and correspond with the Glires and 
Bruta of Linnaeus. Cuvier’s two orders of hoofed 
quadrupeds, the Pachjdermes or Paciiydermata, 
and the Ruminants or Euminantia, correspond with 
the Linnaean groups Belluce and Fecora, and both 
systems are closed by the whales, etc., which form 
Cuvier’s order of Ce'tach or Cetacea. 
The most important new featui’e in Cuvier’s classifi- 
cation of jhe Mammalia consists in the establishment 
of the order Marsupialia. These singular animals which, 
with the exception of the American opossums, are con- 
fined to Australia and the adjacent countries, are dis- 
