454 
difference arises chiefly from the great length of 
the tibia, which is nearly equal to that in the 
Giraffe, the former being to the latter as 16°5 
to 18 inches. In the Rodentia, as the Hare, 
Agouti, and Guinea-pig, we observe a similar 
disproportion in the length of the extremities. 
The Rabbit, in moving slowly, advances the 
anterior feet two or three steps alternately, the 
roa limbs remaining inactive. The body 
ving been elongated by this means, the 
anal legs are suddenly extended and drawn 
$ simultaneously ; thus, the rabbit walks 
with the fore, and leaps with the hinder pair 
of legs. Those quadrupeds in which the 
length of the posterior extremities much pre- 
dominates over that of the anterior, are ob- 
served to descend declivities in a straight line 
with difficulty, on account of the great inclina- 
tion of the axis of the trunk to the plane of 
motion, which puts the animal in constant 
danger of oversetting; they therefore take a 
zigzag course. In ascending a hill, however, 
their progression is greatly facilitated by the 
length of their posterior extremities. The speed 
of the Hare is well known to be greater than 
that of the fleetest horse or hound. 
Ruminantia.— Many of the Ruminantia, 
such as the Deer and Antelope, are beautifully 
and symmetrically organized for rapidity of loco- 
motion ; the Camel for prolonged power of tra- 
versing the arid desert; and the Ox for the 
strength and development of its muscularsystem. 
Amongst the Ruminantia some species have 
the neck of great length, and the head being 
surmounted with massive horns, or antlers, 
renders it necessary that the spinous processes 
of the lower cervical and superior dorsal verte- 
bra be lengthened, so as to form powerful 
levers for the attachment of muscles, and of 
that yellow elastic tissue, the ligamentum 
nuche, which is greatly developed in the Rumi- 
nantia, to support the head and its appendages ; 
the latter acting at the end of a long lever tends 
to throw the centre of gravity forwards nearly 
between the anterior extremities. The figure 
of the trunk is elliptical ; its transverse axis dimi- 
nishes as it approaches the anterior extremities ; 
there are no clavicles ; and from the small degree 
of curvature of the ribs, the arms are thrown 
almost together beneath the trunk, and nearly 
in the plane of the mesial section of the body. 
The Giraffe presents greater length of osseous 
columns for the support of its superstructure 
than is to be found in any other animal; the 
bones of the anterior extremity are directed 
more vertically than those of the posterior, 
which enable it to support, with less weight of 
bone and less expenditure of muscular force, 
its lengthened neck, upon which the head acts 
as at the end of a long lever. The metatarsal 
and metacarpal bones are of great length, and 
being directed vertically, as in the Pachy- 
dermata, the trunk is elevated to a great height. 
The three phalanges of each finger and toe are 
inclined forwards ; the extensor tendons act on 
them by means of a pulley, through the inter- 
same species of animals may be considered nearly 
constant for all ages, sexes, and magnitudes, 
MOTION. 
position of the sesamoid bones, which increase — 
the distance of the direction of the tendons — 
from the axes of the joints, and give them 
greater power. - 
The length of the arms to that of the bes 
in the Giraffe is as 71 to 67 inches, whicl 
gives a difference of four inches in favour of 
the length of the arms. This dispro 
furth the | tenet Coa ) 
er augmented by the len "d 
and by ie: inceeadl angular disposition of 
the posterior extremities. 
In the Camel, the length of the legs is more 
nearly equal than in the Giraffe, the anterior ~ 
being to the posterior limbs as 49 to 47 inches ; 
the spine is consequently directed more hori- — 
zontally than in the Giraffe. The order in which 
the movements of the legs succeed each other in 
the Camel is like that of other quadrupeds. 
The velocity of the camel at its common tra- 
velling pace is estimated at 2} miles an hour.* 
In Deer and Antelopes, the geometrical pro- — 
portions are such as to confer on them great 
speed. The lightness, elegance, and 
of their osseous fabric, the energy of their mus- 
cular system, the freedom of motion in the 
vertebral column, the large are described in tl 
greatest rotation of the ry and pelvis, the 
length and proportions of their extremities, the — 
length of bre olecranon and calcaneum, the 
vertical direction and my of the sal 
and meta bones, the inclined direction — 
and freedom of motion of the three phalanges 
of the fingers and toes, the number and relative 
distances of the joints,—all conspire to perfect 
the progression of these Ruminantia. They 
bound by the sudden flexion and extension of — 
all the legs, which are lifted from the ground 
simultaneously, and which, after projecting t ® 
centre of gravity in a vertical direction, appear 
to arrive agiin synchronously on the plane o 
motion. They walk or trot ier the prineip 
of other quadrupeds, as explained already in— 
the Horse. The Deer and Antelope, celebrated - 
for speed, bound over plains, ascend or des 
mountains, and also possess the power of 
ing across an abyss of great breadth, or dowr 
precipices twenty or thirty feet in a th- 
outsustaining the slightest injury from . 
Proboscidia——The enormous bulk of t 
head and body, and massive proportions of th 
osseous and muscular systems, are more largely 
developed in the ponderous Proboscidia than in 
any other known species of terrestrial quadru- 
peds. The dimensions of the bones of th 
extremities are proportional to the gravity 
the superincumbent weight; the scapula an 
pelvis, as well as the axes of the scapulo-humer 
and ilio-femoral cavities, are directed nearly pe 
pendicular to the plane of progression, and t 
whole column in each extremity presents a le 
angular disposition of the axes of the bon 
than is found in the lighter and more agi 
solidungulous Pachydermata. The olecrano 
and calcaneum, as well as the ers 
afford long and powerful levers for the applica 
tion of muscular action. The ginglymo 
P 
UCHaAal 
* Sce Rennel on the rate of travelling of cam € 
Phil. Trans, 1791, p. 129, ‘ 
