MOTION. 
articulations of the carpal and tarsal bones 
allow a very limited motion. The axes of these 
bones are inclined almost vertically, but those 
of the metatarsal and metacarpal bones are 
directed rather more horizontally. The phalan- 
ges of the toes diverge from each other to give 
a broader base of support to these great digiti- 
grade quadrupeds: their walk is slow and heavy, 
and the order in which the legs move is the 
same as in the Solidungula. 
Carnivora.—tin the structure of carnivorous 
quadrupeds, such as the Lion and Tiger, we 
observe the strength of the more ponderous 
and slow-moving Ruminants, as the Ox, com- 
bined with the agility and speed of those 
lighter forms, as the Stag. ‘This union of 
strength with speed is due to the geometrical 
and physical relations of the elements that enter 
into the composition of these powerful digiti- 
grade Carnivora. The spine possesses greater 
mobility by the retraction of the spinous and 
transverse processes, and the trunk is of less 
weight and bulk compared to their mus- 
cular power than in the herbivorous rumi 
nants. In the Lion the scapula, which is 
directed very obliquely forwards, is unfettered 
in its motions by a clavicle; the humerus is 
long and cylindrical, and has its axis directed 
_ downwards and backwards, forming, with that 
of the scapula, an angle of 110°; the radius 
_ and ulna are articulated so as to allow of pro- 
Ration and supination; the olecranon projects 
several inches beyond the axis of rotation in 
the elbow-joint, and constitutes a powerful 
lever for the application of the tendons of the 
extensor muscles of the arm; the direction of 
__ the sacro-iliac articulation is eccentric to that of 
_ the sacrum, and the pelvis, which is inclined 
very obliquely backwards, forms, with the pro- 
_ jection of the vertebral column, an angle of 
_ about 110°; the femur is directed forwards in 
Standing at an angle with the pelvis of 84°; the 
tibia and fibula are distinct bones; the calca- 
neum is of great length; the tarsus and meta- 
tarsus inclined vertically, the phalanges horizon- 
tally; the last of which is elevated above the 
plane of motion.* In both the arms and legs 
the phalanges terminate in strong, curved, re- 
_ tractile claws for the prehens‘on and laceration 
of prey. The posterior extremities in both the 
~ lion and tiger are longer, and the bones in- 
_ ¢lined more obliquely to each other than the 
anterior, giving them greater elasticity and 
_ power in springing: they walk, trot, and 
gallop upon the same principle as the horse. 
Cheiroptera.—The bat being principally or- 
ganized for flight, is provided with compara- 
tively diminished powers of progression upon 
Solids; the legs are feeble and. incapable of 
Supporting the trunk, and they move by 
a crawling, and sometimes a small leaping 
motion, 
Quadrumana,—Of all Mammalia, the figure 
and organization of the Quadrumana approx- 
imates most nearly to man. They are destined 
* Itis in consequence of the direction which the 
tarsal, metatarsal, aud phalangeal bones take, 
that the Carnivora and other animals are digiti- 
grade, ; 
455 
to climb the trees of the forest; to leap from 
branch to branch; to walk, trot, or gallop as 
Lil iy upon plain surfaces, with the trunk 
directed either horizontally, or to walk as 
bipeds upon the posterior extremities alone, 
with the trunk directed vertically. For these 
several positions of the trunk and modes of 
progression they are furnished with a suitable 
geometrical conformation of their osseous frame- 
work, more especially in the Ourangs and 
Chimpanzee. In the Quadrumana the spinal 
column has greater freedom of motion than in 
the Pachydermata and Ruminantia. The sca- 
pula, which is directed forwards at an acute 
angle with the vertebral column, is supported 
byaclavicle; the ginglymoid cavity is deep, for 
the secure rotation of the head of the humerus ; 
the latter is long, but slender in the Hylobates 
or long-armed Gibbon; the radius and ulna 
are distinct and free from the motions of pro- 
nation and supination; the carpus is often 
composed of nine bones by the division of one 
in the second row, to give greater mobility to 
the hand; the metacarpus and phalanges are 
much lengthened, but the same in number as 
in man ; the iliac bones, which are long and 
narrow, are directed backwards nearly parallel 
to the vertebral column, but presenting with it 
posteriorly a very small angle; the tuberosities 
of the ischium incline outwards, giving a large 
base of support to the animal when resting on its 
callosities. In the Hylobates, the femur is curved 
and of less length than the humerus, but it is 
nearly of equal length in the Chimpanzee and 
Ourangs. The tibia and fibula are long and slen- 
der; the articulations of the astragalus, calcis, 
scaphoid, cuboid, and cuneiform bones are 
directed obliquely, which gives to the ankle- 
joint a motion eccentric to the axis of the leg, 
the effect of which is to throw the animal upon 
the outer edge of the hands and feet. The 
long metatarsal and phalangeal bones are in- 
clined upwards and inwards, by which they are 
adapted for prehension in climbing or standing 
on the branches of trees; the calcaneum is 
short, and its axis of motion is eccentric, 
with respect to the direction of the tendons of 
the gastrocnemius and soleus muscles ; which, 
though not very powerful, act at a mechanical 
disadvantage tending to diminish their effective 
force in a twofold manner. In many Quadru- 
mana, as the Cercopithecus and Semno- 
pithecus, the lengthened and flexible tail is 
employed as an organ of prehension, but in 
the Macacus and others the tail is pendent, 
and not employed in their movements. In the 
Mandrills the tail is very short; the Simia, 
Pithecus and Simia Innuus have merely a tuber- 
cle, whilst the Ourangs and Gibbons are desti- 
tute of this organ altogether; the deficiency of 
the mass of extensor muscles of the ankle- 
joint in the Gibbons and Jockos is alleged by 
Daubenton * as a reason why these apes cannot 
maintain themselves in the erect position. Per- 
rault is of opinion that the straightness of 
the ossa ilia prevents the extensor muscles 
* Encyclop. Méthodique Dictionnaire des Ani- 
maux, p. 20 
