PECULIAR ENDOWMENTS OF HUMAN HAND. 483 
ments of the thumb and fingers are concerned in its particular 
: ions. 
643. The hand of Man is distinguished from the extremity 
of most Quadrupeds by its possession of an opposable thumb, 
—that is, of a finger which can be made to act in a direction 
opposite to that of the rest. But among the Apes and 
Monkeys, we find this peculiarity not only in the superior 
extremity, but also in the inferior ; whence these animals are 
said to be guadrumanous or four-handed, whilst Man is 
bimanous, possessing two hands only. It must not be sup- 
posed, however, that Apes and Monkeys are superior in this 
respect to Man ; for they possess this distinguishing character 
in a much less ‘striking degree than he does. All the four 
extremities of Apes and Monkeys possess the power of grasp- 
ing, but they are all used also for support ; and we find that 
ia consequence of the shortness of the thumb and great toe, the 
grasping power is very inferior to that which Man possesses. 
But of the four extremities of Man, one pair is specially adapted 
for support, and the other for prehension or grasping ; and this 
by the length and mobility of the thumb, which is capable of 
being brought into exact opposition to the extremities of 
all the fingers, whether singly or in combination. But even 
in those Quadrumana which most nearly approach Man, 
the thumb is so short and weak, and the fingers so long 
ad slender, that their tips can scarcely be opposed to each 
other, and then with only a slight degree of force ; hence, 
although completely adapted for clinging round bodies of 
@ certain size,—such as the small branches of trees, &c.—the 
extremities of the Quadrumana can neither seize very minute 
objects with that precision, nor support large ones with that 
mmness, which is essential to the dexterous performance of a 
Variety of actions for which the hand of Man is admirably 
suited. Hence they may be more appropriately termed 
than hands. 
644. In many of the inferior Mammalia, whose extremities 
adapted for support only, we find each row of phalanges 
lidated into two bones, or even into one. This is the 
for example, in the Ruminant Quadrupeds, as the Camel 
_ 229), and in the Horse (§ 652). Such an arrangement 
iously increases the firmness of the limb, though it 
ther deprives it of prehensile power. In other im 
112 
