68 
APES AND MONKEYS. 
unfrequently bright-coloured, afford another character by which we can at once 
distinguish an Old World monkey from any and all of its American cousins. Their 
use is to afford a comfortable rest for the body in the upright sitting posture 
assumed by the monkeys and baboons of the Old World. 
Cheek Another feature absolutely peculiar to the monkeys and baboons 
Pouches. 0 f f} 10 old World, although by no means common to the whole of 
them, is the presence of those pouches in the cheeks, with which all who have fed 
tame monkeys must be perfectly familiar. These cheek-pouches are formed by 
folds in the skin, and when empty lie flat on either side of the face. They can, 
however, be so distended as to contain a large quantity of food, and then stick out 
prominently on either side, so as to communicate a peculiarly bloated appearance 
to the face. The possession of these pouches must obviously be a great advantage 
to the monkeys in which they are found, since by their means a large quantity 
of food can be hurriedly gathered, stowed away, and afterwards eaten at leisure in 
some place of security. It might, indeed, be urged that the monkeys which do 
not possess these convenient receptacles appear to get on in life quite as well as 
their relations who are thus provided; and that, therefore, these pouches are of no 
real advantage. To this it may be replied that such Old World monkeys as have 
no cheek-pouches feed much more on leaves and shoots than on fruits; and that 
they are furnished with a peculiarly complex stomach in which this food can be 
rapidly stowed away previously to undergoing complete digestion. 
With regard to the limbs of the Old World monkeys and baboons, 
it may be observed that the arms never present that great excess in 
length over the legs which we have seen to be the case among the Man-like Apes; 
and the legs may, sometimes, be the longer of the two. The thumb of the Old 
World monkeys and baboons can in all cases be fully opposed to the fingers, 
except, of course, in the African species in which it is either absent or rudimentary, 
and therein have another marked point of difference from the American group. 
Finally, the skeletons of all members of the present group may 
be readily distinguished from those of the Man-like Apes by the 
breast-bone being narrow and flattened from side to side, instead of broad 
and flattened from back to front. Moreover, all of the species have a central bone 
in the wrist,—a characteristic they have in common with the gibbons and orangs 
among the Man-like Apes. 
Limbs. 
Breast-bone. 
Such, then, are the leading features by which the monkeys and 
Distribution. ° J J 
baboons of the Old World (forming a larger group than any other 
in the order) are distinguished from the groups immediately above and below 
them in the zoological scale; and the reader who has followed us carefully thus far 
ought to be able to tell at once whether any particular monkey that is set before 
him should or should not be included in the present group. When we speak of the 
members of this group occupying a position immediately below that of the Man¬ 
like Apes, we must guard ourselves from conveying the idea that the one can in 
any sense be regarded as the ancestor of the other. The difference in the structure 
of the molar teeth of the two groups is alone sufficient to prove that this cannot be 
the case; those of the Man-like Apes being of a more primitive type than are those 
