14 
GUIDE TO THE 
Catarrhine monkeys are inhabitants of the Old 
World, whereas the Platyrrhines are found only in the 
New World. There are other and important charac¬ 
ters, however, in which they differ from one another ; 
for example, very many of the Old World monkeys have 
cheek-pouches in which they store their food, but the New 
World monkeys have none. While no monkey of the 
Old World uses its tail as an organ of prehension, in many 
of the Platyrrhine monkeys of the New World, the tail is 
very muscular and flexible, and the under surface near its 
tip is in many quite bare and extremely sensitive, so much 
so that the animal is able to use it as a fifth hand. These 
latter monkeys are also distinguished by the circumstance 
that their hips have no hardened bare patches ; in the 
majority of them, their teeth are'more numerous than in 
the Catarrhine or Old World monkeys in which the teeth 
are 32 in number as in man ; whereas only the Marmoset 
among the Platyrrhine monkeys has this number. Besides 
these, there are other distinguishing characters which it is 
unnecessary to dwell upon here. 
The Catarrhine monkeys are divisible into two great 
groups, first those which present a general resemblance 
to man and assume a semi-erect or erect position in 
walking and have no trace of a tail, and are known 
as the Anthropoid Apes which are illustrated by the 
Gorilla. Chimpanzee, Orang and Gibbon ; and second, 
those which more resemble ordinary Mammals in 
walking on all fours and in being provided with a tail, 
or a rudimentary tail, or the presence of caudal muscles 
if the tail is absent externally. Of course, these are only the 
most general of their external differences, there being many 
important anatomical features in which they differ. The 
