146 
APES AND MONKEYS. 
who travelled so much in South America, writes as follows: “ This prehensile tail 
is a most curious thing. It has been denominated, very appropriately, a fifth hand. 
It is of manifest advantage to the animal, either when sitting in repose on the 
branch of a tree, or when in its journey onwards in the gloomy recesses of the 
wilderness. You may see this monkey catching hold of the branches with its 
hands, and at the same moment twisting its tail round one of them, as if in want 
of additional support; and this prehensile tail is sufficiently strong to hold the 
animal in its place, even when all its four limbs are detached from the tree, so that 
it can swing to and fro, and 
amuse itself, solely through 
the instrumentality of its pre¬ 
hensile tail, which, by the 
way, would be of no manner 
of use to it did accident or 
misfortune force the monkey 
to take up a temporary abode 
on the ground. For several 
inches from the extremity, by 
nature and by constant use, 
this tail has assumed some¬ 
what the appearance of the 
inside of a man’s finger, being 
entirely denuded of hair or 
fur underneath, but not so on 
the upper part.” 
A more important feature 
of the American monkeys, as 
being common to the whole 
of them, is the great width of 
the vertical partition between 
the two nostrils, of which 
mention has already been 
made. This broad partition 
causes the end of the nose to 
be much expanded; and a 
typical spider-monkeys. comparison of any of our full- 
faced figures of the New 
World monkeys with those of the Old will show what a marked difference there is 
in this respect between the two groups. 
Another character which we must not omit to notice is that in those of the 
American monkeys which are furnished with a thumb, this digit cannot be opposed 
to the other digits of the hand. The American monkeys agree, however, with their 
cousins of the Old World in having all their digits provided with well-developed 
nails. 
We have left to the last the most important and perfectly constant distinction 
between the monkeys of the Old and New World, since it is one which can only be 
