CHAPTER V. 
Apes, Monkeys, and Lemurs,— continued. 
The American Monkeys. 
Family CEBIDJE. 
The monkeys of America differ so remarkably from those of the Old World, 
that they cannot be included in either of the families treated of in the 
two preceding chapters. The true monkeys of the New World form, indeed, a 
perfectly distinct family by themselves, known to zoologists as the Cebidce. In 
addition to these, there is another group of American Primates known as the 
marmosets, which, although nearly related to the Cebidce, constitute a second 
family, which will be treated of in the next chapter. 
Not only is this distinction between the monkeys of the Eastern and Western 
Hemispheres a feature characteristic of the present state of the world’s history, but, 
so far as we know, it was the case throughout geological history, for not a trace of 
a New World monkey has been found in any of the formations of the Old World, 
while those of the New World have yielded remains of species allied to those now 
inhabiting the same regions. We have thus decisive evidence that both these groups 
are of great antiquity; and it has even been suggested that they have taken their 
respective origins from animals probably allied to the lemurs quite independently 
of one another. 
For a long period zoologists were accustomed to class the apes, monkeys, and 
baboons of the Old World in one group, to which they applied the name of narrow¬ 
nosed monkeys (Catarhini), from the circumstance that the partition between the 
nostrils is a thin one; while the American monkeys and marmosets, owing to the 
width of this partition, were grouped together as broad-nosed monkeys ( Platyrldni ). 
Although there is a certain amount of convenience in this arrangement, it has now, 
by common consent, been pretty generally abandoned; and the whole of the 
Primates, exclusive of the lemurs, are divided simply into four families, of which 
two belong to the Old World and two to the New. In the present chapter we shall 
take into consideration only the true monkeys ( Cebidce ) of the New World,—the 
better known representatives of which are popularly designated howlers, spider- 
monkeys, sapajous, and titis—as it is to these alone that the term American monkeys 
should be restricted. 
Characteristics Proceeding to notice the characters by which these animals are 
distinguished from their distant cousins of the Old World, we have 
to mention, in the first place, that no New World monkey has naked callosities 
on the buttocks. This character will at once serve to distinguish any American 
monkey from all those of the Old World, except the larger Man-like Apes, with 
