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CHAPTER X. 
THE MONKEYS OF THE NEW WORLD.* 
THE CEBIDiE — 1. the howlers — 2. the woolly monkeys — 3. the spider monkeys -4. the sajous. 
The Monkeys of the New World — How Distinguished from those of the Old — Their Division into Families — The First Family, 
The Cebidje, with Prehensile Tails — The Howlers — Appropriateness of their Name — Where Found — General De- 
scription — The Yellow-Tailed Howler — Anatomical Peculiarities and Appearance of the Face — Other Members of 
the Family— The Black Howler— Its Locality — The Woolly Monkeys— The Caparro and Barrigudo— First 
noticed by Humboldt — Peculiarities of the Skeleton — The Spider Monkeys — Seen by Humboldt in the Brazilian 
Forests — Remarkable Power of the Tail — Flexibility of the Limbs — Conformation of the Brain— Other Species— The 
Coaita — Curious Stories of them in Captivity— The Chameck— The Black Spider Monkey— Its Geographical 
Range— Its Position in Sleep— The Variegated Spider Monkey— The Sajous— The Caiarara— Observed by Bates 
on the Amazon — Other Varieties — The Brown Sajou — The Capuchin Sajou — Described by Brehm — Their 
Remarkable Dexterity and Cleverness— Diseases of Monkeys. 
Not one of the numerous kinds of Monkeys which have been noticed in the former chapters has ever 
been found in the New World — that is to say, on the American continent. The converse is also true, 
for not one of those which are about to be noticed, and which inhabit the tropical parts of South 
and Central America, has been seen in any other part of the world. 
The two groups are not only distinct as regards their geographical distribution, hut they are also 
different in many very important points of their construction and habits. It is evident that, although 
it may be said that the resemblances between the Baboons, Macaques, and Troglodytes, for instance, 
indicate some kind of relationship, and suggest a community of origin, there is nothing of the sort to be 
traced between any Old and New World Monkeys. They seem to have started from different sources. 
All the Monkeys of the New World have the partition between the nostrils broad, and it separates 
them widely : they open as it were sideways, and the whole of the lower part of the nose is fiat. This 
peculiarity has given the name to the group, as has been explained in the first chapter, and it 
is accompanied by some others. Thus, with one exception, the numerous genera of the New World 
Monkeys have the hinder limbs the longest, and they are wont to go on all-fours, the erect posture 
being only occasionally adopted by the Spider Monkeys. Their thumbs differ less from the other 
fiugers than do those of the Old World Monkeys, and the toe-tlmmb is large and movable ; no cheek- 
pouches or callosities are seen in any of them, and only a few have air sacs. It is usual to say that 
the American Monkeys are known by their prehensile tails, but this is only true in part, for whilst 
some have this member wonderfully developed and useful, others have it incapable of holding on, 
whilst a few have barely a tail at all. The teeth are more numerous than in the Apes and Monkeys 
of the Old World, in one set of New World genera ; and they are of the same number in another. 
In the first instance, there are thirty-six teeth instead of the thirty-two so frequently noticed hitherto, 
and in the last the thirty-two are differently arranged to those possessed by the Old World kinds. 
For example, in the preliensile-tailed Howlers, there are thirty-six teeth, or one extra tooth in each 
jaw and on both sides, over and above the usual thirty-two ; and this tooth is a false molar, or one of 
those between the true grinders and the canine teeth. There are thus three false molars instead 
of two, as in the Old World kinds, on either side in both jaws. 
In the Marmosets, which have only thirty-two teeth, there are only two back grinders in each 
jaw on either side instead of three, as in the Old World Monkeys, but there are three pre-molars in 
each jaw on either side. All these distinctions are useful in the classification of these American 
Monkeys, and therefore they have been divided into two families, one having thirty-six and the other 
thirty-two teeth, and the first family has again been subdivided into the genera with prehensile tails 
and those without them. The first to be described are the Cehidse, and this family contains — first, 
the genera with thirty-six teeth and with prehensile tails; second, the genera without prehensile 
tails and the same number of teeth. 
* Flatyrrhinio 
