anterior thumbs (using the ordinary expression for
them) are placed absolutely on the same line
with the other fingers, are of the same form with
them, act invariably in the same direction, and are
totally incapable of being opposed to them. In the
two remaining genera, Cebus and Callithrix, the
extremities of the anterior limbs have a greater resemblance to the hands of Man, and of the Monkeys of the Old World:—the internal finger is
placed farther back than the general line of the
other fingers, and has, on that account, when superficially noticed, the semblance of being opposed
to them: but, as has been correctly observed by D’Azara, with reference to Call. capucinus, it is less separated than in Man; it is, besides, of precisely the same slender form with the rest, is
weaker than they, absolutely without power of
opposition to them, and habitually acts in the
same direction with them. The impression derived from contemplating the hands of the Old
World Monkeys, might induce the belief that the
extremities of the Cebi are similarly constituted;
but if the knowledge that in Mycetes, Pithecia, &c., there are no opposible thumbs, leads to a
close observation of the anterior extremities of
the Cebs, it will be found that they do not act
as hands, and cannot be considered as possessing
the powers of those organs.”
The Cebidæ are confined to the hotter parts of the Southern American continent, and inhabit the dense forests.
Genus Myceres. (Illiger.)
In this genus, which comprehends the largest and fiercest of the American Monkeys, the hyoid
