-like; and their whole conformation seems intended to adapt them
for dwelling in the great virgin forests of the New World. There is one
particular in which they differ most remarkably from their congeners of
the Old World; that is, in having _prehensile_ tails. With these they
are enabled to suspend themselves from the branches of trees, or swing
their bodies from one to the other; and this prehensile power is far
greater than could be obtained by any clutch of the hand. So great is
it, that even after the animal has died from the effect of a shot or
other wound, its tail will still remain hooped around the branch; and if
the body is not taken down by the hunter, it will hang there till
released by the decay of the tail!

Not all the monkeys of America possess this prehensile power of tail.
Some are entirely without it, and approach nearer to certain kinds in
the Old World; while there are a few species that very closely resemble
the lemurs. These differences have led to a classification of the
American monkeys; and they have been thrown into three groups, though it
may be remarked that these groups are not very natural.

They are as follow:--The _Sapajous_, whose tails are not only
prehensile, but naked underneath, and tubercled near the tips; the
_Sajoas_, who possess the prehensile power, but have hairy tails; and
the _Sajouins_, whose tails are _not_ prehensile.

For want of a better, this classification may be adopted.

The Sapajous are subdivided into three genera, of which the Howlers form
one. They are so denominated from their habit of assembling in troops,
and uttering the most terrible howlings, so loud that the forest is
filled with their sonorous voices. Their cries can be heard at a
half-league's distance, and produce upon a stranger unaccustomed to such
sounds a very disagreeable impression. The unusual strength of voice is
accounted for by a peculiar drum-like construction of the _os hyoides_,
common to all the genera of Sapajous, but more developed in some than in
others; and those in whom the voice is loudest constitute the genus of
_Alouatles_, or Howlers.

Of the true howlers there are about a dozen species known to
naturalists. Most of them are denizens of the tropical forests of
Guiana and Brazil; but some species are not so tropical in their habits,
since one or two extend the kingdom of the monkeys into Mexico on the
north, and southward to Paraguay.

Closely allied to the last, ar