96 ’ THE BLACK YARKE. 
This curious habit, however, is but rarely witnessed, as the animal dislkes to exhibit 
its fastidiousness before spectators, and only when it thinks itself unwatched will it use 
its natural goblet. When in the presence of witnesses it drinks as do other monkeys, 
wetting its beard y ithout compunetion. 
The general colour of this monkey is a erizzled brown, sometimes speckled with rust- 
collenie hairs, and the limbs, tail, and head are black. If, however. , the hair of the body 
be blown aside, a greyish hair takes the place of the dark brown ; for the hairs are much 
lighter towards their insertion, and in many cases are nearly white. The hair of the 
head is remarkable for the mode of its arrangement, which gives it an air as if it had 
been parted artificially. The long black hairs start from a line down the centre of the 
head, and fall over the temples so densely that they quite conceal the ears under their 
thick locks. The large quantity of hair that decorates the head and face increases the 
really great comparative size of the rounded head. The nostrils are rather large, and are 
separated from each other by a dividing cartilage which is larger than is usual even 
in the American monkeys. 
The teeth are so sharp and the jaws so strong, that Humboldt has seen the animal, 
when enraged, drive its weapons deeply into a thick plank. When it suffers from 
a fit of passion, it grinds these sharp teeth, leaps about in fury, and rubs the extremity 
of its long beard. Even when slightly irritated, it grins with savage rage, threatening 
the offender with menacing erimaces, and wrinkling the skin of its jaws and face. 
It is not known to live in companies, as is the wont of most American monkeys, 
but passes a comparatively solitary hfe, limiting its acquaintance to its partner and 
its family. The cry of this animal is rather powerful, and can be heard at a considerable 
distance. The colour of the female Cuxio is not so dark as that of her mate, being 
almost wholly of a rusty brown. It is chiefly nocturnal in its habits. 
BLACK YARKE.—Pithécia Leucocéphala, 
There are several monkeys known by the name of Sakis, among which are reckoned the 
Cuxio, which has just been described, and two other species, which are easily distinguished 
from each other by the colour of their heads. The first of these animals is the ~ BLACK 
YARKE, or WHITE-HEADED SAKI, and the other the CacaJAo, or BLACK-HEADED SAKI. 
The former of these Sakis is a rather elegant creature in form, and of colour more 
