178 APES AND MONKEYS. 



species derives its name. The tail is very thick and hnsliy, and the beard greatly 

 developed. 



Humboldt describes the i-eil-backed .saki as " a robust, active, fierce, and un- 

 tamable animal ; when irritated it raises itself on the liinder extremities, grinds its 

 teeth, rubs the end of the beard violently, and darts upon the person who has 

 excited its displeasure. In conlinenient it is habitually melancholj'', and is never 

 excited to gaiety, except at the moment of receiving its favourite food. It seldom 

 drinks, but when it does so the operation is performed in a peculiar manner. Thus, 

 instead of putting its lips, after the manner of other monkeys, to the water or the 

 vessel containing it, this species convey.s it to its moutli in the hollow of the hand, 

 at the same time bending forwani its head. It is not, however, easy to witness tliis 

 singular trait of character, since the animal is unwilling to satisfj- its thirst when 

 watched or likely to be observerl." In their wild state the same tra\-eller relates 

 that these animals live only in pairs. Their voice, which is but seldom heard, is 

 described as a kind of disagreeable grunt. 



Clo.sclv allied to the precedint: species is the one represented in 

 Black SaJri. , . ' j^ r- i 



tlio figure on the previous page, (P. satanas), which is an inhabitant of 



Brazil. It is readily distinguislied by the absence of the yellowish-red on the back 



and shoulders : the whole of the fur being of a uniform blackish-brown colour, 



generally tending to a more decided black in the males, and being browner in the 



female. In a male example in the Paris Museum the back is bro^\Ti and the wig 



black, while in a female both the back and the wig are more fulvous. Unusually 



black individuals were described bj'^ Dr. Gray as a distinct species, under the name 



of Chiropotes afer. 



The black saki, or cuxio, as this species is termed in Brazil, appeai-s to be 



restricted to the lower parts of the Amazon valle\'. It was observed bj^ Mr. 



Bates at Cameta, on the southern side of the Amazon delta, and is stated to dwell 



in the most retired parts of the forests, in regions where the groimd is not subject 



to inundations. Tliis naturalist was, however, unable to learn anything as to its 



habits in a wild state. 



White-Nosed The last representative of these monkeys is the white-nosed 



Saw. saki (p_ alhinasa), which is likewi.se an inliabitant of the dense forests 



of the valley of the Amazon. It is of a deep black colour, with a paler tinge on 



the tips of the hair, except on the nose, which is pure wliite, and thus renders the 



animal easiljr recognisable. 



The Uakari Moxkeys. 



Genus Uacarla. 



As we find among the monkeys of the Old World a great variation in regard to 

 the relative length of the tail in closely allied forms, so in the New World there is 

 a group of monkeys closely allied to the sakis, but distinguished by the extreme 

 shortness of tliis appendage : and therein diffei'ing from all the other American 

 monkej-s. From their peculiar coloration two of the uakaris, as these monkeys 

 are called, are among the most remarkable mammals in the world. 



