MAMMALIA. 495 



The genus Protopithecus is composed of a fossil species found in Brazil 

 and nearly related to Callitkrix. 



In the genus Pithecia the tail is tufted, whence the name of fox-tailed 

 monkeys, which is commonly given to them. These animals live in small 

 troops of ten or twelve individuals, usually residing in the outskirts of forests 

 bordering rivers. They display a morose and savage temper, menacing the 

 offender with their teeth upon very slight provocation. 



The genus Cebus comprehends the monkeys knowi cts sapajous, ssjous, 

 &c., whose tail is covered with fur to its extrennty. The latter is prehen- 

 sile, but not so delicate an organ of touch as in the following genera. The 

 thumb is present on all the extremities. The species are for the most part 

 of small size, and are very lively and docile in their temper as well as 

 active in their movements ; somewhat capricious, however, in their dispo- 

 sition. They live in troops in their native forests, feeding on fruits, grains, 

 eggs, and insects. They have been termed weepers^ from the plaintive, 

 piping noise which many of them utter. The capucin ((7. capucinus) is 

 represented in j)^- 118, figs. 2 and 3. A fossil species of this genus is 

 described from Brazil. 



The genus Lagothrix (silver-haired monkeys) has a round head, resem- 

 bling Ateles, a thumb to the anterior hands, and the tail rather naked. 

 The species live in the interior of South America. 



The genus Ateles (four-fingered monkeys) is distinguished by the great 

 length, slenderness, and flexibility of their limbs, whence the appellation of 

 spider monkeys, and by the prehensile power of their tail. The anterior 

 thumbs are either totally or nearly hidden under the skin. Their move- 

 ments on the ground are wanting in firmness, even when they are resting 

 on all the four extremities. Their general aspect is rather that of crawlers 

 than of walkers. Thej^ tread on the inner edge of the fore paws and on 

 the outer edge of the hind paws, and endeavor to assist themselves by 

 attaching the tail to any object as they proceed. They often assume the 

 erect attitude, however, and then use the tail as a means of balancing them- 

 selves. The proper place for these monkeys, however, is among the branches 

 of the forest, where their movements are very rapid, easy, and uncon- 

 strained, as they swing from branch to branch by means of their spider-like 

 limbs and their prehensile tails with the greatest agility. The t^l is an 

 organ of touch as well as of prehension ; its end is destitute of hair, and 

 furnished beneath with a sensitive skin. It is capable of seizing small 

 objects with great address. These animals are said to introduce the 

 extremity of their tail, as a feeler, into the fissures and hollows of trees, for 

 the purpose of hooking out the eggs or other substances. 



The genus Mycetus (alouattes), or howling monkej'S, is distinguished 

 from the last by their greater size and the diminished length of their limbs ; 

 by the presence of a thumb which is, however, not opposable. The head 

 is pyramidal. The bowlings uttered by the troops of these monkeys are 

 described by travellers as astounding. They are usually sent forth early 

 in the morning, at sunset, and during the darkness at night ; but they are 

 also heard when the overclouded sky threatens an approaching storm. lu 



699 



