1 84 APES, MONKEYS, AND LEMURS 



ting fall the rest of his body, swings himself till in one of his oscillations he reaches 

 the neighboring branch. The whole file performs the same movements on the same 

 spot. The Indians told the travelers that when these monkeys filled the forests with 

 their howling there was always one that chanted, as leader of the chorus. During 

 a long interval one solitary and strong voice was generally distinguished, till its 

 place was taken by another of a different pitch. 



Writing in relation to a specimen of one of these monkeys, brought to him 

 when traveling on the Lower Amazon, Mr. Bates observes that "the howlers are 

 the only kind of monkeys which the natives have not succeeded in taming. They 

 are often caught, but they do not survive captivity many weeks. The one of which 

 I am speaking (apparently a female of the black howler), was not quite full-grown. 

 It measured sixteen inches in length, exclusive of the tail ; the whole body was cov- 

 ered with long and shining dingy-white hair, the whiskers and beard only being of 

 a tawny hue. It was kept in a house, together with a coaita and a caiarara monkey 

 ( Cebus albifrons) . Both these lively members of the monkey order seemed rather 

 to court attention, but the howler slunk away when any one approached it. When it 

 first arrived, it occasionally made a gruff subdued howling noise early in the morn- 

 ing. The deep volume of sound in the voice of the howling monkeys, as is well 

 known, is produced by a drum-shaped expansion of the larynx. It was curious to 

 watch the animal while venting its hollow cavernous roar, and observe how small 

 was the muscular exertion employed. When howlers are seen in the forest, there 

 are generally three or four of them mounted on the topmost branches of a tree. It 

 does not appear that their harrowing roar is emitted from sudden alarm ; at least, it 

 was not so in captive individuals. It is probable, however, that the noise serves to 

 intimidate their enemies. ' ' 



THE BLACK HOWLER (Mycetes caraya) 



We select as our first example of that group of howlers in which the hair of 

 the forehead is directed forwards so as to overhang the eyes, and the crown of the 

 head is smooth, with radiating hairs, the black howler, either a young male or 

 female of which is alluded to in the passage cited above. 



It is a native of Brazil. The adult males have their fur mainly of a uniform 

 black color, interspersed with red hairs on the flanks and loins. The females and 

 young males are of a dingy white, and were described as belonging to a distinct 

 species, under the name of M. stramineus. At one time there were young males of 

 the black howler in the Jardin des Plantes, at Paris, which actually changed from 

 the white into the black state. Mr. Bates's example was obtained on the Madeira 

 river, the largest southern tributary of the Amazon. 



The yellow-handed howler ( M. belzebul ) is another Brazilian representative of 

 this group, which has been known since the time of L/innseus. It appears to vary 

 considerably in color, so that one variety was described as a distinct species (M. 

 flavimanus) . According to the late Dr. Gray, the general color of the fur may be 

 either uniform black or reddish, with some brown hairs on the shoulders ; but the 

 hands and feet, as well as a line running down the middle of the upper surface of 



