THE HOWLING MONKEYS 185 



the tail, the tip of the same, together with a spot in front of each ear, and another 

 on the knee, are invariably reddish yellow. Mr. Bates states that the variety 

 which is reddish colored all over is the prevalent type of howler in Para, on the 

 southern side of the delta of the Amazon ; while in the island of Marajo, or Macajo, 

 in the middle of the delta, this form is replaced by the darker one with yellowish 

 hands and feet. 



The red-and-yellow howler (M. auratus) is a third species from Brazil belong- 

 ing to this group, in which the general color is dark chestnut brown, with the back 

 and sides golden yellow, and the beard somewhat darker. Dr. Gray also applied 

 distinct names to two other Brazilian howlers. 



OTHER SPECIES 



As the black howler is the most southerly representative of the 

 era ruz g enuS) so. M. villosus, the Vera Cruz howler (of which the head is 



figured on p. 182) is its most northerly example. This species differs 

 from the black howler by its long soft hairs, which near their bases show a rufescent 

 tinge, in the hair of the face being inclined forwards, instead of reversed, and also 

 in the color of the female and young being black, like that of the male. 



The red or golden howler (M. seniculus) is perhaps the best-known 



representative of the group in which the hair is bent back so as to 

 form a ridge across the centre of the crown of the head. The general color is a 

 reddish chestnut, but golden yellow in the middle of the back. It appears that 

 in young individuals the hairs are short and stiff, without any under fur, and 

 uniformly colored throughout their length. In older individuals, however, they 

 become long, soft, and silky, and are brown at the roots, and golden or chestnut 

 colored at their tips ; while at the same time a thick under fur is developed. It 

 was old individuals with this long silky kind of hair that Dr. Gray described as a 

 distinct species, under the name of the silky howler {M. laniger) . 



This howler appears to be mainly a northern form, occurring in Colombia on 

 the west, and in Guiana on the east side of South America ; while, according to 

 Mr. Bates, who describes its fur as being of a shining yellowish-red color, it is the 

 sole representative of the howlers in the Upper Amazon valley. It also occurs in 

 Ecuador ; and, according to Dr. Gray, is represented by a pale variety in Bolivia. 



The red howler is one of the two species of this genus that have been exhibited 

 in the Gardens of the London Zoological Society. It is, however, difficult to keep 

 alive for any length of time, and of two specimens received from the Dekka river, 

 near Cartagena, on August 28th, 1863, the one died on September 25th, and the 

 other on October yth of the same year. Writing of these howlers, which he states 

 are known to the natives as ouarines, and on the Demerara in Guiana are commonly 

 known as red monkeys, the traveler Charles Waterton states ' ' that nothing can 

 sound more dreadful than the nocturnal howlings of this red monkey. Whilst 

 lying in your hammock amid these gloomy and immeasurable wilds, you hear him 

 howling at intervals from eleven o'clock at night till daybreak. You would 

 suppose that half the wild beasts of the forest were collecting for the work of 



