62 APES, MONKEYS, AND LEMURS 



wailing note, audible from afar, and in the countries inhabited by these animals is 

 one of the most familiar forest sounds. The calls commence at daybreak, and are 

 continued until 9 or 10 A.M., several of the flock joining in the cry, like hounds 

 giving tongue. After 9 or 10 o'clock in the morning the animals feed or rest, and 

 remain silent throughout the middle of the day, but recommence calling towards 

 evening, though to a less extent than in the earlier part of the day." 



Like the white-handed gibbon, hoolocks have been exhibited, although less 

 numerously, in the Gardens of the Zoological Society in Regent's Park. 



The Hainan gibbon (//". hainanus), from the island of Hainan, China, is allied 

 to the hoolock, but differs from that and all other species, except the siamang, by 

 the absence of a white band on the forehead, and is thus black throughout. 



THE AGILE GIBBON (Hylobates agilis) 



According to Dr. John Anderson, the agile gibbon is subject to such an amount 

 of individual variation that several so-called species, such as the Malay gibbon (ff. 

 rafflesi), of Sumatra, and the crowned gibbon {H. pileatus), of Siam, have been 

 founded upon what appear to be nothing more than local races of one and the 

 same species. 



Inclusive of all these local varieties, the agile gibbon has a rather wide geo- 

 graphical distribution, ranging from Cochin-China to Siam; it is also found in 

 Sumatra and Borneo, as well as in the small islands of the Sulu Archipelago lying 

 between Borneo and the Philippines. 



The activity of the agile gibbon is sufficiently attested by its name. It was 

 this species which was first observed to have the power of catching birds while on 

 the wing. According to Duvaucel, these animals are capable of taking clear leaps 

 of forty feet when passing from bough to bough. They are stated to live generally 

 in pairs rather than in droves, and are known to the natives of Sumatra as Ungka, 

 or Ungka-puti. 



In the typical form of the agile gibbon from Sumatra the general color is 

 usually dark brown; the face being bluish-black or brown, and surrounded by 

 whitish hair, through which the ears are only partially visible, and the hands and 

 feet of the same general color as the body. It may be distinguished by the promi- 

 nent arches on the skull above the eyes, the comparatively flat nose, and the large 

 nostrils. The color of the back in the darker varieties is lighter than that of the 

 under parts. The variety named after Sir Stamford Raffles, H. rafflesi, is of a 

 nearly black color, tending to brown on the sides and back. The Siamese variety, 

 known as the crowned or tufted gibbon (H. pileatus) , is likewise of a blackish color, 

 but differs in that the hands, feet, and a ring round the crown of the head are 

 white. The white patch on the crown helps to distinguish this variety from the 

 typical agile gibbon ; although it must be confessed that all these Malay gibbons are 

 singularly alike, and often difficult to distinguish even by the practiced zoologist. 

 This so-called variegated gibbon {H. variegatus) appears to be but another of the 

 numerous varieties of H. agilis. 



