252 ANTHROPOID APES. 



in those formed by the gigantic stems of Banibusa 

 macroculmis and Bainhusa gigantea. 



The siamang, properly Si-Amang, since Rosenberg 

 asserts that the first syllable is merely the article, 

 lives gregariously in Sumatra, and possibly in 

 Malacca. Martens saw one of these animals in 

 Sumatra, swinging himself from tree to tree, right 

 across the path, about fifty feet in front of him. 

 Diard states that a powerful old male acts as leader 

 to each troop. They raise a fearful clamour at sun- 

 rise, and keep quiet during the day, always on the 

 watch, and scampering off at tbe slightest noise. 

 They find it easy to get away on trees, but, accord- 

 ing to some accounts, when surprised upon the 

 ground, they show no agility, and are readily 

 captured. Rosenberg says that in Sumatra the 

 siamang and unko inhabit mountainous forests 

 3000 ft. above the sea, keeping to the trees which 

 grow on the mountain-side, and rarely descending 

 to the ground. At the slightest sign of danger 

 they hasten down the mountain with speed which 

 rivals the flight of birds, in order in a few moments 

 to disappear in the dark ravines. In the forests 

 which partly enclose Tobing, as well as on the 

 mountains of Barissa, the siamang is not rare. Bock 

 says that in the recesses of the Sumatran forests, 

 this animal subsists chiefly on the leaves of a plant 

 called Baun simantung. This ape makes a horrible 

 roaring noise.* When a young one is wounded, its 

 mother turns in a threatening manner towards the 

 aggressor, yet without being able to do him any 



* Unter der Kannihalen auf Borneo, p. 327. 



