The White-Handed Gibbon. 



So far as I am aware the white-handed gibbon (Hylobates 

 lar) has been regarded as an animal restricted in range to the 

 mainland of Asia, inhabiting there the Tenasserim Province 

 and the Malay Peninsula only. I therefore wish to place on 

 record its occurrence in the swampy regions of East Sumatra, 

 where it has been met with in large numbers by Dr. W. L. 

 Abbott and myself, particularly in the Siak and Indragiri 

 districts. 



It occurs there, as elsewhere, in the biscuit-coloured, in 

 brown and in sooty pelage, and as far as my observations are 

 worth anything it is impossible to consider these varieties as 

 colour races in any way. I have several times noted, though 

 this does not seem to be general, dark females with pale 

 infants and vice versa and have also shot pie-bald adults with 

 the colours so distributed that it would be impossible to say 

 whether they are dark-furred individuals becoming pale or 

 pale becoming dark. As however the pale form is com- 

 paratively scarce it is to be inferred that the latter metamor- 

 phosis is what is happening and that the light specimens are 

 born so. 



The statement that gibbons are monogamous is one that 

 I thoroughly agree with: whether however they divorce each 

 other and take new partners from time to time we have yet 

 to learn. The point is interesting since such an able reasoner 

 as Westermarck (The Origin of Human Marriage) has come 

 to the conclusion that the marriages of mankind are an in- 

 heritance from some ape-like progenitor. 



I do not ever remember meeting Malayan gibbons in 

 parties of more than five at a time, but the most usual 

 numbers are four or less. A small district may often contain 

 a large number of apes but the little groups seem to live quite 

 independently of each other and do not combine. These 

 parties consist of two parents and their off-spring of different 



R. A. ooc, No. 50, 1908. 



