176 MR. R. I. POCOCK ON A HAINAN GIBBON. { May 16, 
brushed down. In the two skins of H. hainanus in the British 
Museum, however, the hair on the crown is not so markedly up- 
standing, nor so long, as in the living example. On the cheeks 
the direction of the hairs is, generally speaking, upwards. On 
the upper surface or back of the hand and on the corresponding 
surface of the forearm the points of the hairs lie towards the ulnar 
side of the limb, assuming a more and more elbowward direction 
as that joint is approached. On the palmar and radial side of the 
forearm, on the contrary, the hairs point for the most part towards 
the wrist. The palmar surface, however, is marked by a crest 
formed by the meeting of the two opposing streams of hair, the 
crest extending obliquely from the radial side of the elbow to the 
ulnar side of the wrist, the hairs on the ulnar side of it being 
directed proximally, those on the radial side distally. On the 
body the hairs lie backwards, except on the belly, where they 
incline towards the middle line and form a median longitudinal 
crest where the two streams meet. This is the area against 
which the inner sides of the thighs are pressed when the Gibbon is 
in a sitting posture. On the outer side of the thigh the direction 
of the hair is upwards (proximad) and backwards, below the 
knee it is downwards (distad). 
Additional Notes. 
The voice of our Hainan Gibbon is quite different from that of 
the Hoolock. It is a high-pitched trill all on the same note, 
and shriller even than the high note of the Hoolock’s cry. It 
consists of from about three to six distinct cries repeated in very 
rapid succession, suggesting almost production by vibration of the 
tongue, although, as a matter of fact, I believe the lips alone are 
instrumental in producing the effect. There is then a momentary 
pause, after which the cry is repeated. It may perhaps be 
represented in the following way:—hoo hoo hoo hoo—hoo hoo 
hoo—hoo hoo hoo hoo hoo—ke. The Hoolock, on the contrary, 
cries as follows:—hah, hoo, hah, hoo, hah, hah, hoo, hah. The 
“hoo” is on a lower note than the “hah,” with which the cry 
frequently ends. 
The ordinary expression of anger or remonstrance in the 
Hainan Gibbon is a prolonged and guttural grunt, which is 
repeated rapidly and often, and frequently interspersed with a 
kind of warble when the excitement rises. 
Both the Hoolock and the Lar Gibbon in the Gardens drink 
habitually by dipping the back of the hand and knuckles into the 
dish and licking the water off. They do not scoop it up, in the 
strict sense of the word, at all. Hence Col. Tickell’s generalisation 
to the effect that in its habit of scooping up water in its hands the 
Lar Gibbon differs from the Hoolock, which applies its lips directly 
to the fluid, is contradicted on both counts by our specimens of 
these species. The Hainan Gibbon, on the contrary, almost 
invariably drinks direct with her mouth, only very rarely using 
her left hand for the purpose. It is possible she may have 
