178 SYMPHALANGUS 
throat ; second and middle toes united by web up to first joint; supra- 
orbital ridges of skull well developed, occipital region truncate. The 
brain in the young has the cerebellum completely covered by the cere- 
brum; but in the old animal the cerebellum projects beyond the cere- 
brum posteriorly. 
Color. Black. 
Measurements. Skull: total length, 139; occipito-nasal length, 
104.5; Hensel, 101; zygomatic width, 92; intertemporal width, 56.7; 
median length of nasals, 12.8; length of upper molar series, 35.3; length 
of mandible, 94; length of lower molar series, 40.9. . 
If the S. s. continentis Thomas, eventually proves to be a distinct 
race of the Sumatran species, then it is not at all probable that this 
species is to be found anywhere on the Malay Peninsula. 
The Sumatran animal is very large, in fact the greatest of all 
the Gibbons in size, and individuals from South Pagi Island and the 
Malay Peninsula differ from it only in size, and this is relative, the 
Malaccan Gibbon being intermediate, the one from South Pagi Island 
being the smallest. 
Mr. Forbes (1. c.) gives an interesting account of one of these 
Gibbons he had in Sumatra from which the following is taken: “Its 
expression of countenance is most intelligent and often very human; 
but in captivity it generally wears a sad and dejected aspect, which 
quite disappears in its excited moods. * * * It will never put 
its lips to a vessel to drink, but invariably lifts the water to its mouth — 
by dipping in its half-closed hand and then awkwardly licking the 
drops from its knuckles. It generally sits with its arms crossed over 
its chest, and its fingers overlaid behind its head. * * * Although 
it often inflates its laryngeal sac, it rarely gives utterance to more than 
a yawn-like noise or suppressed bark; but this dilatation has no 
reference apparently to its good or bad temper, although when very 
eager and impatient for anything, a low pumping bark is uttered. 
Every evening it makes with me a tour around the village square, 
with one of its hands on my arm. It is a very curious and ludicrous 
sight to see it in the erect attitude on its somewhat bandy legs, hurrying 
along in the most frantic haste, as if to keep its head from outrunning 
its feet, with its long free arm see-sawing in a most odd way over its 
head to balance itself, and now and again touching the ground with its 
finger tips or knuckles. That they can leap the great distances from 
tree to tree ascribed to them is no doubt an accurate observation; 
but they appear to be sometimes terror-stricken and unable to perform 
