158 H¥ELOBATES 
often resemble the females and have a brownish black pelage. The 
species is subject to great individual variation. 
Measurements. Head and body, 520; foot, 150. Skull: total 
length, 114; occipito-nasal length, 93.9; intertemporal width, 49; 
breadth of braincase, 61.5; Hensel, 82.2; zygomatic width, 72.4; median 
length of nasals, .95; palatal length, 45.7; length of upper canines, 21.5; 
length of upper molar series, 29.6; length of mandible, 78.6; length of 
lower molar series, 35. 
The specimen called H. choromandus by Ogilby (1. c.) from an 
unnamed locality, is without doubt this species. It was presented to 
the Zoological Society of London by General Hardwicke many years 
before it was described, and at the same time a typical H. HooLocK 
from the same locality had also been presented, name of donor not 
mentioned. It is stated to be “ashy brown” in color, and is no doubt 
a young male, or a female. The whiskers are stated to be “black.” 
The description is contained in the words quoted, hardly sufficient 
to determine a specimen, even if of a new species, particularly if no 
locality for it was given, but as it was accompanied by a veritable H. 
HOOLOCK, it may without hesitation be referred to it, as no two species 
of HyLosaTEs are known to inhabit the same locality. 
While the general and typical hue of this species is black, many 
varieties are found, even almost wholly white, or yellowish white 
individuals. In general, however, the Hoolocks may be said to be 
more steadfast to a typical style of coloring than any other member 
of the HyLosaTEs group so far as the male is concerned, the variation 
in the color of the pelage being more often observed in the female. 
They represent the changeable sex. 
The Hoolock is confined in its range to a comparatively limited 
district bounded by the Brahmaputra and Irawady Rivers; its aversion 
to water, for it cannot swim, probably preventing it from making any 
effort to cross such broad streams. Like all the members of this 
genus the Hoolock is arboreal, and although it can make a ludicrous 
progress over the ground balancing its body by awkwardly holding 
its long arms bent over its head, its life is passed in the trees, under 
whose branches it swings itself in a trapeze-like performance in so 
swift a progress that it can only be likened to the passage of a bird 
through the air. Mr. Candler has given (1. c.) an interesting account 
of the habits of this ape, short extracts from which are here given. 
“He swings along to the thinnest part of a bough, or to the slender end 
of a bamboo, until it bends to his weight, then with a swing and a 
