PYGATHRIX | 51 
Type locality. Trong, Lower Siam. Type in United States Na- 
tional Museum. 
Geogr. Distr. Lower Siam and southern Tenasserim; Kisseraing, 
and Sir William James Islands, Mergui Archipelago. 
Genl. Char. Of the P. opscura group, but legs from hips pale 
smoke gray, and tail cream color. 
Color. Face bare, upper lip, and space over eye flesh color, 
darker about nose and beneath eyes. Hairs on forehead long, upright, 
and extending to ears brownish black; hairs on lips and lower cheeks 
long, and extending backward beyond ears, blackish; top of head and 
nape yellowish white; dorsal line mummy brown, paler than black; 
rest of upper parts and flanks black tinged with brown; outer side of 
arms very dark hair brown, with a reddish tinge on shoulders, and 
grading into black on wrists and hands; throat sparsely covered with 
dark brown hairs; under parts grayish brown; outer side of legs smoke 
gray, with a brownish tinge from knee to ankle; feet blackish; tail 
uniform cream color. Ex type United States National Museum. 
Measurements. Total length, 1,257; tail, 724. Skull: total length, 
94.7; occipito-nasal length, 77; Hensel, 66.5; zygomatic width, 70; 
intertemporal width, 40.7 ; palatal length, 32.7 ; median length of nasals, 
93 ; length of upper molar series, 24.4; length of mandible, 68.6; length 
of lower molar series, 30. Ex type United States National Museum. 
This very distinct species can at once be recognized by its cream 
colored tail and pale legs. The examples from the islands, of which 
there are only a male and a female, differ slightly in certain particulars. 
The legs are even paler than those of the type, hands and feet jet 
black, strongly contrasted with the arms and legs, and the skulls have 
a flatter braincase and broader rostrum. The material is hardly 
sufficient to enable definite decision to be reached, and I leave these 
island examples under the name of the present species, although they 
may eventually prove to be worthy of a separate designation. 
PYGATHRIX ROBINSONI (Thomas). 
Presbytis robinsoni Thos., Proc. Zool. Soc. Lond., 1910, p. 634. 
ROBINSON’S LANGUR. 
Type locality. Ko-Khan, Trang, Northern Malay Peninsula. 
Type in British Museum. 
Genl. Char. Color white, dark beneath. Occipital hairs directed 
forward, hairs on forehead radiating from points on temples; median 
crest present. 
