12 SIMIADE. 
6. Hylobates agilis. The Slender Gibbon. B.M. 
Fur testaceous brown; back paler; frontal streak and the soft 
fluffy whiskers pale brown. 
Hylobates agilis (Wouwou), F. Cuv. Mamm. Lith. t.; Raffles! 
Cantor! H. variegatus, Desm. 
Hab. Sumatra, Raffles. 
Var. Fur brownish white. B.M. 
Hab. Sumatra? Malacca, Cantor. 
Dr. Dahlbom describes the skeleton of H. agilis (F. Cuv.), and 
states that it has two large, strong tubercles on the bladebone. 
7. Hylobates leuciscus. The Wou-wou. B.M. 
Ashy grey or bluish grey; crown of head with a large square 
black spot ; frontal band and circumference of face paler; whiskers 
soft, full. 2 
Wou-wou, Camper, not F. Cuv. Simia leuciscus, Schreb. Hylo- 
bates leuciscus, Kuhl; Horsfield! Simia Moloch, Audeb. § 2, t. 1. 
Hab. Java; Sumatra. 
See Hylobates funereus, Is. Geoff. Arch. du Mus. v. p. 532, t. 26. 
Dr. Dahlbom deseribes the skeleton as having a bladebone with 
only one tubercle. 
Fur of upper parts of body and outside of limbs ash-grey, of loins 
paler, and forehead blackish. Hab. Solo Islands.—Mus. Paris. 
I am much inclined to believe that all these Malayan Hylobate, 
with perhaps the Indian one, are one species; but I have kept them 
distinct on account of the difference in the skeletons mentioned by 
Dr. Dahlbom. 
Section B. QuapRurEpaL. The arms shorter than, or only as 
long as, the legs. Walking on all fours. Tail distinct, often 
elongate, but never prehensile. Buttocks callous. 
: * 
Tribe III. PRESBYTINA. 
Head roundish. Nostrils on the sloping face. Hands and feet very 
long, slender. Thumb small or wanting. Tail very long. Stomach 
complicated of several pouches. 
Simia semnopithecus, Dahibom. 
a. Thumb short. Asia. 
6. NASALIS. 
Nose very prominent, conical; the nostrils inferior. Body and 
limbs robust. Thumb short, perfect. Cheek-pouches none. Orbits of 
skull moderate or rather small, Hab. Asia. 
Nasalis, Geoff. Rhynchopithecus, Dahlbom, Zool. Stud. p. 91, 1887, 
