compared with other Anthropoids is the fact of the large size of the canines, which are of equal or nearly equal size in the two sexes. The molars on the other hand have been particularly compared to those of Man. The brain is simpler than in the higher forms. But it is not clear that this may not be a case of diminished complexity of convolution going hand in hand with smallness of size.
Fig. 272.—Hoolock. Hylobates hoolock. × 1⁄6.
The Gibbons range through south-eastern Asia from Assam and Burmah to Hainan. The number of species is a little doubtful. It is clear that in the first place we may distinguish the Siamang, H. syndactylus, which indeed some regard as a separate genus. It is mainly to be defined by the syndactylous character of the second and third toes; they are united by skin as far as the last joint. The Hainan species, H. hainanus, is probably distinct, and the following names have been given to various other species or races, viz. H. agilis, H. leuciscus, H. leucogenys, H. lar, H. hoolock. These animals can walk erect; and when they do so, the big toe is separated as in unsophisticated or at least unbooted man. The voice is well known to be loud,
