the callosities on the buttocks. The resemblance of their skulls to the human 
type is, indeed, merely a superficial one, due to the circumstance that small animals 
must necessarily have proportionately larger brains than the larger members of 
the same group; and also to the absence of the strong ridges which are necessary 
for the powerful skulls of the larger forms, but would be quite useless in their 
smaller cousins. The superficial human-like characters of the skulls of the gibbons 
are, however, to a great extent destroyed by their long slender tusks, or canine 
58 APES AND MONKEYS. 
upright forehead, the whole skull strikes one as approaching the human type far 
more nearly than do those of the other apes. This must not, however, be con¬ 
sidered as an indication that the gibbons are of a higher type than the other 
Man-like Apes, since the contrary is clearly demonstrated by their long arms and 
THE WHITE-HANDED GIBBON. 
