.*82 
NATURAL BISTORT. 
lias a very large back portion of the brain, large even in proportion to that of man ; and the 
importance of this difference is all the greater when it is remembered that all the hist investigations 
into the actions of the nerves arising from the sides of the brain towards the back connect them with 
motions of the hands and fore-limbs especially. But it is possible that the back of the brain in the 
Siamang appears to be smaller than it really is, because of the large size of the cerebellum. The skulls 
of the Gibbons are very man-like, and more so than those of the other Apes, and this is because of their 
faces and jaws being smaller in comparison with the brain case. If the young of all the great Apes 
THE AGILE GIBBON. 
"be examined, their skulls will appear much more human than those of the adults, because the brain and 
-face grow up to a certain point together and equally ; but with age the brain does not increase in size 
proportionally with the face, wliicb grows on, and finally preponderates in size. But if the skulls of the 
young Apes be compared one with the other, that of the Siamang will really not look as human as 
that of the Gorilla or Cliimpanzee. 
The Gibbons have a very small appendage to the blindgut, and they have hard bare pads or 
callosities on the seat, and these structures connect them with the next group of Monkeys, which 
cease to be man-shaped ; and indeed the Gibbons and Siamangs, although man-shaped (Anthropo- 
morpha), occupy neutral ground between the Orangs and the Cynomorpha. 
Formerly, in those ages when the Orang lived on the continent of India, the Gibbons roamed far 
-over the vast land surfaces of the period, and lived in Southern France. Portions of the skeleton of 
