ARRANGEMENTS OF THE PAPILLARY RIDGES 165 



slightly oblique, precisely as one would find this part if the palm 

 were used very little for grasping boughs and much for discrimina- 

 ting globular objects procured for its repasts. The wonderful long 

 digits of the gibbon form its main organ for supporting itself on 

 branches and swinging its body rapidly from branch to branch, and 

 the arched or nearly transverse ridges on the digits are 

 placed just as the endless use of them for this purpose would 



Fig. 65. — Gorilla— left hand. 



Fig. 67.— Gibbon — left hand. 



be likely to follow from it. This example is a very clear one 

 for showing, if it exist, the effect of use and habit on the disposition 

 of the ridges. 



Fig. 68 shows the arrangement of papillary ridges in a lemur 

 and 69 that of a brown sapajou. 



Fig. 70 of the Chacma baboon, playfully called by the Boers 

 Adonis, is a very active and wary animal which lives on the rough 

 rocky slopes of the Cape. It is very much of a pedestrian and the 



