It may be bluntly asserted that the ridges are arranged as we find them because, hands and feet being used as they are, the ridges “can do no other,” and that there’s an end of it, and that we cannot derive any help as to the origin of specific difference from such a trifle, the next item on the agenda should be called for. As a piece of dialectics that would be effective, but if taken literally it only goes to prove my simple contention. It will be enough to mention the hand alone of the remaining series with a note as to each animal. Fig. 64 gives the hand of a _chimpanzee_ with ridges on the pulps resembling those of all the _apes_, _monkeys_ and _lemurs_, arched groups on the digits and longitudinal ones on the centre of the palm, both of these last two being exactly what would be found arising from the actions of climbing branches and discriminating globular objects in the palm. [Illustration: Fig. 64.--Chimpanzee--right hand.] [Illustration: Fig. 66.--Orang--right hand.] Fig. 65 is that of a _gorilla_ and its general features resemble closely those of the _chimpanzee_ and of Fig. 66 which is that of an _orang_. [Illustration: Fig. 65.--Gorilla--left hand.] [Illustration: Fig. 67.--Gibbon--left hand.] Fig. 67 of a _Hainan gibbon_ is very different on the palm from the other three apes for its ridges are nearly all longitudinal or slightly oblique, precisely as one would find this part if the _palm_ were used very little for grasping boughs and much for discriminating 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 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 response of its mode of life and use of its forefoot is shown in five great pads of muscle and efficient whorls of ridges for touch, those on the digits being very nearly all transverse in accordance with simple flexion of these joints. This again is what one would expect if my hypothesis be sound. The purely non-slipping mechanism supposed by the rival view is not here well supported by the facts. [Illustration: Fig. 68.--Left foot of ring-tailed lemur.] [Illustration: Fig. 69.--Brown sapajou, right hand.]