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Remarks on Hylobates, chiefly. It is a mistake to suppose that the gibbons are more nearly allied to the orang-utan than to the chimpanzee, as the habitat might be thought to indicate. Though quite distinct as a group, they are much more nearly allied to the chimpanzee, as strongly indicated in the living animal by the expression of visage, as well as by the voice. As remarked by Huxley, in consequence of the inordinate length of their arms, it has been generally overlooked that the lower limbs are really more developed than in the other apes, and when upon level ground they walk with the lower limbs only (a fact which Linnaeus might have known when he designated one of them Homo lar) holding the arms up more to be out of the way than for the purpose of balancing; but they are always ready to seize hold of a bough or any other object to help mem forward when on the ground, though they never touch the ground witii the hands to assist in progression. I have repeatedly seen a pair of H. larascend a considerable flight of steps without once touching them with the hands. A remarkable fact which it is surprising that no one but myself seems to have noticed, though observable in every stuffed specimen, is that both polluxand halluxare separate for a joint further than in any other of the Primates, exhibiting thus three free phalanges. In H. syndactylies, the second and third toes are usually (if not always) joined. In H. agilis, leuciscus, H. lar, this character occurs irregularly, as not rarely in man. So Bartlett assures me, and one of the Keepers now at the Z. G. is an example at hand. Of many specimens of H.hoolockexamined, I never found this character to occur. The gibbons have the hallux particularly

29v

well developed, whereas the reverse is exemplified by the orang-utan. In the gorilla both hands and feet have the four fingers and toes syndactylous for a joint further than in man, &c, extending thus the palms & soles.

[Darwin's annotations:]

Man

(See Isidore Geoffroy if holds excellent case of analagous variation)

2d & 3d toes— is great toe counted??

does it throw light on muscles in common to ones 2 & third finger, ie not counting Thumb??

Leonard How in.

Isidore Geoffroy does notsay any particular finger oftener wanted

(Add when I mention the varying Hallux of the Orang)

(Ch. 3)

When I speak of above marking