This tree is partly an expansion of that of the primates as given by Haeckel.[1] To Dryopithecus I have, according to Gandry's recent view,[2] given a place between the Cercopithecidæ and the Simiidæ. As I have already stated in my first description, I regard as the progenitor of all anthropoid apes Protohylobates, a highly generalized hypothetical form, which, as well as its nearest living relatives, Hylobates, retained, along with many human peculiarities, yet many characters from its monkey-like ancestors that came lower in the scale. As immediate ancestor of Pithecanthropus I have placed Palæopithecus of the Siwalik strata. In this also, as I have convinced myself after a careful examination of the type specimen in the museum at Calcutta, are the characters of Hylobates mingled with those of man. We first find in Pithecanthropus erectus a form in which the human characters preponderate.