Chapter II: The Struggle Over Our Genealogical Tree

OUR APE-RELATIVES AND THE VERTEBRATE-STEM

EXPLANATION OF PLATE II

SKELETONS OF FIVE ANTHROPOID APES

These skeletons of the five living genera of anthropomorpha
are reduced to a common size, in order to show better the
relative proportions of the various parts. The human skeleton
is 1/20th natural size, the gorilla 1/18th, the chimpanzee
1/7th, the orang 1/7th, the gibbon 1/9th. Young specimens of
the chimpanzee and orang have been selected, because they
approach nearer to man than the adult. No one of the living
anthropoid apes is nearest to man in all respects; this cannot
be said of either of the African (gorilla and chimpanzee) or
the Asiatic (orang and gibbon). This anatomic fact is explained
phylogenetically on the ground that none of them are direct
ancestors of man; they represent divergent branches of the
stem, of which man is the crown. However, the small gibbon is
nearest related to the hypothetical common ancestor of all the
anthropomorpha to which we give the name of Prothylobates.
Further information will be found in my _Last Link_ and
_Evolution of Man_ (chap. xxiii.).

PLATE II.

SKELETONS OF FIVE ANTHROPOID APES.

1/20 MAN (Homo)

1/18 GORILLA

1/7 Young CHIMPANZEE (Anthropithecus)

1/7 Young ORANG (Satyrus)

1/9 GIBBON (Hylobates)]