et to 3 feet 7 1/2 inches, and the extent of the
outstretched arms from 7 feet 2 inches to 7 feet 6 inches; the width
of the face from 10 to 13 1/4 inches. The colour and length of the hair
varied in different individuals, and in different parts of the same
individual; some possessed a rudimentary nail on the great toe, others
none at all; but they otherwise present no external differences on which
to establish even varieties of a species.

"Yet, when we examine the crania of these individuals, we find
remarkable differences of form, proportion, and dimension, no two being
exactly alike. The slope of the profile, and the projection of the
muzzle, together with the size of the cranium, offer differences as
decided as those existing between the most strongly marked forms of the
Caucasian and African crania in the human species. The orbits vary in
width and height, the cranial ridge is either single or double, either
much or little developed, and the zygomatic aperture varies considerably
in size. This variation in the proportions of the crania enables
us satisfactorily to explain the marked difference presented by the
single-crested and double-crested skulls, which have been thought to
prove the existence of two large species of Orang. The external surface
of the skull varies considerably in size, as do also the zygomatic
aperture and the temporal muscle; but they bear no necessary relation to
each other, a small muscle often existing with a large cranial surface,
and 'vice versa'. Now, those skulls which have the largest and strongest
jaws and the widest zygomatic aperture, have the muscles so large that
they meet on the crown of the skull, and deposit the bony ridge which
supports them, and which is the highest in that which has the
smallest cranial surface. In those which combine a large surface with
comparatively weak jaws, and small zygomatic aperture, the muscles, on
each side, do not extend to the crown, a space of from l to 2 inches
remaining between them, and along their margins small ridges are formed.
Intermediate forms are found, in which the ridges meet only in the
hinder part of the skull. The form and size of the ridges are therefore
independent of age, being sometimes more strongly developed in the less
aged animal. Professor Temminck states that the series of skulls in the
Leyden Museum shows the same result."

Mr. Wallace observed two male adult Orangs (Mias Kassu of the Dyaks),
however, so very differe