40 
Whether these are distinct species, however, or whether they 
are mere races, and how far any of them are identical with 
the Sumatran Orang, as Mr. Wallace thinks the Mias 
Pappan to be, are problems which are at present undecided ; 
and the variability of these great apes is so extensive, that 
the settlement of the question is a matter of great diffi- 
culty. Of the form called “Mias Pappan,” Mr. Wallace* 
observes, “It is known by its large size, and by the lateral 
expansion of the face into fatty protuberances, or ridges, 
over the temporal muscles, which have been mis-termed cal- 
losities, as they are perfectly soft, smooth, and flexible. Five 
of this form, measured by me, varied only from 4 feet 1 inch 
to 4 feet 2 inches in height, from the heel to the crown of 
the head, the girth of the body from 3 feet to 3 feet 73 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} 
inches. The colour and length of the hair varied in dif- 
ferent individuals, and in different parts of the same indi- 
vidual; 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 dimen- 
sion, 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 
* On the Orang-Utan, or Mias of Borneo, Annals of Natural History, 
1856. 
