of an Orang Otang. 475 
same diameter is 17 lines and a half, it is noless than 7 lines and a 
half, or nearly equal to one-half the breadth of the orbit. Neither 
is the orbit itself in these animals placed on the same plane; but 
while almost vertical in the Satyrus, it forms in the Pongo an 
angle with the horizon of many degrees less. These then appear 
to be some of the most important distinctions. In their absence, 
indeed, the many others which exist in the form of the skull of 
these animals might be attributable to age; for although those 
of the Satyrus seen in Europe have the skull round and smooth, 
and the facial angle large (as is so well exemplified in the skele- 
tons at the Royal Institution, Mr. Brookes's, and at the College 
of Surgeons), while in the Pongo the skull is angular, provided 
with sharp ridges or crests, and the facial angle much smaller, 
such differences, though less apparent, are seen between the 
young and old of most other quadrupeds. 
In addition to other arguments mentioned in favour of the 
identity of the two animals, the French naturalists assert that the 
vertebræ of each kind are the same in number. This conclu- 
sion they seem to draw from the large skeleton of the Pongo 
in the collection of Comparative. Anatomy at Paris, but which, 
being obviously imperfect in several of its parts, I am much 
inclined to consider is deficient in one of its lumbar vertebrae. 
They then state all the proportions of the body and limbs to be 
similar, each to be destitute of the hinder thumb-nail ; each to 
have large cavities communicating with the larynx, and of the 
same form ; neither to possess callosities ; and that the colour 
differs only in being darker in the Pongo, as we see it in most 
adult animals. We also know that they inhabit the same coun- 
try. To these arguments I may with justice add, that the adult 
Simia Satyrus, as distinct from the Pongo, has never been accu- 
rately described; and that the Simia Satyrus seen here is evi- 
dently the young of a large species, as is determined by the 
loose 
