MONKEYS. 143 
common to the greater number of them, and of which 
those of the Old World are entirely destitute. On the 
other hand the American species never exhibit any 
traces of the callosities or of the cheek-pouches, which 
are so common among the Asiatic and African races. 
Each of these grand divisions has been subdivided into 
several minor groups or genera; but zoologists have 
hitherto been by no means unanimous with respect to 
the principles on which this subdivision ought to be 
effected. The arrangement which appears to be most 
generally adopted at the present day is that of M. Cu- 
vier and M. Geoffroy-Saint-Hilaire, which is essentially 
founded on the application of an imaginary rule, first 
employed by Camper for ascertaining the degree of 
intelligence, and consequently of ideal beauty, expressed 
by the human face in its various gradations of elevation 
or debasement, and called by him the facial angle. 
Unfortunately, however, the operations of nature in the 
animal creation can never be subjected to geometrical 
laws; nor can her innumerable phases be expressed 
with the precision of a mathematical theorem. This 
assumed point of comparison varies almost indefinitely, 
not merely in different species, but even in the same 
individual; and the Oran-Otang himself, who is sup- 
posed to approach most nearly to the human form, offers 
the most striking illustration of the truth of this obser- 
vation ; inasmuch as in his young and intellectual state 
his facial angle is equal to 65°, while in his aged and 
debased condition, in which he has actually been re- 
peatedly described as a different animal under the name 
of Pongo, it sinks below 30°; degrading him even beneath 
the level of the most savage and stupid of the Baboons. 
