io8 
APES AND MONKEYS. 
Under the heading of the mangabeys we have seen how these monkeys differ 
from their cousins the guenons in having a heel, and thus live cusps, to their last 
lower molar teeth, and also in the uniform coloration of their individual hairs. 
As this is also the case in the macaques, it is obvious that in this respect the 
mangabeys form a transition to them from the guenons; and we may now 
consider how the macaques and mangabeys are to be distinguished from one 
another. 
In the first place, macaques are always of stouter build than the 
mangabeys; and they are further distinguished by the considerably 
greater prolongation of the muzzle, and the larger size of the naked callosities 
on the buttocks. Some 
of the macaques have 
their tails as long as 
those of the guenons and 
mangabeys; in others 
these appendages are very 
short, while in a few they 
are actually wanting; 
thus showing that the 
presence or absence of a 
tail is of no import either 
as a generic character, 
or as indicative of a 
higher or lower degree 
of organisation. In com¬ 
mon with all the monkeys 
we have hitherto con¬ 
sidered, the nostrils of the 
macaques do not reach as 
far forwards as the ex¬ 
tremity of the muzzle. 
From these characters 
it will be apparent that 
while the macaques are 
sufficientlv distinguished 
v o 
from the mangabeys to be 
entitled to rank as a 
separate genus, yet both 
groups are closely allied. 
And, as we shall see that as in the opposite direction the macaques are intimately 
connected through one singular intermediate form with the baboons of Africa, 
we have evidence that an almost complete transition exists from the guenons 
through the mangabeys to the macaques, and thus to the baboons. 
In speaking of the macaques as Asiatic monkeys, we must guard ourselves by 
mentioning that one solitary outlying species is found in the mountains of North- 
West Africa, and also on the opposite coast of Gibraltar. The greater majority 
THE BUIiMESE PIG-TAILED MONKEY. 
(From Sclater, Proc . Zool . Soc ., 1860.) 
