FEET AND HANDS 
Connected with this carriage of the body are differences 
in the proportions of the limbs, the existence of a heel, 
and the loss of the ape-like great toe, which serves in 
them the functions of athumb. Aman in fact is short 
armed, firmly plantigrade, with a pronounced heel, and 
with no “ thumb ”’ on his feet. Besides, there are minor 
differences which we may properly insist upon as dis- 
tinctive of man. Not, however, all the commonly 
supposed differences. For example, man is not a hairless 
mammal atall. It is true that the hairy covering is not 
obvious everywhere, as it is in apes; but an investiga- 
tion with the microscope will show that the hair follicles 
exist in reality where the hairs themselves are so fine 
as to escape, or almost to escape, detection. It is quite 
possible, moreover, that the wearing of clothes, which 
is doubtless an exceedingly ancient habit of man, is 
responsible for the not great development of hair. 
The smooth and unridged skull is a human attribute, 
and so is the proportionately larger size of the brain 
than in the Anthropoid apes. It must be remembered, 
however, that in the smaller monkeys the brain is some- 
times proportionately large. 
The S-like curvature of the spine is a human char- 
acteristic in so far as it is more perfectly developed in 
man than in apes; and there are, in short, a number of 
other small characters which are merely differences of 
degree and not of kind from the corresponding struc- 
tures in the monkeys. 
This group, Primates, which must therefore include 
man, is easy enough to distinguish from groups lying 
lower in the series if we extend it so as to include the 
lemurs. 
The group is an eminently arboreal one ; in fact, the 
exceptions to this are but few. Co-related with this 
general mode of life are the opposable thumb and great 
toe, a character which is almost universal in the order, 
20 
