CONCLUDING REMARKS 217 
The herbivorous stage was followed by an omnivorous one, 
characterised by the development of powerful canines. In this 
way, as skill in hunting and slaying animals developed, and 
carnivorous diet became of continually greater importance, the 
intestinal tube would appear to have begun to shorten and the 
processus vermiformis to become constricted. 
Laryngeal sinuses may have been developed, which, acting as 
resonators, lent the voice greater strength and carried it farther, 
and thus made it a means of frightening or enticing. The 
lower jaw, the neck and its musculature, were far more powerfully 
developed than now. 
In the male the genital glands may have remained, as _ they 
now normally do in the female, within the abdominal cavity, 
and been thus better protected from injury than at present. At 
a later stage even, when they had changed their position, and had 
reached the pouch-like appendages of the abdominal integument, 
they could still be withdrawn into the cavum abdominis, at least 
temporarily, by means of a well-developed muscle (cremaster). 
This is still indicated by ontogenetic processes. 
There can be no doubt that the ancestors of Man were pro- 
vided with a more extensive mammary system and more numerous 
mamme than he to-day possesses, and the significance of this fact 
is equally clear. It can only be explained by the assumption that 
a greater number of young were originally produced at a birth. 
This, of course, was of advantage in the preservation of the species. 
It follows from the above that in the course of a long 
geological period, Man has gradually lost a great number of 
advantages once possessed by his ancestors, and the question 
arises whether he has acquired any others in exchange for those 
lost. This certainly is the case, and this indeed must have 
been so, otherwise the species Homo would have failed in the 
struggle for existence. We thus have a series of exchanges, based 
Gf we take only the most important organ into consideration) 
upon the unlimited capacity of development of the human brain. 
This one acquisition, supported by an increased functional 
efficiency of the hand and by the development of articulate speech, 
has entirely compensated for the loss of the great series of ad- 
vantageous arrangements mentioned above. They had to be 
sacrificed in order that the brain might successfully develop, and 
that the Homo sapiens of to-day, with his surprising adaptability 
to the most varied conditions of life, might be produced. 
This momentous exchange took place slowly and only after 
