solitary. Among these there are, of course, many stages of transition
from one to the other. The specially communal, including the ants, bees,
termites, and beavers, are those in which there is almost a total loss
of individuality, each member working for the good of the community as a
unit, not for its personal advantage. The result consists in organized
industries, division and specialization of duties, a common home, food
stock, etc. At a lower level in animal life, that of the hydroid polyps,
communism has become so complete that the community has grown into an
actual individual, the members not being free, but acting as organs of
an aggregate mass, in which each performs some special duty for the good
of the community.

The social animals differ from the communal in that the individuality of
the members is fully preserved. There is some measure of work for the
group, some degree of mutual aid, some evidence of leadership and
subordination, but these are confined to a few exigencies of life, while
in most of the details of existence each member of the group acts for
itself. The solitary animals are those which do not form groups larger
than that of the family, and into whose life the principle of mutual
aid, outside the immediate family relations, does not enter. Each acts
for itself alone, and intercourse between the individuals of the species
is greatly restricted.

The advantages of social habits among animals are evident. There is
excellent reason to believe that all animals, and especially such
advanced forms as the vertebrates and the higher arthropods, have some
power of mental development, some facility in devising new methods of
action to meet new situations. Though their reasoning power may be
small, it is not quite lacking, and many examples of the exercise of the
faculty of thought could be cited if necessary.

What we are here concerned with, is the final result of such exercises
of individual thought powers. In the case of the solitary forms, such
new conceptions die with the individual. Though they may exert an
influence on the development of the nervous system, and aid in the
hereditary transmission of more active brain powers, they are lost as
special ideas, fail to be taken up and repeated by other members of the
species. This is not the case with the social animals. Each of these has
some faculty of observation and some tendency to imitation, and useful
steps of advance made by individuals are