evidence for evolution which is to be found in the development
and structure of present-day man. The third and fourth lec-
tures, by Professor Parker and President Angell respectively,
constitute a unit in which the evolution of the highly special-
ized and preëminent nervous system of man together with the
development of intelligence are given consideration. Pro-
fessor Keller, in the fifth chapter, presents the question of evo-
lution in the various institutions of human society, and, finally,
Professor Conklin sets forth his views with regard to the trend,
or future, of evolution. The large attendance at each of the
lectures is sufficient evidence of the extreme interest in the
question of the evolution of man, and it is hoped that the pub-
lication of this book will stimulate an even greater interest
in this very important subject. It is believed that the main
scientific facts which bear upon the question are here presented
from a modern viewpoint in an interesting as well as authori-
tative manner.

In conclusion, as President of the Society and editor of this
volume, I desire to express my deep gratitude to the authors
for their willingness to take the time and energy to prepare the
lectures and to arrange their manuscripts for publication; to
the officers, committees, and members of the Yale Chapter of
Sigma Xi who by their enthusiastic coöperation made it pos-
sible to carry through the year's program successfully; to my
colleagues in the Department of Zoölogy and elsewhere in the
University, who have shown their active interest in the project
in many ways, and, finally, to the Yale University Press for
the splendid attitude they have shown in all matters connected
with the publication of this volume.

GEORGE A. BAITSELL,
President, Yale Chapter, Sigma Xi.
1921-1922.

Osborn Zoölogical Laboratory,
Yale University, July, 1922.

-vi-