PROFESSOR OF ZOÖLOGY, COLUMBIA UNIVERSITY


New York

COLUMBIA UNIVERSITY PRESS

1916

_All rights reserved_

COPYRIGHT, 1911,

By THE COLUMBIA UNIVERSITY PRESS

Set up and electrotyped. Published June, 1911.
Reprinted December, 1912; September, 1916.

Norwood Press
J.S. Cushing Co.--Berwick & Smith Co.
Norwood, Mass., U.S.A.




PREFACE


The present volume consists of a series of eight addresses delivered as
the Hewitt Lectures of Columbia University at Cooper Union in New York