Experimental Morphology 



BY CHARLES BENEDICT DAVENPORT, Ph.D., 



Director of the Biological Laboratory of the Brooklyn Institute of 



Arts and Sciences 



491 pp., 111., 8vo, $3.50 



Why does an organism develop as it does? 



This is the problem with which this book is concerned. 

 The work is intended to serve as an introduction and guide 

 to the study and development of the individual regarded 

 as a complex of processes rather than a mere succession 

 of different forms. The central idea of the work is that 

 ontogeny is a series of reactions to chemical and physical 

 agents. 



The Germ-Cell Cycle in Animals 



BY ROBERT W. HEGNER 



Assistant Professor of Zoology in the University of Michigan, author of 

 " An Introduction to Zoology," and " College Zoology." 



346 pp., 111., 12 mo, $1.75 



An excellent survey of a subject which is extremely 

 important to all biologists and a book available for use 

 as a supplementary text in courses on Cellular Biology, 

 Evolution, Heredity, and Genetics. The term "Germ- 

 Cell Cycle" is meant to include all those phenomena 

 concerned with the origin and history of the germ cells 

 from one generation to the next generation. Contrary 

 to the usual custom, the period of the germ-cell cycle 

 which is emphasized in this book is not the maturation 

 of the germ cells, but the segregation of the germ cells 

 in the developing egg and the visible substances (keimbahn- 

 determinants) concerned in this process. 



THE MACMILLAN COMPANY 



Publishers 64-66 Fifth Avenue New York 



