THE JOURNAL 



OF 



EXPERIMENTAL ZOOLOGY 



EDITED BY 



WILLIAM K. BROOKS 



Johns Hopkins Uni-versity 

 WILLIAM E. CASTLE 



Har'vard Uni'versity 



EDWIN G. CONKLIN 



Uni'versity of Pennsyl'vania 



CHARLES B. DAVENPORT 



Carnegie Institution 



ROSS G. HARRISON 



Yale Uni'versity 

 HERBERT S. JENNINGS 



Johns Hopkins Uni'versity 



FRANK R. LILLIE 



Uni'versity of Chicago 

 JACQUES LOEB 



Uni'versity of California 

 THOMAS H. MORGAN 



Columbia Uni'versity 

 GEORGE H. PARKER 



Har'vard Uni'versity 

 CHARLES O. WHITMAN 



Uni'versity of Chicago 

 EDMUND B.WILSON 



Columbia Uni'versity 



ROSS G. HARRISON, Managing Editor 

 2 HILLHOUSE AVENUE, NEW HAVEN, CONN. 



VOLUME V 



PUBLISHED QUARTERLY BY 



THE WISTAR INSTITUTE OF ANATOMY AND BIOLOGY 



36th STREET AND WOODLAND AVENUE 



PHILADELPHIA, PA, 



