THE JOURNAL 



OF 



EXPERIMENTAL ZOOLOGY 



EDITED BY 



WILLIAM K. BROOKS 



Johns Hopkins Uni'-uersity 



WILLIAM E. CASTLE 



Harnjard University 



EDWIN G. CONKLIN 



Uni'versity of Pennsyl'vania 

 CHARLES B. DAVENPORT 

 Carnegie Institution 



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 



AND 



ROSS G. HARRISON 



Yale Uni'versity 

 Managing Editor 



VOLUME IV 



THE JOURNAL OF EXPERIMENTAL ZOOLOGY 

 BALTIMORE 



1907 



