THE JOURNAL 



OF 



EXPERIMENTAL ZOOLOGY 



EDITED BY 



William E. Castle 



Harvard University 



Edwin G. Conklin 



Princeton University 



Charles B. Davenport 



Carnegie Institution 



Herbert S. Jennings 



Johns Hopkins University 



Frank R. Lillie 



University of Chicago 



Jacques Loeb 



Rocliefeller Institute 



Thomas H. Morgan 



Columbia University 



George H. Parker 



Harvard University 



Edmund B. Wilson, Columbia University 



and 



Ross G. Harrison, Yale University 

 Managing Editor 



VOLUIME 19 

 1915 



\TV. 



THE WISTAR INSTITUTE OF ANATOMY AND BIOLOGY 

 PHILADELPHIA, PA. 



