Pee FOURN AL 
OF 
EXPERIMENTAL ZOOLOGY 
EDITED BY 
WILLIAM E. CASTLE FRANK R. LILLIE 
Harvard University University of Chicago 
EDWIN G. CONKLIN JACQUES LOEB 
Princeton University University of California 
CHARLES B. DAVENPORT THOMAS H. MORGAN 
Carnegie Institution Columbia University 
HORACE JAYNE GEORGE H. PARKER 
The Wistar Institute Harvard University 
HERBERT S. JENNINGS CHARLES O. WHITMAN 
Jéhns Hopkins University University of Chicago 
EDMUND B. WILSON, Columbia University 
and 
ROSS G. HARRISON, Yale University 
Managing Editor 
VOLUME VII 
THE WISTAR INSTITUTE OF ANATOMY AND BIOLOGY 
PHILADELPHIA, PA, 
1909 
