J^emofiam 
WILLIAM KEITH BROOKS 
1848-1908 
THE JOURNAL 
OF 
EXPERIMENTAL ZOOLOGY 
EDITORIAL BOARD 
William E. Castle 
Harvard University 
Edwin G. Conklin 
Princeton University 
Charles B. Davenport 
Carnegie Institution 
Horace Jayne 
The Wistar Institute 
Herbert S. Jennings 
Johns Hopkins University 
Frank R. Lillie 
University of Chicago 
Jacques Loeb 
The Rockefeller Institute 
Thomas H. Morgan 
Columbia University 
George H. Parker 
Harvard University 
Charles 0. Whitman 
University of Chicago 
Edmund B. Wilson, Columbia University 
and 
Ross G. Harrison, Yale University 
Managing Editor 
VOL. 9 No. 4 
DECEMBER, 1910 
PUBLISHED EIGHT TIMES A YEAR BY 
THE WISTAR INSTITUTE OF ANATOMY AND BIOLOGY 
36th STREET AND WOODLAND AVENUE 
PHILADELPHIA, PA. 
Entered as second-class matter May 28, 1909, at the Post Office at Philadelphia, Pa., under Act of March 3, 1879 
