BIOLOGICAL BULLETIN 



OF THE 



flDarine Biological laboratory 



WOODS HOLE, MASS. 



Editorial Staff 



E. G. CONK. MX Princeton University. 



JACQUES LOEB 7Yie Rockefeller Institute for !\Icdical Research. 



T. H. MORGAN Columbia University. 



W. M. WHEELER Harvard University. 



E. B. WILSON Columbia University. 



Managing 



FRANK R. LILLIE The University of Chicago. 



VOLUME XXV. 



WOODS HOLE, MASS. 

 JUNE TO NOVEMBER 1913 



