BIOLOGICAL BULLETIN 



OF THE 



nrmrine Biological laboratory 



WOODS HOLE, MASS. 



Editorial Staff 



E. G. CONKLIN Princeton University. 



JACQUES LOEB The Rockefeller Institute for Medical Research 



T. H. MORGAN Columbia University. 



W. M. WHEELER Harvard University. 



E. B. WILSON Columbia University. 



Managing Editor 



FRANK R. LILLIE The University of Chicago. 



VOLUME XXIII. 



WOODS HOLE, MASS. 

 JUNE TO NOVEMBER, 1912 



