BIOLOGICAL BULLETIN 



OF THE 



flDarine 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. 



flDanasino BMtor 



FRANK R. LILLIE The University of Chicago. 



VOLUME XX. 



WOODS HOLE, MASS. 

 DECEMBER, 1910, TO MAY, 1911 



