BIOLOGICAL BULLETIN 



OF THE 



flDarine Biological laboratory 



WOODS HOLE, MASS. 



EMtorial Staff 



E. G. CONKLIN Princeton University. 



JACQUES LOEB The Rockefeller Institute for Medical Research. 



GEORGE T. MOORE The Missouri Botanic Garden. 



T. H. MORGAN Columbia University. 



W. M. WHEELER Harvard University. 



E. B. WILSON Columbia University. 



Hbanaging Efcitor 



FRANK R. LILLIE The University of Chicago. 



VOLUME XXXIV. 



WOODS HOLE, MASS. 

 JANUARY TO JUNE, 1918 



