BIOLOGICAL BULLETIN 



OF THE 



fiDarine Biological Xaboraton> 



WOODS HOLE, MASS. 



EMtorial Staff 



E. G. CONKLIN Princeton University. 



GEORGE T. MOORE The Missouri Botanic Garden. 



T. H. MORGAN Columbia University. 



W. M. WHEELER Harvard University. 



E. B. WILSON Columbia University. 



Efcitor 



FRANK R. LILLIE The University of Chicago. 



VOLUME XXXVI. 



WOODS HOLE, MASS. 

 JANUARY TO JUNE, 1919 



