BIOLOGICAL BULLETIN 



OF THE 



flDarine Biological Xaborator? 



WOODS HOLE, MASS. 



Editorial 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. 



/IDanagtng 



FRANK R. LILLIE The University of Chicago. 



VOLUME XLI. 



WOODS HOLE, MASS. 

 JULY TO DECEMBER, 1921 



