BIOLOGICAL BULLETIN 



OF THE 



flDarine Biological laboratory 



WOODS HOLE, MASS. 



EMtorial Staff 



E. G. CONKLIN Princeton University. 



GEORGE T. MOORE The Missouri Botatzic Garden. 



T. H. MORGAN Columbia University. 



W. M. WHEELER Harvard University. 



E. B. WILSON Columbia University. 



FRANK R. LILLIE The University of Chicago. 



VOLUME XXXVII. 



WOODS HOLE, MASS. 

 JULY TO DECEMBER, 1919 



