THE 



NAUTILUS 



A QUARTERLY JOURNAL 



DEVOTED TO THE INTERESTS 



OF CONCHOLOGISTS 



VOL. XXXIII 

 JULY, 1919, to APRIL, 1920 



EDITORS AND PUBLISHERS 



HENRY A. PILSBRY 



Curator of the Department of Mollusca, Academy of Natural Sciences 



PHILADELPHIA 



CHARLES W. JOHNSON 



Curator of the Boston Society of Natural History 

 BOSTON 



