THE 



NAUTILUS 



A MONTHLY JOURNAL 



DEVOTED TO THE INTERESTS OF 



CONCHOLOGISTS 



VOL. XX. 

 MAY, 1906, to APRIL, 1007. 



EDITORS AND PUBLISHERS : 

 H. A. Pilbbry, Curator of the Department of Mollusca, Academy of Natural Sciences, 



Philadelphia. 



C. W. Johnson, Curator of the Boston Society of Natural History, 



Boston. 



