THE 



NAUTILUS 



A MONTHLY JOURNAL 



DEVOTED TO THE INTERESTS OF 



CONCHOLOGISTS 



VOL. XX 

 MAY, 1906, to APRIL, 1OO7. 



EDITORS AND PUBLISHERS : 



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



PHILADELPHIA. 



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



BOSTON. 



