INTRODUCTION 
The purpose of this work is to bring together the marine shells of 
the west coast of North America from the Arctic Ocean to San Diego, 
giving the original description, whereabouts of the type and type locality, 
geographical and geological range. The writer has been engaged con¬ 
tinuously for eight years in the preparation of this work, in the museum 
at Stanford University and in the field from Puget Sound to San Diego; 
and has made four journeys to compare material in the eastern museums: 
the United States National Museum, the Philadelphia Academy and the 
American Museum of Natural History in New York. To the authorities 
of these institutions the writer wishes to express her thanks for generous 
assistance. In this work are figured all common species of marine 
mollusca of the Californian province, a great many being figured for the 
first time. When figures are not given, full references are made where 
figures may be seen in papers easily accessible. It is the purpose of 
the writer to make this work useful to the amateur as well as to the 
professional conchologist. 
Acknowledgments are due to Dr. W. H. Dali, of the United States 
National Museum, for his help in identification and classification of speci¬ 
mens and for kindly criticism; to Dr. Paul Bartsch, of the same 
institution, for identification of minute, and descriptions of new species; 
to Mr. T. S. Oldroyd for assistance in field and laboratory; to Dr. 
C. F. Newcombe, Victoria, British Columbia, for specimens; to Dr. 
C. McLean Fraser of the Dominion Station at Nanaimo, British Columbia, 
for use of material; to Dr. J. P. Smith, of Stanford University, for super¬ 
vision of the preparation of this work; to Professor Trevor Kincaid, of 
the University of Washington, for contribution of specimens collected by 
him; to Mr. A. Taylor, Vancouver, British Columbia, for donation of 
specimens used in the preparation of this paper; to Dr. T. C. Frye, of the 
University of Washington, for material dredged in Puget Sound; to 
Dr. B. L. Clark, of the University of California, for specimens and use 
of plates; to Stanford University, for financial aid in furnishing plates for 
illustration and for publication of this work. 
The line or lines preceding the description give the reference to the 
original description and the place where the species is figured. 
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