SMITHSONIAN INSTITUTION 
UNITED STATES NATIONAL MUSEUM 
Bulletin 112 
SUMMARY OF THE MARINE SHELLBEARING MOL- 
LUSKS OF THE NORTHWEST COAST OF AMERICA, 
FROM SAN DIEGO, CALIFORNIA, TO THE POLAR SEA, 
MOSTLY CONTAINED IN THE COLLECTION OF 
THE UNITED STATES NATIONAL MUSEUM, 
WITH ILLUSTRATIONS OF HITHERTO 
UNFIGURED SPECIES 
BY 
WILLIAM HEALEY DALL 
Honorary Curator of Mollusks, United States National Museum 
WASHINGTON 
GOVERNMENT PRINTING OPnCE 
1921 
