(L' 



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 OFFICE 



1921 



