OF THE NORTHWEST COAST OF AMERICA 19 



Gouts Lithophaga Bolten. 1798. 

 Section Diberus Dall. 1898. 



Lithophaga plumula Hanley, 1844. 



Monterey, Cal., to Patagonia. Also Atlantic. 



Section Labis Dall. 1916. 



Lithophaga attenuata Deshayes. 1836. 

 San Diego to Patagonia. 



Section Myoforceps Fischer, 1886. 



Lithophaga aristata Dillwyn, 1817. 



La Jolla, San Diego Co.. Cal.. to Peru. Also Atlantic. 



Genus Musculus Bolten, 1798. 



Musculus niger Gray, 1824. 



Circumboreal. Arctic Ocean to Oregon. 

 Musculus niger variety obesus Dall, 1916. 



Arctic Ocean to Cape Flattery. 

 Musculus protractus Dall. 1916. 



Xunivak Island, Bering Sea, to ^Monterey. 

 Musculus olivaceus Dall, 1916. 



Bering Sea to Catalina Island. Cal. 

 Musculus impressus Dall. 1907. 



Petrel Bank, Bering Sea. 

 Musculus taylori Dall, 1897. 



A^ictoria, Vancouver Island. 

 Musculus laevigatus Gray. 1824. 



Circumboreal. Arctic Ocean to Puget Sound. 

 Musculus discors Linne, 1768. 



Circumboreal. Arctic Ocean to Puget Sound. 

 Musculus vernicosus ]\Iiddendorfif. 1849. 



Bering Sea to Sitka. 

 Musculus phenax Dall. 1915. 



St. George Island. Bering Sea. 

 Musculus marmoratus Forbes. 1838. 



Circiunlioreal. Puget Sound. (P. P. C). 

 Musculus seminudus Dall. 1897. 



Bering Sea to Forrester Island. Alaska. 



• Genus Crenella Brown, 1827. 



Crenella decussata Montagu, 1808. 



Bering Sea to the Santa Barbara Islands. Cal. Atlantic. 

 Crenella leana Dall, 1897. 



Aleutian Islands, eastward to Middleton Island, Alaska. 



