22 PROCEEDINGS OF THE NATIONAL MUSEUM. tol. 65 



Family ISCHNOCHITONIDAE. 

 Genus ISCHNOCHITON Gray, 1847. 



Subgenus Stenoplax Carpenter, 1878. 



ISCHNOCHITON FALLAX Carpenter, 1892; one raWe. 



Living, Vancouver Island-Todos Santos Bay, Lower California. 

 Section LEPIDOZONA Pilsbry, 1892. 

 ISCHNOCHITON COOPERI Carpenter. 1892; three yalves. 



Living, Mendocino County, California-Cataliiui Island. 



Genus CALLISTOCHITON Carpenter, 1882. 



CALLISTOCHITON PALMULATUS MIRABILIS Pilsbry, 1892; two valves. 



Living, San Diego, California. 



CALLISTOCHITON CRASSICOSTATUS Pilsbry. 1892; eleven valves. 



Living, Forrester Island, Alaska-San Diego, California. 



Family MOPALIIDAE. 



Genus MOPALIA Gray, 1847. 



MOPALIA MUSCOSA Gould. 1846; six valves. 



Living, Shumagin Islands, Alaska-Rosario, Lower California. 



MOPALIA MUSCOSA ACUTA Carpenter, 1855; twenty valvea. 



Living, Santa Barbara-San Diego, California. 



Family CRYPTOCHITONIDAE. 

 Genus CRYPTOCHITON MiddendorflF, 1847. 



CRYPTOCHITON 9TELLERI Middendorff, 1847; not rare. 



Living, Bering Island, Aleutian Islands-San Miguel and San Nicolas 

 Islands. 



LAND AND FRESHWATER SPECIES. 



Family ZONITIDAE. 

 Genus ZONITOIDES Lehmann, 1846. 



ZONITOIDES ARBOREUS Say, 1817; two specimens. 



Living Vancouver Island-Oregon. 



Family HELICIDAE. 

 Genus PYRAMIDULA Fleming, 1833. 



PYRAMIDULA CRONKHITEI Newcomb. 1865; one specimen. 



Living, Alaska-Oregon. 



