52 BULLETIN 112, UNITED STATES NATIONAL MUSEUM. 



HEMIMACTRA HEMPHILLI Dal!, 1894. 



Nautilus, vol. 7, No. 12. p. 137, pi. 5, fig. 2. 

 Sau Pedro to San Diego, California. 



HEMIMACTRA CATILLIFORMIS Conrad, 1867. 



Aiuer. Journ. Conch., vol. 3, p. 193; Nautilus, vol. 7, No. 12, p. 137, pi. 5, 



fig. 3. 

 Neah Bay to Sau Diego, California. 



HEMIMACTRA FALCATA Gould, 1850. 



Proc. Boston Soe. Nat. Hist., vol. 3, p. 216; Rep. U. S. Expl. Exp., Moll., 



p. 393, figs. 506 0-6. 

 Puget Sound to Cortez Bank and the Coronado Islands. 



Subgenus Symmokpiiomactea Dall, 1894. 



SYMMORPHOMACTRA PLANULATA Conrad, 1837. (Plate 3, fig. 9.) 



Jouru. Acad. Nat. Sci. Phila., vol. 7, p. 240. 

 Monterey to Cape San Lucas. 



Genus SCHIZOTHAERUS Conrad, 1853. 



SCHIZOTHAERUS NUTTALLII Conrad, 1837. 



Journ. Acad. Nat. Sci. Phila., vol. 7, i*. 235, pi. is, tic 1; Bull. D. S. Fish 



Comin.. vol. 3, No. 23, p. 354, fig. 1. 

 Wrangell, Alaska, to San Diego, California. 



SCHIZOTHAERUS NUTTALLII CAPAX Gould, 1850. 



Proc. Boston Soc. Nat. Hist., vol. 3, p. 217; Conch. Icon. Mactra, pi. 1, lig. 4. 

 Kodiak Island, Alaska, to San Francisco. California. 



Family MESODESMATIDAE. 

 Genus ERVILIA Turton, 1822. 



ERVILIA CALIFORNICA Dall, 1916. 



Proc. U. S. Nat. Mus., vol. 52, No. 2183, p. 414. 

 San Pedro, California, to Magdalena Bay. 



Superfamily MYACEA. 



Family MYACIDAE. 

 Genus MYA (Linnaeus) Lamarck, 1799. 



MYA TRUNCATA Linnaeus, 1758. 



Syst. Nat., ed. 10. p. 670; Binney's Gould's Inv. Mass., p. 58, fig. 376. 

 Circumboreal. Arctic Ocean to Bering Island on the west and to Puget 

 Sound on the east. 



MYA INTERMEDIA Dall, 1898. (Plate 4.) 



Trans. Wagner Inst. Sci., vol. 3, pt. 4, p. 857. 



Arctic Ocean from Point Bari'ow to Montei'ey Bay, California. 



