52 
BULLETIIN- 112, UNITED STATES NATIONAL MUSEUM. 
HEMIMACTRA HEMPHILLI Dali, 1894. 
Nautilus, vol. 7, No. 12, p. 137, pi. 5, fig. 2. 
San Pedro to San Diego, California. ht, H, 
HEMIMACTRA CATILLIFORMIS Conrad, 1867. 
Amer. Journ. Conch., vol. 3, p. 193 ; Nautilus, vol. 7, No. 12, p. 137, pi. 5, 
fig. 3. 
Neah Bay to San Diego, California. 
HEMIMACTRA FALCATA Gould, 1850. 
Proc. Boston Soc. Nat. Hist, vol. 3, p. 216; Rep. U. S. Expl. Exp., Moll., 
p. 393, figs. 506 _ 
Puget Sound to Cortez Bank and the Coronado Islands. Tk.vUp ' 
Tm oyy\MJtX^ ^ f 
Subgenus Symmorphomactea Dali, 1894. _ 
/ SYMMORPHOMACTRA PLANULATA Conrad, 1837. 
j Journ. Acad. Nat. Sci. Phila., vol. 7, p. 240. 
Monterey to Cape San Lucas. 
(Plate 3, fig. 9.) 
Genus SCHIZOTHAERUS Conrad, 1853. 
SCHIZOTHAERUS NUTTALLII Conrad, 1837. 
Journ. Acad. Nat. Sci. Phila., vol. 7, p. 235, pi. 18, fig. 1; Bull. U. S. Fish 
Comm., vol. 3, No. 23, p. 354, fig. 1. ^ 
Wrangell, Alaska, to San Diego, California. ffOLoJLe., 
SCHIZOTHAERUS NUTTALLII CAPAX Gould, 1850. 
Proc. Boston Soc. Nat. Hist, vol. 3, p. 217 ; Conch. Icon. Mactra, pi. 1, fig. 4. 
Kodiak Island, Alaska, to San Francisco, California. 
Family MESODESMATIDAE. 
Genus ERVILIA Turton, 1822. 
ERVILIA CALIFORNICA Dali, 1916. 
Proc. U. S. Nat. Mus., vol. 52, No. 2183, p. 414. 
San Pedro, California, to Magdalena Bay. 
Superfamily MY ACE A. 
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 Dali, 1898. (Plate 4.) 
Trans. Wagner Inst Sci., vol. 3, pt 4, p. 857. 
Arctic Ocean from Point Barrow to Monterey Bay, California. 
