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TERTIARY FAUNA OF FLORIDA 



Family MYACID^. 

 Genus MYA (Liniie) Lamarck. 



< Mya Linne, Syst. Nat., Ed. x., p. 670, 1758. 



< Hiatula (auct.) Schroter, Einl. Conch., ii., p. 599, 1784; Modeer, K. Vetensk. Handl., 



xiv., pp. 178, 182, 1793. 

 ^ Mya Lam., Prodr., p. 83, 1799. Type Mya irimcata L. 

 Not Mya Modeer, op. cit., 1793, nor Mya Humphrey, Mus. Calonnianum, p. 59, 1797; 



^ Unio Retzius, 1788. 



Mya truncata Linne. 

 Mya truncata L., Syst. Nat., Ed. x., p. 670, 1758; Gould, Inv. Mass., p. 42, 1841 ; 



Jeffreys, Brit. Conch., iii., p. 66, pi. 3, fig. i, 1S65. 

 Mya ova/is (young) and Sphenia Swai7isoni Turton, 1822. 

 Mya prcEcisa Gould, Proc. Bost. Soc. Nat. Hist., iii., p. 215, 1850; Moll. U. S. Expl. 



Exp., p. 585, fig. 498. 



Pleistocene of the Arctic and boreal shores of the North Atlantic and 

 Bering Seas; at Portland, Maine; in the Leda clays of the St. Lawrence 

 River, at Quebec, Montreal, and Beauport ; Polaris Bay, Greenland; Bessels ; 

 and south to Massachusetts, and in Alaska to the Sitkan region. 



Mya arenaria Linne. 

 Mya arenaria L., Syst. Nat., Ed. x., p. 670, 1758; Gould, Inv. Mass., p. 40, 1841 ; 



Verrill, Inv. An. Vineyard Sound, p. 672, 1873; Dall, Bull. U. S. Nat. Mus., No. 



37, p. 70, pi. 49, fig. 9 ; pi. 55, fig. 2 ; pi. 69, fig. 2, 1889. 

 Mya ?ncrcc'?iarui Say, Journ. Acad. Nat. Sci. Phila., ii., p. 313, 1822. 

 Mya acuta Say, op. cit., p. 313, 1822. 



Mya alba Agassiz, Mem. Soc. Sci. Nat. Neuchatel, ii., p. i, pi. I, fig. 2-8, 1839. 

 Mya //cmp/iii/ii 'Newcomh, Proc. Cala. Acad. Nat. Sci., v., p. 415, 1874. 

 Mya corpulcnta Conrad, Fos. Medial Tert., p. 68, pi. 39, fig. \, 1845. 



Miocene of York River and Petersburg, Virginia, Burns ; of Gay Head, 

 Massachusetts, Dall ; Pleistocene of the Atlantic coast from Labrador to 

 South Carolina ; recent from Nova Scotia southward to North Carolina. 

 Introduced with seed oysters on the Pacific coast, and erroneously attributed 

 to Porto Rico (Agassiz). 



This well-known and widely distributed species was not originally a native 

 of the Pacific coast, where it was represented by a form which may be called 

 Mya intermedia, which is intermediate in character between M. arenaria and 

 M. truncata, strongly recalling the glacial M. uddevallensis of Sweden. This 

 shell grows to a very large size on the Alaskan Peninsula and is very puzzling. 



