672 EEPOET OF COMMISSIONER OF FISH AND FISHERIES. 



fathoms or more. In Casco Bay it is extremely abundant in rocky, cav- 

 ernous pools, among the ledges at low-water mark, and mostly attached 

 by a byssus, associated with Modiola modiolus. I also found specimens 

 in 10 to 15 fathoms, perforating recent and sound shells of Cyprina 

 Islandica. In the Gulf of Saint Lawrence, near Anticosti Island, where 

 limestone abounds, I have found it burrowing in the limestone in large 

 numbers. South of Cape Cod it is far less abundant, though not un- 

 common in Long Island Sound. Yar. distorta (Say) is common from 

 Fort Macon to Georgia, and is possibly a distinct species. Fossil in the 

 Post-Pliocene of Maine, New Brunswick, Canada, Anticosti, Labrador, 

 Scandinavia, and Great Britain ; in the Coralline andEed Crags of Eng- 

 land, etc. Var. distorta is found in the Miocene of Maryland. 



Mya ARENARIA Linne. Plate XXVI, fig. 179. (pp. 357, 463.) 



Systema Naturre, ed. xii, p. 1112, 1767 ; Gould, Iuvert., ed. i, pp. 40, 359 ; ed. ii, p. 

 55, fig. 375. Mya mercenaria and M. acuta Say, Journal Acad. Nat. Sci., Phila- 

 delphia, vol. ii, p. 313, 1822. 



South Carolina to the Arctic Ocean ; northern coasts of Europe, south 

 to England and France ; northeastern coast of Asia, south to China and 

 Japan (Hakodadi). Sitka (Middendorff). South Carolina (Gibbs). Fort 

 Macon, North Carolina (Dr. Yarrow). Comparatively scarce south of 

 Cape Hatteras. Very abundant from New Jersey northward, both in 

 brackish estuaries and on the open coasts. Particularly large and fine in 

 Long Island Sound (see p. 463). Casco Bay and Bay of Fundy, from 

 half-tide mark to 40 fathoms, those dredged being all young. Fossil in 

 the Post-Pliocene of Scandinavia, Greenland, Labrador, Canada, New 

 England, Virginia, South Carolina, etc.; in the Red-Crag and all later 

 formations in Great Britain ; and in the Miocene of Virginia. 



Corbula contracta Say. Plate XXVII, fig. 191. (p. 418.) 



Journal Acad. Nat. Sciences, Philadelphia, vol. ii, p. 312, 1822; Gould, Invert., 

 ed. i, p. 43, fig. 37 ; ed. ii, p. 60, fig. 377. 



Cape Cod to Florida. Common, living, in Vineyard Sound and Buz- 

 zard's Bay, in 5 to 19 fathoms ; Long Island Sound, near New Haven, 

 not uncommon in shallow water. Georgia (Couper). Fossil in the 

 Post-Pliocene of Virginia, North and South Carolina ; and in the Plio- 

 cene of South Carolina. A closely related species occurs in the Mio- 

 [cene of Maryland. 



Lyonsia hyalina Conrad. Plate XXVII, fig. 194. (p. 35S.) 



American Marine Conchology, p. 51, Plate 11, fig. 2, 1831 ; Gonld, Invert., ed. ii, p. 

 64, fig. 380. Mya hyalina Conrad, Jour. Acad. Nat. Sci., Philadelphia, vol. vi, 

 p. 261, Plate 11, fig. 12, 1831. Osteodesma hyalina Conthouy, Boston Jour. Nat. 

 Hist., vol. ii, p. 166, 1839 ; Gould, Invert., ed. i, p. 46, fig. 31. 



Florida to Gulf of Saint Lawrence. Common in Long Island Sound, 

 Buzzard's Bay, Vineyard Sound, Massachusetts Bay, Casco Bay, and 

 Bay of Fundy ; low-water mark to 30 fathoms ; Beaufort, North Carolina 

 (Coues). 



