246 FISHERIES OF THE UNITED STATES. [62] 



Purpura lapillus, Lamarck. Drill or Whelk. Long Island Sound to 

 Arctic Ocean ; rare and local south of Cape Ood ; abundant on 

 northern coasts of New England and Nova Scotia. 



33652. Wood's Holl, Mass. United States Fish Commission. 



Lunatia heros, Adams. Sea Snail. Georgia to Gulf of Saint Lawrence 

 and Labrador; abundant and large on coasts of New Jersey and 

 Long Island. 



33653. Vineyard Sound. United States Fish Commission. 



Neverita duplicate/,, Stirnpson. Sea Snail. Massachusetts Bay to North- 

 ern Florida ; Northwestern Florida to Yucatan ; local and un- 

 common north of Cape Cod ; abundant fromNantucket south- 

 ward. 



33455. East Greenwich, R. I. A. A. Wilson. 



33610. Great South Bay, -Blue Point, Long Island. F. C. Dayton. 



33657. Vineyard Sound. United States Fish Commission. 



Grepidula plana, Say. Sea Snail or Slipper Shell. Massachusetts Bay 

 to Florida; northern shores of Gulf of Mexico ; local northward 

 of Massachusetts to Gulf of Saint Lawrence ; common in Vine- 

 yard and Long Island Sounds. 



33658. Vineyard Sound. United States Fish Commission. 



Grepidula fomicata, Lamarck. Sea Snail or Boat Shell. Casco Bay, 

 Maine, to Florida; northern shores of Gulf of Mexico; local 

 north of Massachusetts; abundant from Vineyard Sound south- 

 ward. 



33659. Vineyard Sound. United States Fish Commission. 



While the above species of Grepidula are neither directly injurious nor 

 beneficial, they are often associated with destructive Gasteropods. In 

 addition, their absence from an oyster-bed is one of the many indica- 

 tions of its deterioration. 



MOLLUSCA LAMELLIBRANCHIATA. 

 BIVALVE SHELL-FISH. 



Affording food or bait. 



Ostrea virginica, Gmelin. American Oyster. 



— Map showing general distribution along the eastern coast of 

 North America. 



— Map showing location of oyster-beds along the coast of Prince 

 Edward's Island, Nova Scotia, New Brunswick, and shores of 

 the Gulf of Maine and Massachusetts Bay. 



— Series of maps showing the distribution of oysters, and approxi- 

 mate areas and positions of natural and artificial oyster-beds, 

 along the coast of the United States, from Cape Cod to the Kio 

 Graude. 



