FISHERIES OF THE UNITED STATES. [62] 



Purpura Icqnllus, Lamarck. Drill or Wbelk. Long Island Sound to 

 Arctic Ocean ; rare and local south of Cape Cod ; abundant ou 

 nortliern coasts of New England and Nova Scotia. 



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



Neverita diiplicata, Stimpson. 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. Uuited States Fish Commission. 



Crepidula 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. Uuited States Fish Commission. 



Crepidula fornicata, 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. Uuited States Fish Commission. 



While the above species of Crepidula 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 SHELLFISH. 



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 Rio 

 Grande. 



