180 BIOLOGICAL SUKVEY OF 



off Massachusetts coast. Grand Manan common on muddy 



bottoms, Passamaquoddy Bay, oft' Cape des Rosiers in 110 



fathoms. 



YoLDiA Miiller 



Y. sAPOTiLLA (Gould). (Gould, 1870, Inv. Mass., p. 159, 

 fig. 466.) A very common species occurring wherever there 

 is mud. Being a favorite food for fish, it rarely reaches a 

 large size. Stations : D 1, 14, 27, 32, 35, 36, 38, 39, 43, 46, 

 51, 55, 58, 65, 72, 91, 96, 103, 106, 108, 112, 144. Some very 

 large specimens were taken at D 91. Reported from Eastport, 

 Casco Bay, Provincetown, Duxbury, east of Block Island. 

 Grand Manan, Northumberland Strait occasional, and a Cana- 

 dian fossil form. 



Y. (portlandia) thraciaeformis (Storer). ( Nuciila thra- 

 ciaeformis Storer, 1838, Boston Jour. Nat. Hist.; Toldia 

 thraciaeformis Gould, 1870, Inv. Mass., p. 157, fig. 465.) Not 

 a common form except the young. Being a fish food probably 

 accounts for this. Favorite bottom is mud and broken shells. 

 Stations : D 1, 2, 37, 38, 77, 105, 115. No definite record from 

 Woods Hole, though the region is included within the range 

 of the species. Eastport, Casco Bay, off Cape Cod, Bay of 

 Fundy, Halifax, dredged rare by Whiteaves in 200 fathoms 

 between Anticosti and Gaspe. 



Y. limatula (Say). [Nucula limitula Say, 1831, Amer. 

 Conch.; Yoldia limatula Gould, 1870, Inv. Mass., p. 154, fig. 

 462. ) Scarce in the inner Bay and more common on the south 

 side and in Somes Sound. Specimens found average larger 

 than the 2 preceding forms. Stations : D 46, 61, 66, 141. Re- 

 ported from Casco Bay, Salem, Boston Harbor, Buzzards 

 Bay, off New Haven, Bay of Fundy, common through North 

 umberland Strait, rare northern Gulf of St. Lawrence. Fossil 

 in the Leda clay. 



Y. MYALis (Couthouy). {Nucula myalis Couthouy, 1838, 

 Boston Jour. Nat. Hist.; Yoldia myalis Gould, 1870, Inv. 

 Mass., p. 160, fig. 467.) Only a few specimens found in outer 

 Bay. Stations : D 15, 117. Reported from Eastport, Casco 

 Bay, Massachusetts from fish. A more northerly species than 

 Y. limatula. Rather general occurrence to Hudson Strait. 



