39 G EEPORT OF COMMISSIONER OF FISH AND FISHERIES. [690] 



fine sandy mud; common in Casco Bay and Bay of Fuudy, 4 to 100 

 fathoms, mud. Greenport, Long Island (S. Smith). Massachusetts 

 Bay (Gould). Nova Scotia (Willis). Labrador (Packard). Greenland 

 (Morch). 



This species seems to be unknown among our Post-Pliocene shells. 

 Having examined several hundred specimens from many different local 

 ities and depths, I am satisfied that it is perfectly distinct from Y. lima- 

 tula, with which certain writers are inclined to unite it. 



Yoldia Gouldii. 



Nncula Gonldii DeKay, Nat. Hist. New York, Mollusca, p. 180, Plate 13, fig. 

 221, 1843. 



This was originally described by Dekay as from Long Island Sound. 

 I have seen no specimens corresponding with the description in all 

 respects. It is, perhaps, a short variety of Y. sapotilla. 



YOLDIA OBESA Stimpson, 1851. (p. 509.) 



H. and A. Adams, Genera, vol. ii, p. 548, 1858 ; Gould, Invert., ed. ii, p, 155, fig. 

 463. Leda obesa Stimpson, Proc. Boston Soc. Nat. Hist., vol. iv, p. 13, 1851 ; 

 Shells of New England, p. 10, Plate 2, fig. 1, 1851. Nncula navicularis Mighels, 

 Boston Journal Nat. History, p. 323, 1843 (non Couthouy, Gould). 



Block Island to Gulf of Saint Lawrence. East of Block Island, 29 

 fathoms, rare ; Casco Bay and off Cape Elizabeth, 30 to 95 fathoms ; 

 Bay of Fundy, 40 to 100 fathoms, rare ; near Saint George s Bank, 110 

 and 150 fathoms (Packard). Massachusetts Bay (Stimpson). 



YOLDIA THRACIFORMTS Stimpson, 1851. (p. 509.) 



Smithsonian Check-List, p. 2, 1860; H. and A. Adams, Genera, vol. ii, p. 548, 

 1858 (thracifeformis) ; Gould, Invert., ed. ii, p. 157, fig. 465 ; Morch, op. cit., p. 

 21, 1857. Nucula thracicrformis Storer, Boston Jour. Nat. History, vol. ii, p. 122, 

 figure, 1838; Gould, Invert., ed. i, p. 97, fig. 66. Leda thracAccformis Stimpson, 

 Shells of New England, p. 9, 1851. Nucula navicularis Couthouy, Boston Journ. 

 Nat. History, vol. ii, p. 178, Plate 4, fig. 4, 1839, (young) ; Gould, Invert., ed. i, 

 p. 103. Yoldia angularis Moller, op. cit., p. 92, 1842 (t. Morch). 



Long Island to Greenland. Off Fire Island, south of Long Island, in 

 10 fathoms; and off Eace Point, Cape Cod, in 30 fathoms, (Stimpsou). 

 Not uncommon, and of large size, in Casco Bay, 15 to 95 fathoms; and 

 Bay of Fundy, 10 to 100 fathoms ; near Saint George s Bank, 85 fath 

 oms (Packard). 



LEDA TENUISULCATA Stimpson. (p. 509.) 



Shells of New England, p. 10, 1851 ; Gould, Invert., ed. ii, p. 161, fig. 468. Nucula 

 tenuisulcata Couthouy, Boston Journ. Nat. Hist., vol. ii, p. 64, Plate 3, fig. 8, 1838. 

 Nucula minuta Gould, Invert., ed. i, p. 101, 1841 (non Fabricius, sp). 



Rhode Island to Gulf of Saint Lawrence. Common in Massachusetts 

 Bay, Casco Bay, and Bay of Fundy, G to 80 fathoms. Nova Scotia 

 (Willis). Newport, Rhode Island (t. S. Smith). Southern part of the 

 Gulf of Saint Lawrence ( Whiteaves). Particularly abundant in Eastport 

 Harbor, 10 to 30 fathoms ; Saint George s Bank and vicinity, 40 to 150 



