674 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 



and Blizzard's Bay (Gould) ; Labrador (Packard). Fossil in the Post- 

 Pliocene (Leda-clav) at Saco, Maine (Fuller). 



This species burrows so deeply m tlie mud or santl that it is seldom 

 taken alive with the dredge. 



Thracia truncata Migliels and Adams. Plate XXVII, fig. 195. (p. 



509.) 



Boston Jour. Nat. HLst., vol. iv, ji. 38, Plate 4, Tig. 1, 1842; Gould, Invert., etl. ii, 

 p. 72, tig. 38G. 



Long Island to Greenland. Oft" Block Island, 29 fathoms; Casco 

 Bay, 10 to 20 fathoms; Bay of Fnndy. Olf Long Island, 37 fathoms, 

 (Gould). Greenland, in 00 fathoms, (Morcli). 



Ensatella Americatvta Yen-ill. Plate XXVI, lig. 1S2 ; Plate XXXII, 

 fig. 215. (p. 35G.) 



American Jour. Science, vol. ill, pp. 212, 284, 1872. Solen Americanus Gould, Invert., 

 ed. ii, p. 42, 1870 (provisional name). Solcn ensis Gould, op. cit., od. i, p. 28 ; 

 and ed. ii, p. 40 {non Linnet) ; Dekay, Nat. Hist. New York, Moll., p. 242, Plate 

 33, fig. 313. Ensis Americana H. and A. Adams, Genera, vol ii, p. 342. 



Florida to Labrador. Common at Great Egg Harbor, New Jersey; 

 Long Island Sound; Buzzard's Bay ; Vineyard Sound ; INIassachusetts 

 Bay; Casco Bay; Bay of Fuudy ; Galf of Saint Lawrence; low-water 

 mark to 20 fathoms, sandy. Fort Macon, Xorth Carolina, abundant, 

 (Coues). Georgia (Conper). Labrador, rare (Packard). Saint George's 

 Bank (S. I. Smith). 



Fossil in the Post-Pliocene of Portland, Maine ; Point Shirley, Massa- 

 chusetts; Xantucket; Virginia; and South Carolina ; in the Pliocene 

 of South Carolina ; and Miocene of Maryland ; Xorth and South Caro- 

 lina. 



In this species the siphonal tubes, in mature shells, protrude about J 

 35""", and are united together for about liaU" their length, beyond which 

 they are round and divergent, snbequal. Both orifices are surrounded 

 by a similar circle of numerous papilla^, of three sizes ; the larger ones 

 are enlarged in the middle, acute at tips, with a large black spot on 

 each side of the base; alternate with these are somewhat smaller ones 

 of the same form and with similar basal spots ; alternating with the 

 primary and secondary ones are small tapering papillae, less than half 

 the length of the longest ; numerous slender tapering papill.ne are also 

 scattered irregularly over the sides of the free portions of both tubes^ 

 in some cases in irregular rows of four to six, while on the ventral side 

 of the branchial tube two rows of alternating papilla3 extend along the 

 whole length of the siphon. The mantle is closed ventrally for most of 

 its length ; there is a posterior opening for the protrusion of the foot, 

 and a small opening just in advance of it, aiid another opening near the 

 middle of the ventral border ; the latter is fringed with small conical 

 X^apilla^. Foot long; the end bulbous, obliquely truncated and beveled 

 laterallv. 



