674 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 



jand Buzzard's Bay (Gould) ; Labrador (Packard). Fossil iu the Post- 

 ! Pliocene (Leda-clay) at Saco, Maine (Fuller). 



This species burrows so deeply in the mud or sand that it is seldom 

 taken alive with the dredge. 



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



509.) 



Boston Jour. Nat. Hist., vol. iv, p. 38, Plate 4, tig. 1, 1842; Gould, Invert., ed. ii, 

 p. 72, fig. 386. 



Long Island to Greenland. Off Block Island, 29 fathoms; Casco 

 Bay, 10 to 20 fathoms; Bay of Fundy. Off Long Island, 37 fathoms, 

 (Gould). Greenland, in GO fathoms, (Morch). 



Ensatella Americana Verrill. Plate XXVI, fig. 182 ; Plate XXXII, 

 fig. 245. (p. 356.) 



American Jonr. Science, vol. iii, pp. 212, 234, 1872. Solen Americanus Gould, Invert., 

 ed. ii, p. 42, 1870 (provisional name). Solen ensis Gould, op. pit., ed. i, p. 28 ; 

 snd ed. ii, p. 40 (non Linn6) ; 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 ; Massachusetts 

 Bay; Casco Bay; Bay of Fundy; Gulf of Saint Lawrence; low- water 

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

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

 Bank (S. I. Smith). 



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

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

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

 lina. 



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

 35 mm , and are united together for about half their length, beyond which 

 they are round and divergent, subequal. 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 papillae 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 papillae extend along the 

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

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

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

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

 papillae. Foot long ; the end bulbous, obliquely truncated and beveled 

 laterally. 



