13 



Thracia teuncata, Mighels. There can be no doubt of the 

 identity of the specimens which I have taken in our Bay, with 

 Dr. Mighels' species. He makes no mention of an ossiculum, 

 which I have detected in numerous instances. It is, however, 

 very minute, and might easily escape observation. 



The name T. iruncata is preoccupied. But the Thracia trim- 

 cata of Turton and Brown is now considered a variety of T. 

 distorfa. 



The animal of this species, in its broad compressed foot, and 

 in other points, resembles that of Cochlodesma. I shall take 

 some other opportunity of describing at length the animals of 

 this and of the other species here mentioned. 



It was taken from fishes caught on the Middle Bank, (Ayres,) 

 and in deep water off Lynn, (Tufts.) In twenty-two fathoms, 

 eight miles east of Scituate, several specimens occurred to me, 



Thracia Couthouyi, nob. In deep water in various parts of 

 the Bay. 



, Cardium Grcenlandicum, Chemn. Several specimens of the 

 young of this species, finely polished, with well marked ribs, 

 and beautiful zigzag lines of flesh-color were taken in deep 

 water in Cape Cod Bay. 



Nucula delphi^^odonta, Migh. This species is very abundant 

 in Massachusetts Bay, occurring at various depths on sandy and 

 muddy bottoms. It is easily obtained by means of the dredge ; 

 I have sometimes obtained some hundreds at a single cast. I 

 may mention as localities, — off Cape Ann, in thirty fathoms ; 

 Race Point, in twenty-two fathoms ; Broad Sound, in six 

 fathoms, on a sandy bottom, and at Charlestown, in mud, not far 

 below low water mark. 



This little animal has its mantle freely open, with plain 

 margins, and forming no siphons ; the foot, which is protruded 

 from the longer side of the shell, is large, white, and hyaline, 

 with a deep groove and serrated edges. It is very active, 

 making quite extensive journeys along the sandy floor of the 

 ocean, and leaving a little furrow of the size and depth of 

 its shell. It lives at the surface of the sand or buried just 

 below it. 



