PLEUROTOMA. 349 



Taken from fishes caught at the Banks, and one fine specimen 

 from a fish caught in Massachusetts Bay. I liave a specimen also 

 from the coast of Norway. Halifax (^Willis}; Marcouin {Be/l) ; 

 fossil, Montreal (^Daiuson). 



The aspect of this shell is such that I was at first led to refer it, 

 doubtfully, to the genus Paludiiia. It very greatly resembles Pal- 

 udina ponderosa, Say. All doubt, however, on that point, has been 

 since happily removed through the kuidness of Colonel Totten, who 

 furnished me with several specimens containing the sub-spiral oper- 

 culum. 



The remark of Deshayes, that Natica is without an epidermis, 

 will not hold good in regard to this species, nor, indeed, to any of 

 the species found on our coast. He, however, was aware of the 

 small value of this characteristic, and alludes to a species then 

 under his eye, which I take to be N. heros, having the shape and 

 epidermis of Ampullaria, but the operculum of Natica. A specimen 

 sent to me by Dr. Loven was regarded by him as new, and he had 

 applied to it the name of N. exularis. 



Family TURRITID^E, H. and A. Adams. 



Shell turreted, sub-fusiform ; aperture with the fore part chan- 

 nelled, straight, and often much produced ; outer lip detached at 

 the hind part from the body whorl, forming a sinus, or with the 

 margin fissured near the last whorl. 



Genus PLEUROTO^TIA, Lamarck. 1799. 



Shell turreted, generally ribljcd ; aperture terminating in a 

 straight, more or less elongated canal ; outer lip, at its posterior 

 junction, having a fissure or notch. 



Pleurotoma bicarinata. 



Fig. 186. 



Shell ovate-fusiform, turreted, dusky-white ; whorls convex, with two revolv- 

 ing ribs, and other less conspicuous lines and grooves ; notch of the lip shallow. 



Pleurotoma bicarinata, Couthouy, Best Journ. Nat. Hist. ii. 104, pi. 1, fiij. 11. — Gould, 

 Inv. Istcd. 281, fig. 186. — De K.\y, N. Y. Moll. 149, pi. 7, fig. 1 13. — Stuu'SON, 

 Check Lists, 5. 



Mangelia bicarinata, Stimpson, Shells of New England, 49. 



