PLEUROTOMA. 349 



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

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

 from the coast of Norway. Halifax ( Willis) ; Marcouin {Bell) ; 

 fossil, Montreal (^Daicsoii). 



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

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

 iidlna pondcrosa, Say. All doubt, however, on that point, has been 

 since happily removed through the kuidness of Colonel Tottcn, who 

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

 culum. 



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

 will not hold good in regard to this si)ecies, 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. hews, 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 iV. exulans. 



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



Shell turretcd, 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 PLEUROTOITIA, Lamarck. 1799. 



Shell turreted, generally ribl)cd ; 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-Avhite ; whorls convex, with tAVO revolv- 

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



Pleurotoma bicarinata, Couthouy, Best. Jonrn. Nat. Hist. ii. 104, pi. 1, fiff. 11. — Gould, 

 Inv. 1st ed. 281, fig. 186. — De Kay, N. Y. Moll. 149, pi. 7, fig. 1 13. — SxiiirsoN, 

 Check Lists, 5. 



Manjclia bicarinata, Stijipson, Shells of New England, 49. 



