150 NEW-TORK FAUNA — MOLLUSCA. 



Pleurotoma DECUSSATA. 



plate xxxvi. fig. 344. 



Pleurotoma decussala. CouTHouY, Journ. Nat. Hist. Vol. 2, p. 183, pi. 4, fig. 8. 

 P. id. Gould, Invcrtebrata of Mass, p. 281, fig. 186. 



Description. Shell minute, fusiform, turreted. Whorls five or six, convex, plicate, longi- 

 tudinally and obliquely crossed by numerous revolving striae : spire regularly sloping to an 

 acute apex ; suture distinct, with a shoulder near it on the whorls ; aperture oblong oval, 

 with a short canal at the base ; hp acute, with a shght notch above ; columella arched, flat- 

 tened, with its base turned somewhat abruptly to the left. Opercle with concentric elements ; 

 its apex below. 



Color. Epidermis olive-colored ; beneath white, ashen white or flesh-color. 



Length, 0-35. Width, 0-15. 



Found in the stomachs of fishes on the northern coast. Resembles Fusus harpularius, 

 except in the generic distinction. According to Dr. Gould, there is a broad light-colored 

 band in the freshest specimens. 



Pleurotoma plicata. 



PLATE VI. FIG. 120. 



Pleurotoma plicata, Adams, Bost. Jour. Nat. History, Vol. 3, p. 318, pi. 3, fig. 6. 

 P. id. Gould, Invcrtebrata of Mass. p. 282, fig. 187. 



Description. Shell minute, thick, fusiform. Whorls six, convex : body-whorl with about 

 twelve prominent oblique folds, crossed by ten or more revolving threads, rendering the folds 

 somewhat nodulous ; suture deeply impressed ; whorls above with folds and revolving lines ; 

 spire pointed, somewhat turreted. Aperture narrow, less than half the length of the shell : 

 hp arched, thickened by one of the folds ; notch above deep, distinct and smooth. Canal 

 short. 



Color. Epidermis ashen brown ; beneath this, ashen white : lip browish within. 



Length, 0-25. Width, 0-12. 



This species was detected by Mr. Adams, in the mud of New-Bedford harbor. I am 

 indebted to Mr. I. Cozzens for an imperfect specimen of a minute shell from the harbor of 

 New-York, which I refer to this species. 



