MARINE MOLLUSCA OF THE UNITED STATES. 49 



Shell turricnlated, thin, with seven or eight shouldered whorls, 

 apex acute ; surface with twelve to fourteen oblique, compressed 

 ribs, becoming obsolete below the middle of the body-whorl, and 

 numerous, elevated, spiral lines ; outer lip sharp, canal short, open, 

 columella smooth, arcuate. White or yellowish. 



Length 16, diam. 6 mill. 



Massachusetts and northicards ; England. 



Differs from the next species by being broader, more delicate, 

 and by its angulately shouldered whorls. 



2. B. HARPULARiA, Couthouy. Fig. 81. 



iFusus.) Bost. Joiirn. Nat. Hist., ii. 106, t. 1, f. 10. 1838. 

 Shell ovate-oblong ; whorls six to eight, round-shouldered*, with 

 about eighteen oblique rounded ribs, crossed by fine revolving 

 lines, ribs becoming obsolete on lower part of body-whorl. Brown- 

 ish flesh color. Aperture narrow, outer lip sharp, inner lip white, 

 smooth, moderately arched, canal very short. 

 Length 12, diam, 6 mill. 



Massachusetts^ northicard. {Eur.) 



It is constant in its color, which differs from both the preceding 

 and following species. 



3. B. PLEUROTOMARTA, Couthouv. Fig. 82. 



{Fusus.) Bost. Journ. Nat. Hist., ii. 107, t. 1, f. 9. 1888. 

 Fusris rufus, Gould (non auct.), Invert. Mass. 1st edit. 290. 1841. 

 B. pyramidaUs, Strom. 

 B. Vahlii, Beck. 



Shell elongated-fusiform, apex acute ; whorls eight, slightly 

 convex, with eighteen to twent}- undulating longitudinal ribs and 

 equal interstices covered by very fine spiral strije ; body-whorl 

 more than half the length of the shell, slightly shouldered, the 

 ribs obsolete, but spiral striae more conspicuous on the lower por- 

 tion ; aperture small and narrow, canal very short ; reddish-fawn 

 colored. 



Length 12, diam. 3.25 mill. 



Cape Cod, Mass., northward. 



4. B. CANCELLATA, Mighels and Adams. Fig. 83. 



{Fusus.) Bost. Journ. Nat. Hist., iv. 52, t. 4, f. 18. 1842. 



Shell turreted, slender; with seven convex whorls, decussated 

 by twenty longitudinal ribs crossed by numerous raised revolving- 

 lines, giving the surface a cancellated appearance; spire acumiu- 

 4 



