MARINE MOLLUSCA OF THE UNITED STATES. 35 



4. N. acuta, Say. Fig. 54. 



Journ. Philad. Acad., ii. 234. 1822. 

 Conic-acute, cancellate, so as to appear granulate ; granules 

 prominent, somewhat transverse, inequidistant. Spiral grooves 

 six in number; spire longer than the body-whorl, slender, acute. 

 Beak distinguished by a depression from the body-whorl, and 

 slightly reflected; lip thickened, with elevated lines on the fauces, 

 not attaining the margin. Color whitish. 



Length 13 mill. 



Southern Coast. 



5. N. unicincta, Say. Fig. 55. 



Journ. Philad. Acad., v. 211. 1826. 

 Shell sub-ovate, conical. Whorls eight, with ten to twelve re- 

 volving lines and transverse undulations; apex acute; lip with 

 ten revolving striae within ; pillar lip concave in the middle ; two 

 obsolete striae, and a deeper one at the base. Color yellowish- 

 white or ash-gray ; body-whorl with a brown band. 



Length 23 mill. 



South Carolina. 



6. N. consensa, Ravenel. 



Proc. Acad. Nat. Sciences, Philad. 43. 1861. 



Shell ovate-conical, ribbed and crossed by numerous revolving 

 striae ; whorls seven, and the apex ; whorls rounded, with eleven 

 strong ribs ; suture deep, scalloped by the ribs ; revolving striae 

 crossing the ribs, as well as the interstitial spaces. 



Aperture nearly oval, outer lip much thickened, denticulate 

 within, the largest tooth being in the form of a ridge next the 

 canal ; pillar much hollowed, with slight callus above, much thick- 

 ened to form the canal, which is short, oblique, and turned back- 

 wards; lower portion of the pillar white, covered with crowded, 

 inconspicuous, revolving striae, with a deep groove at the edge of 

 the canal. 



Color of the shell generally yellowish-bi*own, with a narrow 

 deep-brown band immediately next the white projection at the 

 canal; next to this, on the body-whorl, is a much wider band of 

 lighter brown, which revolves at the suture to the apex of the 

 shell ; all other portions of the surface are marked by delicate 

 lines, more or less grouped, of j'ellowish-brown. On the thick- 

 ened portion of the outer lip these lines are here and there more 

 deeply colored in spots. 



