68 AMERICAN MARINE CONCHOLOGT. 



twelve very minute lines at the base of the body-whorl. Spire 

 gradually tapering to an acute apex. Aperture elongated, about 

 one-third the length of the shell, acutely angular above, produced 

 and rounded below. Outer lip sharp and thin, entire; pillar lip 

 with a single sharp, oblique fold ; opercule horny ; ivory or soiled 

 white. 



Length 5, diam. 2 mill. 



Mr. Gwjm Jeffreys believes this to be a variety of 0. impressa. 

 Say. 



New England; New York. 



7. 0. seminuda, Adams. Fig. 120. 



(Jaminea.) Bust. Journ. Nat. Hist., ii. 280, t. 4, f. 13. 1839. 



Shell small, acute, conic. Whorls seven, convex; upper whorls 

 and half of the body-whorl longitudinally rugose, crossed by three 

 equidistant revolving lines, presenting a granulated appearance. 

 At the base of the lower whorl are four revolving lines, beginning 

 on the middle, where the folds abruptly terminate. Suture dis- 

 tinct, divided by an indistinct spiral ridge. Aperture oval ; the 

 outer lip very thin, and scalloped by the revolving lines; the pil- 

 lar lip with an inconspicuous fold. Glossy white, translucent. 



Length 3.75, diam. 1.75 mill. 



New England, southwards. 



8. 0. impressa, Say. Fig. 121. 



(Turritella.) Journ. Philad. Acad., ii. 244. 1822. 

 Odostomia insculpta, De Kay, Moll. N. Y. 115, t. 31, f. 297. 1843. 



Shell elevated, thick, opaque, regularly tapering to the apex. 

 Whorls seven, flat, with a deeply impressed suture; body-whorl 

 with ten deeply sculptured closely approximated revolving striae 

 on the lower half, and five distant revolving lines on the upper 

 half; about four on the next whorl, and gradually diminishing in 

 number above. Aperture ovate, acute above, effuse beneath. Lip 

 simple; fold on the pillar-lip near the middle, distinct under the 

 lens, and deepening within. Soiled white, the sculptured lines 

 rufous. 



Length 5, diam. 2 mill. 



New England, southlands. 



Genus ACLIS, Loven. 

 Ind. Moll. Stand. 16. 1846. 

 The animal has a linguiform foot, much produced antcriorlj', 



