100 AMERICAN MARINE CONCHOLOQY. 



front ; outer lip sharp ; columella with a strong spiral fold ; oper- 

 culum horny, elliptical, lamellar. 



Animal white; head truncated and slightly notched in front, 

 furnished posteriorly with recumbent tentacular lobes, and small 

 eyes near their inner bases ; foot oblong, lateral lobes slightly re- 

 flected on the shell. 



There are few living, but over seventy fossil species. Distribu- 

 tion universal. 



1. T. PUNCTO-STIATA, Adams. Fig. 205. 



Bost. Journ. Nat. Hist, 323, t. 3, f. 6. 1840. 



Shell minute, suboval, polished ; whorls four to five ; body 

 whorl large, smooth above the aperture ; beneath it, with ten to 

 fifteen punctate revolving lines ; spire short, rapidly diminishing, 

 with a shoulder near the suture ; suture deeply impressed ; aper- 

 ture two-thirds the length of the body-whorl, becoming wider 

 beneath ; pillar lip with a prominent fold. Umbilicus open in 

 young shells ; white. 



Length 2.5 to 3.T mill. 



New York to Massachusetts. 



Genus RINGICTJLA, Deshayes. 

 Anini. sans Vert., viii. 341. 1838. 



Shell small, ventricose, smooth or concentrically striated ; spire 

 small ; aperture with an oblique notch in front ; columella callous, 

 strongly plicated ; outer lip thickened and reflected; with a mar- 

 ginal callus. 



1. R. NITIDA, Yerrill. 



Am. Journ. Sci., 16th January, 1873. 



Shell small, white, smooth, broad oval, with five whorls ; spire 

 rapidly tapering, subacute, shorter than the aperture; whorls 

 very convex, with deep suture, and a subsutural impressed line ; 

 columella stout, recurved at the end, with two strong, very pro- 

 minent equal, spiral folds, the anterior one projecting beyond the 

 canal, with the end rounded. 



Length 4 -}-, diam. 3 mill. 



England. 



Family BCTLLHLE. 



Synopsis of Genera. 



Shell convolute, ovate or subglobose, smooth, generally mottled ; spire in- 

 volute sunken, causing the apex to be tubular or perforate ; aperture ex- 



