MARINE MOLLUSCA OF THE UNITED STATES. 83 
8. R. ropusta, H. C. Lea. Fig. 155. 
(Cingula.) Bost. Proc. 288, t. 24, f. 4. 1844. 
Shell ovate-acuminate, perforated, smooth, thick, white; spire 
short, subacute; suture impressed; whorls five, somewhat angled 
at the superior suture; last whorl round; base smooth; perfora- 
tion narrow, profound; mouth ovate, large. 
Length 2.5, diam. 2 mill. , 
Cape May, N. J. 
This is a somewhat doubtful species: it (as well as the next) is 
perhaps only the young of a form of R&. latior. Only one speci- 
men was obtained. 
4. R. Mopresta, H. C. Lea. Fig. 156. 
(Cingula.) Bost. Proc. 288, t. 24, f. 5. 1844. 
Shell ovate, imperforate, smooth, thin, diaphanous, greenish 
horn-color; spire short, ovate, not acute; suture small; whorls 
four, flattish; last whorl round; base smooth; mouth ovate; acute 
above, rounded below. 
Length 2.5, diam. 1.8 mill. 
Quite common on the under surface of stones below high-water 
mark. 
Long Island (near Brooklyn). 
5. R. tTurricuna, H. C. Lea. Fig. 157. 
“(Cingula.) Proc. Bost. Soc. Nat. Hist. 289, t. 24, f. 6. 1844. 
Shell elevated, conic, perforate, smooth, thick, tawny; spire 
very much exserted, conical, obtuse, sutures small; whorls six, 
convex; last whorl slightly bullate; base smooth; perforation 
small, narrow, lunate; mouth ovate; columella thick, almost dis- 
joined from the last whorl. 
Length 3, diam. 1.3 mill. 
South Carolina. 
This species has not been detected or identified by subsequent 
collectors. 
6. R. acuLEus, Gould. Fig. 158. 
(Cingula.) Invert. Mass. Edit. 1, 266, f. 172. 1841. 
Shell minute, subcylindrical, elongated, fragile; whorls six, very 
convex, with a deep suture; with numerous revolving lines and 
traces of longitudinal folds towards the apex. Aperture small, 
suboval, oblique. Light horn-color. 
Length 5 mill. 
