GASTEROPODA. 23 



COLUMBELLA,* Lam. 1799. 



BccciNUM (spec.) Adans. 

 PvGMiEA. Humph. 1797. 

 Columbus. Montf. 1810. 

 CoNiDEA.. Swains. 1840. 



Ge7i. Char. Shell generally thick, strong, ovate, or somewhat angular, with a short 

 spire, though sometimes turriculate and elevated ; aperture oblong ; base emarginate ; 

 outer lip thickened and dentated within ; generally more or less tumid in the middle ; 

 inner lip irregularly crenulated, thickened posteriorly, and callous ; operculum small 

 and corneous. 



Shells of this genus have a tropical or subtropical character, and may be 

 considered almost as a recent gi'oup ; a few species have, however, been found in the 

 Touraine beds. The Crag one is rather of an aberrant form, connecting it with 

 Nassa. 



1. COLUMBELLA SULCATA. -7. 8ow. Tab. II, fig. 2, a — d. 



BucciNUM SULCATUM. J. Sow. Min. Con. t. 37;'), fig- 2, 1823. 



— var. p. Min. Con. t. 477, fig. 4. 



CoLUMBELLA SULCATA. S. Wood. Catalogue 1842. 



C. Testa turritd, elongatd ; spird elevatd, apice acuto, anfradibus numerosis, cotwexis, 

 transversim sidcatis ; aperturd elongatd ; labro incrassato, intus denticdato ; had tmncatd, 

 emarginatd ; labro in/erne plicafo. 



Shell elongate, tmTeted, and sulcated ; spire elevated, apex acute, whorls 8 — 10, 

 convex ; aperture elongate, subtrapezoidal ; outer lip nearly straight, thickened, and 

 denticulated within ; base short, open, and truncated ; left lip thin, crenulated. 



Axis, \\ inch. 



LocaUty. Red Crag, Walton Naze. Var. /3, Sutton. 



Abundant at Walton, but rare in all other parts. I am not aware of its having 

 been found in the Coralline Crag. It is very variable in its proportionate dimensions. 

 In one specimen the mouth is nearly one half its length, while in another it is not more 

 than one fourth. The outer lip is thickened and denticulated within, when in its adult 

 state, and no doubt the left lip was also crenated when recent. One specimen shows 

 a few folds upon the lower part of the columella, ^^^th a slight thickening in the middle 

 of the outer lip. These characters are considered sufficient to retain it in the above 

 genus. 



ROSTELLARIA,* Lam. 1801. 

 Strombus (spec.) Linn. 



Gen. Char. Shell turreted or fusiform, with numerous volutions, generally orna- 

 mented on the exterior by longitudinal costge or transverse striae ; aperture ovate, with 



* Etym. (?) The diminutive of Colnmba, a dove. 

 ■|- Etym. Rostellwn, a little beak. 



