GASTEROPODA. 211 
Inhabits the island of Mangsi. Pickering. 
Allied to S. maculata, Quoy, but the spire is less elevated, the aper- 
ture is more rounded, and above all, it is characterized by the plain, 
white, lunate area adjacent to the columella. 
Figures 250, 250 a, aperture and back of the shell; 250 8, sculpture, 
magnified. 
Natica Lewisit (Govwid ). 
Testa pregrandis, solidiuscula, conico-globosa, albida, epidermide sordidé 
stramineo induta, lineis minimis confertissimis, flexuosis cincta : spira 
anfractibus sea ventricosis postice valde constrictis: apertura obovata, 
ampla, callo copioso albo castaneo-tincto umbilicum modicum simplicem 
profundum postice circumambiente, ad anfractum ultimum munita ; 
fauce incarnata. Operculum corneum. 
Natica Lemwisii, Goutp; Proceed. Boston Soc. Nat. Hist., ii. 239. 
July 1847. Expedition Shells, 49. 
Suet very large, not very ponderous, globose-conic; the spire 
rather elevated and acute; colour pale fleshy, covered by a thin, ashy 
epidermis, which is everywhere marked with very delicate, crowded, 
undulating, revolving lines. Surface somewhat undulated by the 
stages of growth. Whorls six, moderately convex, somewhat flattened 
near the suture, the last whorl having a very remarkable broad, well- 
marked constriction, at about its posterior third, which is continued 
also about the middle of the posterior whorls. Aperture obovate, broad, 
having a sharp lip, until it rises on the left margin, when it widens, 
and presents a rounded edge, terminating in a copious white callus, 
which seems to flow down about half way around the umbilicus with- 
out closing it, and having a furrow running obliquely inward, from 
the upper edge of the umbilicus; its edges are somewhat tinted with 
chestnut, and a strong band of callus also fills the upper angle of the 
aperture. Umbilicus moderately long, deep, nearly round, with a slight 
encroachment down the right wall. Interior of the aperture shaded 
with pale flesh-colour. Operculum thin, horny. 
