136 Notice of several species of Shells. 



DESCRIPTION. 



Shell without colored markings, glabrous, with seventeen 

 ribs, of which the upper ones are more prominent and distant, 

 with a small elevated line between them ; spire channeled by 

 the projection of the highest rib ; inner lip expanded over the 

 columella and thin ; outer lip bent suddenly outward, and 

 forming an acute angle with the body whirl, not thickened, 

 with all the ribs passing over it to the extreme edge, which is 

 acute and slightly bent inward ; with fifteen sharp teeth on the 

 inner angle, of which the uppermost three are double ; Colu- 

 mella with a large obtuse solitary tooth on the upper part, a 

 deep hollow in the middle, and two or three prominent oblique 

 plaits below ; base not umbilicated ; spire pervious to the sum- 

 mit, as though it had been rolled round a small straight wire, 



A pretty shell, which may be added as an eighth species to 

 the seven described by Lamarck. 



N. B. The figure of this shell is half, the others full size. 



3. Genus. NATICA. Bruguieres, Lamarck. 



Shell sub-globose, umbilicated. Aperture entire, semi-circular. 

 Inner lip oblique, toothless, callous : the callosity contracting 

 and sometimes covering the umbilicus. Outer lip acute, within 

 smooth. An operculum. 



Nerita. Linne Sys. Nat. p. 1251. " §Umbilicata. ,: 



Nerita. Dilhvyn Rec. Sh. p. 975. " § Umbilicated. y 



SPECIES. 



Natica patula. Sowerby. 



Shell sub-orbicular, depressed, thin, wrinkled, 

 brown, with a, white margin; umbilicus broad, patu- 

 lous and spiral, with a pillar in the center capped by 



