244 Lamarck's Genera of Shells. 



1. Melania*. 

 Shell turiited. Aperture entire, oval or oblong, effuse at the 

 base. Columella smooth, incurved. Operculum horny. 

 Type. Melania tnincata t. 

 Shell turrited, apex truncated, solid, blackish brown ; ribs 

 longitudinal, the superior most projecting, decussated by nu- 

 merous transverse striae ; whorls plano-convex.. 

 Guiana. PI. VIl. Tig. 144. 16 Species. 



2. Melanopsis J. 

 Shell turrited, aperture entire, oblong-oval. Columella cal- 

 lous above, truncated at the base, separated from the right lip 

 by a sinus. An operculum. 



The callus on the upper part of the columella distinguishes 

 the Melanopsis from the Melania, as well as its being truncated 

 at its base like the achatina, which is never the case with the 

 Melania. 



Type. Melanopsis Icevigata '%. 



Shell ovate-conical, smooth, chestnut colour ; six whorls, 

 rather flattened, convex at the spire ; the last whorl towards 

 the spire the longest. 



Archipelago. PI. VII. Fig. 145. 2 species. 

 3. Pircnay. 

 Shell turrited ; aperture longitudinal ; right lip acute, with 

 a sinus at its base, and another at the summit. Base of the 

 columella curved towards the right margin. Operculum horny. 

 Principally distinguished from Melanopsis by having no 

 callus on the columella, and from that genus and melania by 

 a sinus both at the base and summit of the right lip. 



Type. Pirena terebralis^. (Strombus ater, Linn.) 

 Shell subulate-turrited, smooth, black ; whorls flattened ; 

 aperture white. 



India. PI. VII. Fig. 146. 4 species. 



• From jMEXa;, hlack. 



t Truncated— 2nd Species. Lamarck's type is M. asperata. 



X From /xEXac, black, and o^}-l?, a/ace. 



5 .Smoot/i— 2nd Species. Lamarck's type is M.costata. 



11 From mti^n, the pohil of a stvnrd ! 1 1* rom laxbro, to ptercc. 



