HELICINA. 



Lam. 



TESTA subglobosa, heliciformis, imperforata ; 

 apertura subtrigona, peritremate subincrassato, 

 reflexo ; columella incrassata, transversa, supra 

 umbilicum expansa, basi inferiore angulum cum 

 labio externo efFormante. Operculum plerum- 

 t]|ue testaceum, trigonum, baud spirale, nucleo 

 lateral! . 



A PRKTTY little Genus of land shells, apparently belong- 

 ing exclusively to tropical climates: of which we now 

 know about 30 species*. When first proposed by La- 

 marck he united the beautiful little marine shells, which 

 he has since with great propriety separated, under the 

 name of Rotella. In general appearance the Helicinae 

 very much resemble small Helices, from which, however, 

 they may be distinguished by their having an operculum, 

 as well as by the thickened substance of the shell in the 

 place of the umbilicus. They are nearly related to Cy- 

 clostoma, but diifer from that Genus in the circumstance 

 of their apertures not being at all circular and in their 

 operculum not being spiral. We observe that Lamarck 

 has placed them at a distance from Cyclostoma, probably 

 from his not having been acquainted with the animal, 

 which very closely resembles that of the last mentioned 



* Mr. Gray described all the species that were then known, amounting 

 to seventeen in the first volume of the Zoological Journal, 



