800 CLASS XIII. 



turn, with margins disjoined above. Columella arcuate, flat- 

 tened, not truncated at the base. Animal with slender acuminate 

 tentacles and pedunculate eyes at the outside of tentacles. Opercu- 

 lum mostly thick, calcareous. 



The species of this genus are very numerous. Those which shine nacreous 

 and silvery within, with a mostly very thick operculum, are more espe- 

 cially named Turbo, as Turbo clirysostomus L., HUMPH. Amb. Rariteitlc. 

 Tab. 19, fig. E, Turbo argyrostomus L., CHEMN. Conchyl. Tab. 177, figs. 



1758, 1759, Cuv - R - Ani -> ed - iU -> Mo11 - P1 - 4 2 > % I > &c - 



The species which have no nacreous splendour internally, and which 

 have constantly a horny operculum, are united under the following sub- 

 genus. 



Littorina FERUSS. 



Sp. Turbo littoreus L., AUTcruik, Vigneau, Guignette; SWAMMEKD. Bibl. nat. 

 i. pp. 180185, Tab - IX - % J 4, BASTER Natmvr. Uitsp. I. pp. 127, 128, 

 Tab. 14, fig. I ; this little snail, boiled with salt, is eaten in Zealand. 



Phasianella LAM. Shell ovate or conical, solid, imperforate. 

 Columella smooth, rotundate. Aperture ovate, longitudinal. Animal 

 with two laciniate labia. Two long conical tentacles ; eyes seated 

 in tubercles at the base of tentacles. Body margined by a laciniate 

 membrane. 



Comp. CUVIEE Ann. du Mus. XI. pp. 130 135, Mem. s. 1. Moll. No. 15, 

 pp. 1015, figs. 913. 



Sp. Phasianella bulimoldes LAM., Buccinum australe GMEL., BLAINV. Mala- 

 col. PI. 37, fig. 5, from the S. Pacific, at New Zealand and New Holland. 

 Some species of this genus of LAMARCK are referred by DESHAYES to genus 

 Littorina. There are some fossil species of Phasianella from the tertiary 

 formations; LAMARCK Ann. du Mus. iv. pp. 295 297, vm. PL 60, fig. i. 



Turritella LAM. Shell elongato-conical, acuminate, turbinate. 

 Aperture circular, entire, with margins disjoined above, labrum 

 emarginate by a sinus. 



Sp. Turritella bicingulata LAM., BLAINV. Malacol. PI. 21, fig. 3; Turritella 

 duplicata LAM., Turbo duplicatus L., REEVE Conch. Syst. n. PL 224, fig. i, 

 &c. To this genus belong numerous fossil species. 



Paludina LAM. Shell turbinate, with rotundate wreaths. 

 Aperture subrotund, somewhat oblong, angulate above, with mar- 

 gins connected, acute. Operculum horny, orbicular. Animal with 

 tentacles acuminate, eyes sessile at the base of tentacles, mantle 

 alate, appendiculate. 



Sp. Paludina vivipara LAM., Helix vivipara L., SWAMMERDAM Bibl. nat. i. 

 pp. 169 180, Tab. ix. figs. 15 18; Cuv. Ann. du Mus. xi. p. 170, Moll. 



