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 Zurbo, as Turbo chrysostomus L., RumpH. Amb. Rariteith. 
Tab. 19, fig. E, Turbo argyrostomus L., CHEMN. Conchyl. Tab. 177, figs. 
1758, 1759, Cuv. R. Ani., éd. ill., Moll. Pl. 42, fig. 1, &c. 
The species which have no nacreous splendour internally, and which 
have constantly a horny operculum, are united under the following sub- 
genus. 
Littorina FéRuss. 
Sp. Turbo littoreus L., Alikruik, Vigneau, Guignette; SWAMMERD. Bibl. nat. 
I. pp. 180—185, Tab. 1x. fig. 14, BastEeR Natwur. Vitsp. 1. pp. 127, 128, 
Tab. 14, fig. 1; 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. Cuvier Ann. du Mus. X1. pp. 130—135, Mém. s. 1. Moll. No. 15, 
pp. 1o—15, figs. g—13. 
Sp. Phasianella bulimoides Lam., Buccinum australe GMEL., BLAInv. Mala- 
col. Pl. 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, Vill. Pl. Go, fig. 1. 
Turritella LAM. Shell elongato-conical, acuminate, turbinate. 
Aperture circular, entire, with margins disjomed above, labrum 
emarginate by a sinus. 
Sp. Turritella bicingulata Lam., Buatnv. Malacol. Pl. 21, fig. 3; Turritella 
duplicata Lam., Turbo duplicatus L., REEVE Conch. Syst. 11. Pl. 224, fig. 1, 
&e. 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. 1x. figs. 15 —18; Cuv, Ann. dw Mus. xt. p. 170, Moll, 
