29 
Aciiatina. — Shell oval or oblong: aperture entire, longitudinal; the right lip sharp, 
never reflected. Columella smooth, truncated at the base. 
(1) Shells with the last whorl ventricose, not depressed . 
Plate XV. Fig. 5. A. virginea. (Bulla virginea. — Linn.) 
(2) Shell with the last whorl depressed, or attenuated towards the base. 
Plate XV. Fig. 5 (a). A. albo-lineata. (Voluta leucozonias.— Gmel.) [Mrs. Mawe’s Cabinet.] 
Succinea.— Shell oval or ovate-conical: aperture large, entire, longitudinal; the right 
lip sharp, not reflected, united at the lower part to a smooth, sharp, attenuated 
columella. No operculum. 
Plate XV. Fig 6. S. amphibia. (Helix putris.— Linn.) 
Auricula. — Shell suboval or ovate-oblong: aperture longitudinal, very entire at the 
base, contracted at the upper part, where the margins are disunited. Columella 
with one or more plaits ; the lip or margin sometimes reflected outwards, some- 
times simple and sharp. 
(1) Shells with the margin reflected outwards. 
Plate XV. Fig. 7- A. Judge. (Voluta auris Judge — Linn.) 
(2) Shells with the margin simple and acute. 
Plate XV. Fig. 8, 8 (a). A. monile. (Voluta flava. — Gmel.) 
Cyclostoma.— The shape of the shell variable; whorls of the spire cylindrical: aperture 
round, regular ; the margins circularly united, or reflected by age. An oper- 
culum. 
Plate XV. Fig. 9. C. volvulus. (Helix volvulus.— Linn.) [Mrs. Mawe’s Cabinet.] 
LYMN/EANA 3 Genera. 
Shell spirivalve, the external surface mostly smooth; the right margin of the aperture always sharp, 
and not reflected. 
Planorbis. — Shell discoidal, spire depressed, the whole of the whorls shewn above and 
beneath : aperture oblong, lunate, very distant from the axis of the shell ; the 
margin never reflected. No operculum. 
Plate XV. Fig. 10. P. corneus. (Helix cornea.— Linn.) 
Piiysa. — Shell convolute, oval or oblong ; the spire prominent: aperture longitudinal, 
contracted at the upper part. Columella twisted: right lip very thin, sharp, part- 
ly projecting above the plane of the aperture. No operculum. 
Plate XV. Fig. 11. P. rivalis. (Lymnsea rivalis. — Sowerby.) 
Lymnlea.— S hell oblong, sometimes turreted ; the spire prominent : aperture entire, lon- 
gitudinal, outer lip sharp; the lower part ascending over the columella, forms a 
very oblique plait, re-entering the aperture. No operculum. 
Plate XV. Fig. 12. L. stagnalis. (Helix stagnalis. — Linn.) 
