mollusca. 
37 
Involute.] 
spire consisting of five slightly inflated volutions, vvell defined 
by the line of the suture, and terminating in a somewhat obtuse 
apex; aperture oval; outer lip rather thick, but not marginate, 
or reflected; pillar lip a little replicated, but destitute of an 
umbilicus. Length a quarter of an inch ; diameter one-third 
its length. 
Not uncommon in moist situations, residing principally on the 
ground, under old trees, and on the banks of ditches. 
4. Bulimus acdtus, pi. XIV, f. 18. — First Ed., pi. 41, 
f. 18. 
Bulimus acutus, Bruguiere, Ency. Meth., p. 42 ; Draper- 
naud. Hist, des Moll., p. 77, pi. 4, f. 29, 30 ; Lamarck, An. 
San. Vert., VI, pt. 2nd, p. 125; Fleming, Brit. An., p. 265; 
Jeflreys, Linn. Tr., XVI, p. 346 ; Alder, Mag. Zool. and Bot., 
II, p. 109; Forbes, Mai. Mon., p. 10; Thompson, Ann. and 
Mag. Nat. Hist., VI, p. 36 ; Bulimus fasciatus, Turton, Man., 
p. 84, f. 67; and p. 86, f. 79, Bulimus ventricosus ; Helix 
acuta, Muller, Verm., H, p. 110; Dillwyn, Des. Cat., p. 956; 
Helix bifasciatus, Maton and Racket, Linn. Tr., VHI, p. 210; 
Turton, Conch. Diet., p. 63; Brown, Wernerian Mem., H, p. 
529; Turbo fasciatus, Vennant, Brit. Zool., IV, p. 131, pi. 82, 
f. 119; Montagu, Test. Brit., p. 346, pi. 22, f. 1 ; Da Costa, 
Brit. Conch., p. 90; Donovan, Brit. Sh., I, pi. 18, f. 1, 1 ; Elis- 
mafasciata, Leach, Mbll., p. 109- 
Shell oblong, taper, thin, subpellucid, of a yellowish or 
grayish-white, longitudinally streaked, or spirally banded with 
chestnut or umber-brown ; body somewhat more than a third 
of the length of the shell ; spire consisting of nine or ten some- 
what rounded volutions, not very deeply separated by the 
suture, and terminating in a rather acute apex; whole shell 
coarsely wrinkled longitudinally; aperture subovate; outer lip 
thin ; inner lip a little reflected on the columella, with a small 
subumbilicus behind. Length nearly three-quarters of an inch; 
diameter a quarter. 
This species is liable to considerable variety in its markings ; 
sometimes it is longitudinally streaked, at others having a single 
band of interrupted spots at the base of the volutions, in some 
instances it has two bands, which, at the base often become 
confluent, and not unfrequently it is nearly white. It is also 
liable to some variations in shape and size. 
Found on many of the sand and bent pastures of Great 
Britain and Ireland, near the sea shore ; and although local in 
its habitat, generally very abundant where it is found. 
Genus 48 — Balnea. — Gray. 
Shell thin, with the convolutions reversed, covered with a 
slender brown epidermis; body short; spire long and taper, with 
many volutions, gradually decreasing in size as they ascend ; 
aperture small, subquadrate; outer lip entire, a little thickened, 
with a slight fold on the columella ; base entire. 
1. Bal-ea fragilis, pi. XIV, f. 11 — First Ed., pi. 41, 
f. 11. 
Balcea fragilis, Leach, Moll., p. 116; Turton, Man., p. 87, 
f. 70 ; Alder, Mag. Zool. and Bot., H, p. 1 11 ; Balea fragilis, 
Gray, Zool. Journ., I, p. 6l ; Forbes, Mai. Mon., p. 11; Balea 
perversa, Fleming, Brit. An., p. 271 ; Balcea perversa, Thomp-’ 
son, Ann. and Mag. Nat. Flist., VI, p. 41 ; Odostomia perversa. 
Fleming, Edin. Ency., VH, p. 76; Clausilia fragilis, Jeffreys, 
Linn. Tr., XVI, p. 351 ; Pupa fragilis, Drapernaud, Hist, des 
Moll., p. 68, pi. 4, f. 4; Turbo perversus, Montagu, Test. Brit., 
p. 355, pi. 11, f. 12; Maton and Racket, Linn. Tr., VHI, p. 
181, pi. 5, f. 2 ; Brown, Ency. Brit., 6th Ed., VI, p. 456. 
Shell elongated, subpellucid, thin, with a yellowish-brown 
epidermis ; body short ; spire very long, consisting of from five 
to eight somewhat ventricose volutions, well defined by the 
suture, and terminating in a slightly obtuse apex ; aperture 
subquadrate ; outer lip thin, white, a little reflected ; pillar lip 
white, narrowly reflected on the columella, with a small sub- 
umbilicus behind; whole shell covered with slender longitudinal 
strise. Length seldom exceeding a quarter of an inch ; dia- 
meter a fourth of its length. 
Old shells are frequently furnished with an obsolete tooth- 
like fold about the middle of the columella. 
This species has much the aspect of a Clausilia, and may be 
mistaken for a young shell of that genus, but is distinguished 
by the body being convex and simple, and destitute of the 
carinated ridge near the outer edge, as in the young Clausilice. 
The volutions being sinistral, will at once mark it from the 
genera Pupa and Bulimus. 
This is a very local species, inhabiting the trunks of trees, 
under the loose bark, dr lurking in the Lichens which invest 
the bark; and is not unfrequently met with in the clefts of 
rocks. 
Genus 49 — Clausilia. — Drapernaud. 
Shell sinistral, elongated, fusiform, turreted, slender ; spire 
with numerous volutions, terminating in a somewhat obtuse, or 
papillary apex, and swelling gradually towards the body — some 
species are thickest in the centre ; aperture ovate, irregular, 
oblique, peretreine, continuous, united all round, -the lip gene- 
rally thickened on the edge, and reflected ; columella furnished 
with tooth-like plaits, and a small spiral, elastic, shelly plate, 
attached by an elastic pedicle to the columella teeth within ; 
destitute of an operculum. 
The shelly bone which is attached to the columellar teeth is 
termed the clausium, and from whence the generic name is 
derived. Its function seems to be, to close up the aperture, 
when the animal has receded within its shell. A highly dis- 
tinctive character in the shells of this genus, is, that the body 
is usually less in diameter, than the volution next it. 
Section I . — Shell smooth ; the clausium or shelly plate ivith 
a notch at top, fitting into a plait situated on the outer lip of 
the aperture. 
1. Clausilia bidens, pi. XIV, f. 12 — First Ed., pi. 41, 
f. 12. 
Clausilia bidens, Drapernaud, Hist, des Moll., p. 60, pi. 4, f. 
5, 6, 7 ; Pfeiffer, p. 60, pi. 3, f. 25 ; Brard, p. 83, pi. 3, f. 9 ; 
Alder, Mag. Zool. and Bot., II, p. 110; Rossmassler, Icon., I, 
p. 76, pi. 2, f. 29; Fleming, Brit. An., p. 271 ; Thompson, 
Ann. and Mag. Nat. Hist., VI, p. 42 ; Helix bidens, Muller, 
Verm., H, p. 116, No. 315; Turbo laminaius, Montagu, Test. 
Brit., p. 359, pi. 11, f. 4; Clausilia lamellata, Leach, Moll., p. 
118; Turton, Man., p. 70, f. 53; Bulimus bidens, Bruguiere, 
Ency. Meth., p. 352, No. 93. 
K 
