Involute.] 



MOLLUSCA. 



37 



spire consisting of five slightly inflated volutions, well 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 acutus, 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; 

 Jeffreys, 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 ; Heli.v 

 acuta, Muller, Verm., II, p. 110; Dillwyn, Des. Cat., p. 956; 

 Heli.v bifasciatus, Maton and Racket, Linn. Tr., VIII, p. 210; 

 Turton, Conch. Diet., p. 63 ; Brown, Wernerian Mem., II, p. 

 529; Turbo fasciatus, Pennant, 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, Moll., 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^a fkagilis, 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., II, p. 1 1 1 ; Baleafragilis, 

 Gray, Zool. Journ., I, p. 61 ; Forbes, Mai. Mon., p. 11; Balea 

 perversa, Fleming, Brit. An., p. 271 ; Balcea perversa, Thomp- 

 son, Ann. and Mag. Nat. Hist., VI, p. 41 ; Odoslomia perversa, 



Fleming, Edin. Ency., VII, 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., VIII, 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 

 striae. 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 Clausilia. 

 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, or 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 with 

 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. GO, pi. 4, f. 

 5, 6, 7 ; PfeifTer, 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., II, p. 116, No. 315; Turbo laminatus, 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. 



