54 
MOLLUSCA. 
[Gasteropoda 
Discovered by Dr. James Lindsay in Ditcham Wood, near 
Brenton, Hampshire, where he collected about twenty speci- 
mens. Its habitat is among moss at the roots of trees. As 
this shell is a well known continental species, and having been 
found in one locality only, it is probable that it has been intro- 
duced among plants. 
41. Helix margaritacea, pi. XVH, f. 54, 55, 56 First 
Ed., pi. 40, f. 54, 55, 56. 
Shell depressed both above and below, very thin and hyaline; 
spire hardly elevated above the body, and consisting of three 
pretty well rounded and rapidly decreasing volutions ; sides of 
the body inflated, and rather thick in proportion to its size ; 
base rounded, and provided with a small and shallow umbilicus ; 
aperture suborbicular, with a very thin outer lip ; whole surface 
of a pearly white, exhibiting iridescent reflections. Diameter 
an eighth of an inch. 
Discovered by James Gerard, Esq., on an old wall at Cor- 
storphine Hill, near Edinburgh. 
ORDER HI.— GASTEROPODA. 
Animals with straight bodies, never spiral, nor totally en- 
veloped in their shell; the foot, or disc, situated under the 
belly, united to the body nearly its whole length, and serving 
as an organ of locomotion. 
Division I — Pneumobranchi^. 
Branchiie in the form of a vascular net, or the wall of a par- 
ticular cavity, opening by a hole which the animal contracts or 
dilates at pleasure. The animals respire air. 
Family I Limacinea. 
Animals almost wholly naked, with elongated bodies, creep- 
ing by means of a ventral disc, with a narrow mantle bordering 
their sides. 
Genus 1. — Vitrina. — Drapernaud. 
Shell oblong, thin, transparent, fragile, and glassy; spire 
short, depressed, with seldom more than three, rapidly increas- 
ing volutions; body large; aperture very ample, its width being 
generally greater than its length, and somewhat oblong; margin 
of the outer lip thin ; columellar side deeply emarginate by the 
body ; columella merely a simple spiral line. 
1. Vitrina pellucida, pi. XVH, f. 6, 7, and 12 First 
Ed., pi. 40, f. 6, 7, and 12. 
Vib'ina pellucida, Drapernaud, p. 119, ph 8, f. 34 to 37 ; 
Lamarck, An. San. Vert., VI, pt. 2nd, p. 53 ; Fleming, Brit. 
An., p. 267 ; Ib., Phil. Zook, II, p. 459, ph 4, f. 1 ; Turton, 
Man., p. 31, f. 21 ; Alder, Mag. Zool. and Bot., H, p. 105; 
Forbes, Mai. Mon., p. 7 ; Thompson, Ann. and Mag. Nat. 
Hist., VI, p. 19; Vitrina Dillwynii, depressa, and diaphana, 
JefiTreys, Linn. Tr., XVI, p. 326; Vib'ina Miilleri, Jeffreys, 
Linn. Tr., XV, p. 326 ; Vitrina Drapernaudi, Leach, Moll., 
p. 80; Jefireys, Linn. Tr., XVI, p. 326; Vitrina heryllina, 
Pfeiffer, p. 47, pi. 3, f. 1 ; Vitrina elongata, Turton, Man., p. 
31, f. 22; Helix pellucida, Muller, Verm., H, p. 16; Pennant, 
Brit. Zool., IV, p. 138, No. 134; Helix elliptica. Brown, Wer- 
nerian Mem., H, p. 525, pi. 24, f. 8; Helicolimax pelluddus, 
Ferussac, Hist. Moll., pi. 9, f- 6. 
Shell elliptical, subdepressed, very thin, of a pale yellowish- 
green colour, hyaline, and extremely glossy ; body very large, 
oblique ; spire very small, and consisting of two volutions, 
which rise but little above the body, and terminate in an obtuse 
apex, well defined by a striated sutural line, discoverable only 
by the aid of a lens ; aperture oval, and very large, interrupted 
above by the superior portion of the body ; outer lip tbin, fre- 
quently with a pale brown margin ; pillar lip slightly reflected, 
and a little concave above. 
Subject to some variety both in form and colour ; but all I 
have seen are only entitled to rank as one species. 
This species is found in all localities ; for I have met with it 
in very moist situations, among decayed leaves, under stones, 
&c., and I have procured specimens near the summit of 
Arthur’s Seat, at Edinburgh, eight hundred feet above the 
level of the sea. It prevails all over Ireland, and Thompson 
has found it in high mountain localities. 
I first observed this species in the cabinet of Mr. Dixon, of 
Bishop- Wearmouth, in 1810, and drew and described it under 
the name of Helix virides; as it was the green variety. I after- 
wards met with the pale yellowish-white variety, in 1814, at 
Farbane, King’s County, Ireland. 
Genus 2. — Testacella — Cuvier. 
Shell very small, compressed, placed externally on the animal, 
auriform ; apex obsoletely spiral, consisting of less than two vo- 
lutions; aperture very large, wide, and oblique; columella flat; 
outer lip reflected, and thin, with a slight sinus behind. 
This singular univalve is found attached to the back of the 
animal, near its posterior extremity. 
1. Testacella Haliotoidea, pi. XVIII,* f. 15, 16. 
Testacella Haliotoidea, Drapernaud, p. 121, pi. 8, f. 44, 45 ; 
Lamarck, An. San. Vert., VI, pt. 2nd, p. 52; Cuvier, An. du 
Mus., V, p. 440, pi. 29, f. 6, 7 ; Thompson, Ann. and Mag. 
Nat. Hist., VI, p. 19; Testacella scutulum, Sowerby, Gen. Rec. 
and Foss. Sh., f. 3, 3; Testacellus Haliotoideus, Ferussac, Hist., 
pi. 8, f. 5 to 9; Sowerby, Gen., f. 1, 2; Alder, Mag. Zool. and 
Bot., H, p. 105 ; Testacella Europcea, Roissy. Buffon, V, p. 
252. 
Variety 1. Testacella scutulum, Sowerby. 
Shell auriform, ovoid, or elongated ; vertex rather large, 
acute, placed at one extremity, and pointing to one side ; aper- 
ture very large ; pillar lip, near its upper extremity, broad, flat, 
and very slightly reflected at the edge ; outer lip dilated. 
Inhabits gardens, at Lambetb, and other localities near Lon- 
don. It was found many years ago at Youghal, Ireland, by 
Robert Ball, Esq., of Dublin. The Irish specimens agree with 
the T. scutulum of Sowerby. Mr. Thompson says it has also 
been found in a garden at Bandon, by Mr. G. S. Allman. I 
concur with Mr. Ball and Mr. Thompson, in considering the T. 
Haliotoidea as an indigenous British and Irish species. 
