24 MOLLUSCA. 
rounded above, and slightly contracted below, inside of a fine 
purple hue; outer lip thin, slightly reflected ; inner lip broad, 
flattened as in Haliotis, and white; outside covered with a 
rather smooth fuscous epidermis. Length about a tenth of an 
inch. 
Found by Dr. Leach on the Devonshire coast. 
3. G. Otis; Helix apertura patentessine, Walker, Min. 
Sh., pl. I, £.173; Helix Otis, Turton, Conch. Dic. p. 70; Ve- 
lutina Otis, Fleming, Brit. An., p. 326. 
Shell transversely oblong; with three smooth, semitransparent, 
glossy volutions; aperture transversely oblong; outer lip thin; 
inner lip a little thickened and flattish. 
Famity V.—IANTHINIA. 
Animal capable of raising itself in the water, and floating. 
Genus 30.—IJANTHINA.—Lamarck. 
Animal provided with a visicle, attached to its foot, by means 
of which it can raise itself to the surface of the water, and float 
on the ocean. 
Shell ventricose, subglobose, and subconic; thin, diaphanous, 
and brittle; aperture subtriangular, produced at its lower region 
and at its outer side, but is considerably rounded at the angle 
formed by the union of the upper and lower halves of the outer 
lip; columella straight, and elongated beyond the base of the 
outer lip, with the inner lip reflected over it; the outer lip 
formed into an angular sinus, by the projection of its upper 
half. 
1. J. communis, pl. VIL, f. 1, 2—First Ed., pl. 51, f. 1, 25 
Lanthina communis, Lamarck, VI, pt. 2nd, p. 206; Fleming, 
Brit. An., p. 326; Janthina fragilis, Ency. Meth., pl. 456. f. 1, 
a,b; Helix ianthena, Gmelin, Linné, 3645, No. 103; Helix 
ianthina, Brown, Wernerian Memoirs, II, p. 525; Ib., Ency. 
Brit., VI, p. 460, pl. 155, f. 6. 
Shell subconic, umbilicate; body extremely large; spire very 
small, consisting of three somewhat inflated volutions, separated 
by a deep suture, terminating in an obtuse apex, on the pinnacle 
of which is inserted a very small bead-like process, of a pearla- 
ceous lustre; the centre of the body produced into a rounded, 
subearinated ridge; base produced; aperture subtriangular, 
smooth, and glossy within, much produced below; outer lip 
greatly expanded, thin, and acute; inner lip straight, somewhat 
reflected over the small umbilicus; whole shell covered with 
undulous, rather wide spiral striz, and crossed by strong irregu- 
lar stri, following the direction of the lines of growth; colour 
of a reddish purple, or lilac, the superior volutions whitish. 
Length upwards of an inch; breadth nearly an inch and a 
quarter. 
Many hundreds of this shell were found alive at Portrush, 
county of Antrim, Ireland, by Mrs. Clewlow and Miss Kelly, of 
Belfast, after a storm. Some of them floated on the surface of 
the sea, and were buoyed up by the reticulated, viscous mem- 
brane which is attached to the foot of the animal. It was after- 
wards found alive in Bantry Bay, by Miss Hutchins, and has 
since been met with on various parts of the coast of Ireland, 
and Wales. 
2. I. exigua, pl. VILI, f. 16, 17; Lanthina exigua, Lamarck, 
VI, pt. 2nd, p. 206; Ency. Method., pl. 456, f. 2, a, b. 
[ TRACHELIPoDA. 
Shell ovate-conical, very thin, subhyaline, with four rounded 
volutions ; spire produced, terminating in a subacute apex, and 
elegantly striated longitudinally ; aperture triangular ; pillar lip 
curved, and terminating in a produced, oblique point; the whole 
shell of a beautiful reddish violet colour. Length two lines and 
a half; breadth two lines. 
Found by my friend R. J. Shuttleworth, Esq., at Conomaura, 
west coast of Ireland. 
Famity VI.—NERITACEA. 
Shells subglobose, or oval; destitute of a columella; the outer 
lip margined and transverse; aperture enclosed by an opercu- 
lum. They inhabit both the sea and fresh waters. 
Genus 31.—NatTica.—Adamson. 
Shell subglobose, oval, or oblong; umbilicate; spire short, 
sometimes very short, with the apex very rarely pointed; aper- 
ture large, semicircular, and very seldom effuse; outer lip sharp 
edged, smooth within; columellar lip oblique, destitute of teeth, 
generally thickened, and sometimes spread thickly over the um- 
bilicus ; umbilicus usually large, having a spiral callosity within, 
which sometimes increases so as to cover the umbilicus; it is 
sometimes very small, and in a few instances nearly obsolete, so 
much so, as to be hardly perceptible ; operculum testaceous in 
some species, and horny in others. 
1. NV. monilifera, pl. XII, f. 1, 2, 8, and 10.—First Ed., pl. 
43, f. 1, 2, 8, and 10; Natica monilifera, Lamarck, An. San. 
Vert., VI, pt. 2nd, p. 196; Forbes, Mal. Mon., p. 29; WV. glau- 
cina, Fleming, Brit. An., p. 319; Nerita glaucina, Donovan, 
Brit. Sh., I, pl. 20, f. 1; Brown, Ency. Brit., VI, p. 462; Maton 
and Racket, Linn. Tr., VIII, p. ; Montagu, Test. Brit., p. 
469; Turton, Brit. Fa., p. 195. 
Shell subglobose, strong, smooth, glossy; spire small, consist- 
ing of six somewhat inflated, rapidly decreasing volutions, slightly 
flattened above, and well defined by the suture; body very large 
in proportion to the spire, and ventricose; aperture suboval and 
sublunate ; outer lip thin and even, and considerably protruded 
at its juncture with the body; pillar lip thick, callous, broadly 
spread over the columella above, narrowed beneath, and slightly 
reflected over the umbilicus, which is large, deep, and striated 
internally ; whole shell covered with minute, nearly obsolete, 
irregular, longitudinal strie, which are only perceptible by the 
aid of a lens; colour sometimes livid, or purplish, but for the 
most part ferruginous, or chestnut, with a series of longitudinal 
purplish-brown streaks on the superior portion of the volutions; 
operculum horny, very thin, transparent, and elastic, with diver- 
gent strie. The young shell, f. 1, 2, is generally ornamented 
with a series of streaks, or girdles of spots, or zig-zag lines. Size 
varying from an inch and a half to two inches in length; and 
from an inch and a quarter to an inch and a half in diameter. 
Found on most of the British and Irish coasts, and seems to 
be a deep water species. Mr. Nicol states that he found it 
buried in sand, at very low tides, in the Frith of Forth. 
Mr. Forbes, in his “ Malacologia Monensis,” says, the body 
of this species is “minutely striated spirally.” I have examined 
specimens from almost every coast in the kingdom, and have 
never met with a single specimen with this character. 
