several but much thinner epiphragms, behind which it rests in a torpid state during the winter ; thus it remains unconscious of what is going on around it-sleeping through the winter months, until the genial showers of April call it forth. Its specific name pomatia is derived from the Greek poma, an operculum, from the thick calcareous epiphragm it forms.

This snail has been the object of numerous experiments, with the view of ascertaining the extent of the remedial power among land mollusks. The Abbé Spallanzani cut off the tentacles, which were reproduced even to the eyes at the end of two months; not content with subjecting the creature to such torture, he tested the reparative power in a greater degree, by removing the entire head, which was reproduced to perfection. The snails thus experimented upon, retired immediately into their shells, and there remained weeks or months, outwardly in a state of quiescence, but internally the wonderful power of reproduction was silently at work until the end was attained.

The Helices diminish in size with their range in elevation; but H. pomatia, on the other hand, increases in size according to the altitude attained. It is found on the Vaudois Alps, up to the very verge of the forests, 5,850 feet above the level of the sea.

Some writers have asserted that this species has no claim to rank as indigenous to this country, but that it was introduced either as an article of food, or for medicinal purposes.

HELIX ARBUSTORUM (Pl. VII., fig. 62), as the specific name implies, the "Shrub Snail," is a tenant of our woods and groves, preferring moist situations, but more frequently its habitat is among the willows and reeds of our ditch sides and river banks.

The shell of H. arbustorum is certainly handsome; it is globular, about three-fourths of an inch in diameter, generally brown, marbled with yellowish spots, and having a single blackish band winding round the middle of each whorl. The animal is covered with tubercles, and is of a greenish-black colour, of a light grey beneath the foot; the tentacles are short and black, with very globular extremities.

The shell presents numerous variations, both in form, and more especially in colour. Some are very thin and almost transparent, of a dark colour, with or without the band; in others the shells are variegated, with a brown band, or more strongly marked with a black one; whilst in others the spire is much more prominent.

The Shrub Snail is distributed over the greater part of Europe; in Great Britain it is somewhat localized, though it has a place in most local

lists. This species reaches a higher elevation than any other, being found high up on mountain-sides; in the Alps it attains to the region of perpetual snow. At this great altitude the shell is smaller, and the spire more elevated, and is the variety alpina (Pl. VII., fig. 62a).

HELIX FULCHELLA-(the Pretty or White Snail) (Pl. VIII., fig. 67)—is another of the little-isms of molluscan life. The animal is milk-white, and its black eyes contrast strongly with the transparency of the upper tentacles. The shell partakes of the colour of the animal, is rather opaque and depressed in form; there are three and a half rounded whorls, the last one exceeding the rest of the shell in size: the circular aperture has a very thick and strongly reflected margin, forming a complete peristome; the umbilicus is large and deep; the diameter is a tenth of an inch.

The accompanying figure represents the striated horny jaw of this Fig. 22. Jaw of little beauty. The number of

H. pulchella.

teeth far exceeds in number those of Helicella cellaria, which possesses a shell many times the size of this minute species; the dental formula is 15.1.15 = 1860.

60

It is widely distributed throughout Britain and Europe, and ranges to Siberia, and is found in Madeira and the Azores.

This species is usually regarded as an inhabitant of North America, but the species there is clearly distinct from the European H. pulchella; the American H. minuta of Say is clearly indigenous, for it is widely and abundantly distributed, and in regions remote from the sea, throughout North America.

It frequents walls, under stones, and among the short herbage of downs.

A variety-H. pulchella B. costata (Pl. VIII., fig. 69)—has the shell furnished with elevated, transverse, and curved ridges, and is stated to be peculiar to marshy and damp situations. In this I do not acquiesce, for I have found both living together in dry places, as on the walls of Hastings Castle, under stones on the Chalk Downs of Sussex, and at Bristol; and in damp and low situations, as among the osier beds bordering the banks of the river Thames, both the smooth form and costated variety occur. In a parcel of shells of this species from any of these localities, specimens showing the transition from the ridged variety to the smooth form are

not rare.

The variety costata should be regarded as the normal form, as the ribless condition results from the disappearance of the costæ upon the shell, which is due to the occasional wearing away by age, just as in the case of H. aculeata, which is

sometimes found without the longitudinal plates which generally cover the shell.

HELIX LAPICIDA—(the Variegated Rock Snail) (Pl. VIII., fig. 79)-the technical name, signifying "a stone-cutter," is very inappropriate, and was given to this species by the great Linnæus, from an erroneous idea that it ate or excavated limestones.

The shell is depressed, lens-shaped, convex above and below, with a sharp keel on its outer circumference; the aperture is longitudinally oval and angular; the white and reflected peristome is united all round; the edge is acute but not thickened. The colour of the shell resembles that of H. rotundata, is yellowish-red, irregularly streaked across the whorls with reddish-brown ; the surface is also striated with closely-set lines of growth; the umbilicus is large. The dental formula is 40 · 1.4 0

150

This snail is truly a woodland species, and is confined to the central and southern counties of England; it is found as far north as Brockerdale near Pontefract. It has a wide range in Europe.

It has been supposed to be restricted to limestone tracts, but I have found it very general in the woods of the Wealden district, where the rocks are especially characterized by the absence of the calcareous element. In Gloucestershire,