Part 4

Vitrea crystallina.--The smallest of the genus. Shell transparent, pearly white. Umbilicus (i.e. the opening in the centre of the underside showing the whorls) very narrow. Subterranean in habit. Whorls, four; whereas H. pura has five; also more compressed.

Euconulus fulvus.--Distinctively pyramidal in shape. Small. Brown. Common under rotten branches and moss in woods. Hardly hibernates.

Zonitoides nitidus.--Chocolate-brown, with no white round the umbilicus (as has H. nitudula). Larger than, but not unlike, H. radiatula. Gregarious. Chiefly found by water; also in damp hothouses. Amphibious.

Zonitoides excavatus.--Its broad and deep umbilicus is quite distinctive. Mainly British. Dislikes lime, and is most plentiful on the coal measures.

We come now to the Helicidæ family and its genus Helix, in which there are various sub-genera of which the name is given in brackets. The shell in this genus can wholly contain the body; the tentacles are always four; the shell conical, and rarely with a depressed spire. The word "helix" is Greek, and means a coil.

Helix (Gonyodiscus) rotundata.--Very common under stones, moss, etc. Circular, flat, with a large open umbilicus. Horn colour with brown markings.

H. (Pyramidula) rupestris, i.e. inhabiting rocks.--Small. Gregarious. Dark brown. Mainly on exposed dry walls and cliffs.

H. (Punctum) pygmæum.--Very small. Yellowish brown and glossy shell. Mainly on moist dead leaves. Not unlike H. rupestris except as to habitat.

H. (Acanthinula) lamellata.--Small. Horn-colour. Epidermis raised into lamellæ or ridges in the line of growth. Mainly northern. Frequents dead leaves, especially beech and holly.

H. (Acanthinula) aculeata.--More common than the former; which it resembles in habitat. Differs chiefly by the ridges being produced into spines.

H. (Vallonia) pulchella.--Tiny. White. Mouth trumpet-shaped. Umbilicus wide. Under stones and at the roots of grass. Its variety costata (which some make a separate species) is strongly ribbed.

H. (Helicigona) lapicida.--Circular, flattened, dark brown, strong white reflected rim to mouth. Large umbilicus. Marked keel, which distinguishes it from all other British land shells. Chiefly on chalk soils. Often on beech tree trunks.

H. (Gonostoma) obvoluta.--Common abroad, but confined in England to a few spots in Sussex and Hants. Circular, flat above, mouth triangular, with a strong pinkish-white rim with three denticles.

H. (Pomatia) pomatia.--Described earlier. Found in Hants, Sussex, Kent, Surrey, Oxford, Gloucester, and Bedfordshire; but very local. Elsewhere it may well be an escape from captivity, or the remains of an attempt (always unsuccessful) to establish a colony. Box Hill and Caterham are two good localities for Londoners. In Kent it has two centres, Charing and Shoreham with their contiguous parishes, but there is a great gap between them, and it is absent from places on the same chalk ridge which are identical in soil and vegetation.

H. (Cryptomphalus) aspersa.--The sub-generic name means that the umbilicus is hidden in adult shells by a fold of the pillar lip; the specific name means sprinkled (with brown blotches); but it may be a slip of the pen, for aspera, or rough, from the rough shagreening of its surface. Five banded, like so many of the Helicidæ, but usually the second and third band unite. No umbilicus. The variety exalbida (chiefly found in Kent and the West) is straw colour and somewhat transparent. Commonly sold for food on the Continent as well as pomatia, which is cultivated in "snail-farms," but not native in Germany or Switzerland, and in France chiefly found in the coast departments. Insipid; but as nourishing as calf's-foot jelly. Fond of gardens (whence its common name), but not of gardeners. As most animals are marvellously gifted with a knowledge of what food to eat and what to avoid, it is curious that aspersa will eat voraciously the leaves of the spindle-tree, though this soon poisons them. It is said also that they share with cows and horses the ignorance that the leaves of the yew should be avoided on pain of sickness or even of death.

H. (Cepæa) nemoralis.--As already stated, this is the most brilliantly and variously coloured and diversely banded of all our English land shells with the exception of its very close connection H. (Tachea) hortensis. It is happily very common, and so the attention of beginners should first be directed to this. Thrushes and mice are its great enemies, the former smashing it on some stone which may be found surrounded by the broken shells. The "mouth" or peristome is normally black, the shell larger and stouter than hortensis, in which the mouth is white. When a white-mouthed nemoralis or dark-mouthed hortensis (both rare) is found, the shape of the internal flinty dart at once distinguishes them. In some places both live together: in most one is found and not the other. Nemoralis is fond of sand-hills by the coast, but is chiefly a hedge-snail, and the edges of main roads are preferred because of the greater variety of food, because the traffic scares away their bird enemies, and because the dust gives them abundance of already prepared material for their shells. When, however, the collector comes to a wayside cottage where fowls are kept he need not waste his time in looking for snails in the neighbouring hedge. The more the chicken industry extends and the more the Bird Protection Acts operates, the worse it is for collectors of snails. The banding is probably protective, as in the case of the tiger and the zebra, and renders the shell less visible.

Helix (Cepæa) hortensis.--Rarely found in gardens in spite of its specific name. A hedge-snail. White forms not uncommon, though almost unknown in nemoralis. Though the weaker form, the coalescence of the five bands into one broad one is more common here than in nemoralis. Also the variety with only one band, and that on the periphery, is very common in nemoralis and rare in hortensis. It is more dependent on shade and moisture than its congener. Smells of garlic when immersed in boiling water to be killed. Hortensis is a more northern, and nemoralis a more southern, shell by origin and distribution. There are 89 possible band variations in any normally five-banded shell, and all have been noted in the case of nemoralis, but in hortensis only 61. They are distinguished, for purposes of record and exchange, by numbers. Thus the type is 12345, the usual one-banded variety 00300, the common coalescence of the second and third band is 1(23)45, and when all bands unite (12345). The unicolourous or bandless variations would be 00000.

H. (Arianta) arbustorum.--Local. Usually found in hedges and by ditches on chalk and limestone. Shell globose, brown or yellow, with a check or willow leaf pattern, and a single dark band on the periphery. Lip strong and white. Animal usually nearly black. Very fond of moisture. Anatomically related to A. lapicida, but no external resemblance.

Helix (Theba) cantiana.--First observed in Kent (where it is especially fine and abundant), whence its specific name, but generally dispersed in South and East England. A dull, creamy white shell with a pink tinge, sometimes becoming partially or wholly reddish.

Helix (Theba) cartusiana (first noticed near a Carthusian monastery). Much resembles cantiana, but is much smaller and more smooth. Chiefly found on the downs of Kent and Sussex. Used to be common on Deal sand-hills--now devastated by golf! The tint in this is brown, in the former red.

H. (Hygromia) rufescens.--A flattish, dark brown shell, abundant in the south of England, and not rare elsewhere. Has a semi-lunar mouth with a white internal rib. In gardens seems to prefer violet beds.

H. (Hygromia) hispida, i.e. hairy.--These hairs are deciduous, and the hairless variety used to be considered a separate species under the name of concinna (i.e. neat), but would now be the variety depilata, or bald. Broad and deep umbilicus. Common, except in Ireland. Usually associates with H. rufescens in moist places.

H. (Hygromia) granulata is also hairy with white silky bristles. Yellowish in colour. Shell thin. Local, but abundant where found. Its umbilicus is very small. It falls from its food plants at the least shake.

H. (Hygromia) revelata.--Scantily haired. Globular thin shell. Pale green. Mainly found in Cornwall and South Devon. In cold or dry weather it buries itself rather deeply.

H. (Hygromia) fusca.--Very thin, glossy, brown shell. Local. Hardy, and even active in frost. Chiefly found on nettles, which many shells like as food, though avoiding the commonly associated horehound.

H. (Euparypha) pisana.--First noticed at Pisa. Somewhat like Helicella virgata, but larger, sub-globular, and solid shell, yellowish-white with dark lines or bands. Aperture or mouth yellowish or rosy. Most common in Portugal and Morocco, and all round the Mediterranean, dry places, especially near the sea. In England chiefly confined to Tenby and other parts of Pembrokeshire; also in the Channel Islands. Varies much in tint and markings. Swarms where found; it loves sun and heat. Seems to lend itself better to colonization than most species.

H. (Helicella) itala.--So named by Linnæus, who probably received it first from Italy. Shell almost circular, flat. Umbilicus very large and open. Common on heaths and downs, especially near the sea.

H. (Candidula) caperata.--(The specific name means wrinkled, like a goat's horn.) Careless of heat or cold. Distinguished from the young of H. virgata by being more depressed, having a larger umbilicus, regular and strong striation, and round mouth with white internal rib. Found under stones and on grass. Common.