Our British Snails

by J. W. Horsley

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.