Page:The Zoologist, 3rd series, vol 2 (1878).djvu/146

124 stems of Scolopendrium vulgare.—B. On Chailey Common, near Lewes, on the under side of the leaves of Filix mas.—U.

Balia perversa, vel fragilis. The Fragile Moss Shell.—Not uncommon under lichens and the bark of thorns on the Downs.—H. On old ash trees at Offham, near Lewes, and on the garden wall of the Rectory al East Blatchington, near Seaford.—B. Common near Brighton (M) and at Eastbourne (G). In the neighbourhood of Uppark it is one of the commonest shells, and may be collected in great numbers on the mossy bark of old beech trees.—W and H.

Clausilia laminata. The Laminated Close Shell.—The shells of the genus Clausilia are worth examining carefully on account of a remarkable peculiarity in structure—namely, a lid to the mouth of the shell, which closes, so to say, with a spring. If the outer part of the last whorl be broken off, there will be found a spoon-shaped calcareous plate or valve, attached to the columu of the spire by an elastic filament. When the animal protrudes from its shell, this plate is thrust aside, and when it withdraws it closes the door, as it were, behind it. This curious structure, and also the plaits of the mouth, which are intimately connected with it, are not formed until the animal has nearly reached maturity. Four species of the genus are found in Sussex. Clausilia laminata, about three-quarters of an inch in length, is common under stones, dead leaves, &c, and is fond of ascending trees in wet weather. Mr. Unwin includes it in his 'List of Lewes Shells' under the specific name bidens.

Clausilia biplicata. The Folded Closed Shell.—About half an inch in length. Abundant on old trees and walls, and under dead wood in shady places.

Clausilia nigricans, vel rugosa, vel perversa. The Dark Close Shell.—Smaller than the last named, and the smallest of the four species included in this catalogue. Equally common with the lastmentioned on walls, fences and trees, amongst moss and under stones in the same localities. Abundant in the neighbourhood of Lewes, where Mr. Unwin has frequently met with the variety C. parvula.

Clausilia Rolphii. Rolph's Close Shell.—Larger than nigricans and a little smaller than biplicata. Sparingly distributed amongst moss and under dead wood, especially on the chalk. Found at