Page:The Zoologist, 3rd series, vol 2 (1878).djvu/145

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LAND AND FRESHWATER MOLLUSCA OF SUSSEX.
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also in the neighbourhood of Chichester (J), Brighton (M), and Eastbourne (G). The young have their shells encrusted with earth or the spores of lichens and mosses, in the same way as Bulimus obscurus; and even adult specimens have occasionally a similar covering. From this circumstance Mr. Gwyn Jeffreys is of opinion that the coat is not made purposely by the animal, as suggested by the Rev. Revett Sheppard, but is involuntarily caused by the accidental adhesion of extraneous matter to the outer surface of the shell, by means of the slime, or a glutinous film which exudes from or invests the epidermis. The species of the genus Pupa are all of small size and gregarious habits. Besides their variation in size and colour, they may be distinguished by the curious processes called "teeth," which fence in and contract the mouth of the shell.

Pupa umbilicata, vel cylindracea. The Umbilicated Chrysalis Shell.—Common on the downs under stones, and on old walls under grass-roots and moss. Found also among dead leaves and beneath the bark of trees. Very common in the neighbourhood of Lewes on old walls and under chalk-stones.

Pupa marginata, vel muscorum. The Margined Chrysalis Shell.—Found on similar situations to the last-named and on tiled roofs of old buildings.—W.

Vertigo antivertigo. The Marsh Whorl Shell.—Rare or local. Under stones in the level near Newtimber.—B. Near Eastbourne.—G. By the side of a ditch in the level near Lewes.—U. Mr. Unvvin includes it in his list under the name palustris, under which name it is also included amongst the shells found in the vicinity of Brighton.—M. The eight or nine species which compose the genus Vertigo are closely allied to Pupa, of which they are but miniature forms, and of similar habits. The chief difference is to be found rather in the animal than in the shell, the inhabitant of which has two tentacles instead of four, as in Pupa.

Vertigo pygmæa. The Dwarf Whorl Shell.—Rare. Under old bark fallen from larch rails at Cowfold, near Horsham.—B. At Uppark.—W. At the roots of moss and grass on the eastern bank of Ashcombe Plantation, Lewes.—U. In the neighbourhood of Brighton.—M.

Vertigo edentula. The Toothless Whorl Shell.—Occurs sparingly at Cowfold amongst dead leaves, and at Lindfield on