The Aciculidae are a family of small land snails that have opercula (an operculum is a little door that closes the shell when the animal retracts into it). In other words, Aciculidae are terrestrial operculate gastropods.
Even though Aciculidae are land snails, they live in rather wet conditions, among mosses and dead leaves and they have sometimes been described as "winkles come ashore".
Horst Janus, 1965. The Young Specialist Looks at Land and Freshwater Molluscs, Burke, London
Egorov, R. V., 2009, Kladovaja rakovin Rossii [Treasure of Russian shells]. Supplement 3. A review of the genera of the recent terrestrial pectinibranch molluscs (synopsis mainly based on published data). Part II, Littoriniformes. Hainesiidae, Aciculidae, Cyclophoridae, Craspedopomatidae. Moscow. 58 pp
