What is "aciculidae"

The Aciculidae are a family of minute land snails which 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".