Peringia ulvae

Peringia ulvae, commonly known as the Laver spire shell or mudsnail, is a European species of very small aquatic snail with gills and an operculum, a gastropod mollusk in the family Hydrobiidae.

This is arguably a marine snail, but it is often also listed as a non-marine species because it tolerates brackish water and lives in salt marshes and similar habitats.

Peringia ulvae is the type species of the genus Peringia.