Een eerste overzicht van de land- en zoetwatermollusken van de Twigen, een natuurgebied nabij Joure, Friesland

A malacological survey of the nature area the Twigen near Joure, province of Friesland, has resulted so far in the registration of 45 species: 20 terrestrial gastropods and 25 freshwater mollusc species. Only two species, both freshwater snails, have to be considered introduced species: Potamopyrgus antipodarum and Ferrissia fragilis. Noteworthy species among the local freshwater species are: Myxas glutinosa, Planorbis carinatus and Pisidium pseudosphaerium.