Growth rate of Chilostoma faustinum (Rossmassler, 1835) (Gastropoda: Pulmonata: Helicidae) under natural condition

Growth of Chilostoma faustinum (Rossmässler, 1835) was recorded under natural conditions in Romincka Forest (NE. Poland), one of the northernmost localities of the species. During the growing season (April–October) the average growth rate was 0.22 whorl/month. In the local conditions Ch. faustinum Leeds three growing seasons to complete its shell growth. Shells of Ch. faustinum from Romincka Forest are slightly smaller than in the other studied populations: their average width is 16.5 mm (range 13–19 mm); and the average number of whorls is 4.5 (range 4–5).