On the occurrence of Helicigona lapicida (L.) (Mollusca, Gastropoda) in the Netherlands

During a visit to southern Limburg in the summer of 1942 several living specimens of Helicigona lapicida (L.) were discovered near Kamerig. In this locality the species was found in such large numbers that it seems almost astonishing that its occurrence in such abundance there had hitherto escaped attention. So far the occurrence of undoubtedly living specimens of this characteristic snail in the Netherlands has only been reported by Vervoort (1941), who recorded specimens from a couple of localities also situated in southern Limburg, where, however, the species had only been found in small numbers. Henrard and Koumans (1936) had previously drawn the attention to the occurrence of more or less fossilized specimens in various localities in the same region. They mentioned shells found in situ in the disintegrated stratum immediately covering the cretaceous layers which come to the surface in numerous places in the province of Limburg (e.g., specimens from Gronsveld), as well as shells apparently washed from this stratum by the rain (e.g., specimens found at the base of cretaceous slopes near Epen). All these specimens are reported to be more or less corroded, calcareous and deprived of their periostracum, though the original colour is often vestigial and represented by pale purple transverse bands. These authors, failing to discover a single living snail, consequently concluded that Helicigona lapicida is not indigenous and that it occurs only in a subfossil state. Other localities have been given by Van Benthem Jutting (1927, 1933). In her first paper Helicigona lapicida is marked with a f, which means that no living specimens were collected. The localities mentioned are: Bloemen-