[Proceedings of the symposium 'Molluscan Palaeontology' : 11th International Malacological Congress, Siena (Italy) 30th August - 5th September 1992 / A.W. Janssen and R. Janssen (editors)]: The distribution of Cerastoderma glaucum (Poiret), Macoma balthica (Linnaeus), Mya arenaria (Linnaeus) and Mytilus edulis (Linnaeus), in Holocene bottom sediments of the southern Baltic Sea

Investigations were carried out at the State Geological Institute (Marine Geology Branch, Sopot, Poland) on the base of 2500 samples collected by means of a van Veen grab during research cruises in 1973-1990. For a macroscopic description of four species of Mollusca present in the bottom sediment samples, i.e. Cerastodermas glaucum (Poiret), Macoma balthica (Linnaeus), Mya arenaria (Linnaeus), and Mytilus edulis (Linnaeus), both living and dead specimens have been taken into account. A biofacial distribution map for these four species is presented. It is concluded that the type of sediment and the sea depth are the most important factors influencing the distribution of the species.