Notes on some land and freshwater Mollusca from Auvergne, France

From August 16 till September 1, 1955, Dr. H. C. Blöte, Mr. J. J. Barkman, and the present author were the leaders of an excursion of students in biology of the University at Leiden to Central France. For some two weeks the party was hospitably lodged in the "Station Biologique" in the village Besse-en-Chandesse (département Puy de Dôme), 30 km S.S.W. of Clermont-Ferrand. Thanks to the generosity of Prof. R. Hovasse and Dr. L. Olivier, we could stay in this biological institute, which belongs to the University at Clermont-Ferrand. During the excursion the author paid special attention to the collecting of land and freshwater Mollusca. The very dry and hot weather during our stay was one of the main difficulties in carrying the project into execution; moreover, the region has a rather poor malacofauna as a result of the nearly complete absence of lime in the soil. The climate of the here discussed part of Auvergne, the massif of the Monts Dore, is typically Atlantic; the region has a considerable amount of rainfall (1150—2500 mm per annum). The highlands are situated at the northwestern border of the Massif Central, representing an area completely exposed to the northern and western winds of the Atlantic Ocean. The warmest month is August with an average temperature of 14.80 C. The Massif Central is of volcanic origin; it consists mainly of metamorphous granite, formed during the Lower Carboniferous, on which beds of lava and volcanic ashes were deposited during the Tertiary. The cones of four extinguished volcanoes rise from a slightly undulating table-land of a height of about 1000 m; the highest of these mountains, the Puy de Sancy, attains a height of 1866 m. Mineral sources are the only remains of volcanic