Het klein drijfhorentje Rissoa parva (da Costa, 1778) van het Banjaardstrand

In a sample of small shells originating from a sand suppletion, a huge variation was noted in specimens of Rissoa parva. Ribbed and smooth forms, as well as intermediates have been found. The author and Van der Linden (1987) found these forms also together within a single tidal pool in Spain and France, respectively. The extraordinary wide range in forms of the sample from the Banjaard beach is interpreted to be the result of the mixing of material from several strata, mainly Eemian, but possibly also Holocene.