Since I published my paper on this subject (Notes Leyden Museum, Vol. XXXIV, 1912, p. 240), the following localities of our coast where this American mollusc also has been collected, have come to my knowledge: Vlissingen, isle of Walcheren; south-east of Domburg (see sketch of the coast of the Netherlands in the cited paper). Eastern-Schelde, between Ierseke and Tholen. Zandvoort, between Noordwijk and Petten. Terschelling, the island next to Vlieland in nord-east direction. Leiden Museum, Jan. 7, 1915.