HELIX ASPERSA. 77 



NOTE III. 

 HELIX ASPERSA MULLER IN HOLLAND. 



BY 



Dr. J. H, VERNHOUT. 



In „Nachrichtsblatt der Deutschen MalakozooL Gesellsch. 

 1910, p. 134" Mr. V. Franz (Helgoland) gives a note on 

 the occurrence of Helix aspersa in Holland at Vlissingen. 

 He suggests that the animals have been transported for- 

 tuitously to that locality. Now I will not discuss the pos- 

 sibility this having been the case here, in the neighborhood 

 of the harbour, where the snails can have been brought 

 with ships from England or Belgium. But the occurrence 

 of Helix aspersa at Ylissingen is not at all curious, as it 

 is considered since many years as belonging to the Dutch 

 fauna. In his list of Dutch molluscs, published in 1858, 

 Mr. Maitland ') cites already Helix aspera, and gives various 

 localities in Holland, including also the isle of Walcheren, 

 where Vlissingen is situated. Herklots -) calls Helix aspersa 

 a very common snail in Holland. The Leyden Museum 

 possesses specimens from the neighborhood of Leyden and 

 of the Hague, and from Zeist in the province of Utrecht. 

 It needs not wonder this snail, whose moving forward 

 from the North of France to England and Belgium has 

 been observed, having also transgressed our frontier. Cer- 

 tainly a careful looking for this species will supply more 

 localities in our country. 



Leyden Museum, Nov. 7, 1912. 



1) R. T. Maitland. Week- en Schelpdieren in Nederland waargenomen, in' 

 Bouwstoffen voor eene Fauna van Nederland, II, p. 86. Leiden, 1858. 



2) J. A. Herklots. De Weekdieren en lagere Dieren van Nederland, p. 35. 

 Amsterdam, 1859 -1862. 



Notes from the Leyden Miuseum, Vol. XXXV. 



