NELSON AND TAYLOR : ON YORKSHIRE MOLLUSCA. 33 



7. Went Vale— Went Bridge, J.W. 



12. Lower Calder — Canal at Heath Bridge near Wakefield, a few speci- 

 mens, J.W. 

 Mr. J. Emmet has recently informed us that the var. 

 depressa occurs with the type at Boston Spa, and also con- 

 firms the York record. 



Var. subcylindrica Jeffr. 



6. Tvent — Conisborough, 1873, J.W. 



7. Went Vale — River Went near Ackworth, J.H. 



11. Upper Calder — Reservoir near Halifax, 1S72, J.W. 



12. Lower Oalder — Canal, Heath Bridge, Wakefield, J.W. 



13. Airedale — Canal at Saltaire, 1873, J.W. 



Var. acuminata Jeffr. 



3. Vale of York — Foss Drift, Hugh Richardson. 

 24. Holderness — In the drift, Beverley Beck, in the Beverley and Barm- 

 ston Drain, and at Figham, J.D.B. 



Var. pusilla Miill. 



Shell smaller, with 4 to 4^ whorls, diam. 4 mill., alt. 4 mill. 



7. Went Vale — A single specimen amongst a few sent to us from Hems- 

 worth dam, by Mr. Hugh Richardson. 



Var. albina Taylor. 



7. Went Vale — Mr. Wilcock has found whitish specimens appi-oaching 

 this variety at Went Bridge, in 1863, and at intervals since. 



Mr. Wilcock has found somewhat scalariform monstrosities 

 at Wentbridge, 1869; near Halifax, 1872, Heath Bridge near 

 Wakefield, 1872 ; and New Miller Dam, 1874. 



:o: 



Valvata cristata (Muller). 



Abundant, but very local. 



This species appears to have three areas of distribution, 

 all in the eastern half of the county, corresponding to the low- 



c 3 



