MOLLUSCA OF MID-WEST YORKSHIRE. I9I 



P. fontinale var. cinerea Alder. — Common in Shipley Glen ; 

 occurs at Eavestone near Ripon 



P. pusillum (Gmelin). — Eavestone, common in a ditch; 

 Swinsty reservoir, Washburndale ; Pannal ; Osmondthorpe 

 and Chapel AUerton near Leeds ; Bishopthorpe Ings, 

 common ; Malham Tarn marsh, 1,200 feet above sea-level, 

 common ; Baildon Moor and Shipley Glen. 



P. nitidum Jen. — Baildon Green, several specimens. 



Uniotumidus Phil. — The lake at Roundhay Park near Leeds. 



U. pictorum (L.). — Abundant at Studley Royal. 



Anodonta cygnea (L.). — Abundant in Shepherd's Pond and 

 in Roundhay Park lake, Leeds ; and in Studley Lake near 

 Ripon ; also shown from Tadcaster. 



A. anatina (L.). — Studley Lake near Ripon. 



Dreissena polymorpha (Pallas). — Common in the Leeds 

 and Liverpool canal at Newlay, Kirkstall, Armley, &c. 



Neritina fluviatilis (L.). — Rivers Ure, at Hackfall ; Ouse, at 

 York ; Wharfe, at Tadcaster. 



N. fluviatilis var. nigrescens Colb. — Common in the Ouse, 

 at York, along with the type. 



Paludina vivipara (L.). — Common in the Ouse, at York; 

 also in the canal at Selby. 



Bythinia tentaculata (L.). — Staveley mill-pond ; canal, 



Ripon ; Askham Bog ; Tadcaster ; stream at Allerton 



Bywater ; common in the canal at Armley, Kirkstall, 



Newlay, Saltaire, and Bingley ; common in a pond at 



Gisburn ; a few in Malham Tarn. 



[B. Leachii has not as yet been authenticated by specimens from this 

 district]. 



Valvata piscinaiis (Miill.).^ — ^Malham Tarn; pond at Gisburn; 



not yet shown from east of the Pennine Hills. 

 V. cristata Miill. —Common in Askham Bog ; Barlow 



Common near Selby. 

 Planorbis lineatus Walk. — Askham Bog, abundant. 

 P. nitidus (Miill.). — Asp ponds, Knaresborough ; Cambles- 



forth. 



