42 NELSON AND TAYLOR : ON YORKSHIRE MOLLUSCA. 



7. Went Vale — Ackworth, common, with type, C.A. 



12. Lower Calder — Ossett and Cold Hiendley, occurring with the type, 



J.W. 



13. Airedale — Pond, Oak Tree Farm, Horse Shoe Lane, Leeds I pond, 



Osmondthorpe, rather common ! Roundhay Grange, very plentiful 



and characteristic, J. Abbott ! 

 17. Wensleydale — Skelton near Ripon ! 

 24. Holderness — Ditch bordering Swinemoor, Beverley, with the type, 



abundant, J. D. B, ; pond near Springhead, Hull, J.D.B. 



Planorbis albus Mlill. 



Planorbis hirsutus Gould ! 



Common and widely distributed. 



This is more widely dispersed in Yorkshire than any other 

 species of the genus, having been reported from nineteen of the 

 twenty-four districts into which the county is divided. 



Its northern limit in Britain is given by Dr. Jeffreys as 

 Aberdeen, but it has since been found in the extreme north of 

 Scotland, at the Lake of Brickigo, Caithness. 



Pla7iorbis hirsutus of Gould, a native of North America, is 

 considered by Dr. Jeffreys to be identical with the present 

 species, and it is closely represented in South America, accord- 

 ing to Hermann Jordan, by Planorbis Pfeifferi of Strobel, a 

 species inhabiting the Argentine Republic. 



According to the observations of Mr. Borrer, this species 

 is found in ponds on the clay, and not in those situate on the 

 chalk or sand. 



3. Vale of York — Not common in the York district, most so if anywhere in 



the Foss ; in some ponds at Strensall Common ; in Osbaldwick 

 direction about 1859 ; Askham ; Hobmoor, R.M.C. ; Clifton Ings, 

 York, W. C. Hey ; Hobmoor ponds, W. C. Hey ; Tadcaster, F. 

 G. Binnie ; Strensall ! Woodhall Bridge near Wetherby ! Malton, 

 1880, J.D.B. ; stream at Scarcroft, W.D.R. ! frequent at Colling- 

 ham and Boston Spa, J. Emmet. 



4. Number —Carlton pond near Snaith, abundant, W.D.R. ! ditch near 



canal, Gateforth ! canal near Burton Hall ! 



5. Hatfield and Thome — Auckley Common, May 14, 18S3 ! 



Trans.Y.N.U., 1SS3 (pub. 18S5). Series C 



