LAND AND FRESH WATER MOLLUSCA OF THE EAST RIDING. 171 



Pisidum pulchellum Jenyns. 



Derwentland. — Very abundant in shallow ditches near York (W.C.H.); 

 "Common enough, I believe" (R.M.C.). 



Wolds.— Risby (T.P.). 



Holderness. — Saltend Common, cattlepond (T.P., Trans. I., p. 104). 



Pisidium cinereum Alder. 



Derwentland. — Ponds on Tilmire (R.M.C.). 



Wolds.— Lowthorpe (Y.N.U. 1890). 



Holderness. — Beverley, ditch near station, extremely abundant (J.D.B. 3). 

 Hornsea Mere (C. Reid, p. 83 as casertanum ; T. P. specimens identified 

 by Mr. J. W. Taylor). 



Pisidium pusillum (Gmelin.). 



Derwentland. — York (S.W.N.) ; very abundant in shallow ditches near 

 York (W.C.H.) ; generally distributed (W.C.H. in R.M.C.). Derwent 

 at Kirkham Abbey (Y.N.U. 1889). Pocklington canal (Y.N.U. 1893). 



Wolds.— Pond near Danes Dyke House (Y.N.U. 1886; W.C.H. "Flam 

 borough" p. 137). Lowthorpe (Y.N.U. 1890). Kildwick Percy 

 (Y.N.U. 1885 ; circular 106). Welton ; Brantinghamthorpe (Y.N.U. 

 1901). 



Holderness. — Driffield canal (J.D.B. circular 145 ; L. B. Ross, J. of C. 4, 

 p. 356). Leven canal ; ditch parallel to Leven canal ; shallow ditch, 

 Swinemoor ; extremely abundant (J.D.B. 3). Hornsea, ditch near 

 Wassand end of Mere (J.D.B. 2 ; Mere, C. Reid, p. 83 ; T.P.) Leven 

 canal and Keyingham drain (J.D.B. 1). Withernsea (F.W.F. circular 

 99). Saltend, ditch inside guard bank (T.P. Trans. III. p. 41). 

 Hedon ; Thorngumbald ; Grimston ; Aldborough ; Mappleton • 

 Hornsea Burton ; common everywhere (T.P.). 



Var. obtusalis (Lam.). Hornsea Mere; Kelleythorpe (T.P.). 



Subfossil. Bridlington (W.C.H. Nat. 12, p. 374). Hornsea (C. Reid, 

 p. 82). Sandlemere (C. Reid, p. 84). South of Withernsea (W.D.R. 

 J. of C. 7, p. 88). Kilnsea ; Easington; Holmpton ; Neville's Dyke ;. 

 Mappleton; Atwick Gap ; Atwick ; Skipsea ; Ulrome (T.P. 1892). 



Pisidium nitidum Jenyns. 



Derwentland.— York (S.W.N. ). 



Wolds.— Pond near Danes Dyke House (Y.N.U. 1886; W.C.H. "Flam- 

 borough" p. 137). Flamborough (F.W.F. circular 116). 



Holderness. — Common, Spring Dyke ; Skidby drain ; (J.D.B. 1). Ditch 

 bordering the Hull Road, Figham ; ditch parallel to Leven canal 

 (J.D.B. 3). Hornsea Mere, specimens identified by Mr J. W. 

 Taylor (T.P.). 



