NSLSON and TAYLOR: ON YORKSHIRE MOLLUSCA. it 



No Yarieties of this fine shell have been designated by British 

 authors ; continental conchologists, howeYer, describe eight or 

 more, seYeral of them as distinct species. We haYe no doubt 

 some of these ^vill be found in Yorkshire by attention being 

 drawn to them. 

 4. Number — Goole. common, R. W. M. 



7. Went Vale — Stream, Bentley ! 



8. Decline — Canal, Cudworth ! 



10. Colne — Elland, common, J.^Vh. 



11. Upper Calder — Halifax I 



12. Lower Ca/o^er— New Miller Dam, J.W. Canal, Stanley ! Canal, Heath ! 



13. y4//-eQ'a/e— Bingley, J.W. Canal, Armley, H.S. ! Kirkstall, H.S. ! New- 



sam Green, H.S.! Oulton ! 

 17. Wensleydale — River Ure at Coverbridge ! 

 15. Wharfedale—Rivev Wharfe at Otley, H.S- ! 

 22. Denuent — Scarbro', AY.B. 

 24. //o/c/er/7 ess— Barmston Drain, J.D.B. Leven Canal, J.D.B. 



:0: 



Pisidium fontinale, (Drap.) 



Pisidium Adamsi, Prime. 



Dr. Jeffreys reduces to the rank of a synonym of this species 

 the F. Adamsi of Prime, a native of North America. 



A specimen of this species found at Bentley, near Doncaster 

 exhibits a constriction of the front margin, a peculiarity that 

 has been made use of by many authors as a basis to describe 

 many new species of Sphperiidte, the present specimen being the 

 PisidiiDH sinuation of Bourg. 



3. \'ale of York — Knaresbro' ! Tadcaster, H.C. 



7. Went Vale — Common in ponds, Ackworth, C.A, 

 10. Colne — Canal, Elland, common, J.Wh. 

 12. Lower Calder— ISlew Miller Dam, J.W. Pond, Sandal, J.H. 

 IT,- Airedale — Roundhay Lake ! 



Var. Henslowana, (Shepp.) 

 This is regarded by some authors as distinct, seven varieties 

 being enumerated by continental conchologists, some of them 

 destitute of the umbonal appendages. 



6. Trent — Conisbro', J.W. 



7. Went Vale — Artificial stream, Ackworth, common, C.A. Laminar um- 



bonal appendage but slightly developed. 



12. Lower Calder — Wakefield and Barnsley Canal, J.H. 



13. Airedale — Newsam Green, H.S. ! Osmondthorpe I 

 24 Hotderness—lxvm Canal, J.D. 



