190 MOLLUSCA OF MID-WEST YORKSHIRE. 



(Leeds), H. Shaw (Leeds), C. Smethurst (Leeds), J. W. Taylor, 

 (Leeds), the late James Varley (Huddersfield), William West, 

 M.C.S. (Bradford), Rev. E. P. Knubley (Staveley), and R. M. 

 Christy (late of York). 



The great value of an ' authenticated ' list being that every 

 record included in it has been verified by means of the specimens 

 upon which it is based having been submitted to the Society's 

 Referees and carefully determined by them, it has not been 

 thought necessary to append the collectors' initials to their 

 records. Suffice it to say that Messrs. John W. Taylor and 

 William Nelson, the referees, have examined all the specimens 

 referred to ; and it may be added that the present paper is not — 

 and does not aim at being — a complete list of the shells of the 

 area under consideration, for it does not profess to do more than 

 summarize what the referees have actually had before them. 



Sphaerium corneum (L.). — Common at Gisburn, Ribbles- 



dale ; plentiful at various points, and no doubt all along the 



Leeds and Liverpool canal ; in a stream at Meanwood ; 



canal, Ripon ; ponds, Masham ; Askham Bog ; Knares- 



borough, Wetherby, Bramham, and Tadcaster. 

 S. corneum var. nucleus (Stud.). — Numerous specimens in 



Malham Tarn. 

 S. rivicola (Leach). — Adel near Leeds ; canal at Shipley, at 



Kirkstall, and at Monk Bridge, Leeds. 

 S. lacustre (Miill.). — Occurs in ponds at Baildon Green, 



Gilstead near Bingley, Newton Kyme, and at Osmond- 



thorpe and Whinmoor near Leeds. 

 S. lacustre var. Ryckholtii (Norm.). — In a pond at Black 



Hills, Leeds, 

 Pisidium amnicum (Miill). — A few dead valves found in the 



Wharfe near Woodhall Bridge. 

 P. fontinale (Drap.). — Ingleborough, diVaougst Folytrichum and 



Sphagnum ; Knaresborough ] Starbotton in Wharfedale ; 



Malham ; Grewelthorpe near Ripon ; Whinmoor near 



Leeds ; Tadcaster. 



J.C, iv., April, 1884. 



