266 ROEBUCK : THE CONCHOLOGY OF MALHAM. 



Vertigo pusilla. Malham ; W. West. 



Balea perversa. Occurs on walls in great profusion. Malham ; 

 W. West and T. Rogers. Janet's Cave near Malham; W.I). R. 



Clausilia rugosa. A well-distributed and abundant species. 



Common at Bell Busk ; W.D.R. Kirkby Malham; W. Nelson. 



Hanlith ; W. West. Abundant on limestone rocks at Malham ; 



W. West. Above Malham Cove; W. West. Gordale, at 



I, coo ft. alt.; W. West. Street Gate, Gordale Beck, on Silurian 



rocks, alt. 1,300 ft.; W.D.R. 

 Clausilia dubia var. suttoni Wstld. is very abundant. Gordale 



Scar ; W. Nelson. Abundant on limestone rocks at Malham ; 



W. West. Janet's Cave ; W.D.R. Abundant close to Malham 



Tarn House ; W.D.R. On old walls, Malham Moor ; E. Collier. 

 Azeca tridens. Malham ; W. West. Malham Cove ; E. Collier. 

 Zua lubrica. Malham; W. West. 

 Bythinia tentaculata. A few in Malham Tarn ; J. D. Butterell 



and W.D.R. 

 Valvata piscinalis. Malham Tarn, approaching var. acuminata ; 



J. D. Butterell and W.D.R. 

 Planobis nautileus. One found in Malham Tarn ; W.D.R. 

 Planorbis spirorbis. Common in Malham Tarn Moss at 1,300 ft. 



alt. ; W. West. 

 Planorbis COntortus. Abundant, but small, in Malham Tarn ; 



W.D.R. and J. D. Butterell. 

 Limnsea peregra. Common. Malham; W. West. Malham 



Tarn Moss ; W. West and E. Collier. Malham Tarn ; W.D.R. 



Airton ; W. Nelson. 



The var. ovata occurs in Malham Tarn ; J. D. Butterell and 



W.D.R. River Aire at Malham Cove; W.D.R. 



The var. acuminata has been found at Malham, but not 



characteristic ; W. West. This form is very peculiar ; Dr. E. von 



Martens has referred it to L. lagotis Kob. 

 Limnaea stagnalis var. fragilis-variegata. Abundant on 



Potamogeton lucens in Malham Tarn ; J. D. Butterell and W.D.R. 

 Limnsea truncatula. Malham ; W. West. Common on Malham 



Tarn Moss, at 1,300 ft. alt. ; W. West. 

 Ancylus fluviatilis. Malham ; W. West. Common in the Aire 



at its issue from Malham Cove ; W. West. 



The var. capuloides has been found. Malham ; E. Collier. 



Malham Cove ; T. Rogers. 



The var. albida is common in the river Aire just where it 



issues from Malham Cove ; W. C. Hey. 



Naturalist, 



