78 NELSON AND TAYLOR : ON YORKSHIRE MOLLUSC A. 



eggs of Z. ovata, which he placed in springs or rivulets, yielded 

 Z. peregra, whilst those of the typical form, placed under suit- 

 able conditions, produced the var. ovata. 



1. Mersey — ^Mossley, H. Crowther! Saddleworth ! Lees near Oldham ! 



2. Lune and /?/66/e— Plentiful in stream at Barn Gill, near Hammerton 



Hall, Aug. 9th, 1885, W.D.R. ! near Ingleborough, Geo. Roberts, 

 Zool., 1868, p. 1382; Chapel-le-dale Valley, April 23rd, 1886, 

 W.D.R. ! River Ribble and Scaleber Beck, April 2Sth, 1885, Rev. 

 W. C. Hey, Nat., June, 1885, p. 258 ; common in horse-trough, 

 Grunsagill Bridge, Aug. loth, 1885, W.D.R.! Nevvton-in-Bowland, 

 August 9th, 1885, W.D.R.! Ebbing and Flowing Well, Settle, 

 1878 ! ditch, Ingleton, September, 1878 ! pond by river, Gisburn, 

 April i8th, 1881, W.D.R. ! River Hodder, Bashall Eaves, August 

 8th, 1885, W.D.R. ! stream, Smithies Bridge, near Sawley, abundant 

 but small, August 8th, 1885, W.D.R. ! Bracewell, near Skipton, 

 common, April i8th, 18S1, W.D.R.! 



3. Valeof York — In the greatest abundance about York, R.M.Christy, Zool., 



p. 183, May, 1881 ; Askham Bog, R. M. Christy, Nat. Hist. Jour., 

 Nov., 1879, p. 130; ditches by the Foss above Yearsley Bridge, 1858, 

 W. Whitwell; ditch, Huntington ! Knavesmire, April, 1882! pond, 

 Bootham Junction, April, 1882 ! ditch and pond, Bootham Stray, 

 April, 1882! Naburn Lock, February, 1878, J. Grassham ! Acomb, 

 April, 1882! Steeton near York, 1880! Clifton Ings, April, 1882! 

 Hobmoor, R. M. Christy, August, 1883 ; River Foss, April, 1886, 

 O. Morland! ditches, Middlethorpe Ings, 1865, R. Whitwell; very 

 large, Bishopthorpe, 1858, W. AVhitwell ; River Ouse, where it lives 

 in quite deep water, and though very plentiful is quite dwarfed. Rev. 

 W. C. Hey, Report Yorks. Phil. Soc. 1883, p. 35 ; common about 

 Boston Spa, J. Emmet, 1882 ; Oxton near Tadcaster, 1888 ! road- 

 side ditches, Brafferton, September nth, 1882, W.D.R. ! stream, 

 Bolton Percy, July 13th, 1880 ! ditch, Thorner, May 15th, 1S83, H. 

 Pollard ! water-trough near Rigton, 1876 ! Collingham Mill Dam, 

 October 30th, 1879 ! ditch, Bardsey, April 15th, 1877 ! Bishop Dyke 

 near Milford, April 12th, 1888 ! Hook Moor, October 6th, 1866 ! 

 Seacroft, common, June i8th, 1882, B. Holgate ! Asp Ponds, 

 Knaresbro', July, 1S82 ! Pond, Sicklinghall ! Newthorpe near Sher- 

 burn, February 12th, 1882, H. Crowther ! Hollin Lake near 

 Harewood! stream, Spofforth I River Cock, Towton, March, 1884! 

 pond, Harlethorpe near Bubwith ! pond, Follifoot ! water-trough, 

 near Pompocali, April 15th, 1877! pond, Lazencroft, 1880 ! Barlby, 

 common on bank of Ouse, September 6th, 1879, W.D.R. ! stream, 

 Church Fenton, Aug., 1881 ! Healaugh Hall, 1877, H. Crowther 

 Strensall Common, September, 1880, W. Raine ; pond, Sicklinghall, 

 October, 1882 ! pond, Huddlestone, 1879 ! pond, Riccall, June, 

 1879 ! boggy ground, Newton Kyme, 1881 ! pond, near Ulleskelf, 



Trans, Y.N.U., 1890 (pub. 1891). • Series C 



