NELSON AND TAYLOR: ON YORKSHIRE MOLLUSCA. 57 



Var. rhombea (Turton). 



Planorbis draparnaldi Shepp. has, by some conchologists, 

 been confounded with this variety, from which it is, of course, 

 very distinct. 



Dr. Gray considered that this variety — the Helix rhombea 

 of Turton — is only the young state of P. co?nplanatus. 



3. Vale of York — A few in a pond at Bishopthorpe, and in one of the 



Hobmoor ponds, R.M.C., 1881 ; pond near York, immature, Feb. 



22nd, 1885, W.C.H. ! brick-pond at Stanks, near Seacroft, 1871 1 



near Harrogate, Lister Peace, 1880 ! 

 7. Went Vale — Pond in a field about 300 yards above Wentbridge, II. 



Richardson, 1883 ; near Norton, 1884, G. Roberts ; Askern, 1884, 



G. Roberts. 



12. Lower Calder — Barnsley canal, J.W., 1883. 



Var. albinos Baudon, 1859. 

 Planorbis complanatus var. 2 albida Jeffreys, 1862. 

 4. Number— A wide ditch at Fairburn, July, 1885, G. Roberts ! 



Monst. sinistrorsum Taylor. 

 Shell reversed (Journal of Conchology, vol iv. p. 37, 1883). 

 7. Went Vale — Askern, J. Wilcock. 



Monst. terebrum Turton, 1819. 



Monst. trochiformis Baudon, 1884. 

 Dr. Baudon published no description of the form he names 

 monst. trochiformis, but the figure he gives (Journal de Conchy- 

 liologie, vol. xxiv., pi. x., fig. 2, 1884) shows conclusively that it 

 is identical with monst. terebrum. 



6. 7/-enf— Doncaster, J.W., 1885 ! 



13. Airedale — Leventhorpe Pastures, May i6th, 1864, J.B. ; one specimen 

 in a small brook near Wilkinson's mill, Hunslet, i860, since built 

 over, Goodman Street now occupying the site ! 



