NELSON AND TAYLOR: ON YORKSHIRE MOLLtJSCA. ^t 



The most noticeable variations are "in size — which varies 

 from 6 to 21 mill — and in colom* from very pale horny to an 

 intense reddish hue, which latter is the var. rubraYzn den Broeck> 

 In this country it is often found living associated with jP. spiroihis 

 and L. glabra, as already noted under P. spirorbis. 



P. hypnorum is essentially a circumpolar species and would 

 appear to attain its greatest development in the cool temperate 

 regions of North America, as the largest specimens we have 

 ever seen were collected by Mr. R. M. Christy in Manitoba and 

 measured over 21 mill, in length. 



According to Jeffreys and Reeve its southern range in 

 Europe is bounded by the Pyrenees, but Graells has recorded it 

 for several localities in Spain. 



Its British distribution is summarised by Dr. Jeffreys as 



from the Moray Firth district to Guernsey and so far our 



researches have not enabled us to extend its range further 



northwards. 



3. Vale of York -\'ery abundant in the York district, and I lbini< un- 

 usually fine. In vast numbers in a certain pond at Bisbopthorpe, 

 where I could obtain it by handfuls once, when it was dried up. 

 One individual measured 4-5ths of an inch in length ; also common 

 in the ditches Ijy Acomb Wood, the stream on Clifton Ings, a dirty 

 ditch beside the public footpath to the north end of Scarborough 

 bridge, Poppleton, Bootham, Tillmire, "Strensall, Knavesmire, and 

 elsewhere, pond near Burton Lane, Clifton (H. Richardson), 

 R. M. Christy, Zool., p. 183, 1881 ; a small ditch, Huntington ! 

 in one ditch at Askham, R. M. Christy, Nat. Hist. Journ., iii., 

 130, Nov. 1879; Knavesmire, April, 1882! rather scarce in the 

 Foss, n. Richardson; Wighill; .Shircoaks Wood, near Tadcasler; 

 Catterton ; Healaugh ; Bilbrough, Sec, F. G. Binnie ; Wetherby, 

 May 2ist, 1877, H.C. ! ditches by roadsides east of Brafi'erton, 

 abundant, Sep. 11, 1882, W.D. R. ! ditch near Woodhall Bridge! 

 pond near Church Fenton Station, 1879 ! ditch by railroad side. 

 Milford Junction, April I2th, 1868! Carforth. April 17th. 1876, 

 Nat., i. 160. May, 1876! South Milford. June, 1876, G. Roberts, 

 Topog. and Nat. Hist, of Lofthouse. ii. 312. 1885 ; pond, Ilarle- 

 thorpe, near Bubwith ! Sherburn ! Rudding, F. R. Fitzgerald ! 

 pond near Grimbald Crag, Knaresborough. June, 187 1 ! Ferrcnsby, 

 near Knaresborough, April. 1884 I rare in ditch, 15oston Spa, first 

 found in 1858. J. Enmiet ; Strensall Common, very local, but 

 common where it is found, W. Ilewett. 1884. 



