butterell: the mollusca of bevfrley. 291 



Pisidium amnicum Mull. Locally abundant: occurs in the 

 Beverley and Barmston Drain near Arram, in Leven 

 Canal and in the River Hull at Grovehill. In the last 

 locality it is generally accompanied by P. fontinale var. 

 Henslowana and a form which is, I believe, Baudon's 

 P. Henslowiamnn var. inappendiculata^ the umboes being- 

 more acute than in the typical P. jcntinale. 



P. fontinale Drap. Long Lane, Figham and Leven Canal: 

 moderately plentiful. 



P. fontinale var. Henslowana Shepp. Leven Canal, Barmston 

 Drain near Arram, ditch parallel with Leven Canal, 

 Cottingham and River Hull at Grovehill, where its 

 scarcity or abundance appears to be determined by the 

 action of the tides. 



P, fontinale van cinerea Alder. Ditch near Beverley Station: 

 extremely abundant. 



P. pusillum Gmelin. Leven Canal, ditch parallel with Leven 

 Canal, and shallow ditch strongly impregnated with 

 iron, on Swiiiemoor: extremely abundant. Specimens 

 from the last locality are so thickly encrusted with dirt 

 as to resemble small pellets of mud. 



P. nitidum Jenyns. Ditch bordering the Hull Road, Figham, 

 and ditch parallel with Leven Canal. 



P. roseum Scholtz. Specimens determined as this species occur 

 sparingly in a ditch in Long Lane near Beverley Minster. 



Anodonta cygnea Lin. Risby Fishpond: fine specimens, but 

 now much less numerous than formerly. Fragments of 

 shells of this species are found on the banks of Leven 

 Canal, and broken shells are occasionally to be seen in 

 the fields near Cottingham, the latter probably having 

 been carried by birds from their native habitat. 



