312 hay: l. and f. w. shells of Yorkshire. 



Planorbis contortus. Askham Bog and Clifton Ings. 



Physa hypnorum. A small ditch on Clifton Ings; also 

 Burlington. 



P. fontinalis. Near York and Coatliam Marsh. 



Limnasa peregra. Everywhere. 



Var. ovata. Askham. Extraordinary large variety 

 from Bempton, near Flambro'. 



L. auricularia. Fine in the Foss at York. 



L. stagnalis. Sometimes very abundant in Askham Bog. 

 It appears and disappears periodically in a remarkable way. 

 Strensall Common. 



L. palustris. Small at Askham Bog. Very large and fine 

 in a mill pond at Burlington. 



Var. decollata. Guisborough. 



L. truncatula. York, Guisborough, &c. 



L. glabra. Abundant in a small ditch highly charged with 

 iron, near Clifton, York. Ponds about York. In profusion in a 

 pond on Flambro' Head, where the water is also quite red. This 

 has produced decollation in many cases. A nearly white variety 

 occurs at York. 



Ancylus fluviatilis. Foss near York. Fine in the Swale 

 at Richmond. Stunted in mountain streams near Guisborough. 



A. lacustris. On the stalks of reeds in Dringhouses Bog, 

 York. Also in the Foss. 



Succinea putris. Remarkably fine on Clifton Ings, near 

 York. 



S. elegans. Same as last. 



Vitrina pellucida. York. In profusion in Guisborough 

 Woods. 



Zonites cellar! us. York, Guisborough, Bempton, Rich- 

 mond, 6^c. 



J.C., ii., Oct., 1879 



