436 Geographical Distribution of Mollusca. 



Arioii atev L. 1 Hygromia rufescens Penn. 



Agriolimax agresiis L. Helix aspevsa Miill. 



Pyramidula nipestris Drap. | Pupa cylindvacea da Costa. 



This species, though by no means restricted to calcareous 



soils, is characteristic of the limestone pavements. On the 



Hygromia nifescens Pennant. Associated with : — 



Avion ater L. Vitvea nitidula Drap. 



Agriolimax agresiis 'L. Helix horteiisis Mull. (rare). 

 Vitrea cellaria Miill. ,, nemoralis L. (locally). 



alliaria Miller. Cochlicopa luhrica Miill. 



This species might at first sight appear to be universal, 

 but apart from the neighbourhood of gardens, and the influence 

 of such artificial habitats, its place would seem to be on the 

 margins of the Oak-Birch woods of a somewhat damp type, 

 occurring plentifully among the nettles and brambles. 



Vertigo alpestris Aid. Associated species : — 



Vitrina pellucida Miill. Pupa cylindracea da Costa. 



Vitrea alliaria Miller. Vertigo pusilla Miill. 



Euconulus fiilvus Miill. Sphyradiiim edentulum Drap. (rare). 



Hygromia rufescens Penn. Clausilia bidentata Strom. 

 Cochlicopa luhrica Miill. 



This species is characteristic of the marginal wood, and 

 while associated constantly with V. pusilla, it is evident that 

 its true place is here rather than in the Ash woods. Its centre 

 of distribution is further north. It is the Vertigo of the Lake 

 District, while V. pusilla gradually disappears in that direction, 

 ranging further south, however, than V. alpestris. While 

 abundant in the Limestone area, it is even more abundant in 

 the Silurian region. It is thoroughly well distributed, and 

 where it occurs is found plentifully in damp situations on the 

 low mossy walls. 



Zonitoides excavatus Bean. Associated with Pyramidula 



rotundata Miill. (Dominant), and : — ■ 



Limax arborum B. Ch. 

 Agriolimax IcBvis Miill. 

 Arion subfuscus Drap. 



Vitrina pellucida Miill. 



Vitrea cellaria Miill. 



Vitrea nitidula Drap. 



,, crystallina Miill. 

 Euconulus fulvus Miill. 

 Punctum pygmcBum Drap. 

 Cochlicopa luhrica Miill. 



alliaria Miller. 



This species is characteristic of the purer Oak woods of 

 a somewhat damp type, and of which this association is typical.. 

 It is, however, not so abundant in this district as it is in the 

 Oak woods of the Coal Measures in South Lancashire and 

 Cheshire, in which the characteristic flora is blue-bell, soft grass 

 and bracken. 



(6) Dy : Heathy Section. 



Beyond an occasional Pyramidula rotundata there are no 

 conchological features that can be at present given. 



Naturalist,. 



