XXXVlll MOLLUSCA OF SOMERSET: 
Agriolimax agrestis, Linné. 
Vitrea alliaria, Miller. 
Walls. Wedgerows are often replaced by walls on the 
Carboniferous Limestone. On these we find 
Pyramidula rupestris, Draparnaud (dominant) : associated with 
Helicigona lapicida, Linné. 
Hygromia hispida, Linné. 
Hygromia rufescens, Pennant. 
Helicella caperata, Montagu. 
Jaminia cylindracea, da Costa. 
The usual association on old walls in the vicinity of towns, 
villages, and isolated farms on the Oolite is: 
Helicigona lapicida, Linné (dominant) : with 
Helicella caperata, Montagu. 
Hygromia hispida, Linné. 
Hygromia rufescens, Pennant. 
Helix aspersa, Miiller. 
Vallonia pulchella, Willer. 
Vallonia costata, Miller. 
Jaminia cylindracea, da Costa. 
The two species of Vallonia, with J. cylindracea, haunt the 
edges of the flat slabs which frequently cap the walls. J. 
cylindracea sometimes occurs in almost incredible numbers 
amongst the roots of Festuca rigida, Knuth, Festuca ovina, 
Linné, Poa pratensis, Linné, and other wall-loving grasses. 
Wherever the Red Valerian (Kentranthus ruber, D.C.) occurs, 
we find H. aspersa in large numbers. H. rufescens and H. 
hispida appear to be more particularly associated with ivy. 
In permanent pastures we find the following association : 
Agriolimax agrestis, Linné. 
Vitrea nitidula, Draparnaud. 
Vitrea cellaria, Miiller. 
Helicella virgata, da Costa. 
Helicella itala, Linné. 
