26 INTRODUCTION. 



Pupa anglica, 



Vertigo alpestris, 



angustior, 



' palustris, 



Planorbis Icevis, 

 and 2 or 3 Pisidiums. 



On the other hand, many of the British shells find 

 their southern limits in France and Germany, for 

 only 22 of them are found in Sicily, and only 17 in 

 Corsica. Of these southern species, the greater part, 

 viz., the 18 following, are common to those countries, 

 Britain, and Sweden, viz., — 



Paludina achatina, 



crystallina, 



Bithinia impura, 



Succinea putris, 



Helix nemoralisy 



pidchella, 



ericetorum, 



Zonites radiatus, 



• cettarius, 



Achatina acicula, 



Clausilia Rolphii (?) 



rugosa, 



.. Limnceus pereger, 



stagnalis, 



palustris, 



■ fossariusy 



glaber, 



Anodon cygneus* 



There are only a very few species of the British 

 land and fresh-water Mollusca which appear to be 

 commoa to the American continent. 



