26 INTRODUCTION. 



Pupa anglica, 



Vertigo alpestris, 



angustior, 



palustrisy 



Planorbis Iceiris, 

 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, 



crystalling 



Bithinia impura, 



Succinea putris, 



Helix nemoralis, 



pulchella, 



ericetorum^. 



Zonites radiatus, 



cellarius, 



Acliatina acicula., 



Clausilia Rolphii (?} 



. rugosa, 



LimncBUS pereger^ 



. stagnalis, 



palustriS) 



fossarius, 



glober, 



Anodon cygneus* 



There are only a very few species of the British 

 land and fresh-water Mollusca which appear to be 

 eommon to the American continent. 



