aERMA^IC EEGION. 89 



1. Geemais^ic Eegion. 



Tho "whole of Northern Europe and xlsia bounded by the 

 Pyrenees, Alps, Carpathians, Caucasus, and Altai, constitutes 

 but one province, with a fauna by no means proportioned in 

 richness to its extent.* 



The land-snails amount to more than 200, but nearly all (or 

 at least fiye-sixths) are common to the Lusitanian region. f 



Helix 00 Pupa' 44 Cyclostoma 1 



Bulimulus 10 Clausilia 52 Acicula 1 



Zua J Vitrina 5 Limax 9 



Azeca > 5 Succinea 5 Arion 4 



Cionella ) Balea 1 Carj-chium 1 



The fresh-water shells belong to these genera and sub 

 genera : — 



Liran^a 20 Velletia 1 Unio, sp. ar.d vars. ... 20 



Amphipeplea 2 Neritina, vars 3 Anodon, vars 20 



Pliysa 5 Paludina and Bithynia 23 Alasmodon 3 



Aplexa 1 Valvata 5 Cjrlas 6 



Planorbis 16 Conovulus (Alexia)... 3 Pisidium 11 



Ancylus 7 Driessena 1 



According to Eeeve, there are 199 British molluscs, of which 

 176 dwell on the land and 23 in the water. Of the species for- 

 merly thought peculiar, Pu;pa anglica and Helix fusca haye been 

 found in France, and Helix lameUata in Holstein. Helix excavata 

 (Bean) is still unknown upon the Continent ; and Geonmlacui 

 raacidosus and Limncea involida have only been met with in 

 the south-west of Ireland, but are possibly Lusitanian species. 

 Dreisena jpohjmorpha has been permanently naturalised in canals 

 (p. 424), and Testacella Maugci and Imliotidea in gardens; Bu- 

 Ihnus decollatus and Goodalli have been often established in 

 greenhouses. Some species are now very scarce in England 

 that were formerly abundant, as : — 



Clausilia plicatula. Vertigo Venetzii. Succinea oblonga. 



Vertigo minutissiraa. Helix lamellata Acicula fusca. 



Others, which occur in tho newer tertiary deposits, have 

 become quite extinct in England, such as : — 



* The mean temperature of the winter and summer months averages Z&° — 67" ; in 

 Western Europe autumn rains prevail, and summer rains in Eastern Europe and 

 Siberia. 



t It was the opinion of Professor E. Forbes that all the species of the Post-pliocene 

 land of Northern Eiurope and Aeia had originated beyond the botmds of that region. 



