XX EXPLANATION OF MAP. 



excepting Geomalaeus maculosus, Assiminea Graijana, and Li/mncea in- 

 volutes, which, so far as we know at present, are peculiar to Britain, are, if 

 not of Germanic origin, Germanic now. The most obvious subdivision of 

 the British land and freshwater mollusks iu their Continental range, is to 

 separate, as shown iu our Tables of Distribution (pp. 242 to 24-9), those 

 inhabiting Europe throughout, from those which inhabit the Centre and 

 North, and the Centre and South. The species furthest removed from the 

 Centre of Europe on the northern side is Helix lamellata, and it is the 

 most northerly species in Britain. The species furthest removed from the 

 Centre on the southern side is Helix Pisana, and it is the most southerly 

 species in Britain. 



Molluscan life increases vastly in its development towards the Equator, 

 and it follows that there are many more Germanic species common to the 

 Lusitanian region, than there are Lusitanian species common to the Ger- 

 manic. The Azores and Canary Islands are outlying fragments of the 

 Lusitanian region, inhabited chiefly by continental species. Madeira is 

 also Lusitanian in type, but it is inhabited to a very limited extent by 

 continental species, having a very characteristic inland moUuscan fauna of 

 its own. 



Of the Asiatic range of the British species little is known beyond the 

 information supplied by Gerstfeldt of those inhabiting the valley of the 

 Amoor, and by Drs. Hooker and Thomson and M. Jacquemont of those 

 inhabiting Cashmere and Thibet. It is certain, however, that Malayan 

 species, having a copious and highly developed specific centre in the Indian 

 Archipelago, inhabit Burmah and Siam, while they mingle with Caucasian 

 species in the North-western provinces of India, in the valley of the Amoor, 

 and in Japan. 



Of the remaining nine Provinces, divisible into twenty-five regions, the 

 North American is the only one in which there are any species of land 

 or freshwater mollusks common to Britain, for particulars of which see 

 ' Distribution and Origin of Species,' p. 252. 



