1897] THE PROBLEMS OF BRITISH FAUNA 307 
animals have been recognised which undoubtedly show similar 
faunistic relationships. Some of these are new discoveries, and 
are apparently confined to Ireland, such as the millipede Poly- 
desmus gallicus, the earthworms Allolobophora veneta and A. georgii,? 
and the weevil Otiorrhynchus awropunctatus.? Others have long 
been known as British animals, and their occurrence in the west of 
Great Britain as well as in Ireland has probably caused their 
faunistic import to be overlooked. Such are the snail Helix pisana, 
the wood-louse Platyarthrus hoffmanseggii, the ground beetle Hury- 
nebria complanata, and the weevil Mesites tardyi. Some of these 
animals are found both in the east and west of Ireland, others only 
on the east coast. In Great Britain they occur mostly in the 
south-west, but the last-named is an example of a section which 
ranges northward into western Scotland, Abroad all are charac- 
teristic of southern and south-western Europe, while several are 
found in the Azores, Madeira, and Canary Islands. It is most 
important to take the foreign range into consideration when assign- 
ing animals to a distributional type. Just as the Common Hare is 
spread far to the north in Great Britain, as compared with many 
other members of the ‘Siberian’ fauna, so a number of animals 
belonging to the South-western fauna range farther to the east than 
the more typical species of the group. For instance, the slugs 
of the genus TZestacella must be referred to the South-western 
section, when we consider the general range of the genus, though 
some species occur in our eastern counties. And Dr Scharff would 
add to this fauna many of our widely distributed species—the 
Bullfinch among birds, for example. 
He believes moreover that this South-western fauna merges 
sradually into a ‘South-central’ fauna, including the Badger 
among mammals, and Helix virgata, H. acuta, and H. nemoralis 
among snails. And to these combined southern groups he is 
inclined to ascribe the bulk of the Irish animals, even those with 
a wide range both in Ireland and in Great Britain; except a few 
species that may have invaded the country since it became an 
island—such as the white butterflies, Pzeris brassicae and 
P. rapae, and the ‘painted lady, Pyrameis cardwi, or that have 
been apparently introduced by man—such as the rats and the 
house mouse. 
A few remarks are necessary regarding the relative ages which 
are to be ascribed to these different sections of the British fauna. The 
South-western group, the most typical members of which are found 
in the most remote parts of the country, with ranges often discon- 
tinuous, are evidently the oldest. The ‘Siberian’ animals, which 
1R. I. Pocock, Irish Nat., vol. ii., pp. 809-312. * H. Friend, id., vol. v., pp. 69-73. 
3G. H. Carpenter, its vol. iv., pp. 213-218. 
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