324 THE ZOOLOGIST. 
Weaseu.—Common in Wales. Unknown in Ireland. 
Sroat.—Common in both countries, though the Irish Stoat 
is by some zoologists regarded as a distinct species, Putorius 
hibernicus. 
Witp Cat.—Extinct in Wales. Unknown in Ireland, though 
it probably occurred early in the historic period. 
Common Harze.—Common in Wales. Unknown in Ireland,* 
where its place is taken by the Irish Hare—a form of Mountain 
Hare. This last has also been introduced into Wales. 
Dormovuse.—F airly common in the eastern counties of Wales ; 
rarer in the west. Unknown in Ireland. 
~Harvest Movusr.—Of rare or doubtful occurrence in Wales 
and the neighbouring counties. Unknown in Ireland. 
Fretp VouE, Bank Vone, Water Voie. — All common in 
Wales. Unknown in Ireland. ; 
Ror Dseer.—Extinct in Wales in the wild state. Unknown 
in Ireland. 
A glance through the above list reveals some striking 
anomalies. The absence of Snakes from Ireland is so familiar 
that it passes without comment, but that there should be no 
species of Vole, no Mole, no Weasel, nor Polecat is indeed 
remarkable. 
In my former paper on the Birds of the two countries I 
refrained from offering any theory to account for the facts. 
May not the successive cutting off from the mainland of, first, 
Ireland and then Great Britain, account for some of the pheno- 
mena ? 
Take, for example, such a comparatively sedentary bird as 
the Tawny Owl. May it not have established itself in Great 
Britain whilst still connected with the Continent, but after 
Ireland had been cut off by the sea? The same argument 
might apply to the Woodpeckers and other birds that do not 
habitually cross the sea or perform regular migrations. The 
idea is not a new one. It has been advanced by several writers, 
but more particularly by Mr. Charles Dixon in his book on the 
‘Migration of Birds,’ in which he applies it as a principle to 
account for the routes taken by birds on migration, these follow- 
ing the ancient land-connections between North Africa and South 
* Introduced recently into Ireland, 
