os, 
THE ZOOLOGIST 

No. 807.—September, 1908. 

VERTEBRATES OF WALES AND IRELAND. 
By H. HK. Forrest. 
In ‘ The Zoologist,’ 1903, I published a paper contrasting the 
avifauna of North-west Wales with that of the opposite counties 
of Ireland. From the details therein given it was seen that a 
considerable number of species which are common in Wales are 
absent or very rare in Ireland. In some few instances the con- 
verse of this was noted. 
In the present paper I propose to deal in a similar way with 
the other Vertebrates—Mammals, Reptiles, Amphibians, and 
Freshwater Fishes.* 
To take these groups collectively has this advantage—that it 
emphasizes the difference in the factors which govern the geo- 
graphical distribution of Birds and of the other Vertebrates. 
Whilst the former can pass through the air in any direction, the 
latter can travel only by land or along rivers. 
Geologists tell us that the British Isles were formerly con- 
nected with the neighbouring parts of Kurope by land. Subse- 
quently subsidence took place, the lowest-lying parts becoming 
submerged first. The sea between England and the Netherlands 
is shallow, as also is the sea between England and the Isle of 
Man, but to the west of this is a deep channel (over fifty 
fathoms) which is continuous along the whole length of Ireland. 
** Marine species are omitted, as they are common to the seas of both 
countries. 
Zool. 4th ser. vol. XII., September, 1908. 2¢ 
