54 



[Proc. B.N.F.Cr 



Scotland — some even to remote Scottish Islands — and not have 

 reached Ireland ? I need only mention two well-known instances, 

 namely, the Roe Deer and the Mole. The Roe Deer once flourished 

 all over Great Britain. At present it is confined to the North of 

 Scotland, having become extinct in England within the last few 

 centuries. The Mole still exists all over Great Britain. We 

 possess no evidence that either of these species ever succeeded in 

 penetrating to Ireland. Some of the Voles — those mouse-like 

 creatures which occasionally do such injury to crops and are 

 dreaded by the farmer — occur even in the outlying Scottish 

 islands. Yet none of them are known to have lived in Ireland. 



The most obvious answer to the question why all these and 

 many others have not spread to Ireland, and the one usually- 

 given, is that Ireland became a separate island before all the 

 British Mammals had time to take advantage of the previously 

 existing land-connection between the two countries. But among 

 the British Mammals that are absent from Ireland we have, as I 

 mentioned, the Roe Deer and the Voles, and also the English 

 Hare, all of which are supposed to spread with great rapidity. 

 The Voles, moreover, have been resident in England and Scotland 

 sufficiently long to have formed several markedly distinct varieties 

 and species. The usual answer to the question why these animals 

 have not reached Ireland is, therefore, scarcely satisfactory. And 

 yet how are we to explain their absence from Ireland? We might 

 suppose that they were once present in Ireland and had sub- 

 sequently become extinct. If that had been the case we should 

 surely by now have come across some Palseontological evidence in 

 support of such a theory. Not a single fragment of a bone of any 

 of these Mammals has so far been discovered in Ireland. We 

 are thus unable as yet to give a satisfactory answer to the question 

 raised. 



Another question that occurs to us is whether there was a 

 single land-connection between Great Britain and Ireland by 

 which all recent and extinct Mammals alluded to invaded Ireland. 



