134 The Irish Naturalist April, 



bridges last existed. But it seems to me thai we have some- 

 thing else to consider besides the presence of particular groups 

 of species and the absence of particular groups of species • 

 and that is the general poverty of our fauna as a whole. For 

 recent investigation seems to me to have gradually bored 

 away the old explanations that used to be offered on that sub- 

 ject, and to have made it more difficult, instead of more easy 

 than before, to understand why Ireland has not as rich a fauna 

 and flora as England, and why England has not as rich a fauna 

 and flora as the little kingdom of Belgium on the near conti- 

 nental shore. 



No doubt, if we restrict ourselves to the simple and time- 

 honoured process of taking the animals one by one, we get at 

 results that can be summed up conveniently in a few words. 

 A great many of the animals and plants which now inhabit 

 Western Europe had not — it is supposed — arrived at that part 

 of their present range by the time that England — or rather the 

 whole ' : Britannic ? ' area — w r as finally broken off from the Con- 

 tinent; so that those animals and plants, by the time they 

 reached the Straits of Dover, found themselves too late to 

 catch the last bridge into Britain. But some of those that did 

 catch the last bridge into Britain, and have been able in con- 

 sequence to constitute themselves parts of the fauna and flora 

 of England, Wales, and Scotland, were, nevertheless, prevented 

 from reaching Ireland, because Ireland had become a separate 

 island at a yet earlier date than that which saw the final in- 

 sulation of Great Britain. At first sight it might seem that on 

 this principle the poverty of our present fauna is completely 

 explained by our very early severance from the Continent of 

 Eu rope. 



But what was Europe like — what were the western parts of 

 the Continent like — when that early severance took place? 

 Was the fauna of the whole West of Europe then as poor in 

 point of number of species as the Irish fauna is at the present 

 day? And, if so, how can that poverty be explained? Dr. 

 Scharff has given us strong reasons for believing that what he 

 calls the Siberian members of the British fauna were at that 

 time still unknown in Western Europe, or, at least, were only 

 beginning to find their way to those regions across the great 

 Central Plain that had lately been left dry. I quite believe in 



