4 g [Proe. B.N.F.C.,. 



crossing it? We may assume that these animals had either 

 originated in Great Britain or Ireland. They could not have 

 independently originated in both countries. All authorities are 

 now in agreement that the great majority of the species of animals 

 living in Ireland have come from distant countries, and that they 

 have gradually penetrated to Ireland by way of Great Britain. 

 Our first enquiry, therefore, concerns the methods by means of 

 which animals have found their way to Ireland. 



There exists a very widespread belief that we owe our fauna 

 largely to what is known as accidental dispersal. Many naturalists 

 hold that an island may receive its animals and plants by all 

 manner of chance opportunities — winds, sea currents, birds, ships, 

 and human beings are supposed to be constantly bringing new 

 additions to our fauna and flora. And there can be no doubt 

 that a certain number of small creatures, as well as seeds of 

 plants, have thus been transported to Ireland. Yet these do not 

 constitute the whole fauna and flora of Ireland. We know for 

 certain that within the memory of man none of our larger 

 terrestrial wild beasts or mammals have reached Ireland in that 

 accidental manner. Hence we must conclude that they are 

 practically unaffected by such modes of conveyance. Even 

 Wallace, who expressed such a strong belief in the power of 

 accidental dispersal, remarks that " Whenever we find that a 

 considerable number of the mammals of two countries exhibit 

 distinct marks of relationship, we may be sure that an actual land- 

 connection, or at all events, an approach to within very few miles 

 of each other, has at one time existed." As regards Ireland, 

 Wallace does not entertain the slightest doubt as to its having 

 received its animals and plants from the Continent by way of 

 Great Britain during a time when the British Islands all formed 

 part of the Continent. 



Now, among the Beasts or Mammals living in Ireland at the 

 present time some, as you know, inhabit the water, others, like the 

 Bats, pursue their prey in the air, while most of them are bound 



