1913-1914. J - ,. 



or whether there were two distinct connections ? It is conceivable 

 and even probable that some of the species mentioned by me came 

 to Ireland at a much earlier date than others did. It must be 

 borne in mind also that we have to deal with at least two distinct 

 groups, one having a northern, the other a southern origin. Did 

 the first group enter the country during cold, and the other during 

 warm climatic conditions ? 



There are a great many other questions we should like to have 

 answered, but it would lead me too far to discuss them adequately 

 in the brief space of time at my disposal. I purposely refrained 

 to-night from touching upon problems which have been widely 

 discussed on purely geological reasoning such as that of the Ice 

 Age. It would be obviously out of place in a short zoological 

 essay to trespass into one of the most complex chapters of 

 Geology. As I mentioned before, it was merely my intention to 

 show you how we can deduct from zoological arguments that 

 Ireland had undergone changes of level in recent geological times. 



So far we have dealt with the geographical distribution of the 

 larger animals or Mammals, and I have argued that the bulk of 

 them must have crossed to Ireland from Great Britain on a land- 

 bridge. It is not necessary to confine our studies to these large 

 creatures in order to enable us to infer these important results. 

 Some of the small animals, even very inconspicuous Crustaceans 

 and Insects, do just as well. If you examine an ordinary Ants' 

 nest in the south of Ireland, you may sometimes detect among the 

 Ants a few larger perfectly white creatures. These white creatures 

 which move about very deliberately are no near relations of the 

 Ants. They belong to quite a different group of animals. Being 

 totally blind they require a place of that kind where they can pick 

 up bits of food without having to go far in search of it. They thus 

 act as scavengers to the Ants, and the latter apparently do not 

 mind them, but allow them to pursue their calling unmolested. 

 Now, it is quite conceivable that at a time when the winged 

 members of the Ant community take to flight in order to form new 



