tgiy. Southern — The State of Ireland. II 



forms. The absence of any well known and important 

 limiting barrier on our west coast makes it equally absurd 

 to expect that the fauna would have a wholly northern, 

 or wholly southern distribution. The only other alternative 

 would be that the fauna was peculiar to the west coast 

 of Ireland, and occurred nowhere else, which would indeed 

 be an interesting fact ! The preponderance of species 

 liaving a distribution mainly to the south is also what 

 c ne v/ould expect a priori, even when the effects of ths 

 warm water of the North European branch of the Gulf 

 Stream, flowing past our west coast in a north, and north- 

 eastern direction, and of the current flowing out of the 

 Mediterranean, the effects of which can be traced as far 

 north as the south coast of Ireland, are left out of con- 

 sideration. In almost all orders of marine animals, the 

 total number of species diminishes as one travels north- 

 wards from the tropics, and consequently there must 

 necessarily be more species, at any given place on the 

 west coast of Europe, having a southern distribution than 

 a northern one. In the same way the marine fauna of the 

 cast and west coasts of America, and the east coast of Asia 

 has a mainly north-south distribution, whilst that of the 

 x^rctic and Antarctic, and of the south coast of Asia has 

 a distribution mainly east-west. 



In the above paragraphs the writer must disclaim any 

 intention of attacking the legitimate study of Geographical 

 Distribution. Though it has not realised all the expecta- 

 tions of its earliest followers, nor 3/ielded results com- 

 mensurate with the amount of labour devoted to it, it has 

 its real, if subsidiary, function. 



The remedy for the present devitalised state of Natural 

 History in Ireland is to return to the study of living things 

 themselves, their physical characteristics, their adaptations 

 and habits, and their reactions to the environment. When 

 an adequate knowledge of our fauna and flora has been 

 accumulated from this point of view, we may perhaps 

 be able to derive some intelligent satisfaction from the 

 contemplation of their Geographical Distribution. 



Fisheries Office, Dublin. 



