94 The Irish Nahiralist. May, 



DUBLIN NATURALISTS FIELD CLUB. 



February 24.— The Vice-President, \V. F. Gunn in the chair. The 

 second discussion on problems raised by the Clare Island Survey was 

 opened by R. Soithern, who read a paper on the " Marine Biology of 

 the Clare Island District." The paper was illustrated by diagrams and 

 maps, showing the distribution of the various elements in the marine 

 fauna. The effects of such I'uvironmental conditions as ocean currents, 

 the salinity and temperature of the sea-water, the nature of the sea- 

 bottom and of the materials composing it, the food supply, (S:c., were 

 considered, and special importance was attached to the pelagic stage in 

 the life-history of marine animals, as a dominant factor in their dispersal. 

 The fauna was analysed into its component geographical elements, four 

 groups being recognised, viz., the Cosmopolitan, the Boreal, the Celtic, 

 and the Lusitanian. 'I'he proportions of these groups on the west and 

 east coasts of Ireland were compared, and an attempt was made to trace 

 the origin and history of the littoral and shallow -water fauna of the 

 Irish coasts. A discussion ensued, in which the following members took 

 part:— Prof. G. H. Carpenter, R. LI. Praeger, G. H. Pethybridge, J. de 

 W. Hinch, A. R. Nichols, and N. Colgan. 



Alexander M'Henry, M.R.I. A., and D. R. Pack -Beres ford, D.L., 

 M.R.I. A., were elected members of the Club. 



April ii. — R.Lloyd Praeger in the chair. The final discussion on 

 problems raised by the Clare Island Survey was opened by Dr. R. F. 

 ScHARi-F, who dealt with the terrestrial fauna. Attention was directed 

 to the poverty of the Clare Island fauna among the Mammalia and other 

 groups as compared with the mainland, and the explanation given by 

 Moffat of the readiness with which certain species isolated on small islands 

 might become exterminated was mentioned. No doubt could l)C enter- 

 tained that the majority of the animals inhabiting Clare Island had made 

 their way thither over a land connection, and the same conclusion must 

 be drawn with regard to the immigration of animals into Ireland from 

 Britain or the Continent. Clare Island, as an isolated part of the West, 

 afforded an object lesson in the mixture of northern and southern forms 

 of life that is characteristic of our Atlantic coast. The southern (Lusi- 

 tanian) clement in the Irish fauna, especially marked as it was along the 

 west coast, was shown by the discontinuous range of its members to be 

 the most ancient element ; perhaps as Edward Forbes had long ago 

 suggested for the Lusitanian plants, some sjiecies might have surviv'ed in 

 our area since Miocene times. The question of survival through the Glacial 

 Period raised many difficulties and apparently serious differences of opinion 

 between biologists and geologists, but the evidence afforded by animal 

 and plant distribution must be allowed its full weight. The presence of 

 North American animals and plants in western Ireland supported the 

 theory that a land connection stretched north of the Atlantic by way of 

 Norway and Greenland ; the warm waters of the .\tlantic thus cut off 

 from the Arctic regions might have ensured a comj'aratively mild climate 

 along the old Continental coast-line to the west of our present western 

 Irish shore, even during the Glacial Period. 



