272 



Prof. E. Forbes read a paper ' On the Distribution of Endemic 

 Plants, more especially those of the British Islands, considered with 

 regard to Geological Changes.' The author stated that the hypothe- 

 sis of the descent of all the individuals of a species, either from a first 

 pair, or from a first individual, being assumed, the isolation of assem- 

 blages of individuals from those centres, and the existence of endemic 

 or very local plants remains to be accounted for. Natural transport, 

 the agency of sea, rivers, and winds, and carriage by animals or 

 through the agency of man, are means in the majority of cases insuf- 

 ficient. The true cause the author proposed to seek in an ancient 

 connexion of the outposts or isolated areas with the original centres, 

 and the subsequent isolation of the former through geological changes 

 and events, especially those dependent on the elevation and depression 

 of land. Selecting the Flora of the British Isles as a means of test- 

 ing his theory, he divided its vegetation into five Floras : first, a west 

 Pyrenean, confined to the west of Ireland, and mostly to the moun- 

 tains of that district ; second, a Flora related to that of the south- 

 west of France, extending from the Channel Isles across Devon and 

 Cornwall to the south-east, and part of the south-west of Ireland ; 

 third, a Flora common to the north of France and south-east of Eng- 

 land, and especially developed in the chalk districts ; fourth, an Al- 

 pine Flora developed in the mountains of Wales, north of England 

 and Scotland ; and fifth, a Germanic Flora, extending over the greater 

 part of Great Britain and Ireland, mingling with the other Floras, and 

 diminishing, though slightly, as we proceed westwards, indicating its 

 easterly origin and relation to the characteristic Flora of northern and 

 western Germany. The author then went into details, pointing out 

 the circumstances which gave a probable age to each of these British 

 Floras, and the geological changes which had occurred to isolate 

 them from Floras of other parts of Europe, with which they were for- 

 merly in connexion, and with which they had a common parentage. 

 He maintained, in conclusion, that the peculiar distribution of en- 

 demic animals, especially of the terrestrial Mollusca, bore him out in 

 these views. He proposed to pursue the subject in detail, with refe- 

 rence to both animal and vegetable life, in connexion with the re- 

 searches of the Geological Survey. 



This paper produced a long and interesting discussion. Mr. J. 

 Ball argued against the hypothesis of there being only a single species 

 created. If there were but one individual we were not in a position 

 to say what were its characters from our present forms. He saw no 

 objection to the view that the same species might be created at two 



