1 8 HISTORY OF THE EUROPEAN FAUNA. 



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A very curious statement was made by a well- 

 known French conchologist, the late M. Bourguignat, 

 with regard to introductions of mollusca. Whether 

 he had any actual facts collected in support of it, I 

 cannot say, but he maintained that species accidentally 

 transported, with the exception of those under mari- 

 time influence, can only be acclimatised from north to 

 south, and not from south to north from east to 

 west, but not from west to east (p. 353). 



The whole theory of the accidental or abnormal 

 dispersal of mollusca appears to have been originated 

 by Darwin, in order to account for their presence on so- 

 called Oceanic islands. His views v/ere strongly sup- 

 ported by Wallace, who defines these islands (p. 243) 

 as those which are of volcanic or coralline formation 

 usually far from continents, entirely without indi- 

 genous land mammals or amphibians, but with a fair 

 number of birds and insects, and usually with some 

 reptiles. 



I do not wish it to be understood that I am in any 

 way undervaluing the great works of these dis- 

 tinguished naturalists. Darwin's views have had 

 more influence in advancing Zoology than those of any 

 man, and his fame is unassailable. Nevertheless, I 

 feel that his theories regarding the origin of the faunas 

 of oceanic islands require revision. 



The formerly prevalent belief of the permanence of 

 ocean basins has been shaken by the utterances of 

 some of the greatest geologists of our day, whilst 

 many positively assert that what is now deep sea 



