3o8 THE MIGRATION OF BRITISH BIRDS 



Southern Hemisphere, as those naturalists that so stren- 

 uously assert its former existence appear to believe. 

 The fauna and flora of Antarctica must have been exter- 

 minated with the destruction of that area — continent 

 and inhabitants alike perishing together ; the only forms, 

 nay the only types, that would survive being those that 

 chanced to have Northern Bases beyond the devastating 

 influences which have succeeded in destroying pretty 

 well half the sedentary population of the earth. 

 Antarctica can therefore never explain the dispersal of 

 species and types in now wide distant areas of the 

 Southern Hemisphere ; for not a single relic of the 

 drowned and lost South Polar continent has been pre- 

 served to us by retreat from the slowly threatening 

 doom, or by a Northern Emigration contrary to the 

 inexorable Law of Life's dispersal. Such widely dis- 

 persed forms in many cases obviously of common origin 

 only indicate the bases and the sources from which that 

 doomed South Polar land has derived its inhabitants, 

 from a previously much more continuous, more northern, 

 or even equatorial base. (Conf, p. 57.) 



The distribution of Life suggests to me the following 

 conclusions. Firstly, where the land masses are greatest 

 south of the Equator we should expect to find, and do 

 find, the most important and extensive assemblages of 

 species and types presenting the greatest amount of 

 differences from such assemblages of types and species 

 dwelling on the land masses north of the Equator ; and 

 these assemblages will to a great extent be homogeneous 

 or otherwise in proportion to longitudinal continuity cqua- 

 torially ^ of such Southern Hemisphere areas. Secondly, 



* I use the term "cquatorially " more especially in contradistinc- 

 tion to Polar. 



