LINXEAN SOCIETY OF LONDON. 83 



islands by the way, established a uniformity of fauna and flora. 

 Thus Dr. Michaelson writes (Journ. West. Aust. Nat. Hist. Soc. 

 v., July 1908, p. 13): " There is no need for the supposition of an 

 ancient great Antarctic continent \Ahich connected Australia and 

 South America as some scientific men still suppose. Certain 

 littoral Oligochajta consisting of euryhaline forms, for which the 

 salt sea is no barrier, can be transported by the west wind drift 

 over the stations on the different islands lying between one 

 continent and another." 



The flora of the circum antarctic islands, as instanced by 

 Kerguelen, was thought by W. Schimper to have been conveyed 

 by sea birds and ocean drift (Schimper, AVissenschaft. Ergebn. 

 Valdivia, ii. 1905, p. 75). Although this niiglit apply to species 

 which recur through several archipelagoes, such would not explain 

 the presence of endemic plants and on Kerguelen the occurrence 

 of an endemic snail, Ampliidoxa JiooJceri. 



Such transport accounts only for a wide range of individual 

 species capable of air or water carriage. It has doubtless been a 

 small but real factor in distribution. Eut it does not account 

 for the existence of related and representative species, for the 

 subtropical element, or for the species incapable of such convey- 

 ance. Px'of. W. B. Benham raises the objection that a species 

 might drift yet never land : — " When I stood at the top of the 

 sheer cliffs, some 500 ft. to 1000 ft. in height, which form the 

 whole of the west coast of Auckland Island, and saw the 

 tremendous breakers which even in moderately calm weather dash 

 with incredible force against the rocks, I was more than ever 

 convinced that the ' west- wind drift ,' cannot account for the 

 transference of Oligochieta from the various land surfaces of this 

 subantarctic region " (Benham, ' Subantarctic Islands of New 

 Zealand,' i. 1909, p. 254). 



III. 



That a trans-Pacific continent conveyed to New Zealand, 

 Australia, and South America a common stock otherwise recognised 

 as the Antarctic element (ITutton, Proc. Linn. Soc. N. S. Wales, 

 xxi. 1896, p. 36 ; Baur, ' American Naturalist,' xxxi. 1897, p. 661). 



This alternative seems the weakest. Had a trans-Pacific bridge 

 really disseminated the species under discussion, then they should 

 be best developed in the central remaining portion (for instance, in 

 Tahiti or Samoa) and least at the extremity (as in Chili or 

 Tasmania). Actually the reverse is the case : Soutli America is 

 the most closely associated with Tasmania, then New Zealand is 

 less so, and the Mid-Pacific islands not at all. 



Those who consider the demand for land between Tasmania and 

 Antarctica as exorbitant are not consistent in asking so much 

 larger a grant in the Pacific. 



Another difficulty is why that South American contingent 

 which flooded Tertiary Antarctica, and then Australia, failed to 

 include such characteristic South American fauna as the humming- 



9^ 



