TROPICAL CYCLONES AND THE DISPERSAL OF LIFE 

 FROM ISLAND TO ISLAND IN THE PACIFIC ^ 



By Prof. Stephen Saegbnt Visheb 

 Indiana University 



EVIDENCE FOR AND AGAINST A PACIFIC CONTINENT 



One of the mooted questions concerning the Pacific is how the 

 biota now found uj3on the scattered islands got there. There are two 

 great schools of thought in respect to the matter. One believes that 

 the presence of numerous Asiatic forms can only be explained on the 

 assumption that at some earlier time many of the now remote islands 

 were connected into a continent. Some members of this school think 

 that the continent extended as far as the Low Archipelago and Ha 

 waii." Others do not ask for so much land, but assume a southeast- 

 ward extension of Asia, to include the East Indies, Philippines, New 

 Caledonia, Fiji, and Samoa. Certain large islands are also believed 

 to have existed, for example, one that would include all the Hawaiian 

 Islands and another that would unite the Cook, Austral, Society, and 

 Tuamotu islands.^ 



The other school of thought is opposed to the idea of a Pacific con- 

 tinent, or of vast islands in it, and to the extension of Asia and 

 Australia beyond New Caledonia.* They contend that the agencies 

 distributing life from island to island are sufficiently efficient to have 

 enabled the land forms to spread to the remote islands upon which 

 they are found. 



However, there are several features of the distribution of land 

 forms that are difficult to explain on the basis of prevailing winds 

 and ocean currents. One is the fact that many of the forms of 

 even the easternmost islands are related to Asiatic forms rather 

 than to American forms. That is not true of all types of life; a 



1 Reprinted by permission from Tlie American Naturalist, Vol. LIX, January- 

 February, 1925. 



^ Campbell, Douglass H., " Some botanical and environmental aspects of Hawaii," 

 Ecology, Vol. I, pp. 257-269, 1920 ; Bryan, Wnr. A., " Hawaiian fauna and flora," Pro- 

 ceedings First Pan Pacific Scientific Conference, Vol. 1,. p., 158, Honolulu, 1921 ; Scbarfif, 

 R. F., " Distribution and Orisin of Life in America." 1911. 



^ Pilsbry, H. A., " Tlie dispersal and affinities of Polynesian land snails," Proc. 

 pan-Pacific Scientific Conf., Vol. I, pp. 147-151, 1921. 



* Many geologists and biologists belong to this school. Including T. C. Chamberlin, 

 C. Schuchert, H. E. Gregory, D. S. Jordan, F. Muir, etc. 



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