PALEOGEOGKAPHY OF ANTARCTICA HEDLEY. 449 



Placostylus extends from Now Zealand to Fiji and New Guinea, 

 ''giving testimony," as Pilsbry remarks, "to the former existence of 

 an Antarctic land connecting the austral continents of the two hemi- 

 spheres." C^Ian. Condi., Index, vols. 10-14, 1902, p. ix.) 



The Biiprestidae, a family of large and handsome beetles, exhibit a 

 striking affinity between Australia and South America; so much so 

 that, opposed as Wallace was to the Antarctic connection, he here 

 conceded that some exchange between the two areas was required. 

 He thouglit that it took the form of larvss in floating timber drifting 

 round the Antarctic seas in a warm period. 



Among early Tertiary vegetation brought from Seymour Island in 

 the Antarctic by Dr. Nordenskjold's expedition, Dus6n has recognized 

 a species of Fagus and an Araucaria like A. hrasiliensis. (Schwe- 

 dische Sudpolar. Exp., Bd. Ill, Lief 3, 1908.) In the light of this 

 discovery the range of the living species of these genera acquires an 

 importance for the student of the Antarctic hypothesis. The dis- 

 tribution of the beech trees is a particularly interesting one, for on 

 the principle of Antarctic extension it is simple and intelligible, but 

 without it is complicated and inexplicable. 



This genus Fagus, sensu latu, has two representatives in Europe, 

 one in North America, and several in China and Japan. But in 

 South America there are 11, in New Zealand 7, and in Tasmania 

 with Australia 3. The northern forms are deciduous, but with 

 one or two exceptions the southern are evergreen. The genus 

 being a natural one is certainly not of polyphyletic origin, and the 

 question before us is, from what center of migration has it spread? 

 Did the southern species radiate from the south or converge from the 

 north ? It is a strong argument for a southern origin that the bulk 

 of the species are southern. Again, the evergreen state is primitive, 

 the deciduous derived, and this indicates that the northerners are 

 offshoots from an evergreen stock. Thirdly, the southern species 

 more closely resemble each other than any northern does any southern 

 form. Even, as Mr. Rodway (Proc. Austr. Assoc. Adv. Sci., 1912) 

 points out, the same parasite aflSicts Tasmanian and South American 

 trees. This agrees better with radiation from the south than with 

 convergence from the north. 



Another aspect of Antarctic distribution is presented by the genus 

 Araucaria. None of the 15 existing species reach the Northern 

 Hemisphere, so the complication of a boreal factor is absent. It is 

 chiefly subtropical and characterizes a zone external to that of Fagus. 

 In South America there are three species, in New Caledonia eight, in 

 Norfolk Island one, in New Guinea one, and in Australia two. The 

 latter pair are unlike each other, but one, A. hidwiUi, from Queens- 

 land, stands very close to the Chilean A. imbricata. This indicates 

 that the genus had already differentiated almost to its present 



