84 PROCEEDINGS OF THE 



hirtls, platyrhine monkeys, hystricomorph rodents, edentates, or 

 notoiinguliites. Dr. von Jheritig explains (Trans. N.Z. Inst. xxiv. 

 1891, J). VM ; and X. Jalirb. f. iMineralogio, &c. Beil.-Bd. xxxii. 

 1911, p. 170, pi. V.) that two former subcontinents, of late 

 niesozoic or early tertiary age, are now fused in the present South 

 America. Before the rise of the Andes these were separated 

 from each other by a broad sea and maintained distinct fauna and 

 flora. The southern tract, which he calls " Archiplata," comprised 

 what is now Chili, Argentina, and Southern Brazil. The 

 northern area, called " Archiguyana," embraced Xorthern Brazil, 

 Venezuela, and Guiana. 



It was from Archiplata that the last phase of Antarctica had 

 its American derivatives, and that at a time when many forrcs 

 now regarded as typically South American had not yet reached 

 Archiplata. Not until after Antarctica was i-eh^ased from 

 Archi|)lata did the latter join Archiguyana, and then the southern 

 fauna sufft^red the usual fate from the incursion of the more 

 highly organised northern types. 



3. The Austeal Fauna and Flora. 



More space than is here available would be required to 

 enumerate the Antarctic refugees in austral lands. A few of the 

 more striking instances are now selected. 



Recent marsupials are restricted to Australasia and to the 

 Americas, the monotremes to the former. It seems to have been 

 assumed generally that marsupials necessarily had a Eui'opean 

 origin and travelled across Siberia to North America. A shorter 

 connection between Western Europe and South America by way 

 of Archhelenis is at any rate worth debate. Had the entry to 

 Australia been by the Malay Archipelago, as opponents of the 

 Antarctic hypothesis advance, then stragglers by the way should 

 have lingered in the East Indies. In Australasia marsupials and 

 monotremes are least developed in the north ; proceeding south- 

 wards more groups successively appear till ultimately Tasmania 

 has, as Professor Spencer expressed it, " a condensation of most 

 that is noteworthy in the Australian region" (Spencer, Proc. Austr. 

 Assoc. Adv. Sci. 1892, p. 106). Indeed, the most convincing 

 proof of the Antarctic theory is the fact that in Australasia the 

 South American affiuities regularly increase as Tasmania is 

 approached and there attain their maximum. Those who 

 deny marsupial migration across Antarctica are obhged to 

 assume that the Thylacinida? were independently evolved in each 

 hemisphere. That Tasmania was the point of entry is supported 

 by the discovery in Tasmania of the earliest fossil Australian 

 marsupial. This, Wi/nyufdia bassiana, is apparently one of the 

 Phalangeridae, but the unique example is too imperfect for 

 positive identification (Spencer, Proc. Zool. Soc. 1900, p. 776). 



