TERTIARY MAMMAL HORIZONS. 51 



eluding southern Asia and the Malayan islands ; the Malagasy^ 

 including Madagascar ; the Ncarctic and the Palcearctic. There 

 is no question, as suggested by Professor Newton in his term 

 '' Holarctic," and by Professor Allen in 1892, in his term *' North 

 temperate," that the North American (Nearctic) and Eurasiatic 

 (Palaearctic) regions are now so closely similar that they might be 

 united into one. When, however, the zoological or existing char- 

 acteristics of these regions are put to a pala^ontological test it is 

 found necessary to separate them, because throughout the Ter- 

 tiary period North America and Eurasia were so remote that, to a 

 certain extent, they constituted centers, not only of independent 

 family, but to a limited degree of ordinal radiation. At the same 

 time they were unified, both by frequent intermigrations and by 

 a simultaneous evolution of allied animals. 



The Continent Antarctica 



We now come to one of the greatest triumphs of recent bi- 

 ological investigation, namely, the concurrence of botanical, 

 zoological and palaeontological testimony in the reconstruction of 

 a great southern continent to which the name Antarctica has been 

 given. Following Blanford ('90), Eorbes ('93) made the first 

 strong plea for this continent. The flood of evidence for the Ant- 

 arctica theory has now become so strong that only a few details 

 can be mentioned: Forbes ('93) and Milne-Edwards from 

 the consideration of the birds ; Beddard from the study of 

 worms and other invertebrates ; Moore from the study of the 

 flora of South Africa ; Spencer from the study of the fauna 

 of Australia; Ameghino, Hatcher and Ortmann from studies 

 and collections of vertebrate and invertebrate fossils in Pata- 

 gonia not yet fully published ; Moreno, from the disc oveiy of 

 Miolania, an Australian fossil reptile recently found in South 

 America ; from these and many other sources has been brought 

 fourth the body of testimony which draws us almost irresist- 

 ibly ^ to the conclusion that there was an antarctic continent 

 at various times connecting South America, South Africa, Aus- 



^ After discussing the evidence with great fairness Lydekker ('96), takes a 

 more conservative position. 



