420 



ISLAND LIFE. 



[PAKT. II. 



tbose which have been more or less secured by their isolated 

 position from the incursions of the more highly-developed 

 forms of later times. This explains why it is that the nearest 

 allies of the Madagascar fauna and flora are now so often to be 

 found in South America or Australia — countries in which low 

 forms of mammalia and birds still largely prevail ; — it being on 

 account of the long-continued isolation of all these countries 

 that similar forms (descendants of ancient types) are preserved 

 in them. Had the numerous suggested continental extensions 

 connecting these remote continents at various geological periods 

 been realities, the result would have been that all these interest- 

 ing archaic forms, all these helpless insular types, would long 

 ago have been exterminated, and one comparatively monotonous 

 fauna have reigned over the whole earth. So far from explain- 

 ing the anomalous facts, the alleged continental extensions, had 

 they existed, would have left no such facts to be explained. 



