408 THE DISTRIBUTION OF ANIMALS AND PLANTS 



evolution of the Darwinian type is " the key to distribution," 

 he departs widely from any basis of scientific fact. This be- 

 comes apparent when we consider the following results, which 

 appear everywhere in the discussion of the various insular 

 faunas and floras : (i) None of these islands, however remote, 

 can be affirmed to have been peopled by the spontaneous 

 evolution of the higher animals or plants from lower forms. 

 Their population is in every case not autochthonous, but de- 

 rived. (2) Even in those which are most distant from the 

 continents, and may be supposed to have been colonized in 

 very ancient times, there is no evidence of any very important 

 modification of their inhabitants. (3) While the facts point 

 to the origin of most forms of terrestrial life in the Palearctic 

 and Nearctic regions, they afford no information as to the 

 manner or cause of their origination. In short, so far is evo- 

 lution from being a key to distribution, that the whole question 

 would become much more simple if this element were omitted 

 altogether. A few examples may be useful to illustrate this, as 

 well as the actual explanation of the phenomena afforded by 

 legitimate science. 



The Azores are situated in a warm temperate latitude 

 about 900 miles west of Portugal, and separated from it by a 

 sea 2,500 fathoms in depth. The islands themselves are al- 

 most wholly volcanic, and the oldest rocks known in them are 

 of late Miocene age. There is no'probability that these islands 

 have ever been connected with Europe or Africa, nor is there 

 at present any certainty that they have been joined to one 

 another, or have formed part of any larger insular tract. In 

 these islands there is only one indigenous mammal, a bat, 

 which is identical with a European species, and no doubt 

 reached the islands by flight. There is no indigenous reptile, 

 amphibian, or fresh-water fish. Of birds there are, exclusive 

 of waterfowl, which may be regarded as visitors, twenty-two 

 land birds ; but of these, four are regarded as merely accidental 



