314 GEOGRAPHICAL DISTRIBUTION 



liere to go much into details.^ The question, often mooted, of 

 recognizing a distinct Circumpolar Region need not be discussed, 

 for it has not become practical ; and whatever ma}' be the case 

 as regards other Classes, it seems almost impossible for the orni- 

 thologist reasonably to refuse recognition, as regards Birds, of the 

 .s^a; Geographical Regions — New- Zealand, Australian, Neotropical, 

 Holarctic, Ethiopian, and Indian, brigading, if he so please, the 

 first three as Notogxa, and the last three as Ardogssa, but always 

 bearing in mind that the differences between each of the component 

 parts of the former, and especially the differences between New 

 Zealand and all the rest of the world, are not only more striking, 

 but far more essential than those presented b}^ the component parts 

 of the latter. 



It is admitted by nearly all naturalists that the study of the 

 extinct organisms of any country leads the investigator to a proper 

 appreciation of its existing Flora or Fauna : while on the other hand 

 a due consideration of the plants or animals which predominate 

 within its bounds cannot fail to throw more or less light on the 

 changes it has in the course of ages undergone. That is to say, 

 the Distribution of living creatures in Time is so much connected 

 with their Distribution in Space that the one can hardly be con- 

 sidered without the other. Granting this as a general truth, it 

 must yet be acknowledged as a special fact already foreshadowed 

 Avhen treating of FossiL Birds, that we at present have in them 

 but scanty means of arriving at precise results which would justify 

 bold generalization as regards the Distribution of the Class. Com- 

 pared with other Vertebrates, fossil remains of Birds are exceedingly 

 scarce, and have been until lately little investigated. However 

 suggestive be the discovery in Finance of somewhat early remains 

 of Birds allied to those which we at present only know as living 

 denizens of tropical countries, and the recognition of far later 

 remains of species identical Avith those that now flourish in arctic 

 lands, these facts merely corroborate what is from other sources 

 within the cognoscence of every geologist — the vicissitudes, namely, 

 to which that part of Europe has been subjected. Even the former 

 existence of Ratita^ in England and other countries Avhere they are 

 not now found only proves that they were once not confined to their 

 present limits, and possibly pervaded the greatest part of the earth. 

 Almost the same is to be said of every other case, and perhaps in 

 the whole range of zoology there is no Class from the fossil 

 remains of which we learn less as regards the physical history of 

 oui" planet than we do from the Birds. We therefore have to turn 

 to the other side of the question and try to find whether the 



1 Prof. Heilprin has stated {loc. primo cit.) the probability that "portions 

 of Californi;i, Texas, and Florida -will have to be relegated to the Neotropical 

 realm." Mexico would naturally follow ; but hereon more will be said hereafter. 



