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PREFACE. 



The present work is an attempt to collect and summarize the 

 existing information on the Distribution of Land Animals; 

 and to explain the more remarkable and interesting of the 

 facts, by means of established laws of physical and organic 



change. 



The main idea, which is here worked out in some detail for 

 the whole earth, was stated sixteen years ago in the concluding 

 pages of a paper on the " Zoological Geography of the Malay 

 Archipelago," which appeared in the Journal of Proceedings oj 

 the Linnean Society for 1860 ; and again, in a paper read before 

 the Eoyal Geographical Society in 1863, it was briefly sum- 

 marized in the following passage : — 



"My object has been to show the important bearing of 

 researches into the natural history of every part of the world, 

 upon the study of its past history. An accurate knowledge of 

 any groups of birds or of insects and of their geographical dis- 

 tribution, may enable us to map out the islands and continents 

 of a former epoch,— the amount of difference that exists be- 

 tween the animals of adjacent districts being closely related 

 to preceding geological changes. By the collection of such 

 minute facts, alone, can we hope to fill up a great gap in the 



