PREFACE. 



TN this volume I have attempted to give the principal 

 -*- facts and conclusions of Zoogeography, without an 

 undue profusion of detail. A few examples only have 

 been selected to illustrate the principles. As far as 

 possible I have endeavoured to use instances that have 

 not been made use of by Mr Wallace in his two works 

 upon this subject. I have taken Kerguelen Island and 

 Fernando Noronha as examples of oceanic islands; the 

 facts of distribution and the inferences to be drawn are 

 illustrated largely by the earthworms; and in other 

 places I have availed myself of some of the more recent 

 sources of information. Naturally a large portion of this 

 book, as must be the case with any book upon Geographical 

 Distribution, is based upon the two indispensable treatises 

 of Mr Wallace. I have also found great assistance in 

 Prof. Heilprin's work upon Distribution in the Inter- 

 national Scientific Series, and in an excellent manual 



