EXCERPTS FROM THE ORIGINAL PREFACE 



When I finished my essay on "The Ecological Foundations of 

 Animal Distribution" which appeared in Hettner's Geographische 

 Zeitschrift (1913) I had thought to turn to other work, but this mate- 

 rial had fascinated me and I could not leave it. So, after twelve 

 years of steady work, which was not completely interrupted by twenty 

 months of army service, I offer this book to the friends of zoogeog- 

 raphy, hoping for a favorable reception. 



For the first time an exposition of animal geography is presented 

 which gives approximately equal space to the animal life of the sea, 

 of fresh water, and of land. There is an understandable demand for 

 such treatment, but the material to be mastered before this is possible 

 is very extensive. Since the founding of the Zoological Station at 

 Naples, there have been opened an increasingly large number of 

 marine biological research stations, and the great expeditions for the 

 exploration of marine life in which almost all civilized nations have 

 participated have resulted in the collection of a mass of material 

 almost too great for mastery. Researches upon animal life in fresh 

 water have also come into the foreground in all civilized countries. 

 These sources have yielded results of practical importance for the 

 promotion of fisheries as well as of significance for theoretical biology. 



Ecological animal geography is a young science, and its presenta- 

 tion cannot result in so clear a picture as, for example, the classical 

 "Lectures on Comparative Anatomy" of Butschli. In this new field 

 the fundamental questions are yet to be formulated , in order that a 

 rich phase of biology may be opened for further work. I hope this 

 book may be thought of as such an attempt; it deals largely with 

 problems which are taken up separately and arranged in order, and 

 but relatively little space is given to presenting satisfactory solutions. 

 Such treatment does show that the problems of ecological animal 

 geography are capable of exact solution and indicates further in what 

 direction, through observation and experimentation, the solution is to 

 be sought. I hope that this treatment will stimulate further expedi- 

 tionary researches in this field. We have had an over-supply of travel 

 which yielded animal pelts and alcoholic material; we need rather 

 observations on the relations between animals and their environment. 



I have been almost frightened by the accumulation of animal 



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