Vlll 
PREFACE 
for allowing me to reproduce two of their beautiful oroscopic 
maps, while the council of the Royal Irish Academy, Prof. 
Osborn, Dr. von Ihering, Dr. Ortmann, Mr. Thompson Seton, 
Dr. True and Dr. Hornaday were good enough to give me 
permission to copy maps illustrating their works. 
I can scarcely hope that all the conclusions I have arrived 
at in this book will be readily accepted, but I trust to have 
succeeded in impressing those who have not made a serious 
study of the science of geographical distribution of animals 
with the profound importance of the subject as an aid to 
palaeogeographical researches. 
R. F. S. 
Tudor House, 
Dundritm, Co. Dublin, 
November 2Wi, 1911. 
