14 INTRODUCTION 
sees in it a reflection of the difference between the 
two forests, which interests the other less, and only 
incidentally. 
REFERENCES. A realization of the connexion between the study of 
the facts of animal distribution and the general theory of evolution may 
best be obtained from Darwin’s Origin of Species and Wallace’s Dar- 
winism. Wallace’s classical work on Geographical Distribution (two vols., 
London, 1876) should also be consulted. An interesting discussion of 
the purely geographical standpoint will be found in the chapters on 
animal geography in de Martonne’s T’raité de Géographie Physique (Paris, 
1909), which gives copious references. 
