PHYSIOLOGICAL ANIMAL GEOGRAPHY Dae 
The materials of animal geography may be roughly classified 
into fact and interpretation. Interpretations have been related 
to genetic or historical geography, fields in which speculation 
has been common. Since the methods employed and the con- 
clusions reached are quite familiar, we will take up the discussion 
so far as possible, from the point of view of facts. 
The facts of animal geography fall under two main heads: 
(a) facts concerning the structural and the taxonomic differences 
and resemblances of the animals of different parts of the world, 
and (b) facts concerning the physiological and ecological charac- 
ters of animals which enable them to live under the geographic 
conditions in which they are found, and the effect of geographic 
environments upon their behavior, physiology, and mode of life. 
The former is what is commonly known as faunistic animal 
geography, the field in which nearly all the InvesHee won has 
been concentrated. 
1. FAUNISTIC ANIMAL GEOGRAPHY 
a. Point of view. The point of view is essentially that of 
speculative evolution, of the evolution of animal groups and of 
the evolution of barriers and land masses as related to the dis- 
tribution and dispersal of animals from the supposed centers of 
origin (Wallace, ’76; Osborn, ’02). The subject is even more 
strongly committed to speculative evolution than any other 
phase of biological science. 
The study of so many phases of biology from the point of view 
of an inadequate conception of evolution, which has been so prev- 
alent during the past forty or fifty years, has probably materially 
retarded the unification and progress of biological science as a 
whole. In the case of the geographic aspect, the damage done 
is quite beyond repair, for the great mass of ecological data accu- 
mulated during that period has not been preserved and the condi- 
tions which make such observations possible have passed away, 
too frequently forever, before the hand of civilization (Haddon, 
03; Webb, ’03). | 
