504 VICTOR E. SHELFORD 
b. History. The history (Ortmann, 796) of faunistic animal 
geography is largely that of the ideas of regions, centers of dis- 
persal, barriers, ete. The only recent writer who has advanced 
other ideas is Seitz (’91), who called attention to the resemblances 
of the forms of similar habitats in different parts of the world 
(Beddard, ’95). 
2. PHYSIOLOGICAL ANIMAL GEOGRAPHY 
a. Point of view. There are two distinct points of view for 
biological investigation. One is that of evolution; the other, that 
of physiology, or the explanation of the organism in terms of 
physics and chemistry. One may make a physiological explan- 
ation of the behavior or structure of an organism and in no wise 
explain its evolution. On the other hand one may make an evo- 
lutionary explanation of an organism without making any con- 
tribution to its physiology. The study of physiological animal 
geography may be conducted independently of the problems of 
evolution. It does not need to be concerned with centers of 
origin, or paths of dispersal, or with other problems of faunistic 
animal geography. In this paper we are concerned solely with 
the physiological relations of animals to natural environments. 
b. History. Crude expression of some of the ideas which 
should be included in this subject is no doubt as old as biology 
itself. From the standpoint of particular taxonomic groups, 
various writers on natural historyy ecology, behavior and physi-* 
ology have from time to time touched upon the relation of habits, 
ecology, or physiology to geographic distribution of particular 
species (Semper, ’81).2. Ortmann (’07) especially emphasizes 
the importance of a knowledge of the habits as a means of inter- 
preting distribution. Indeed, this is an important principle of 
ecology, and lacks definite formulation rather than recognition. 
From the point of view of all the animals of a given set of 
environmental conditions, Thomson gives the early history 
in his introduction to Brehm (’96). The early observations were 
made by men whom Thomson designates as naturalist travelers 
> Semper brought a large number of these facts together as they existed in 1879. 
