CORRESPONDENCE OF CLIMATIC COMMUNITIES 313 



a forest community. In the savanna or prairie climate the marsh 

 margin thicket may become a climatic thicket or forest margin. In the 

 savanna or prairie climate the communities of all the various soils and 

 the low prairie community may converge to the prairie climate com- 

 munity, or to the forest community as is shown below for the forest 

 climate. In the forest climate and locally in the savanna climate the 

 communities of all the various soils pass through a thicket community 

 stage (T), related to a climatic forest. The thicket communities of all 

 the dry soils are related to the forest margin thicket community of the 

 savanna climate. 



I. CORRESPONDENCE OF COMMUNITIES OF DIFFERENT PARTS OF 

 THE WORLD (55) 



The botanists have abundant evidence for the correspondence of 

 the formations of similar climates (580). The vegetation of different 

 parts of the world which have similar climates is similar and the plants 

 though usually belonging to different taxonomic groups are similar in 

 growth, form, and appearance. Correspondence and similarity of 

 vegetation is not limited to the climatic or extensive formations, but 

 applies also to strictly local situations wherever the physical conditions 

 are similar. On the animal side we have less trustworthy evidence of 

 similarity or correspondence. If the physiological similarity occurs in 

 the same community, due, as has just been stated, to selection of habitat 

 and modification of behavior, we conclude that it occurs in all communi- 

 ties occupying similar conditions and that similar situations in different 

 parts of the world have physiologically similar communities, and identical 

 situations approximately identical communities. 



The direct evidences for the correspondence of formations in different 

 parts of the world are as follows : (a) the existence of identical or closely 

 corresponding species has long been known to naturalists (3, 199, 192); 

 (b) similarity of physiological life histories of many species is well known, 

 as, for example, corresponding species in the United States and Europe 

 or Japan, and a general concentration of breeding in the rainy season in 

 all arid climates, etc.; (c) certain animals in similar environments in 

 different parts of the world appear from the accounts of naturalists to 

 behave alike with reference to the physical condition of different parts 

 of the day, year, and different weather. For example, it appears that 

 there is a close physiological and ecological similarity between certain 

 antelopes of the savannas of Africa and certain savanna kangaroos of 

 Australia (200). In other words certain kangaroos are ecologically and 



