HISTORICAL DEVELOPMENT OF THE CONCEPT 9 



was based upon the idea of the uniformity of the i)hysiological re- 

 sponses of the important animals in the community (1914, a, b, c; 

 1915). However, this physiological basis for community classifica- 

 tion was found to be impracticable because of the lack of response 

 data, and the plan was ai)andoned as not yet susceptible of clear 

 expression. 



Enderlein (1908). Enclerlcin followed Dahl in employing the term 

 biocenose for a wide range of communities, and fui'ther adopted the 

 latter's grouping on the basis of habitats. However, he departed from 

 Dahl's usage by distinguishing areas of more or less unrelated biocen- 

 oses as biosynecies or biosynecic districts, a departure criticized by 

 Dahl in the same year as unwarranted (1908). Enderlein regarded 

 the occurrence of a species in a single biocenose or its extension over 

 two or more as marking a significant distinction, designating the one 

 as homocene, the other as heterocene. The same concept was extended 

 to the biosynecie, for which corresponding terms, stenotope and eury- 

 tope, were proposed. Upon this basis, four groups of species were 

 recognized in accordance with their occurrence in one or more of both 

 types of community: for example, stenotope-homoccne, found in but 

 one biocenose and one biosynecie; stenotope-heterocene, present in a 

 single biosynecie but in two or more biocenoses. These distinctions 

 seem not to have been applied by the author himself in his studies of 

 the insects of moor and dune in west Prussia, though stenotope and 

 eurytope have been utilized in a small degree, while the distinction 

 between biocenose and biosynecie appears to have dropped from view. 

 In fact, the extensive account of the distribution of insects is based 

 upon taxonomic groups and not upon communities, though the com- 

 position of the plant cover is discussed as a background. 



France (1913). France has advanced the concept of the edaphon, 

 as the counterpart of the plankton, comprising under this term the 

 community of the permanent animal and plant organisms of the soil 

 (geobionts). This consists of the most varied types, but ones mutually 

 tolerant and thus able to hold their own; they are distinguished by a 

 number of adaptations and an entirely distinct and peculiar mode of 

 life. 



The habitat of the edaphon is characterized by a more or less 

 complete absence of light, periodic limitation of moisture by drought 

 or frost, and an excess of nitrogen. The groups of organisms regarded 

 as belonging to the edaphon are as follows: (1) bacteria, (2) fungi, 

 (3) algae, (4) Protozoa, (5) Rotatoria, (6) worms, (7) arachnids. The 

 inclusion of mycorhiza and earthworms was said to require further 

 consideration, while the subterrene mammals, insect larvae, and rooted 

 plants were ruled out of the communal life. 



Vestal (1913-1914) . In connection with the successional study of 

 a sand prairie in Illinois, Vestal has tested the assumption that plant 

 and animal associations are coextensive and to a large degree inter- 

 dependent, the animals being entirely dependent upon the plants and 

 the latter partly so upon the animals. In such case, the limits of the 

 animal community are those of the i~)lant association, and both may be 

 spoken of as a single biotic community, composed of plant and ani- 



