92 VICTOR E. SHELFORD. 



'i I, p. 523). Abbot ('70, p. 104) makes a similar statement about 

 fish. It is apparent then that one species may have several 

 mores (Bohn, '10 et al.)- Different species may sometimes have 

 identical mores; these cases are usually separated geographically 

 (Shelford, '11, p. 32; 'n 2 , p. 147; 'n 4 , p. 604). In addition to 

 these relations, the relation of ecology to species is largely a matter 

 of language, names being necessary as a means of referring to 

 animals. 



Animal ecology has very much in common with plant ecology. 

 Diatoms, flatworms and many other marine animals and plants 

 meet the same conditions in the same or similar ways (Loeb, '06, 

 p. 121 ; Bohn, '10, p. 156; Holmes, 'n, p. 155). Sessile animals, 

 such as reef-forming corals, show growth form differences (Woods- 

 Jones, '10) under different conditions, just as sessile plants do. 

 Comparable plants and animals show comparable responses. 

 The physiological life history aspect of plant ecology (Ganong, 

 '07) is parallel with the same phenomenon in animals, but the 

 activities of motile animals correspond roughly to the growth- 

 form phenomena in sessile plants (Shelford, 'i I 4 , p. 593). Results 

 of study of the environment are equally applicable to plants and 

 to animals. Since mores and growth-form are correlated with the 

 environment much progress can be made by the study of the en- 

 vironment; in fact, study of the environment is necessary for 

 progress. 



On the other hand the study of the environment must be ac- 

 companied by experiments designed to determine the relative 

 importance of the different factor to animals, or the results, like 

 so many of our meteorological records, will prove to be of ques- 

 tionable value for the purpose for which they are intended. In 

 the case of the forest animal communities which we have studied, 

 experiments must be undertaken to determine the physiological 

 relations of animals to materials for abode, soil moisture, light 

 and the condition of the atmosphere before the subject can pro- 

 gress beyond the suggestive stage which this paper necessarily 

 represents. 



Ecology or ethology of single isolated species is a very old 

 branch of biological study. The developments of the last 

 twenty years have been in the direction of organization of these 



