AN EXPERIMENTAL STUDY OF THE BEHAVIOR 



AGREEMENT AMONG THE ANIMALS OF AN 



ANIMAL COMMUNITY. 



, 



VICTOR E. SHELFORD. 



PAGE. 



I. Introduction 294 



II. Material 295 



III. Reactions to Current 297 



1. Methods 297 



2. Specific Peculiarities of Reaction in Water Current 298 



3. Method of Reading 300 



4. Progress up Stream '. 300 



5. Typical Results 300 



IV. Reactions to Bottom 304 



1. Methods 304 



2. Specific Peculiarities 305 



3. Typical Results 306 



4. Reaction to Stones 307 



V. Reactions to Light 308 



1. Specific Peculiarities and General Results of Preliminary Experi- 



ments 308 



2. Method of Show Te^ts and Typical Results 310 



VI. Summary and Discussion 312 



I. INTRODUCTION. 



On the basis of literature, naturalistic observation, and pre- 

 liminary experiments the writer has several times stated ('13) 

 that a physiological agreement exists among the animals of 

 animal communities. The object of this investigation was to 

 determine the extent and character of such agreement with 

 particular reference to the rapids community of a large creek. 

 It is the purpose of this paper to show that, considering the 

 community as a whole, there is (i) a general agreement in reactions 

 to certain factors, (2) disagreement in respect to factors differing 

 in intensity vertically and (3) a sharp difference between different 

 communities. 



The rapids community was selected for detailed study because 

 it was anticipated that the animals were governed mainly by 



294 



