MODIFICATION OF THE BEHAVIOR OF LAND ANIMALS 49 



great care necessary in the preparation of each current control. 

 The modification of behavior in gradients here discussed, has 

 been made evident solely by the graphic method of recording 

 the movements of the animals. It is quite possible that appli- 

 cation of similar methods to reactions to gradients generally, 

 may show that such modification is the rule, from the more simply 

 organized animals upward. 



ACKNOWLEDGMENTS AND BIBLIOGRAPHY 



The writer is indebted to Dr. Harvey A. Carr and Mr. M. M. 



Wells for suggestions during the preparation of the manuscript. 



All other literature consulted is cited in Shelf ord and Allee, '14. 



Holmes, S. J. Evolution of Animal Intelligence. Holt. 



1911. 

 Schaeffer, A. A. Habit Formation in Frogs. Jour. Animal Behavior, Vol. I, pp. 



1911. 309-335. 

 Shelford, V. E. and Allee, W. C. The Reactions of Fishes to Gradients of Dis- 



1913. solved Atmospheric Gases. Jour. Expt. Zool, Vol. XIV, pp. 207-266. 

 Shelford, V. E. and Allee, W. C. Rapid modification of the Behavior of Fishes 



1914. by Contact with Abnormal Water. Jour. Animal Behavior, Vol. 

 IV, pp. 1-30. 



Shelford, V. E. Reaction of Certain Animals to Gradients of Evaporating Power 



1913. of Air, with a Method of the Establishment of Evaporation Grad- 

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 Henderson, L. A. The Regulation of Neutrality in the Animal Body. Science 



1913a. N. S., Vol. XXXVII, pp. 389-395. 



1913. The Fitness of the Environment. New York. 

 Loeb, J. Dynamics of Living Matter. 



1906. 

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1911. 



