CONTENTS xi 



CHAPTER VIII 

 Reactions of Infusoria to Light and to Gravity 



PAGE 



1. Reactions to Light 128 



A. Negative Reaction to Light : Stentor caruleus 128 



B. Positive Reaction to Light : Etiglena viridis 134 



C. Negative and Positive Reactions compared 141 



D. Reactions to Light in Other Infusoria 141 



2. Reaction to Gravity and to Centrifugal Force 149 



Literature jcq 



CHAPTER IX 

 Reactions of Infusoria to the Electric Current 



1. Diverse Reactions of Different Species of Infusoria 151 



A. Reaction to Induction Shocks 151 



B. Reaction to the Constant Current 152 



2. Summary .............. 162 



3. Theories of the Reaction to Electricity 164 



Literature 169 



CHAPTER X 



Modifiability of Behavior in Infusoria, and Behavior under 

 Natural Conditions. Food Habits 



1. Modifiability of Behavior 170 



2. The Behavior of Infusoria under Natural Conditions . . . , . . 1 79 



3. Food Habits 182 



Literature ^87 



PART II 



BEHAVIOR OF THE LOWER METAZOA 



CHAPTER XI 



Introduction and Behavior of Ccelenterata 



Introduction 



Behavior of Ccelenterata 



I. Aqtion Systejn. Spontaneous Acti.vities 



2. , Conditions required for Retaining a Given Position : Righting Reactions, etc. . 192 



3. Gejieral Reaction to Intense Stimuli 197 



4. Localized Reactions ............ 



5. The Rejecting Reaction of Sea Anemones 202 



6. Locomotor Reactions in Hydra and Sea Anemones 203 



