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 : Eitglena 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 150 



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 179 



3. Food Habits 182 



Literature 187 



PART II 



BEHAVIOR OF THE LOWER METAZOA 



CHAPTER XI 

 INTRODUCTION AND BEHAVIOR OF CCELENTERATA 



Introduction 188 



Behavior of Ccelenterata 188 



1. Action System. Spontaneous Activities 189 



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



3. General Reaction to Intense Stimuli 197 



4. Localized Reactions 198 



5. The Rejecting Reaction of Sea Anemones 202 



6. Locomotor Reactions in Hydra and Sea Anemones 203 



