54 University of California Publications i)i Zoology. [Vol. 4 



PAGE 



Seizing parts of the starfish 78 



Independent reactions and transmission of stimuli 79 



Influences determining variation and modification of reactions in the 



pedicellariae 82 



Capture of food 84 



Introductory 84 



Typical case of food capture 85 



Animals used as food 87 



Combat between starfish and sea urchin 88 



Capture of large living fish _ 89 



Nature of stimuli causing the food reaction 91 



Food pulled away from pedicellariae by the tube feet 92 



Feeling about in search of food 93 



Conveying food to the mouth 93 



Action of the stomach in taking food 94 



Behavior of the starfish in selecting the conditions of existence 94 



Introductory; necessity of selecting proper environmental conditions 94 



Exploratory movements 95 



Adaptiveness of the movements 96 



Current erroneous explanation of the negative reaction 96 



Method of locomotion in the starfish; erroneous current view 98 



Three classes of protective reactions 101 



Eeaction to light 102 



Movement away from the light 103 



General stimulating effect of increased light 104 



Movement toward darker regions, and coming to rest in the shade.... 104 



Direction of rays versus differences in illumination 105 



Position taken when confined in a uniformly illuminated field 108 



Effect of light on the righting reaction 110 



Vision in the starfish? 110 



Positive reactions 113 



Factors determining the nature and variations of the reactions to 



given external stimuli 114 



Interaction and interference of stimuli 114 



Effects of position of the body 115 



Persistence of impulse to move in a certain direction 115 



Effect of previous stimuli 117 



Effects of physiological condition; reaction to situation as a wdiole 118 



The righting reaction 120 



Previous work 121 



Variability (Preyer) 121 



Driesch 's formulation 122 



Plan of present account 123 



Designation of the rays 123 



Variability 125 



Different types of the reaction 125 



