36 Herbert Eugene Walter 



B In changing directive light 87 



Changes in intensity 87 



Changes in direction 88 



Summary go 



C In combination with other responses 89 



Geotaxis 00 



Thigmotaxis 02 



Goniotaxis 04 



Chemotaxis q4 



Summary 06 



3 Kinds of behavior 07 



A Generic and specific behavior 08 



Percentage of negativeness 98 



Character of the course in directive light 09 



Duration of movement 105 



Degree of wandering 106 



Rate of locomotion 107 



Time requited to leave a unit circle 107 



The effects of fatigue 1 08 



Responses to changes in intensity 109 



Manner of coming to rest 1 10 



Summary no 



B Individual behavior in 



Rate on successive days 112 



Relative value of individual behavior n3 



A cave planarian 114 



Summary 116 



{Pages Iiy to 162 are printed in vvl. v, no. 2) 



4 Basis of behavior 117 



A Morphological basis of behavior 117 



a General form of the body 118 



h Photoreceptors 122 



Summary 127 



B Physiological basis of behavior 128 



a Classification of physiological states 129 



h Changes in physiological states induced by light 130 



Effect of different intensities 130 



Effect of excessive light 131 



Effect of sudden change in light conditions 131 



Effect of continued exposure to light 131 



Effect of previous exposure to dark 132 



Summary 133 



C Psychological basis of behavior 134 



a How much can planarians see ? 134 



h Are planarians able to learn ? 135 



Summary 138 



