xii CONTENTS. 



Pages 

 Romanes's conception of the psychic activity of Proto- 



organisms 105 



Irritability and cellular psychology loy-iio 



Correspondence between Ch. Richet and Alfred Binet, ap- 

 pearing in the Revue Philosophique of February, 1888, re- 

 printed from The Open Court of December 27, 1888.110-115 



APPENDIX. 



Additional cuts illustrative of : 



The Conjugation of the Paramacium aurelia iit6 



The Conjugation of the Stenlor candeus 116 



The Copulation of the Stylonichia mytilus 116 



The Conjugation of the Carchesium polypinuvi 117 



The Conjugation of the Chilodon cucuihdus (with explana- 

 tions) 118 



Addenda. Notes and References omitted in the text 121 



