xii CONTENTS. 



Pages 

 Romanes's conception of the psychic activity of Proto- 



organisms , . . , 105 



Irritability and cellular psychology 107-110 



Correspondence between Ch. Richet and Alfred Binet, ap- 

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

 printed from THE OPEN COURT of December 27, 1888.110-115 



APPENDIX. 



Additional cuts illustrative of : 



The Conjugation of the Param&cium awelia 116 



The Conjugation of the Stentor c&ruleus 116 



The Copulation of the Stylonichia mytilus 116 



The Conjugation of the Carcheshtrn polypinum 117 



The Conjugation of the Chilodon cuciilluhts (with explana- 

 tions) 1 18 



Addenda. Notes and References omitted in the text. 121 



