X CONTENTS. 



Pages 

 Volvox. — Difference between a pluricellular organism and 

 a colony of unicellular organisms. — Voluntary combina- 

 tions. — The Bodo caudatus 53"6i 



V. 



THE PSYCHOLOGY OF PROTO-ORGANISMS. 



Remarks upon the psychology of Micro-organisms. — Their 

 various actions are direct responses to stimuli from the out- 

 ward world. — Perception of external bodies. — Choice. — 

 Calculation of the positions occupied by external bodies. 

 — Movements of Micro-organisms ; . . . 61-65 



VI. 



FECUNDATION. 



Fecundation among Infusoria. — Historical. — Psychological 

 preliminaries of fecundation — Observations of M. Bal- 

 biani upofl the Paramaecia, the Spirostomes, and the Sten- 

 tors. — Copulation. — Fecundation among the Vorticels. — 

 Observation of Engelmaun. — Material phenomena in fec- 

 undation. — The role of the nucleus, and the role of the 

 nucleolus. — Description of the phenomena as seen in the 

 Chilodoii cucullulus (see appendix), the Paramecium bursa- 

 ria and in the Parami^cium aurelia. — Observation of M. 

 Balbiani upon Paramaecia, of which the nucleus is overrun 

 with parasites 65-75 



FECUNDATION IN HIGHER ANIMALS AND PLANTS. 



Fecundation in higher animals and plants. — The spermato- 

 zoid and the ovule can be compared to Micro-organisms. — 

 The elements can live for a certain time independent of 

 the animals from which they come. — Their motor organs. 

 — The movements of the spermatozoid towards the ovule. 

 — Length of road to be traveled. — Obstacles to be over- 

 come. — Windings and intricacies of the path. — The sper- 

 matozoid of the silk-worm. — Arrival of the spermatozoid in 

 contact with the ovule. — Obsi'j-yation of Fol upon the 

 fecundation of the star-fish. — The cone of attraction. — 



