CONTENTS 



PAGE 



XVI. Analysis of the Original Method of Producing Arti- 

 ficial Parthenogenesis by Hypertonic Solutions 

 Alone - - 159 



XVII. Membrane Formation and Cytolysis ... 173 



XVIII. The Fertilizing Effect of Foreign Blood and Foreign 



Cell Extracts - 191 



XIX. The Fertilizing Effect of Sperm Extract - - 201 



XX. The Mechanism of the Formation of the Fertilization 



Membrane - - 207 



XXI. Is Development of the Sea-Urchin Egg Possible with- 

 out Membrane Formation or without the Second 

 (Corrective) Factor? - 219 



XXII. The Action of the Spermatozoon upon the Egg. I. 



Heterogeneous Hybridization - 225 



XXIII. The Action of the Spermatozoon upon the Egg. II. 



The Combination of Artificial Parthenogenesis and 

 Fertilization with Sperm in the Same Egg - 233 



XXIV. Conditions for the Maturation of the Egg - 243 

 XXV. Artificial Parthenogenesis in the Eggs of the Starfish - 249 



XXVI. Artificial Parthenogenesis in the Eggs of Annelids - 257 



XXVII. Experiments with the Eggs of Molluscs - - 267 



XXVIII. Artificial Parthenogenesis in the Eggs of Frogs - - 271 



XXIX. Artificial Parthenogenesis in Plants - - 277 



XXX. Preservation of the Life of the Egg by the Act of 



Fertilization - - 281 



XXXI. Artificial Parthenogenesis and Heredity - - - 291 

 XXXII. Can an Embryo Develop from a Spermatozoon ? - 303 



