CONTENTS. XIX 



CHAPTEE XIII. Page 



Geneagenesis. — First Phenomena of Geneagenesis dis- 

 covered in Animals. — Agamic Generation (Aphides). 

 — Reproduction by Fissuration and by Gemmation 

 (Polyps, Hydras, Compound Ascidians) 124 



CHAPTER XIV. 



Discovery of Alternate Generation (Salpse and Medusae) 145 



CHAPTEE XV. 



New Explanation of Facts long known 157 



CHAPTEE XVI. 

 Geneagenetic Phenomena in Annulosa and Mollusca ... 166 



CHAPTEE XVII. 

 Geneagenetic Phenomena of Eadiata 172 



CHAPTEE XVIII. 



Geneagenesis in the Helminthes or intestinal Worms. — 



Spontaneous Generation 201 



CHAPTEE XIX. 

 Theory of Geneagenesis 219 



