XIV CONTENTS. 



CHAPTER XII. 



PAGE 



Theory of Fertilisation ----- 157-168 

 § I. Old theories — 



(a) Ovists, (/>) animalculists, {c) the " anra 

 se/fivialis." 

 § 2. Modern morphological theories — 



{a. ) Nuclei all - important. Hertwig, Stras- 



burger, &c. 

 {d.) Cell-substance also important. Nussbaum, 

 Boveri, &c. 

 § 3. Modern physiological theories — 



Sachs, De Bary, Marshall Ward, &c. 



Cienkowski and Rolph. 



Weismann's view. 



Critique and statement of present theory. 



§ 4. Use of fertilisation to the species — 



(a.) Rejuvenescence — 



Van Beneden and Blitschli. 

 Galton and Hensen. 

 Weismann's critique. 

 (d.) The observations of Maupas. 

 (c.) A source of variation. Brooks and Weismann. 



CHAPTER XHI. 

 Degenerate Sexual Reproduction or Parthenogenesis 169-187 

 §1. Histor}' of discovery. 

 § 2. Degrees of parthenogenesis — 



Artificial, pathological, occasional, partial, sea- 

 sonal, total. 

 § 3. Occurrence in animals — 



Rotifers, crustaceans, insects. 

 § 4. Occurrence in plants — 



Phanerogams and fungi. 

 § 5. The offspring of parthenogenesis. 

 § 6. Effects on the species. 

 § 7. Peculiarities of parthenogenetic ova — 



Weismann 's discovery. 

 § S. Theory of parthenogenesis — 

 Minot and Balfour. 

 Rolph and Strasburger. 

 Weismann. 

 The present. 

 § 9. Origin of parthenogenesis. 

 § 10. Case of bees. 



CHAPTER XIV. 

 Asexual Reproduction - . . . . 188-199 



§ I. Artificial division. 

 § 2. Regeneration. 



§ 3. Degrees of asexual reproduction. 

 § 4. Asexual reproduction in plants and animals. 



