Xll CONTENTS. 



PAGE 



§8. "Body" versus reproductive cells, and the continuity 

 of the latter. 



Owen. 



Hoeckel. 



Rauber. 



Brooks. 



Jager. 



Galton. 



Nussbaum. 

 § 9. Weismann's theory of the continuity of the germ-plasma. 



CHAPTER VIII. 

 The Egg-Cell or Ovum ..... 97-108 



§ I. Structure of ovum — 



Cell-substance and protoplasm. 



Nucleus and chromatin. 

 §2. Growth of ovum — 



Transition from amoeboid to encysted phase. 

 § 3. The yolk- 

 Its threefold mode of origin. 



Its diffuse, polar, or central disposition. 



Resulting influence on segmentation. 

 4. Composite ova. 

 § 5* Egg-envelopes — 



((/.) From ovum itself. 



{b.) P'rom surrounding cells. 



(f. ) From special glands. 

 § 6. Birds' eggs — 



Concrete illustration of facts and problems. 

 § 7. Chemistry of the ovum — 



Its capital of anastates. 

 § 8. Maturation of ovum — 



Occurrence, formation, history of polar globules ; 

 parthenogenetic ova. 

 § 9. Theories of polar globules — 



1. Minot, Balfour, Van Beneden, &c. 



2. Biltschli, Hertwig, Boveri, i\:c. 



3. Weismann. 



CHAPTER IX. 



The Male-Cell OR Sperm ..... 109-116 



§ I. General contrast between sperm and ovum — 



An index to contrast between male and female. 

 §2. History of discovery — 



(a.) Hamm and Leuwenhoek. 



{/^) Animalculists. 



(<:. ) Classed as Entozoa or parasites. 



(^/. ) Kolliker's demonstration of cellular origin. 



