xii • CONTENTS 



CHAPTER IX P.,oE 



The Morphology of the Chromosomes 114 



Size and general form — Spindle-attachment region — Nucleolus-forming 

 region — Other specialized regions — The chromosome complement — Arrange- 

 ment of chromosomes in the mitotic figure — Chromosome complements in 

 related organisms. 



CHAPTER X 



The Structure of the Chromosomes 132 



Chromonema theory — The mitotic cycle — Slender and small chromosomes — 

 Chromonemata in sporocytes — Alveolation theory — Chromomere theory — 

 Chromomeres in the chromonema — Chromosome structure and the gene 

 theory — Continuity of the chromosome. 



CHAPTER XI 



The Achromatic Figure 149 



Anastral figures — Amphiastral figures — Mechanism of mitosis. 



CHAPTER XII 



Cytokinesis and the Cell Wall 165 



Furrowing in plants — Furrowing in animals — Cytokinesis by cell-plates — 

 Cell wall^Composition of the cell wall — Ultramicroscopic structure of 

 wall — Walls of spores — Cell membranes of animals. 



CHAPTER XIII 



Atypical Mitosis and Other Nuclear Phenomena 183 



Amitosis — Induced aberrations of mitosis — Karyosome nuclei — Blue-green 

 algse — Bacteria — Chromidia. 



CHAPTER XIV 



Gametogenesis and Sporogenesis 196 



Alga) — Fungi — Bryophytes — Pteridophytes-^Gymnosperms — Angiosperms 

 — Oogenesis in animals — Spermatogenesis in animals — Structure of other 

 ciliated cells. 



CHAPTER XV 



Syngamy 226 



Plants: Algae — Fungi — Bryophytes and Pteridophytes — Gymnosperms — 

 Angiosperms. Animals: Nucleus — Centrosome — Cytoplasm and chondrio- 

 somes — Conjugation and endomixis — Physiology of fertilization — Con- 

 clusion. 



CHAPTER XVI 



Meiosis 250 



Stage of life cycle at which meiosis occurs — Preliminary sketch — Detailed 

 description — Disjunctional and equational division — The chiasma — The 

 synaptic reaction — Meiosis in lower organisms — Conclusion. 



CHAPTER XVII 



Chromosomes and Mendelian Heredity 284 



Development and heredity — Role of the nucleus — Examples of Mendelian 

 heredity — Terminology — Cytological basis of Mendelian heredity — Linkage 



