CONTENTS 



CHAP. PAGE 



I. THE CELL ........ i 



Definition The cell theory Protoplasm Fixation 

 and staining. 



II. CELL ORGANS, THE NUCLEUS, MITOCHONDRIA AND 



GOLGI APPARATUS 13 



The nucleus; its functions Nucleo-plasmatic relation 

 Structure of the nucleus Chromatin Mitochondria 

 Golgi bodies. 



III. CELL DIVISION 26 



Amitotic division Mitotic division or Karyokinesis 

 Chromosomes A chromatic spindle Chromosomes in 

 mitosis Cytoplasmic division. 



IV. THE CENTROSOMES, SPINDLE AND ASTERS . . 42 



The centrosome and its origin The achromatic 

 spindle Mechanism of mitosis The spindle and cyto- 

 plasmic division Multipolar spindles. 



V. THE MATURATION OF THE GERM-CELLS; SPER- 



MATOGENESIS ...... 59 



Chromosome reduction Comparison of spermato- 

 genesis and oogenesis Meiotic phase Sperm ato- 

 genesis of Lepidosiren Terminology Origin of 

 bivalent chromosomes Tetrads Segregation of chro- 

 mosomes. 



VI. THE MATURATION OF THE GERM-CELLS (CONTIN- 



UED). THE MATURATION OF THE EGG AND 



THE NATURE OF THE MEIOTIC PHASE . . 74 



The ovarian egg Deposition of yolk Polar divisions 

 Fate of polar nuclei The meiotic pairing of chromo- 

 somes Interpretation of meiosis Chiasmatypy. 



