x CYTOLOGY 



PAGE 



4. Which of the two Divisions of the M eiotic Phase effecls 



the Separation of the Homologous Chromosomes f . 54 



5. Synizesis . . . . . .54 



C. MEIOSIS IN THE FEMALE . . . . -55 



1 . The Continuity of the Chromosomes . . -59 



2. The Relation between the Chromosomes ar.d the Nudeoli 62 



3. The Connection between the Germinal Vesicle and Yolk 



Formation . . . . . -63 



4. Does any Stage comparable to the Germinal Vesicle occur 



in Spermatogenesis f . . . . .65 



CHAPTER III 



SYNGAMY, EARLY DEVELOPMENT, PARTHENOGENESIS . . 67 



A. THE DEVELOPMENT OF THE SPERMATOZOON . . .67 



B. SYNGAMY .... .71 



C. GONOMERY ....... 77 



D. THE GERM-TRACK . . . . . -79 



E. PARTHENOGENESIS . . 86 



1. Obligatory Parthenogenesis . . . -87 



2. Facultative Parthenogenesis . . . .91 



3. The Homology of the M eiotic Divisions in Obligatory 



and Facultative Parthenogenesis . . .94 



4. Artificial Parthenogenesis . -94 



CHAPTER IV 



THE SEX CHROMOSOMES . . . . . -98 



1. The Sex Chromosomes in Insects . . .98 



2. Which of the two M eiotic Divisions acts as the Reduction 



Division for the Sex Chromosomes ? . . .102 



3. Various Forms of the X and Y Chromosomes . .104 



4. Behaviour of the Sex Chromosomes during Syndesis and 



the M eiotic Prophase, and outside the M eiotic Phase . 1 06 



5. Sex Chromosomes in Animals other than Insects . 109 



6. Cases where the Differential Sex Chromosome is present 



in the Female . . . . . 1 1 1 



7. Some Special Life Histories . . . 113 



8. 77?^ Relation between the Sex Chromosomes and the 



Determination of Sex . . . .121 



