THE CELL 



57 



daughter centrosome around which they become grouped- In this 

 way are formed two daughter stars, the mitotic figure being known 

 at this stage as the diastcr (Fig. lo, C). These daughter stars are at 

 first connected by the fibrils of the achromatic spindle. In this 

 stage may also occur beginning division of the cell body. In actively 

 dividing cells each centrosome frequently undergoes division at this 

 stage, resulting in four centrosomes to the cell. 



Fig. io. — Diagrams of Successive Phases of Mitosis. 



E, Metaphase. Longitudinal cleavage; splitting of chromosomes to form daughter 

 chromosomes, ep; n, cast-off nucleolus. 



F, Anaphase. Daughter chromosomes passing along fibrils of acromatic spindle 

 toward centrosomes; division of centrosomes; if, interzonal fibres or central spindle. 



G, Late anaphase. Formation of diaster; beginning division of cell body. 



H, Telopliase. Reappearance of nuclear membrane and nucleolus; two complete 

 daughter cells, each containing a resting nucleus. (E.B.Wilson, "The Cell," The 

 Macmillan Co.) 



(d) Telophase (Fig. lo, H). — This is marked by di\asion of the 

 cell protoplasm and consists of a cycle of changes, by means of which 

 each group of daughter chromosomes is transformed into the chro- 

 matin network of a resting nucleus. These changes are the same 

 as those described in the prophase, but occur in the reverse order, the 

 chromosomes uniting to form the spireme, and the spireme becoming 

 transformed into the nuclear network. The result is the formation 



