OUTLINE OF I.XDIRECT DIVISION 



69 



known as the karyokiiictic or mitotic figure. It may be described as 

 consisting of two distinct parts; namely, i, the chromatic figure, 

 formed by the deeply staining chromosomes ; and, 2, the achromatic 

 figure, consisting of the spindle and asters which, in general, stain 

 but slightly. The fibrous substance of the achromatic figure is gener- 



Fig. 26. — Diagrams of the later phases of mitosis. 



G. Metaphase; splitting of the chromosomes {e.p.^. ». The cast-off nucleolus. //. Ana- 

 phase ; the daughter-chromosomes diverging, between them the interzonal-fibres (/./.). or central 

 spindle; centrosomes already doubled in anticipation of the ensuing -division. /. Late anaphase 

 or telophase, showing division of the cell-body, mid-body at the equator of the spindle and bcgm- 

 ning reconstruction of the daughter-nuclei. J. Division completed. 



ally known as archoplasm (Boveri, '88), but this term is not applied 

 to the centrosome within the aster. 



2. Metaphase. — TYiO, prophases of mitosis are, on the whole, pre- 

 paratory in character. The metaphase, which follows, forms the 

 initial phase of actual division. Each chromosome splits lengthwise 

 into two exactly similar halves, which afterward diverge to opposite 

 poles of the spindle, and here each group of daughter-chromosomes 



