ORIGIN OF THE MITOTIC FIGURE 



73 



tory and apparently irreconcilable results. Fol ('79) derived the 

 spindle from the nuclear material, the asters from the cytoplasm. 

 Strasburger ('80) asserted that the entire achromatic figure arose 



A 



C 



D 



Fig. 27. — The prophases of mitosis (heterotypical form) in primary spermatocytes of 



Sahimandra. [Meves.] 



A. Early segmented spireme; two centrosomes outside the nucleus in the remains of the 

 attraction-sphere. B. Longitudinal splitting of the spireme, appearance of the astral rays, disin- 

 tegration of the sphere. C. Early amphiaster and central spindle. D. Chromosomes in the form 

 of rings, nuclear membrane disappeared, amphiaster enlarging, mantle-fibres developing. 



from the cytoplasm, and to that view, in a modified form, he still 

 adheres. Flemming ('82), on the whole, inclined to the opinion 

 that the achromatic figure arose inside the nucleus, yet expressed the 



