OTHER MODES OF NUCLEAR DIVISION 



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by the nuclei of higher organisms, they show in the division and distribu- 

 tion of their chromatic elements many of the characteristics of true 

 mitosis. In the evolution of the nucleus through such a series of stages 

 we have an illustration of "the conception of cell structure which im- 



FIG. 73. Nuclear division in Protozoa. 



A, one form of mitosis in Amoeba diplomilotica. (From Minchin, after Aragao.) B, 

 Nuclear division in Coccidium schubergi. X 2250. (From Minchin, after Schaudinn.) 

 C, mitotic division of micronucleus of Paramcecium (horizontal figure on smaller scale 

 than others.) (From Minchin, after Hertwig.) 



plies differentiated regions of a colloidal system in which special processes 

 have become localized and tend to remain fixed" (Harper 1919). 



Protozoa. Such an apparent derivation of mitosis from a simpler, 

 more indefinite division of a less sharply delimited mass of special 



