VII 



POLYPLOID NUCLEI IN PROTISTA 



211 



^ 



4^ 



o 



F ^ 



Fig. 89. 



Nuclear multiplication in Aulacantha. (Borgert.Z././l., 1901, and A.P.K., 1909.) A-C, stages in the division 

 of the primary nucleus during binary fission of the animal ; D-G, preliminary stages in gamete formation. 

 A, resting nucleus ; B, mitosis, equatorial plate ; C, portion of an anaphase shown on a larger scale ; D, 

 formation of secondary nuclei (the little dark specks in the cytoplasm) from the primary nucleus ; E, the 

 primary nucleus is almost used up in the production of the secondary nuclei ; I'", a few secondary nuclei 

 under a higher magnification, showing the single chromatin thread in each ; G, secondary nuclei in mitosis. 



