THE CELL 



21 



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Fig. 12. — a, A resting plant cell showing the granular appearance of the chroma- 

 tin in the nucleus (with two nucleoli) prior to the formation of a thread; b, the 

 thread or spireme (with one nucleolus) ; c, breaking of the spireme into indi\ddual 

 chromosomes and splitting of the latter (and disappearance of the nucleolus 

 and nuclear membrane); d, the equatorial plate; e, the chromosomes migrating 

 to their respective poles; /, the chromosomes at the poles with spindle fibers 

 thickened at their midpoints; g, the forming of the two daughter nuclei and the 

 primitive wall, (a, b, c, f, g, Vicia, from W. Robyns: d, e, Iris, from V. Jungers.) 



