ELEMENTS OF MICROBIAL CYTOLOGY 



2 9 



move to the two poles where they make two polar plates. The cen- 



trioles located here seem to have some attraction for the chromosomes. 



Finally comes the telo phase or phase of reconstitution of the two 



nuclei which terminates the process. In this phase, the chromosomes 



X 



wm^***%^^N^, 



^ 



3 



& 



f? 



b 



. 



y 



5 



FIG. 20. Karyokinesis (metamitosis) . A, 'Acanthocystis aculeata; (a) nucleus 

 in state of repose with an intranuclear centriole; (6) (prophase) the centriole moves 

 to the periphery and out of the nucleus and forms an aster (After Hertwig) ; (c) the 

 division of the centriole and spireme; (d) the formation of the equatorial plates and 

 the achromatic spindle; (e) equatorial plates; (/) anaphase; (g) telophase. (After 

 Schaudinn.) B, In Coleosporium senecionis (Uredineae) . (a] Nucleus at rest with 

 its centriole extranuclear; (&) formation of chromosomes; (c) equatorial plate; (d) 

 metaphase; (e) anaphase; (/) (g) (i] telophase. (After Madame Moreau.) 



form a spiral chromatic cluster making a spireme at each of the poles 

 (dispireme stage, Fig. 20, Ajg); each of the spiremes is then surrounded 



