KARYOKINESIS 255 



The " pull " exercised in opposite directions would in 

 time produce a continuous looping as in the above figure, 

 and the equatorial plane would be the situation where 

 division would be expected to result from the continued 

 pull (Fig. 91). 



Without being able to explain why, we must presume 

 that the loops when formed are still attractable to both 

 poles, for they remain at the equator. (We are speaking 

 of double chromosome karyokinesis.) And we would suggest 

 that the " monaster " is due to the loops adjusting themselves 

 to the radiating planes of force-lines which meet at the 





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Fig. 91. — A further stage of Fig. 90. The convoluted thread 

 broken at the equatorial plane, looped chromosomes being the 

 result. 



equator, somewhat as represented in Fig. 92. This is the 

 position preceding splitting. 



In single chromosome karyokinesis the chromosomes do 

 not split, but as soon as they are formed one half retires 

 to one pole, and the other half to the other. 



After the dyaster stage has been reached the cell divides ; 

 the chromosomes retire to their special poles, and do so 

 along the lines of attracting force. As ths achromatic poles 

 induced equatorial nuclear division, so probably do the 

 chromosomes induce equatorial protoplasmic division. 



The cell has now divided, and is controlled by a single 



