SEX AND HEREDITY 



465 



cytoplasmic filaments, which originate outside the nuclear membrane. Their 

 position is at -first irregular, but presently they become arranged so as to con- 



VII. 



II. 



VIII. 



III. 



VI. 



FIG. 393. 



Successive stages of division of scimatir rails of the same root of A Ilium cepa, drawn 

 by Dr. J. M. Thompson. ( x 730.) For detailed description see Text. 



verge to two poles, thus constituting the nuclear spindle (iii. iv.). The nuclear 

 membrane cannot now be recognised, and the half-chromosomes attached to 

 B.B. 20 



