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- 



II. HI. 



VII. 



V. 



VIII. 



VI. 



FIG. 392. 



Successive stages of division of somatic cells of the same root of Allium 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. 2G 



