2 8o CALIFORNIA ACADEMY OF SCIENCES. [Proc. 3D Ser. 



EXPLANATION OF PLATE XXVL 



Fig. 9. The spindle cones completely developed; the exterior fibres dis- 

 appearing. 



Figs. 10 and 11. Disappearance ol the nuclear wall; beginning of stellar 

 stage. 



Fig. 12. The nuclear wall has completely disappeared, but the chromosomes 

 retain their original arrangement. Two of the cones seem to 

 dominate the rest, but this is only a temporary arrangement. 



Fig. 13. Beginning o{ fascicular stage; the fibres are assuming a parallel 

 arrangement; the cones are separated into two groups; fibres are 

 becoming attached to chromosomes in bundles. 



Fig. 14. The parallel arrangement of the fibres and their attachment to 

 chromosomes is more pronounced. 



Fig. 15. The cones have increased in number; the chromosomes are assem- 

 bled in the equatorial region. 



Fig. 16. Completed spindle; not strictly bipolar, since each end is drawn out 

 into two or more points. 



