I0O9 ) Y AM ANOUCHI— MITOSIS IN FUCUS 197 



10 that there is now a homogeneous chromatin reticulum throughout the whole 



avity of the fusion nucleus. 



Figs. 72a, 726.— Early prophase of the first division in the fusion nucleus: 

 parts of chromatin threads begin to become pronounced, suggesting prochromo- 

 somes. 



Fig. 73. — Late prophase. 



Fig. 74.— Early metaphase: nuclear membrane has disappeared; chromo- 

 somes not yet split. 



Figs. 75a, 756, 75c— Same stage as fig. 74, cut perpendicular to the axis of 



H 



Cases 0} polyspermy 



Fig. 76.— Nucleus of fertilized egg with three sperms: a centrosome with 

 radiations started in connection with each of the spots where the sperms 

 entered. 



Fig. 77.— Early prophase: one of the four poles not shown. 



Fig. 78— "Prophase, showing quadripolar spindle: one of the four poles not 

 shown. 



Figs. 79a, 796.— Two sections of the nucleus in early metaphase; six equatorial 

 plates shown from various views, one of them showing a polar view with 21 

 chromosomes. 



