HISTOLOGY 



FlG. 41. Same process at time of formation of equatorial 

 plate of chromosomes. 



the astral fibrils. These latter are very long and stretch out into the 



cytoplasm almost to the cell-wall in some places. The chromosomes are 



mossy at this time 

 and the nucleolus 

 sometimes persists as 

 it has done in our 

 example. 



Figure 41 shows 

 the figure completed 

 and ready for the 

 division of the chro- 

 matin. The spindle 

 fibrils are at their 

 best development, 

 and some of them 

 can plainly be seen 

 to have become at- 

 tached to opposite 

 sides of the chromo- 

 somes and be pull- 

 ing them apart. The 



chromosomes are shorter and smoother than they were in the preceding 



stage. They are bent or V-shaped rods which are first split at their 



apex. It can be seen 



in this figure that the 



strain on the spindle has 



caused a sinking in of 



the whole surface at the 



point where this strain 



is greatest. 



A peripheral layer of 



the cell is left in its origi- 

 nal position. The next 



figure (42) represents a 



stage, subsequent to the 



last, in which the chro- 

 mosomes have been 



drawn apart. The form 



is well shown. As .in 



the hyacinth figure, the 



spindle fibrils are shown 



between the parting groups of chromosomes, while the fibrils which 



are seen between the chromosome groups and the centrosomes 



FIG. 42. A cell of the same kind showing separation of 

 the chromosomes. 



