BOT.-VOL. II.] HUS— CASSIA TOMENTOSA L. 339 



suggestion of Williams (1899, p. 194; vide Went, 1887, 

 p.''258, figs. 8-10) that it is caused by the drawing together 

 of the poles, appears very acceptable. In the case of Cassia 

 tomeniosa the spindle poles either reach to the outer edge 

 of the granular zone, or else pass through it (figs. 13, 14), 

 yet the daughter nuclei are always formed well within it. 



The most interesting point at this stage is the behavior 

 of the granular zone, which shows a tendency to accumu- 

 late around the daughter nuclei as they are about to be 

 formed. Gradually it surrounds them on all sides except 

 where the connecting fibers remain. As soon as a wall is 

 formed around the daughter nuclei, they become entirely 

 surrounded by granular matter. 



It was the last stages of this process which were particu- 

 larly easy to follow in my preparations. To say that the 

 granular matter encroached upon that part of the cell which 

 contained the yet remaining continuous fibers would not be 

 quite true; the fibers seemed rather to thicken at various 

 places in the immediate neighborhood of the daughter 

 nuclei, and this apparently at the cost of the immediately 

 adjacent parts of the fibers. This process continued until 

 nothing was left of that part of the continuous fibers but a 

 granular thread, which sooner or later lost its continuity, 

 so that gradually the place where the threads were, was 

 entirely taken up by granules. 



This process takes place very gradually, beginning at 

 the sides of the daughter nuclei and proceeding toward 

 the axis of the cell. At first the meshes formed by the 

 transformation of the connecting fibers into granular matter 

 are fairly large, but soon they can no longer be differen- 

 tiated from those of the rest of the granular zone. This 

 change, especially in its later stages, is very slow, and may 

 not be consummated until the daughter nuclei are already 

 forming spindles. 



The daughter nuclei now lie in a granular mass in no 

 way different apparently from that which surrounded the 

 mother nucleus. The shape of the granular zone is not 

 quite circular, but more or less ellipsoidal, shghtly con- 

 stricted about the middle. 



