﻿i9i6] MERRIM AN— NUCLEAR DIVISION 315 



with one drawn at 8:50 p.m., where a nucleus with its barriers still 

 unbroken can be seen, the larger granules vibrating above and 

 below, with the same nucleus drawn 10 minutes later, where the 

 previously spherical body has become completely diffused in the 

 enveloping plasm. While this change takes place, the merged mass 

 of central body and enveloping plasm is no longer spherical, but 

 exhibits amoeboid movements (figs. 3, 4, 14), the various parts 

 appearing to change constantly in density. In some cases there 

 seemed to be no streaming of the larger granules, the latter appear- 

 ing either stationary or oscillatory. The overflow of nuclear con- 

 tent is but the manifestation of the disturbance of the ratio of 

 nuclear mass to cytoplasm advanced by Hertwig (4) as the cause 

 of karyokinesis. This enlargement of the nucleus is coincident 

 with the increase on all sides in the size of the suspensors (fig. 4). 

 This appearance suggests that the suspensors act as the main 

 channels, enlarged now as inlets for the superabundant assimilatory 

 products derived from the chain of pyrenoids with which they are 

 connected. 



Finally, those suspensors which attach the nucleus to the 

 chromatophores in the long axis of the cell appear to enlarge more 

 rapidly than the others, showing that the main currents are now 

 diverted in this direction. Meanwhile the large vesicles, gathered 

 above the nucleus and appearing to aggregate there in a plane 

 through the short axis of the cell, show active Brownian movements. 



During this constant amoeboid movement of the more or less 

 spherical mass, the turbidity which before extended through the 

 mass to the bordering translucent rim now appears to clear in 

 certain regions (fig. 5). It is to be noted, however, that in this 

 turbid mass there is no trace of organization. Regions where 

 changes take place are indicated in the drawings, where turbidity is 

 shown by the gray shading. Lessening of the turbidity is to be 

 seen, not at the equator, but at the lighter areas at some distance 

 and also in the regions near the bordering rim. 



Meanwhile, this whirlpool-like activity shapes the spherical 

 mass into that of an ellipsoid. The granular folds of protoplasm 

 that were constituents of the suspensors, and that lay at the 

 margin of the more homogeneous protoplasm enveloping the 



