208 Mr J. M. Macfarlano on the . 



forces, acting along the long axis of the cell ; in fact, that 

 from this point onward the nucleolus presides over, guides, 

 and impels the movements of the nucleus. Owing to Stras- 

 burger's attaching no special importance to the nucleolus, 

 and his observation of the cells with rather a low power, he, 

 while figuring pretty correctly the phenomena already 

 described, does not fully appreciate their importance. Pro- 

 bably also, from the latter reason, he has not noticed the 

 formation of the beautiful nuclear barrel, and succeeding 

 cell plate, which is, however, only a confirmation of his 

 renowned researches on other plants. But he describes and 

 figures very carefully the evolution from the peripheral 

 protoplasm, of what is at first a single row of minute spots 

 or granules, as seen in Plate X. fig. 6, but which increase 

 afterwards so as to form a double row, or even an irregular 

 belt. These granules, first seen when the nucleoplasm is 

 forced out, but frequently not appearing till a later stage, 

 mark the area where subsequent folding in of the protoplasm 

 takes place, with coincident formation of the cellulose 

 septum. 



As in Ornithogal'um, so here also the nucleoplasm is 

 densest on the sides away from the nucleolus. 



Hitherto the nuclear membrane has not in any way 

 altered, but soon at the two poles a solution of its continuity 

 becomes apparent, while, as indicated in Plate X. fig. 5, a 

 slight elongation of it is also effected ; this breaking up at 

 the poles goes on till the nuclear membrane is undistinguish- 

 able. After dissolution at the poles is accomplished, the 

 appearance is such as is represented in Plate X. fig. 6 ; the 

 polar masses are, especially towards the outer sides, dark, 

 compact, fibrous, amceboid-like lumps, giving off on their 

 inner sides fibrous strands which run to the nucleolus, while 

 above and below are two darker strands — the remains of the 

 nuclear membrane. This fibrous area constitutes, from this 

 period onwards, the nuclear barrel. 



The nucleolus next splits into two daughter nucleoli, each 

 of which seems to carry along with it a nucleolo-nucleus, 

 since one at least is usually to be made out in each sister 

 form. It is important to notice now how completely these 

 regulate the movements of the polar masses and nuclear 

 barrel. As they retreat from each other they drive the 



