494 WARO NAKAHARA 



An interesting point to be noted is the relation of the apparent 

 vacuohzation of the cj^toplasm to the form of amitosis. The 

 nuclear division in highly vacuolated cells looks somewhat as 

 though it were a fragmentation of the nucleus due to a mechanical 

 interference of vacuoles, although the process is of course essen- 

 tially the same as in the normal case just described. This is 

 illustrated in figures 25 to 27. 



A phenomenon of entirely different nature is represented in 

 figure 28, where it appears as if the nucleus is divided into two 

 by the big vacuole located in the middle; but, changing the focus, 

 it was seen that the apparent two nuclei were continuous and 

 really parts of a single nucleus. Figure 29 shows another case 

 of similar nature. 



It was once believed that the amitotic nuclear division is al- 

 ways initiated by the division of nucleolus, and that each daughter 

 nucleus receives a single nucleolus. Since this is now known as 

 "one of the rarest forms of cell division," it was with great in- 

 terest that I observed in some adipose cells of Simulium larvae, 

 a process of amitosis taking place in accordance with Remak's 

 scheme. Figures 31 to 33 illustrate the main feature of the 

 process. This is, however, not the usual method of nuclear 

 division in this form, and the relation of the nucleolus to the 

 division is by no means constant. Figures 34 to 36 show that 

 one of the daughter nuclei may contain more nucleoli than does 

 the other. Evidently there is no reason for believing that nu- 

 cleoli play such a role as is supposed in the Remakian amitosis. 



Throughout my observations, I have not been able to detect 

 the centrosome in the adipose cell. Obviously the relation of 

 the centrosome is not of any importance to the process of 

 amitosis in the cell under consideration, even if this 'cell-organ' 

 may really be present in the cell. 



Lastly, I should mention that I have gone over preparations of 

 Calliphora larvae, and have found that, contrary to Perez's 

 statement, no nuclear division takes place in the larval adipose 

 cells in this form, the amitotic figure can be easily detected. 

 One of those nuclei apparently dividing by amitosis is represented 

 in figure 30. 



