GOLGI BODIES IN DYTISCUS 155 



two parts of the nucleolus have separated and the nucleus is 

 greatly constricted, but the dictyosomes are still irregularly 

 scattered : while in the cell shown in fig. 4, when the two 

 parts of the nucleus are completely separated, the dictyosomes 

 are still irregularly disposed around them. 



It will be noticed that the nucleolus appears to play quite 

 an important part in this process : its division seeming to 

 initiate the division of the nucleus. This process has been 

 verified by observations on material prepared by fixation in 

 corrosive acetic and Bouin, and stained with Mann's methyl 

 blue eosin (7). In such preparations the nucleolus stains 

 oxyphil, and is apparently of the nature of a plasmosome. 

 Its appearance is the same in both kinds of preparations. 

 This type of amitosis, originally described by Eemak, in which 

 the nucleolus appears to play an important part, has been 

 found by recent workers to be exceptional rather than typical, 

 and Macklin, observing amitosis in living cells, says ' the 

 division of the nucleolus has no direct relationship to nuclear 

 division. It may, however, have to do with the size of the 

 nuclear portions ' (8). 



The extent to which the dictyosomes are distributed in the 

 resting follicle cell is subject to variation. In some cases, 

 evidently owing to the large size of the nucleus in comparison 

 with the width of the cell, the elements of the apparatus are 

 crowded together towards its outer wall and appear in rare 

 cases to be attached to an archoplasm ; but this does not occur 

 when the cell is dividing amitotically, and in no case has the 

 separation of two distinct groups of dictyosomes, as occurs in 

 mitosis, been observed. 



4. Discussion. 



Gatenby has suggested (3) that the scattering of the Golgi 

 elements during oogenesis is a means whereby it is able to 

 exert a maximum formative influence upon the cytoplasm, 

 as well as prepare for even distribution in the cells of the seg- 

 menting ovum. In a previous paper (6) I have described 

 how the dispersing dictyosomes influence the formation of 



NO. 261 M 



