Are the Oentrosomes in the Antheridial Cells 

 of Marchantia polymorpha 



Imaginary ? 



BY 



S. Ikeno. 



In a preliminary note, published in the last number of this Journal", 

 Miyake describes, among others, his observations regarding successive 

 nuclear divisions in the antheridial cells of Marchantia polymorpha. 

 According to his description 2 ', " when the nuclear division is about to 



take place there appears at each pole of the nucleus a cytoplasmic 



radiation. Each radiating structure or aster seems to centre to a point 

 just outside of the nuclear membrane almost in close contact with the 

 latter. Here in the centre of the radiation a minute dot, which might be 

 taken for a centrosome has sometimes been observed. But it is not at 



all a distinct or constant structure When the spindle is formed the 



aster entirely disappears, and one fails to see in the spindle-pole any 

 structure, which might be taken for a centrosome m K In short, his con- 

 clusion about the nuclear division in the young antheridium of Marchantia 

 is that, " either in the resting stage or in any other stage of the dividing 

 nucleus of the young antheridium I failed to see the structure correspond- 

 ing to the centrosome of Ikeno " 4) . 



From the statement of Miyake above cited, which is diametrically 

 opposite to my observations published in 1903% man might perhaps be 

 led to the conclusion that my description of the centrosomes in Marchantia 

 were wholly imaginary and so it will be not quite superfluous here to 

 publish the following short note. 



1) Vol. XIX, p. 98. 



2) 1. c, p. 99. 



3) The italics are due to me. 



4) 1. c, p. 99. 



5) Beih. z. l.'ot. Centralb. Bd. XV, 1903, p. 65. 



