250 C. ISHTKAWA : 



from a part of tlie general cytoi^lasm of tlie body, before every 

 division or spornlntion. 



What becomes of the centrosome after the completion of 

 division has to be left, as hitherto, an open qnestion. 



C, The Formation of the Flagellum of Spores from the 

 Fibres of the Central-Spindle, and the Relation 

 of the Centrosome to the Flagellum. 



" From the position of the archoplasm, and from tlie man- 

 ner of its division in the foregoing stages, it is clear that the free 

 end of the spore corresponds to the equatorial part of the areho- 

 plasmic spindle, while the end attached to the surface of the 

 mother-animal is the pole of the spindle" ('94, c). This con- 

 clusion as to the formation of the flagellum from Üie fibres 

 of the archoplasmic spindle was come to by me four years 

 ago and further investigations of the matter have proved beyond 

 all doubt that it was the right one, as may be seen in Figs. 7, 

 8, 9 and 10, which show the later stages of the division of the 

 nuclei that go to form the spores. Figs. 7 and 8 represent the 

 penultimate stage ; Fig. 9, the last stage of nuclear division, 

 drawn under a high power (Zeiss' Apoch). In the cell situated 

 on the right hand side of Fig. 9, the central spindle-fibres are 

 still continuous between the two dau2;hter- cells, while in the one 

 on the left, representing only one daughter-cell, these fibres have 

 parted from the corresponding cell and are very probal)ly under- 

 going the process of elongation. Lastly,- in Fig. 11 are given 

 two spores which are about to leave the maternal body, and in 

 which the fiagellum is well developed. In these cells, as well 

 as in the cells shown in Fig. 10, representing the penultimate 



