NUCLEAR DIVTSIOX OF XOCTILIICA. 251 



division of tlie spore-buds, we can very distinctly perceive the 

 dark coloured centrosome lying at the centre of the granular 

 archoplasm. While, however, in the cells shown by Fig. 10, 

 two centrosomes are seen to be lying close together in a clear 

 common space, there is in the spores of Fig. 11 only a single 

 centrosome situated at some distance from, but in a line with, 

 the base of the flagellum. In all the preparations shown in 

 these figures, the animal was killed with Flemming's fluid and 

 stained with iron-hsematoxylin and rubin, which latter stain 

 gives to the cytoplasm and the spindle a red colour that con- 

 trasts strongly with the dark purple of the nucleus and the 

 centrosome. 



The formation of the flagellum out of the fibres of the 

 central spindle and the persistence of the centrosome in ripe 

 spores at the base of the flagellum are points which deserve 

 some attention. As early as 1889, Hermann ('89) observed the 

 formation of the middle piece in the sperm-cells oî Salamandra 

 maculosa out of the " Kebenkern " of the spermatid cells. 

 Strasburger ('92, h) in 1892 gave numerous cases of plant 

 cells in which there occurs at the base of the cilia, a small 

 darkly stainable body which according to his conjecture should 

 represent the centrosome, while the cilia should develop out of 

 his "Kinoplasm." In the spermatozoid cells of Oharaceœ, Bela- 

 JEFF ('94, a) observed also in the cytoplasm close to the nu- 

 cleus a deeply stainable body called by him the " farbbare 

 Höcker " and identified with the attraction-sphere of other cells. 

 From this " Höcker " should develop two short, elastic threads, 

 both of which run parallel to the side-wall of the sper- 

 matogenous cell, but in different directions. In his latest work 

 on the formation of cilia in the spermatid cells of Gymnogramme 



