256 c. isHiKAWA : 



the same way as the microniiclei of Paramœcium during the 

 act of copulation. 



Such a close resemblance between the spindles of the micro- 

 nuclei of Paramœcium and of the nucleus of Noctiluca can not 

 but be indications of the close similarity of the kinetic centres 

 in Faramœcium and in Noctiluca, as above enunciated. 



jE". Abnormal Multipolar Division. 



While searching after spore-forming Noctiluca last summer 

 at the Misaki-Marine-Station, I once came across an individual 

 which was probably preparing to form spores, but in which the 

 archoplasmic spindle was tripolar instead of being bipolar as 

 usual. The case is shown in Fig. 12, drawn from life under a 

 low magnifying power. The individual in question was perfectly 

 spherical in shape, and no true centrospheres was observed in 

 it, except a granular mass of cytoplasm at each pole of the 

 spindles, sending out numerous, rather fine and irregularly ar- 

 ranged pseudopodia-like processes. The spindle-fibres running 

 between the masses of cytoplasm are very distinctly visible. 

 Neither the tentacle nor the "Staborgan" is to be seen, which 

 makes it very probable that the individual was preparing itself 

 for spore-formation, but by some cause had become abnormal 

 and produced a tripolar spindle. The abnormality of the spin- 

 dle is, moreover, to be observed in the shape of the nucleus, 

 which remains quite spherical in form and shows no sign of 

 division. It is just this abnormality which is a point worthy 

 of special consideration, since it clearly demonstrates that the 

 kinetic centre of the nuclear division in Noctiluca lie outside 

 the nucleus and can form spindles quite independently of it, — 



