244 c. iSHiKAWA : 



It will, however, be observed that in Noctiluca all the 

 substance of the archoplasm does not go to form the fibrous 

 structures as in higher animals. The greater part of it retains 

 its usual granular appearance and sends out irregularly numer- 

 ous pseudopodia-like processes, while the fibres are present only 

 between the two archoplasms and between the archoplasms and 

 the chromosomes, — the central or archoplasmic fi1)res and the 

 radial or mantle fibres. The question as to how the latter fibres 

 are attached to the chromosomes is rather an interesting one. 

 In my last paper on Noctiluca ('94 c), I have stated that the 

 "fibres wdiich are found within the nucleus and probably at- 

 tached to the chromosomes, appear to come into close juxtaposi- 

 tion, but not to be continuous with those without, i. e., those 

 seen within and without the nucleus appear to be different from 

 each other, the former originating from the nucleoplasm and 

 the latter from the cytoplasm, just as Brauer thinks concerning 

 the formation of the spindle fibres of Ascaris megalocephala 

 hivalens^ I now find, however, that this statement is not quite 

 in accordance with the fact, since there is formed a break in 

 the nuclear membrane at the point where these fibres pass into 

 the nucleus and become attached to the chromosomes (Figs. 5, 

 6, rf). But as regards their origin I still hold the view that 

 they develop in part from the substance of the archoplasm, the 

 rest arising from that of the nucleoplasm, a special accumula- 

 tion of which will be observed at either pole-ends of the chro- 

 mosomes (Fig. o, and my former Fig. 37 Plate XIV). Now 

 what are we to say of this nucleoplasmic accumulation ? Does 

 it correspond to the pole- plate which is so commonly found in 

 other Protozoan-nuclei or does it represent quite a new plasma 

 peculiar to the nucleus of Noctiluca f From its position at the 



