10 



period tlie nucleus reinained clearl}^ demarcated from the 

 surroundin;^- proto[)lasm. The nucleus is at first spindle 

 shaped, a form which it retains for as much as half the 

 period of division. The only alterations visible are at the 

 apices of the spindle, which are at times blunter, at other 

 times more pointed. Presently the spindle becomes 

 flatter and shorter, the apices swell, and the central region 

 contracts slightly. The nucleus has then a dumb-bell form. 

 Later on the median part begins to swell, whilst the 

 lateral parts adjoining the new nuclei become reduced to 

 fine threads. Finally, the connection is brt^ken in the 

 neighbourhood of one of tlie new nuclei, but the connect- 

 ing region is not absorbed into the other nucleus, as might 

 be expected. On the other hand, a further separation 

 between the second nucleus and the median connecting 

 band takes place, and the intermediate region is thrown 

 off and finally disappears. In the spindle stage, Berthold 

 made out clearly filaments passing 'through the mass, 

 having" the imcleoli between them, and also certain 

 granules which he considers as the equivalent of a nuclear 

 plate. When the spindle elongates and the poles swell, 

 the filaments thicken, and their substance is gradually 

 transferred into the swollen ends. Berthold was unable 

 to observe any movement in the surrounding plasma 

 during division. (See also Zimmermann, Die Morph. u. 

 Phys. cles pflanzliclieii Zellkemes. Jena. 189(3.) 



The rhizoids are continuous with the medullary region 

 of the plant, which is composed of intimately interwoven 

 branched filaments, forming a " tissue," not unlike a 

 fungus mycelium. Ninnerous partitions, of the nature 

 already described, occur in the coui'se of the hy[>ha', 

 dividing the filaments up into nmlti-nucleate pieces, com- 

 parable to the segments of a Cladophoni filament. 



As the hypha) become erect they proceed to give off 



