CoDIUM. . 335 
period the nucleus remained clearly demarcated from the 
surrounding protoplasm. 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 broken in the 
neighbourhood of one of the 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 nucleoli 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. w. 
Phys. des pflanzlichen Zellkernes. Jena. 1896.) 
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. Numerous partitions, of the nature 
already described, occur in the course of the hyphe, 
dividing the filaments up into multi-nucleate pieces, com- 
parable to the segments of a Cladophora filament. 
As the hyphe become erect they proceed to give off 
