666 Lewis — The Life History of Griffthsia Bornetianct. 
Not all the nucleolus goes to form the chromosomes. As already 
mentioned, part of the nucleolar substance passes out of the nucleus and 
becomes deposited in the vacuolar cytoplasm, and part may remain in the 
nuclear cavity, where it forms irregular masses. The part remaining in 
the nucleus ultimately disappears in the cytoplasm after the nuclear 
membrane is dissolved. 
The details of the organization of the spindle are made out with 
difficulty. During prophase, kinoplasmic caps are formed at the poles of 
the nucleus by differentiation of cytoplasm at these points. In most cases, 
at the centre of each kinoplasmic mass is a darkly staining body (Fig. n 6), 
probably comparable to the ‘ centrosphere-like-structures ’ of Polysiphonia 
(Yamanouchi, 93 ). In some cases these are large and prominent; in others 
they could not be demonstrated at all. They are certainly not permanent 
structures ; they seem rather to be the expressions of some temporary 
kinoplasmic activity. To them the spindle fibres are attached. The 
spindle is entirely intranuclear, and is probably differentiated from materials 
within the nuclear cavity, as no evidence has been seen to indicate that the 
fibres grow in from without, as is the case in Spirogyra (Berghs, 4 ). The 
spindle is truncate at the poles and slightly broader at the equatorial plate 
(Figs, ii 6, 1 1 7). The chromosomes, which lay scattered in the nuclear 
cavity before the formation of the spindle, now move in toward the centre 
of the nucleus (Fig. 1 1 8) ; here they become arranged on the equatorial 
plate. Some preparations (Fig. 119) seem to indicate that during this 
process they become associated in pairs, which soon separate ; but on this 
point it is impossible for me to speak with certainty at present. The 
number of chromosomes in the equatorial plate is approximately fourteen. 
They are small rounded bodies, not lying exactly in the same plane (Fig. 1 20). 
The axis of the spindle seems to bear no constant relation to the axis 
of the cell. It is more usual, however, to find the long axis of the spindle 
coincident with the long axis of the mother-cell. The outline of the 
nucleus at metaphase is nearly circular, or more often, slightly elongated 
in the direction of the axis of the spindle (Fig. 116). 
At anaphase the chromosomes separate into two groups, probably of 
seven each (Fig. 121). As the groups of chromosomes approach the poles 
of the spindle, the nuclear membrane fades away, and the cavity of the 
nucleus is obliterated by the cytoplasm. In some cases, however, this 
does not happen ; the nuclear membrane persists throughout mitosis. 
During anaphase, it elongates and then pulls apart in the middle (Fig. 122). 
Whether this diversity in the behaviour of the nuclear membrane is in any 
way connected with certain irregularities of development to be described 
later, is not obvious. 
As each group of chromosomes approaches the pole of the spindle, the 
individual chromosomes unite to form a densely staining spherical mass, 
