Davis. — Nuclear Studies on Pellia . 155 
ments and dissolves, but not until the chromosomes are 
organized and mitosis has nearly reached the metaphase. 
The changes that most interest us are, however, those of the 
kinoplasm. The homogeneous granular zone becomes differ- 
entiated by irregular lines plainly made up of rows of granules. 
These soon take the definite form of fibrillae distributed 
irregularly around the nuclear membrane. But the fibrillae 
develop most numerously in the four regions where the lobes 
of the cell diverge from the centrally placed nucleus, as is 
shown in Fig. 5. Farmer reported the presence of four 
centrosomes at the points corresponding with the lobes of 
the spore-mother-cell, but I have failed to find such structures 
in my preparations. 
The nuclear membrane becomes faint and then irregular 
in outline (Fig. 4), finally disappearing, whereupon the fibrillar 
kinoplasm immediately begins to occupy the nuclear space, 
previously clear except for the chromosomes, nucleoli and 
some granular material. Interesting stages in this process 
of dissolution are shown in Figs. 6 and 7. In the former 
case the fibrillae have begun to enter the nuclear space on 
two sides. In the latter we find the remnant of the nuclear 
membrane at one point, all the rest of the area being filled 
with delicate fibrillar kinoplasm. 
It is at this period that we have appearances most similar 
to the quadripolar spindle reported by Farmer (’ 94 ) for 
P allavicinia, and likewise described and figured for Pellia. 
The nucleus may become four-pointed and each point capped 
with fibrillar kinoplasm actually extending into the four lobes 
of the spore-mother-cell which are to become the spores. 
Fig. 5 shows such a condition previous to the dissolution of 
the nuclear membrane, and the appearance becomes far more 
marked later (see Figs. 6 and 7), when the kinoplasm increases 
in quantity. This condition is apparently the stage believed by 
Farmer to be related to a quadripolar spindle, but the writer 
cannot attach to it the same importance as that author. 
It is true that preparations may be so deeply stained that 
the nucleus has the clear outline of a four-pointed star, but 
