655 
Beer. — Studies in Spore Development. III. 
chromosomes (Fig. 36). The chromosome bodies become, to a certain 
extent, vacuolated (Fig. 36), but this is not so conspicuous a phenomenon 
as is the case in some other plants. Besides this vacuolation the substance 
of the chromosomes is distributed along the anastomotic connexions which 
join them together ; new anastomotic junctions develop and the chromosome 
substance becomes diffused along these in turn. By these means the 
material composing the chromosomes becomes gradually more or less 
evenly distributed through the nuclear cavity to form a typical resting 
nucleus in which the bodies of the chromosomes are only faintly indicated 
(Fig. 35) and eventually altogether lost to view (Fig. 37). One or more 
small nucleoli make their appearance in each of the daughter nuclei. 
A feature of some interest in the transformation of the chromosomes 
during the telophase is the gradual elongation of these short, dense bodies 
and the dispersal of the greater part of their material along certain definite 
lines. In Fig. 34 the elongation of the chromosome bodies, which are 
already united with one another by anastomotic junctions, is clearly seen, 
whilst in Fig. 35, which represents a later stage, the substance of the 
chromosomes has become much more diffused, but the definite lines along 
which the chromatic material has principally spread, and which represent 
the cores (so to speak) of the chromosome bodies, are perfectly distinct. 
A little later, when the diffusion of the chromatic contents has 
proceeded still further and new cross connexions have been developed, the 
nucleus attains a condition of complete * rest 5 in which the elongated 
remains of the chromosome bodies can no longer be traced (Fig. 37). 
During the prophase of the succeeding homotype division, however, the 
chromatic contents of the nuclei again become concentrated along certain 
definite lines which by further concentration develop into the elongated, 
slender chromosomes characteristic of the homotype division in this plant 
(Fig. 38). It would seem, from these facts, to be quite probable that the 
transformation of the short, thick heterotype chromosomes into the com- 
paratively long, slender chromosomes of the succeeding division is already 
prepared for during the telophase of the heterotype division. The first 
manifestation of the homotype division is seen, as I have already mentioned, 
in the appearance of certain definite lines of concentration into which 
the strands and cross connexions of the nuclear reticulum become with- 
drawn (Fig. 38). These lines of concentration map out the bodies of 
the future chromosomes. There are usually several medium-sized nucleoli 
present at this stage. As concentration proceeds the chromosomes become 
more distinctly recognizable, but they are for some time irregular in outline 
and remain united together by anastomotic junctions. Fig. 39 shows this 
stage, and it will also be noticed from the figure that the chromosome 
rudiments have increased considerably in staining power. The nuclear 
membrane still remains intact, but a mantle of spindle fibres has developed 
f 
