SOMATIC CHROMOSOMES IN TRADESCANTIA 
343 
at various points where their substance becomes drawn out to form anasto- 
moses (fig. 5). Although it is possible that some of the anastomoses, 
which become very numerous in later stages, may originate after the manner 
of pseudopodia, it is clear that the earlier ones must be formed mainly by 
the coherence of the viscid substance of neighboring chromosomes originally 
in contact. Meanwhile the karyolymph has begun to form, the nuclear 
membrane differentiating where it comes in contact with the cytoplasm. 
The telophasic alveolation or vacuolation of the chromosomes begins 
at about the time the latter begin to separate as above described. The 
vacuoles first appear within the chromosomes as somewhat obscure though 
rather sharply limited regions of circular or oval form (fig. 5). They 
develop not only along the axis of the chromosome but also near or against 
its periphery; in fact, an inspection of the figures shows that they may 
occur in almost every conceivable position and with no regular arrangement 
with respect to each other. At a slightly later stage they become clearer 
and more numerous (fig. 6). 
This variety and irregularity in the arrangement of the vacuoles calls 
for special emphasis, because of the fact that the writers named in the 
first .paragraph of this paper have interpreted the telophasic alveolation 
as a splitting, the chromosomes from this stage onward being consequently 
regarded as double. Attention is therefore directed to the conditions 
illustrated in figures 6-9. It is noticeable that the vacuoles may nearly all 
be along the margin of the chromosome (right edge of upper nucleus in 
figure 6), and also that two or three may lie side by side across the width of 
the chromosome (left edge of same nucleus). In figure 7 are shown two 
chromosomes in which the latter condition is especially pronounced; here 
it is manifestly impossible to speak of a split. Transverse sections of the 
chromosomes at these stages are particularly instructive (fig. 9). Such a 
section passing through a region where there is but one large vacuole more 
or less centrally placed has an appearance represented in figure 9a. A 
chromosome with a series of such central vacuoles would appear double 
if viewed from the side. This, however, is only a special case of a more 
general condition. Figures gb-gf show sections passing through regions 
occupied by several vacuoles side by side, as in the chromosomes of figure 7 
and those at the left in figure 6. It would seem to require no further argu- 
ment to show that the chromosomes during these and the later telophase 
stages are not split ribbons or threads, but are irregularly alveolated cylin- 
ders; and that they can no more be called "double" than triple or 
quadruple. 
The above described changes continue, gradually transforming the 
alveolated chromosomes with their anastomoses into a common reticulum. 
An examination of figures 10-13 will serve better than a written description 
to make clear the manner in which this transformation is accomplished. 
The whole nucleus enlarges, nucleoli appear, the anastomoses lengthen and 
