A critical study of the cytology of Crepis virens. 
107 
subsequently be clrawii upon for the evolution of the chroraosomes. It 
is probable that, in some cases, the chromatic bodies may be actual por- 
tions of the chroniosomes of the preceding mitosis which have remained 
concentrated during the late telophase; but, as a rule, the fact that the 
late telophase is finely granulär in character, and shotvs no defmite chroni- 
atic aggregations, points to the conclusion that the bodies, present in the 
resting stage, are for the most part formed ‘de novo’ by a progressive 
concentration of chromatm. 
Prophase. 
As the ‘restmg’ nucleus passes into prophase the linm reticnlum be- 
comes more defmite in character (fig. 10) and extends throughout the 
nuclear cavity (fig. 11). The chi'omatic bodies gradually disintegrate, 
and theu- substance is dispersed throughout the reticulum as chromatic 
beads, which take up a position at the intersecting points of the Strands 
(figs. 11 and 12). Nakao (37) has noticed that the chromatic granules 
seem to be closely associated with the linin, whereas the ‘prochromo- 
somes’ appear to be independent of it. Li Crepis, as in Oenothera (5), 
the chromatic bodies evidently coutribute their substance to the linin, 
beconiing themselves at length unrecognisable. 
The transition froni ‘rest’ to the ensuing prophase may therefore 
be recognised by the gradual disappearance of the bright refractive 
bodies in the cytoplasni, and by the breaking up of the chromatic bodies 
into beads withm the nucleus. 
The beads, carried on the linin reticulum, are arranged and grouped 
in many different ways. They may form an irregulär duster (fig. 15), 
or two, three, or four may üe together (figs. 13 and 14), or they may be 
arranged serially on an isolated linin Strand (fig. 16) or two such beaded 
Strands may run closely parallel to one another (figs. 13 and 16). At 
this stage it is easy to acquire an exaggerated idea of the number of paired 
Strands, for those that lie at the periphery of the nucleus coustantly 
appear to be defiiiitely pah’ed (fig. 12), when in reality this may be mainly 
due to their position relative to the curve of the nucleus. Nevertheless, 
in nearly every nucleus, even in the very early prophase, closely ap- 
proximated or paired Strands can usually be seen, indicating the origin 
of the future chromosomes, for each Strand will become a daughter 
chromosome at the approaching mitosis. As the prophase advances 
the linin reticulum graduaUy fornis thicker and more definite tracts 
which become increasingly impregnated with chroniatin. Sometimes 
the beads may join closely together leaving no length of linin thread 
