A critical study of the cytology of Crepis virens. 
113 
The differences in nuniber, form, and arrangcment of chroniatic bodies 
might be described ‘ad mfinitiim’ (figs. 42, 43, 44 and 45). The result 
of this Investigation seenis to point conclusively to the.fact that the 
number of the chromatic bodies in premeiotic resting nuclei 
is inconstant. Apparently the number niay vary between one and six, 
for in a completely resting nucleus not more than six have been seen. 
These facts point to the conclusion that the chromatic bodies instead 
of being ‘prochromosomes’ in the sense of Overton (40), are rather store- 
houses of chromatin, a Suggestion formulated by Tischler (60), Laibach 
(26) and others. In C. virens, and forms which show definite chromatic 
bodies, designated by Rosenberg (44) as the Capselia type, the chromatin 
is concentrated or stored in a variable number of definite masses, instead 
of being more or less diffused throughout the nucleus as in the Fritillaria 
type. 
The resting nucleus passes imperceptibly into the prophase of the 
heterotype division. 
Prophase of first meiotic division. 
The first indication of the onset of prophase is to be seen in the more 
definite appearance of the linin (fig. 45), and in the fission observable in 
the hitherto homogeneous chroniatic bodies (fig. 46). At first sight it 
would be impossible to deterniine whether the paired appearance of the 
bodies might be due to the approximation of two individuals, or to the 
fission of a single individual. Rosenberg (46) considers that the paired 
chromatic bodies of the heterotype prophases represent the association 
of two homologous chromosome Segments. On the other hand, the result 
of this study of initial stages points strongly to the conclusion that this 
double character is due, not to approximation, but to fission. 
A refractive line appears in the substance of a chromatic body (figs. 47 
and 48), and this gradually separates the two sides which may divaricate 
to form a V (fig. 47 and Fl. X, fig. 113). A definite linin strand is seen 
to proceed from both of the free ends. Gradually the two sides separate, 
and become once more rounded in form resulting in two closely approxi- 
mated chromatic bodies (PI. IX, fig. 49 and PI. X, fig. 114). Occasionally 
they are so disposed towards one another, as to form a cross (PI. IX, 
fig. 47). At this stage nuclei may be found showing clearly the fission 
of the bodies, the segments of the several pairs being united by fine threads 
(fig. 54). Sometimes there may be three or four such bodies in the act 
of Splitting (fig. 52), or there may be fewer (fig. 50) or there may be more 
(fig. 54). It is again realised that their number is inconstant. As the 
Archiv f. Zellforschung. XII. 8 
