A critical study of the cytology of Crepis virens. 
137 
chromatic bodies, whilst in the second, the chromatic Contents, in 
the form of fine granules, are withdrawn with the reticulum, into 
synapsis. 
5. Globules of a faintly staining substance may be given off from 
the synaptic knot, and from the mass of the second contraction. These 
globules are at first attached to the nuclear contents, but the Connections 
are broken as they pass into the cytoplasm where they become chromatic 
in staining reaction. 
6. The evolution of the heterotype chromosomes is somewhat obscure 
o-wing to the viscous nature of the chromatic contents. IMevertheless, 
events strongly suggest that, durtng synapsis, homologous univalent 
Segments are for the most part arranged side by side, in pairs. As the 
loops come out of synapsis all degrees in the Separation of the univalent 
Segments can be seen. Throughout the postsynaptic stages the imivalent 
Segments of each pair may either show a parallel (parasynapsis), or a 
terminal (telosynapsis) association, or many an intermediate an'angement. 
In some cases the lengths of parallel spireme are so closely approximated 
that the resulting bivalent Segment exhibits no trace of its duplex nature ; 
in others the univalent lengths may diverge for part of their length, whUe 
in others they may be entirely separate except at their ends which join, 
and thus form a loop. The univalent spireme segments graduaUy concen- 
trate, and finally disjoin, as univalent chromosomes, on the heterotype 
spindle. 
7. In the meiotic phase true fission (homologous vnth that of the 
somatic divisions) which ultimately divides the univalent chromosomes 
into their daughter halves on the homotj^pe spindle, makes its first ap- 
pearance as the spüt in the chromatic bodies of the coarser chromatic 
presynaptic prophases. These chromatic bodies are considered to be 
portions of whole somatic chromosomes. In the finer chromatic presynap- 
tic phases the future fission is represented by the space between parallel 
beaded threads, which are condensing to form lengths of whole univalent 
spireme. The fission becomes obhterated tlu’oughout the postsynaptic 
and second contraction phases. It may be once more recognised in the 
substance of the univalent segments as they condense to form the hetero- 
type chromosome, and later is evident in the chromosomes as they pass 
to the poles of the heterotype spindle; and again is once more strikingly 
apparent at the telophase of the heterotype division. There is no rest 
between the heterotype and homotype divisions, and the fission directly 
cleaves the univalent chromosomes, into their daughter halves, on the 
homotype spindle. 
