1903] GAMETOPHYTES AND EMBRYO OF TAXODIUM 115 
Synapsis has occurred, and the nuclear reticulum forms a 
dense tangle near the nucleolus. The latter can now be dis- 
tinctly seen to be of compound structure, and from it threads 
can be traced into the network. Fine threads also connect the 
conspicuous central tangle with the nuclear walls. Such a 
synapsis stage is described by Murrill in the nucleus of the cen- 
tral cell of Tsuga. In fig. 72 the reticulum has begun to move 
back into its original position. The nucleolus is now distinctly 
fragmented into a number of granules of apparently equal size, 
which gradually become more and more separated into a broken 
ring or coiled thread (figs. 78-80). These granules retain the 
deep red stain characteristic of the nucleolus in previous stages. 
The ring, or thread, is now broken up more and more into sepa- 
rate parts and distributed near the periphery of the nucleus (figs. 
81-84) and the reticulum of the nucleus begins to arrange itself 
for the formation of the spindle (figs. 83-85). The fibrous con- 
nections between the reticulum and the nucleolar thread are to 
be noticed at all stages of its-distribution. 
The red-staining granules derived from the nucleolus have 
not lost their identity at any stage. They become gradually 
elongated and thin (figs. 85, 86), and thus approach more and 
more the characteristic structure of the chromosomes. The fibers 
of the reticulum draw together at different points of the nucleus 
and certain centrally placed ones become distinguishable as 
Spindle fibers, while the mantle threads pass gradually into the 
unmodified reticulum of the nucleus. The granular nature of 
the spindle is evident even at so late a stage as fig. 86. The 
nuclear wall has meanwhile disappeared, but its position is indi- 
cated by the arrangement of the fibers until the anaphase stage 
of division (jig. 87). The chromosomes, as they are drawn 
-apart, are of the usual V or U shape (fg. 87). The transforma- 
tion of the nucleolus into the chromosomes may be followed 
without interruption through its whole course, not only by reac- 
tions in staining, but in serial development. 
Chromatin nucleoli have frequently been described, but prin- 
‘cipally among the lower plants. Strasburger (00) in his recent 
work devotes considerable space to the discussion of the part 
