rott] BROWN—LACHNEA SCUTELLATA 279 
nitely whether or not the spireme is continuous. Often several 
loops are tangled together, so that it is impossible to foHow indi- 
vidual parts. Still more frequently parts of the spireme run along 
the nuclear membrane for considerable distances, so that even if it 
were continuous it could be followed only with considerable diffi- 
culty. At other times there appear to be definite breaks. This 
appearance may be due to a failure of the spireme to take the stain 
or to poor fixation, but there is nothing to indicate that such is the 
case. The spireme, soon after its formation, appears to contract 
and divide to form five chromosomes (figs. 3, 4). ‘The chromosomes 
may be rather widely separated (fig. 4), but frequently they are col- 
lected together into a compact group resembling a second nucleolus 
(figs. 5,6). The group can be distinguished, however, from a nucleo- 
lus by its irregular outlines. This grouping of the chromosomes is 
not confined to the ascogonium, but can be seen throughout the 
ascogenous hyphae and in the prophases of the second and third 
divisions of the ascus. It is probably also the explanation of the 
grouping of the chromatin seen in the vegetative nuclei. 
While the chromosomes are being formed, linin fibers make 
their appearance in the nucleus. At the same time a centrosome 
appears on the nuclear membrane. This was not visible during 
the resting condition and appears to arise de novo. The centrosome 
is not a point, but rather a flattened area, apparently composed of 
many granules. When the centrosome was first observed, it was 
already connected with the chromosomes by the linin fibers in the 
nuclear cavity (fig. 7). Soon after this the centrosome (fig. 8) 
divides, and the daughter centrosomes move apart and come to be 
Situated at the opposite poles of the complete spindle (fig. 9). The 
centrosomes in fig. 8 are against the nuclear membrane, but owing 
to their position appear in the figure to be within the nucleus. 
The five chromosomes then divide and five daughter chromosomes 
Proceed to each of the opposite poles (fig. 10). The nuclear mem- 
brane now breaks down, and the two groups of chromosomes and 
the nucleolus, which soon disappears, are left free in the cytoplasm 
(fig. 11). The two groups of chromosomes are usually separated 
far enough so that when they reorganize the daughter nuclei are 
Separated by an appreciable distance (fig. 12). F requently, how- 
