340 BOTANICAL GAZETTE [NOVEMBER 
indications external to the nuclei themselves—for those cysts which 
are of critical age usually contain short series of closely connected 
stages which frequently enable one to assure himself concerning diffi- 
cult points, such as the formation of the spindle or the origin of the 
asters. Nuclei of widely different phase in the same cyst are very rare: 
fig. 5 is a case where the small nuclei in the cyst were still in the 
vegetative condition while the large nuclei had passed into spirem; 
fig. 35 shows a case where the small nuclei had reached late anaphase 
while the large nuclei were still in metaphase; fig. 36 of the previous 
paper (5) is a case where the reverse was true, the small nuclei being 
in metaphase while the large ones were in anaphase. It would be a 
matter of great interest to ascertain the mechanism by which the 
nuclei are kept in phase. While not throwing much light on the 
nature of the stimulus, the behavior of newly segmented cysts is 
interesting in this connection. In such a cyst, long before the walls 
of the zoosporangia appear, while the segments are still separated 
from each other only by an exceedingly delicate plasmatic membrane, 
each nucleus has become entirely independent of the others; and one 
finds vegetative nuclei, metaphases, and telophases in adjacent seg- 
ments, showing how slight a separation suffices to establish the com- 
plete physiological autonomy of the individual nucleus (fig. 33): 
All of the mitoses of Synchytrium are of the same type. It is 
true that none of the later nuclei undergo such a shrinkage in volume 
with its associated peculiarities as occurs preparatory to the primary 
mitosis (STEVENS 18), but these phenomena are probably due simply 
to the enormous size of this overgrown nucleus. It may be recalled 
that similar peculiarities are usually observed in very large nuclei 
wherever they are found. CHAMBERLAIN (1), for example, was not 
able to interpret the structures he found in the enormous egg nucleus 
of Dioon. But aside from these peculiarities of the primary nucleus, 
the only differences that could be detected were in the size of the 
spindles, those in the early stages being fairly large, while those in the 
last mitoses of the sporangium are exceedingly minute (figs. 32-34): 
In the resting nuclei of Synchytrium the chromatin is all concen 
trated in a single globular karyosome (jigs. r, 31). Except in those 
cases where vacuoles have appeared on the removal of the chromatin 
preparatory to mitosis or nuclear gemmation (fig. 36), the karyosome 
