1912] GRIGGS—RHODOCHYTRIUM 157 
in one primary nucleus, in which case the residual chromatin was 
much more abundant than in the smaller nuclei. 
MITosIS OF THE SECOND TYPE.—The second type of mitosis is 
limited to the last few divisions before sporulation. Unfortunately 
nearly all of the mitoses of this type that were found occurred 
in cysts packed full of starch, which greatly interfered with 
observation. 
The difficulties occasioned by this cause were especially serious 
in studying the prophases. In the cyst from which the figures of 
prophase were taken, all stages of prophase were certainly present, 
but could not be made out satisfactorily. The nuclei of the upper 
half of the sporangium had already passed into the metaphase, 
while those in the rhizoidal end were still in the vegetative condition 
(fig. 60), and above them 4ll transitions to metaphase were present. 
As far as could be determined, these prophases were similar to those 
of the smaller nuclei of Synchytrium. A spirem is formed which 
in this case involves but little change from the vegetative condition. 
This then shortens and thickens until it comes to occupy only the > 
equatorial region of the nucleus (fig. 61). The spindle then appears, 
whether as a new formation or as a metamorphosis of linin strands 
as in Synchytrium could not be determined. 
The chromosomes in this type of mitosis are small and spherical 
(fig. 62), but apparently stretch out somewhat in fission, for at the 
poles in telophase they are distinctly oblong (fig. 63). In early 
telophase they are bunched together in a compact mass resembling 
the familiar “daughter star,”’ but later begin to spread out (fig. 64) 
and assume irregular shapes (fig. 65), while vacuoles of karyo- 
lymph begin to appear among them, soon producing the charac- 
teristic vegetative nuclei (fig. 66). As may be seen from the 
figures, these stages are practically similar in all respects, save in 
the absence of cell plate, to the familiar anaphases and telophases 
of the higher plants. 
Amitosis 
Amitosis, which forms such a conspicuous feature of the cytology 
of Synchytrium, is almost absent from the zoosporangia of Rhodochyt- 
rium, or at least from the material studied. The nuclei of a few 
