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GEORGE S. BRYAN 
from the disintegrated canal cells above. Sometimes these bodies lie close 
to the ventral canal cell (figs. 3, 8). A rare exception is shown in figure 4 
in which a body from the neck has apparently joined itself to the protoplast 
of the ventral canal cell. 
The Fusion of the Protoplasts 
As illustrated by figures 4, 5, and 6, the protoplasts unite completely. 
This fusion is followed later by the union of the nuclei. Unfortunately the 
killing agent employed, while giving excellent morphological results and 
little plasmolysis, is not very satisfactory from a cytological standpoint, 
hence the details of chromatin behavior cannot be accurately reported. 
In general the chromatin of the two nuclei appears to be more or less inter- 
mingled. There is no tendency for each mass to remain distinct. 
Every nucleus of Sphagnum suhsecundum which has been observed thus 
far, with the exception of that of the fusion cell here described, whether it 
be of the gametophyte or of the sporophyte generation, is characterized by 
one conspicuous well-rounded nucleolus. The fertilized egg may prove an 
exception, since its nucleus has not been seen in a satisfactory preparation. 
The only other exception is to be found in this fusion nucleus. No case 
has yet been observed in which the two nucleoli of ventral canal cell and egg 
have united, though such a condition would seem perfectly possible. In all 
the cases so far observed the fusion occurs while the neck of ,the arche- 
gonium is still closed. There is, therefore, no danger of mistaking this 
fusion nucleus for that of a fertilized egg. 
The Disintegration of the Ventral Canal Cell 
In the material studied, clear cases of the disintegration of the ventral 
canal cell have been found a number of times. There is no doubt that the 
ventral canal cell frequently disintegrates ; but a summary of the large num- 
ber of slides studied thus far shows that the number of cases of the union 
of the two cells about equals the number of cases in which it is certain that 
the ventral canal cell has disintegrated. In a large number of cases the 
ventral canal cell was still persistent and was more or less in contact with 
the egg, as illustrated in figure 3. Two cases were found in which the nu- 
cleus of the egg appeared to be degenerating, while that of the ventral canal 
protoplast just above it was very clear, and sharply defined. 
Discussion 
It is evident from an examination of the literature quoted that the 
rounded appearance of the protoplasts of the mature archegonium is not 
due to the killing agent but is a condition which may be observed and even 
measured in living material. The average of a number of measurements of 
the diameters of living protoplasts compared with a like average of killed 
and stained protoplasts shows that there has been some contraction due to 
the killing, both in protoplasts and in nuclei, but the contraction is relatively 
