Mar., 1923] SHOWALTER — RICCARDIA PINGUIS l6l 
Another type of disintegration frequently found is apparently due to 
the failure of the egg to be fertilized. Although the time during which the 
egg is capable of functioning as a gamete is probably short, the process of 
disintegration seems to be relatively slow. One sometimes finds the egg 
nucleus easily recognizable after the protoplasts have disappeared from the 
other cells of the archegonium. In the case shown in figure 40, the cyto¬ 
plasm of the egg is represented only by a droplet of non-staining liquid in 
which are suspended globules of deeply staining material, while the nuclear 
membrane and nucleolus seem to be intact. Figure 39 represents an early 
stage of disintegration in which the cytoplasm still shows some of its al¬ 
veolar structure but takes the basic stain. 
Disintegration is also found to occur even after the first segmentation 
of the fertilized egg. Figure 41 represents a disintegrating embryo of two 
cells in an archegonium from the cells of whose wall all protoplasmic con¬ 
tents have disappeared. In this case the conditions inhibiting normal 
development probably obtained before the segmentation of the zygote, 
which has not elongated into the typical haustorial cell and epibasal cell 
(fig. 14, PI. XVI; see also Miss Clapp’s fig. 34). 
The striking resemblance of many of these disintegrating cells to the 
figures shown by Florin and Miss Clapp arouses some doubt as to whether 
the cells figured by these workers were in all cases functional eggs. I have 
not found a case exactly similar to the one shown by Florin in his figure 1, 
but such a case would be comparable to some of those figured in the present 
paper. He says: 
In one archegonium [his fig. 1] I found four cells in a row, all morphologically and 
probably physiologically equivalent and supplied with large nuclei and deeply staining 
cytoplasm. They had also the appearance normally possessed only by the egg. 
In view of the conditions found in my material, I should rather suspect 
that the archegonium represented in his figure is one in which disintegration 
had begun simultaneously in all four of the axial cells of about the stage 
shown in my figures 27 and 28, Plate XVII. Certainly the cells figured 
show little resemblance to the functional egg (fig. 33, PI. XVIII). Miss 
Clapp’s figure 33 is much more nearly typical, but probably represents 
an early stage of disintegration due to the lack of fertilization such as is 
represented in the present paper by figure 39, Plate XIX. 
No attempt has been made to follow the sequence of cell divisions in 
the growth of the wall of the archegonium. These divisions appear to be 
quite irregular and frequent until the time of fertilization and afterward. 
The mature archegonium is a massive structure, and, as described by 
Miss Clapp, its wall, except for a very small terminal portion, has two layers 
of cells (figs. 30-33, 35, 36, PI. XVIII; figs. 42-50, PI. XIX; Miss Clapp’s 
figs. 32, 33). The neck of the archegonium is not made up of five longi¬ 
tudinal rows of cells as described by Janczewski for the Jungermanniales 
