1895. ] Briefer Articles. 77 
One group, the Anthocerotez, as is well known, differs very much 
in the appearance of the archegonium from the other Hepaticez. In- 
stead of projecting above the thallus it is completely sunk in it, and 
the limits of the neck cells are extremely obscure, while only the cover 
cells of the neck, or the uppermost cells of the axial row are free. A 
comparison of the earlier stages with the corresponding ones of the 
pteridophytes shows a striking resemblance, and renders the conclu- 
sion irresistible that the so-called mother cell of the archegonium of 
the latter is really homologous only with the axial row of cells of the 
bryophytic archegonium. It is equally evident that the four-rowed 
neck of the pteridophytic archegonium is a development of the four 
cap cells of the liverwort archegonium and cannot be properly com- 
pared to the six rows of neck cells in the latter. These are no longer 
clearly discernible but are more or less completely suppressed as in 
Anthoceros. As might be expected the departure from the bryophytic 
type is least marked in the Eusporangiate which in other respects 
come nearer to the Hepatice. 
The Anthocerotee differ from all the other bryophytes in having 
the antheridium of endogenous origin. The antheridium (or anthe- 
tidia) is covered by two layers of cells and the cavity within which it 
lies is completely closed from the first. The antheridial cell may give 
rise to a single antheridium, or more commonly, to a group of anthe- 
tidia varying much in number even in the same species. 
A study of the earlier stages, as was the case with the archegonium, 
shows very Significant resemblances to the corresponding stages of the 
Cusporangiate pteridophytes, and at once suggests that by a suppres- 
Sion of the wall and stalk of the antheridium of some form with a 
Single antheridium, the type found in all the eusporangiate pterid- 
ophytes may have been at once formed. In the latter, the cell which 
in the Anthocerotez gives rise to the outer wall of the cavity contain- 
ing the antheridia becomes at once the outer wall of the antheridium 
itself, while the inner one develops directly the mass of sperm cells. 
It is to be noted that this wall is double in some of the eusporangiate 
ferns, while in those that approach the Leptosporangiatz it is single, 
and not infrequently projects somewhat so that the antheridium ap- 
Proaches the free condition found in normal Leptosporangiate. The 
greatest difficulty that remains is the origin of the multi-ciliate sperm- 
atozoids of the Filicinee and Equisetinez, to which, as yet, there 
1s absolutely no clue. 
In conclusion then, it seems probable that the origin of the pterid- 
ophytes is to be looked for from forms which, like Anthoceros, had the 
Sexual organs completely submersed, and that the elongated archego- 
