102 Humphrey . — The Development of 
Further transverse divisions, followed by vertical ones, occur in the 
archesporium with considerable regularity, as seen in Text-Figs. 8, F, and 
7, C. In Fossombronia pusilla , according to Leitgeb *, the somewhat 
elongated egg divides by transverse walls into three cells, and then occur 
vertical divisions in both the end-cells, resulting in the rather rapid 
development of the capsular and foot regions. Further than this the two 
species agree in the development of the embryo. The archesporial cells 
rapidly increase in number, completely filling the space of the capsule. 
Several slides were obtained showing the early stages in the development 
of the elaters and spore-mother-cell. Fig. 50, PL VI, shows a group of 
archesporial cells where cells of different sizes are shown. In Fig. 53, 
PI. VI, a later stage is shown, where the difference between the spore- 
mother-cells and the elater-initials has become very pronounced. In the 
latter the cell-contents seem to have contracted and elongated, while the 
spore-mother-cells are more regular in outline and the greater mass of cell- 
contents has drawn away from the cell-wall into a more spherical body, 
which ultimately forms the spore-tetrad. The original cell-walls persist 
for some time, being still faintly perceptible at the time of tetrad-formation, 
but finally breaking down. 
The mitosis of the sporogenous cell was carefully studied and found 
to agree with Farmer’s 2 account of the same in F. Dumortieri, with the 
exception of a failure to find centrospheres at any stage. Structures in 
a few cases were present that resembled vague radiations, but these also 
bore a resemblance to an irregular streaming disposition of the cytoplasm 
at either pole of the nucleus, as in Fig. 50, PI. VI. Very prominent asters 
have been figured by Garber 3 for Riccio carpus natans, and it is possible 
that by using his methods they will be found to occur in F. longiseta. 
Anything like a complete series of satisfactory stages in the formation of 
spores has not yet been obtained for this species. As stated by P'armer, 
the sporogonia at the time of mitosis in the spore-mother-cell are fixed 
with great difficulty. The utmost care was employed throughout the 
whole process of fixation, dehydration, and embedding, but the exceedingly 
interesting and important matter of the mitoses that occurs in the spore - 
mother-cell remains a subject for subsequent study. 
Stages just preceding the appearance of the spindle in the first mitosis 
were obtained, which are of interest here. Previous to any change in 
the nucleus, which usually occupies an approximately central position 
in the mother-cell, instead of lying in one lobe of the cell as described 
by Davis 4 for Pellia , the wall of the spore-mother-cell constricts at four 
opposite points as figured by Farmer 5 for F. Dumortieri, Davis for Pellia 
1 loc. cit., vol. iii, p. 117. 2 Farmer, Ann. Bot. (’ 95 ), vol. ix, pp. 470-1. 
3 Garber, vol. xxxvii, Fig. 35. 4 Davis, vol. v, xv. 
5 loc. cit. 
