io 6 
Cavers. — Oil the Structure and 
lower cell undergoes irregular divisions and gives rise to the short stalk, 
whilst the upper cell becomes divided by three vertical walls which intersect 
each other so as to separate a central cell from three outer cells (Fig. 31, 
I-IV). The central cell, which is triangular in cross-section, next divides 
by a transverse wall, cutting off a small upper cell (‘cover-cell’) from 
a large lower cell (V). The cover-cell then divides into four by vertical 
walls that intersect at right angles (VI, X), whilst each of the three outer 
cells divides into two by a radial longitudinal wall (XI). Transverse 
divisions then occur both in 
the large central cell and the 
six outer cells, so that the 
young archegonium now con- 
sists of two tiers of cells, the 
upper forming the neck and 
the lower the venter (VI). 
The axial cell of the neck 
undergoes repeated trans- 
verse divisions, giving rise 
to the row of neck-canal- 
cells, whilst the axial cell 
of the venter divides by a 
single transverse wall, cut- 
ting off a small upper cell 
(ventral-canal-cell) from the 
large egg-cell (VII, VIII). 
The four cover-cells either 
remain undivided or undergo 
longitudinal divisions, so as 
to increase in number to six 
or seven in the mature arche- 
gonium. The neck-cells di- 
vide repeatedly by transverse 
walls, giving rise to the long neck, which eventually consists of about twenty 
tiers of cells ; the neck-canal-cells do not divide so rapidly, and there are 
never more than eight or nine altogether (Figs. 30, 31). During its 
development the archegonium becomes carried downwards on to the lower 
surface of the receptacle, whilst the tissue around it grows out to form 
a sheath, the tissue of which contains air-chambers ; beyond the opening 
of this sheath hangs the long neck, which is curved upwards and 
outwards. 
In a paper by Gayet (1897), we find an account of the development 
of the archegonium in various Hepaticae which differs considerably from 
that here given for the archegonium of Fegatella , as well as from those 
Fig. 31. I- VIII. Longitudinal sections of developing 
archegonia. The small figures above, I-IV, show the cor- 
responding stages in transverse section. IX. Venter of a 
mature but unfertilized archegonium ; the upper portion 
of the egg-cell is hyaline, forming a ‘ receptive spot.’ 
X. Cover-cells in transverse section, corresponding to stage 
shown in VII or VIII. XI. Transverse of neck, showing 
six neck-cells and a neck-canal-cell, x 360. 
