7 
Calobryum Bluniei , iV. ab E. 
of the median line, and is intersected by two similar walls, so as to show 
in cross-section a single triangular cell surrounded by three peripheral 
ones, exactly as in the young arch egonium. These walls may be inclined so 
as to meet the primary wall, when seen in longitudinal section (Fig. n), or 
less frequently they are nearly vertical, and in longitudinal section the axial 
cell extends to the apex of the antheridium, and later a cap-cell is cut off 
from it (Figs. 16, 17). The resemblance of these young antheridia to 
archegonia is quite extraordinary. 
A much rarer departure from the type is shown in Text-fig. 3, B. 
The first divisions were much more like those in the Marchantiales, i. e. 
there were regular octant divisions before the cutting off of the peri- 
pheral cells. 
The subsequent development of the antheridium may be briefly 
summarized. The primary stalk-cell divides by intersecting vertical 
walls into four, which give rise to the four rows of cells in the stalk of 
the mature antheridium. The wall of the antheridium consists of a 
single layer of cells, within which are the numerous sperm cells. 
The development of the spermatozoids was followed somewhat in 
detail, but no notable departure from the type found in other Liverworts was 
discovered. The nuclei contain eight chromosomes (Fig. 18), and the 
spermatocytes are not in pairs as is the case in many Hepaticae. The 
spermatocyte is nearly globular, and surrounded by an evident membrane. 
The development of the spermatozoid from the contents of the spermato- 
cyte agrees with the accounts given by other investigators for various 
Hepaticae. As in other cases, the greater part of the body of the spermato- 
zoid is derived from the nucleus, while the cilia arise from the blepharo- 
plast (Fig. 19). 
The origin of the first archegonia is exactly the same as in the foliose 
or ‘acrogynous’ Jungermanniales (Text-fig. 2, G). Each segment of the 
apical cell produces a single archegonium, until about half a dozen are pro- 
duced, when the apical cell is itself transformed into an archegonium, and 
thus the further growth of the shoot is stopped (Fig. 20). Calobryum 
is thus truly ‘ acrogynous while in the related Haplomitrium the apical 
cell does not give rise to an archegonium. Many more archegonia are 
developed, however, but these are all intercalary, and there is no evident 
relation between them and the earlier formed ones. The number of arche- 
gonia may be considerable, but no accurate count was made. Goebel’s 
estimate of ‘ thirty or more ’ is probably correct. Archegonia of very 
different ages occur together, the younger ones arising close to the base of 
much older ones. 
The early stages of the archegonium, like the antheridium, show 
remarkable variation. As in other Liverworts, there are first formed three 
intersecting walls enclosing an axial cell (Fig. 24), but very often these 
