206 
DOUGLAS HOUGHTON CAMPBELL 
as may occur in Podomitrium and some other Liverworts is confined 
to the peripheral neck cells. ^ 
The transverse walls which separate the ventral and neck regions 
of the young archegonium are formed before any division takes place 
in the cap cell. The neck may become much elongated, especially 
when fertilization fails to occur (fig. 5, i^). 
As usual the lower of the primary axial cells divides the egg and 
ventral canal-cell (fig. 5, £), and from the other, by a succession of 
divisions, the row of neck canal cells is formed. The exact number 
of the latter could not be made out with certainty, but is probably 
eight. 
In the ventral region, occasional periclinals may form in the periph- 
eral cells, so that at the time of fertilization the wall of the venter is 
incompletely two-layered (fig. 5, jE). 
The Embryo 
Most of the archegonia fail to be fertilized and only a small num- 
ber of young embryos could be found in the material collected. To 
judge from the few that were secured, the early divisions seem to re- 
semble very much those in the embryo of Blyttia. Figure 6, A , shows 
the youngest embryo that was found. This was somewhat shrunken 
but showed an apparent division into two cells by means of an obliquely 
transverse wall. This first wall is probably followed by one or two 
more transverse walls before any vertical divisions are formed, but 
embryos showing these stages were not seen. The basal cell of the 
young embryo, and probably also the cell above it, give rise to a con- 
spicuous appendage or haustorium, which, however, is not so large as 
in Blyttia. 
Fig. 6, B, shows two nearly median longitudinal sections of an 
older embryo in which all but the lowest of the primary cells had 
divided by median vertical walls. In the upper regions there were also 
secondary transverse divisions, but as yet no periclinal walls. 
No stages were encountered between the one just described and 
very much older ones in which the sporogenous tissue was already 
evident, and it is impossible to say just what is the relation of the 
different parts of the young sporophyte to the primary divisions of 
the embryo. It is certain, however, that the basal cell, and probably 
^ Gayet, L. A. Recherches sur le developpement de I'archegone chez les 
muscinees. Ann. Sci. Nat. Bot. VIII. 3. 1897. 
