350 
MUSCINEM. 
produces the pedicel, the upper one the archegonium itself. The lower cell 
undergoes numerous transverse and longitudinal divisions into several rows of cells. 
In the mother-cell of the archegonium there arise three longitudinal walls, by which 
three outer cells are formed ; these, on their part, enclosing an internal cell which 
overtops them. The three outer cells are divided by radial longitudinal walls and 
thus form five or six investing cells ; the median cell is divided by a transverse 
septum into an upper (stigmatic) and a lower cell. After the whole structure has 
increased somewhat in length, it comes to consist of two tiers in consequence of the 
Fig. 236.— Later stages in the development of the archeg-onia and origin of the sporogonium of Marchatitia polymorpha ; 
/, //, young archegonia ; ///, IV, after absorption of the axial row of cells of the neck; /^when ready for fertilisation; 
VI-VIII the cells of the^outh of the neck x relaxed after fertilisation ; the fertilised oosphere / shows its first divisions. In 
these figures /-^^j/ is the ventral canal-cell which is last converted into mucilage, e the unfertilised oosphere; // in V-VII 
the perigynium in process of development; IX t\\& unripe sporogonium in the ventral portion of the archegonium which has 
developed into the calyptra ; a neck of the archegonium ; ./wall of the sporogonium ; st its stalk (foot) ; inside the sporogonium 
are the young elaters arranged in rays, among them the spores. (/- VIII X 300, IX about 30.) 
division of each of the six investing cells, like the internal cell, by a transverse 
septum. The lower tier forms the ventral portion, the upper the neck of the 
archegonium. The internal cell of the ventral portion, the central cell, increases 
considerably in size and is divided by a transverse septum into a large inferior cell, 
the oosphere, and a small upper cell, the ventral canal-cell. Meanwhile the upper tier 
of cells, the neck of the archegonium, elongates; its axial cell dividing into four, 
eight, or sixteen long narrow cells, the canal-cells of the fieck. Further transverse 
