92 S lurch. — Harvey ella mirabilis ( Schmitz & Reinke). 
is fertilized. If the trichogyne does not become fertilized, 
it eventually withers and disappears, while the auxiliary cell 
and its two small sterile filaments do not undergo any further 
development. They usually increase somewhat in size, and 
become pressed together by the growth of the ordinary 
thallus-cells surrounding them, until they form a small rosette 
of cells. They are often seen remaining in the mature 
cystocarpic plant in this state. When the trichogyne is ready 
for fertilization, it projects a considerable distance beyond 
the surface of the plant ; it is covered by a thick gelatinous 
sheath, and is more or less swollen at its apex. The carpo- 
gonium is prolonged at the side of the 3-celled carpogonial 
branch until it nearly touches the upper part of the auxiliary 
cell, or even quite touches it (Fig. 11) But in all cases this 
part of the carpogonium and the upper part of the auxiliary 
cell are very near to each other. When mature, the trichogyne 
stains deeply and rapidly with Hoffmann’s blue, as do also 
the three cells of the carpogonial branch, the auxiliary cell, 
its two small filaments, and frequently also the ordinary 
thallus-cell beneath the auxiliary cell, to which the latter 
is attached ; this thallus-cell sometimes cuts off a small cell 
at its side (Fig. 11). When the trichogyne becomes aborted, 
the contents of all these cells become more granular, and 
only their nuclei stain deeply. 
After fertilization, the trichogyne is cut off from the carpo- 
gonium by a transverse wall (Fig. 12); and then that part 
of the carpogonium which is almost touching the auxiliary 
cell fuses with it (Fig. 13). At this stage the auxiliary cell 
is unaltered : but immediately after fusion with the carpo- 
gonium, it becomes more or less fused with the cells of its 
two small sterile filaments. This fusion, which commences by 
an enlargement of the pit-connexions of the cells (Fig. 13), 
eventually produces a large cell of very irregular shape, which 
is soon divided by a curved transverse wall into an upper 
smaller hemispherical cell (Fig. 14, gonbl.) and a lower, larger, 
irregularly-shaped cell (Fig. 14). Both these cells are easily 
seen in the thallus, as they stain very rapidly and deeply 
