Biology of Fegatella conic a. 
99 
Antheridium (See Fig. 28). 
The superficial cell which will give rise to an antheridium projects 
above the surface and becomes divided by a transverse wall. The lower 
undergoes little further development, whilst the upper undergoes division 
by a series of transverse walls, so that the young antheridium consists of 
a row of cells, four or five in number (Fig. 28, V). The lowest cell of 
this row forms the short stalk, the body of the antheridium being derived 
from the upper cells, in each of which there next occur two vertical divi- 
sions, the walls intersecting each other at right angles and thus dividing 
the cell into quadrants (II, VI). 
The next divisions are also vertical, 
but the walls lie parallel with the 
surface of the antheridium, so that 
each tier of cells becomes divided 
into four central cells (sperm-cells) 
and four peripheral cells (wall-cells). 
The sperm-cells (III, IV, VII) are 
distinguished from the wall-cells by 
their denser protoplasmic contents, 
they undergo repeated divisions and 
give rise to the antherozoids, whilst 
the wall-cells divide only by anti- 
clinal septa (i. e. septa perpendicular 
to the outer surface of the antheri- 
dium) and form the single-layered 
antheridial wall (VIII, IX). The 
sperm-cells divide with great regu- 
larity, remaining nearly cubical in 
form, and the first-formed walls 
suffer very little displacement, being 
easily traced in the nearly mature 
antheridium (IX). The writer hopes 
shortly to publish a detailed account 
of the development of the anthero- 
zoid in Fegatella. 
Each of the cells composing the 
wall of the antheridium contains 
a few large chlorophyll-grains, the colour of which usually changes from 
green to yellow or red during the ripening of the antheridium. The 
cells are flattened, except at the apex of the antheridium, where there is 
a pointed beak made up of elongated cells. 
The development of the antheridia is accompanied by that of air- 
H 2 
Fig. 28. I-IV. Transverse sections of develop- 
ing antheridia. V-VI 1 I. Longitudinal sections 
of corresponding stages. IX. Longitudinal 
section of well- grown antheridium, showing the 
regular arrangement of the sperm- cells. I- VIII, 
x 160 ; IX, x 80. 
