REPRODUCTION 433 
In the group of Fungi similar differentiation of gametes 
occurs, but motile antherozoids are very rare, confined 
indeed to the genus Monoblepharis. In many cases they 
are undifferentiated masses of protoplasm which do 
not escape from their antheridia, but are conducted 
directly from it into the female organ, where the process 
of fusion takes place. In Pythiwm the oogonium is a 
swelling at the end of a hypha, which is cut off from the 
rest by a transverse wall. Its contents divide up into an 
oosphere and a certain amount of protoplasm, which sur- 
rounds the sexual cell. The antheridium is another hyphal 
branch, which becomes closely pressed to the oogonium. 
A tube is put out by the antheridium, which perforates the 
wall of the oogonium, and the male cell, which is formed 
in the same way as the female one, 
passes over into the female organ and 
fuses with the oosphere. 
In some other Fungi a similar 
arrangement of the organs is brought 
about, but the male cell does not pass 
over into the oogonitum. 
A curious variation ig seen in the 
red seaweeds, the Rhodophycece. The 
female organ, known as a procarpium, 
does not produce any differentiated 
oosphere, but the contents of the 
male cell pass by means of an elon- 
gated structure, called a trichogyne 
(fig. 172), to its interior and appa- 
rently fuse with the whole of itg 
Bids ae ates °F protoplasm. The male cell in these 
tr, trichogyne. plants is not naked as in other cases, 
but has a cell-wall. A somewhat simi- 
lar condition is met with among the Ascomycetes, though 
whether fusion of the contents of the cells takes place is 
disputed. 
Except in the Angiosperms the gametangia of the plants 
28 
