172 FUNGI. 
fecundation, should become the reproductive body, vegetable 
egg, or oospore. The gonosphere having been formed, the 
antheridium shoots out from the centre of its face, close against 
the oogonium, a straight tube, which perforates the walls of 
the female cell, and traversing the protoplasm of its periphery, 
directs itself to the gonosphere. It ceases to elongate itself 
as soon as it touches it, and the gonosphere becomes clothed 
with a membrane of cellulose, and takes a regular spheroidal 
form. 
Considering the great resemblance of these organs with the 
sexual organs of the Saprolegnie, which 
are closely allied to the Alge, and of 
which the sexuality has been proved, 
De Bary adds, we have no doubt what- 
ever that the phenomena just described 
represent an act of fecundation, and 
Fie. 99, — Antheridia ang t2at the tube pushed out by the anthe- 
cogonium of Peronospora. (De ridium should be regarded as a fecun- 
Bary.) dating tube. It is remarkable that 
amongst these fungi the tube projected by the antheridium 
effects fecundation only by contact. Its extremity never opens, 
and we never find antherozoids; on the contrary, the anthe- 
ridium presents, up to the maturity of the oospore, the appear- 
ance which it presented at the moment of fecundation. 
The primitive membrane of the oospore, at first very thin, 
soon acquires a more sensible thickness, and becomes surrounded 
by an external layer (epospore), which is formed at the expense 
of the protoplasm of the periphery. This disappears in propor- 
tion as the epispore attains maturity, and finally there only. re- 
mains a quantity of granules, suspended in a transparent watery 
fluid. At the period of maturity, the epispore is a slightly thick- 
ened, resistant membrane, of a yellowish-brown colour, and finely 
punctate. The surface is almost always provided with brownish 
warts, which are large and obtuse, sometimes isolated, and some- 
times confluent, forming irregular crests. These warts are com- 
posed of cellulose, which reagents colour of a deep blue, whilst 
the membrane which bears them preserves its primitive colour. 
