SEXUAL REPRODUCTION. 177 
terminates in an obtuse manner at the summit of the same cell. 
At its base it is also limited by a septum, and soon after another 
appears a little below its extremity at a point indicated before- 
hand by a constriction. This new septum defines a terminal 
short obtuse cell, the antheridium, which is thus borne on a 
narrow tube like a sort of pedicel. Immediately after the 
formation of the antheridia new productions show themselves, 
both around the oocyst and within it. Underneath this cell cight 
or ten tubes are seen to spring from the filament which bears it; 
these join themselves by the sides to each other and to the pedi- 
cel of the antheridium, while they apply their inner face to the 
oocyst, above which their extremities soon meet. Each of the 
tubes is then divided by transverse septa into two or three dis- 
tinct cells, and in this manner the cellular walls of the peri- 
thecia come into existence. 
During this time the oocyst enlarges and divides, without 
ils being possible precisely to determine the way in which it 
happens, into a central cell and an outer layer, ordinarily 
simple, of smaller cells, contiguous to the general enveloping 
wall. The central cell becomes the single ascus, which is 
characteristic of the species, and the layer which surrounds it 
constitutes the inner wall of its perithecium. The only 
changes afterwards observed are the increase in size of the 
perithecium, the production of the root-like filaments which 
proceed from its outer wall, the brown tint which it assumes, 
and finally the formation of the sporidia in the ascus. The 
antheridium remains for a long time recognizable without under- 
going any essential modification, but the dark colour of the 
perithecium soon hides it from the observer’s eye. De Bary 
thinks that he is authorized in assuming the probability that 
the conceptacles and organs of fructification of others of the 
Ascomycetes, including the Discomycetes and the Tuberacei, are” 
the results of sexual generation. 
Certain phenomena which have been observed amongst 
the Coniomycetes are cited as examples of sexual association. 
Amongst these may be named the conjugation of the slender 
spores of the first gencration, produced on the germinating 
