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 eight 

 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 Jbecomes 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. Tho 

 antheridium remains for a longtime 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 

 Ascomycctes, including the Discomycetcs 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 generation, produced on the germinating 



