Mas see. — A Monograph of the Geoglosseae. 229 
duction are said to be as follows (1) the existence of distinct 
gametes ; (2) the fusion of nuclei ; (3) the determinate number 
of bipartitions of the sexual nucleus. 
This mode of sexual reproduction, so far as the Asco- 
mycetes are concerned, was first clearly observed by Dangeard 
in Peziza vesiculosa , Bull., and may be briefly summarized 
as follows : — 
The stroma or hypothecium gives origin to the asci and 
paraphyses ; the latter are simply unmodified filaments of 
mycelium, and require no special notice ; on the other hand, 
each ascus owes its existence to the presence of an oospore, 
which originates as follows : — 
Two filaments approach each other until they are in 
contact at the tips, the apical cell of each contains a single 
nucleus ; these are the two gametes, male and female 
respectively ; the apical cells of these gametes anastomose 
or conjugate, their protoplasm mixes, and the two large 
nucleolate nuclei fuse almost immediately, forming the 
oospore, which occupies the extremity of two conjugating 
filaments. Finally the apex of the oospore elongates and 
grows into an ascus, into which the nucleus ascends, and by 
repeated bipartition produces a nucleus for each spore con- 
tained in the ascus (Fig. 92). 
Immediately following the above statement, Dangeard 
adds, as a rider, that in addition to the production of the 
oospore by the conjugation of two distinct gametes, he has 
observed that in Peziza vesiculosa the oospore is sometimes 
formed by the fusion of the contents of two adjacent cells 
of the same hypha ; this admission, although speaking volumes 
for the unbiassed disposition of the author, rather clashes 
with one of the three fundamental constants of his theory 
of sexual reproduction, viz. the existence of distinct gametes. 
I have examined Peziza vesiculosa , and also other species 
belonging to the Discomycetes, and have been able to confirm 
Dangeard’s statements relating to the origin of the asci, both 
from the conjugation of two independent hyphae, and also 
from a single hypha, but at the same time I regret to say 
