Wager. — The Sexuality of the Fungi. 581 
the process of conjugation is of secondary importance, and 
not sexually significant in the group 1 . 
Dangeard 2 , however, does not agree with Leger’s inter- 
pretation of the ‘spheres embryonnaires.’ For him the 
ultimate fate of the nuclei has not been determined. 
In the Entomophthoreae we also have fusion of similar 
cells formed on different filaments, but the only genus in 
which the cytology of the process of conjugation has been 
investigated is Basidiobolus 3 , which presents a feature of 
peculiar interest, in that its zygotes are normally formed 
by the fusion of adjacent cells (as sometimes occurs ex- 
ceptionally in the Alga Spirogyra ), which are uninucleate. 
Unlike Spirogyra , however, the nuclei before fusion undergo 
mitotic division into two. One daughter nucleus in each cell 
becomes cut off and degenerates, the other two nuclei with 
their protoplasm fuse together to form the zygote. The 
fusion of nuclei takes place at a late stage, and Raciborski has 
shown that it may even be delayed until germination has 
taken place ; in such cases the germ-tube then contains two 
nuclei. 
Hartog 4 regards the adjacent cells as progametes, ‘each 
of which by unequal divisions forms two gametes, the apical 
one arrested, the other functional.’ 
Higher Fungi. 
In the Ascomycetes the single nucleus of the young ascus 
is produced by the fusion of two or more cells derived from 
the mycelium 5 . Dangeard, who has investigated a large 
1 L^ger, loc. cit. 
2 Dangeard, Considerations snr les phenomenes de reproduction chez les 
Phycomycetes. Le Botaniste, vol. iv, 1894-5, p. 249. 
3 Eidam, Cohn’s Beitrage zur Biol. d. Pflanzen, Bd. iv, p. 181. Fairchild, 
Ueber Kerntheilung und Befruchtung bei Basidiobolus ranarum Eidam, Jahrb. 
f. wiss. Bot., xxx, 1897, p. 285. RaciborsH, Ueber den Einfluss ausserer Bedingungen 
auf die Wachsthumsweise der Basidiobolus ranarum. Flora, 1896, p. 107. 
Chmielewskij, see Bot. Centralbl., vols. xxxviii and I. 
* Hartog, loc. cit., Q. J. M. S., p. 27. 
5 Dangeard, La Reproduction sexuelle des Ascomycetes. Le Botaniste, s&\ iv, 
1894-5. Harper, Beitrage zur Kenntniss der Kerntheilung und Sporenbildung im 
Ascus, Ber. d. Deut. Bot. Ges., 1895. 
Q q 2 
