310 Wisconsin Academy of Sciences, Arts, and Letters. 
between them. Eight chromosomes are found in the complete equa¬ 
torial plate. In the three successive nuclear divisions in the ascus 
eight chromosomes always appear. The daughter nuclei of the 
first division are smaller than the mother nucleus. They divide at 
once or after a short period of rest. At the end of the third divi¬ 
sion each ascus contains eight nuclei. Only two spores are found 
in the ascus; the other six of the eight nuclei resulting from the 
three divisions of the fusion nucleus disintegrate. After the third 
division the polar asters persist, especially those connected with 
the two nuclei that are to form the spore nuclei. A nuclear beak 
is formed as in Erysiphe and the spores and delimited by the activ¬ 
ity of kinoplasmic fibres that radiate from the central body. The 
remaining fibres now disappear; the central body breaks away from 
the plasma membrane of the young spore. The nucleus is re¬ 
formed, becomes spherical, the central body lying against its mem¬ 
brane, and a spore wall is formed. Harper holds that the primary 
ascus nucleus contains quadrivalent chromosomes, which are sep¬ 
arated into univalent chrosomes in the course of the three succes¬ 
sive nuclear divisions. The fusion of nuclei in the ascus is a vege¬ 
tative process and the ascus may be regarded as a spore mother cell. 
Harper considers that there is a true alternation of generations in 
the Ascomycetes. 
I have taken up the work of Harper in detail as it represents 
the development of de Bary’s fundamental conceptions in addition 
to Harper ^s own interpretation of the phylogeny and morphology 
of the fungi. His work developed the whole field of fungous mor- 
thology far beyond the grasp of the men of de Bary’s time and his 
views have been, until recently, accepted as the best interpretation 
of the cytological processes concerned in the life history of the 
fungi. Dangeard (1903-04) on the other hand, inclines toward 
the views of Brefeld, regarding the sex organs as non-functional 
and the ascogenous hyphae as parthenogenetic outgrowths of func¬ 
tionless sex organs. The only nucleus fusion is in the ascus. He 
maintains that the union of gametes in the ascus has all the char¬ 
acteristics of a sexual fusion and the ascus all the characteristics 
of a sexual organ. The chromosome number doubled by fusion in 
the ascus is reduced by the first division, and the two succeeding 
divisions are homotypic. 
Many contributions by various workers have been added to the 
literature substantiating one or the other of these views, but in the 
main supporting the ideas of Harper. Kecently, however, a paper 
