Baird—History of Phycomyces Nitens (Agardh) Kunze. 361 
nuclear cavity. At first the two nucleoles lie separate, but later 
fuse. In his description of nuclear division in this paper, he con¬ 
forms to his previous report. 
Miss Keene (1914) in her cytological studies of Sporodinia 
grandis finds that the nucleus in this form is granular in structure 
and contains a centrally placed nucleole which she considers 
chromatin in nature. She believes that nuclear divisions occur in 
the tips of the two sexual branches. As the mixing of the two 
fusing gametes takes place, nuclear fusions occur. Miss Keene 
describes no divisions in the zygospore preceding nuclear fusions, 
as was described by Dangeard and Moreau. She describes nuclear 
degeneration of unfused nuclei in the zygospore, but her descrip¬ 
tion of the process is somewhat different from that given by other 
workers. According to her, the process is first accompanied by an 
enlargment of the nucleole which does not stain as deeply as in 
preceding conditions. The nucleus eventually becomes a homo¬ 
geneous-staining mass. According to her the fusion nuclei are in 
evidence in zygospores two and three months old. 
Later, Miss Keene (1915) has contributed results of cytological 
studies of Phycomyces nitens. She has figured the nuclei in ger¬ 
minating asexual spores as containing one or two deep-staining 
bodies. The resting nucleus is described by her as bounded by a 
membrane and containing a deep-staining body, probably the 
nucleole, and chromatin granules throughout the nuclear cavity. 
She states that in the germinating spores, the young sporange, sus- 
pensors, and progametes, the nuclei show conditions that are very 
suggestive of division figures. She suggests that in nuclear divi¬ 
sion figures containing three bodies, two may be chromosomes and 
the third the nucleole. In the young zygospore she finds that many 
of the nuclei are arranged in groups of twelve to sixteen. Some 
of these nuclei fuse in pairs; others do not fuse. Later the unfused 
nuclei of the zygospore coalesce to form one or two large amorphous 
masses that persist in the zygospore several months old. Similar 
masses are formed within the suspensors. The fused nuclei persist 
in the zygospore and are confined to a thin peripheral zone of the 
cytoplasm. 
Burgeff (1915) has contributed a very interesting description, 
without figures, of his studies of the cytology of Phycomyces nitens 
and mutants of this species. His observations as to the structure 
of the nucleus or as to the facts of nuclear fusion are not fully in 
accord with those of either Keene or Moreau. He describes the 
