350 Wisconsin Academy of Sciences, Arts, and Letters. 
The Formation op the Ascospores 
As the ascHS elongates, nuclear division proceeds within it. The 
second mitosis is probably homoetypic and the next two vegetative 
divisions, so that there are produced eventually eight spores for 
the eight nuclei. Since there was only one nuclear fusion, there is 
necessary only one reduction of chromatin material. Examples of 
the vegetative divisions in process are few, but those observed show 
the typical spindle with masses of chromatin passing toward the 
poles. Three divisions of the ascus nucleus have been mentioned 
for some of the Exoascaceae. 
Ikeno (1903) in Taphrina cerasi, and Dangeard (1894) in Ex- 
oascus deformans, mention three divisions. This would be probable 
in types that have no basal cell, but where there is such a cell con¬ 
taining at some time a nucleus, it is evident that there must be four 
nuclear divisions: a division of the fusion nucleus and three suc¬ 
cessive divisions of the primary ascus nucleus and its derivatives. 
Nuclear division is seen more frequently in material collected in 
the early morning. Ikeno (1901) mentions many division figures 
at the time of the development of the spores of Taphrina Johan- 
sonii. 
The nuclei formed are small and are often found in a resting 
condition. They contain a deeply staining nucleole and chromatin 
arranged upon a linin network (figs. 28, 29, 30). In a mature 
spore the nucleus occupies about one-third or one-fourth of its 
volume, and in the formation of the spores dense masses of cyto¬ 
plasm collect about each of the eight nuclei. Sometimes this cyto¬ 
plasm takes up so much stain that the nucleus can scarcely be seen 
through it (fig. 35). The plasma membrane of a spore seems to 
be formed by the union of membranes of vacuoles; this plasma 
membrane secretes a thick, clear wall, darkly stained only at in¬ 
tervals (figs. 31, 32). Vacuoles are especially conspicuous at the 
time of spore formation and are in such a position that each spore 
is entirely encircled by them, the inner vacuolar membranes uniting 
to form the boundary of the spore. This would conform to the 
description given by Brown (1911) for the delimiting of the spores 
of Lachnea scntellata. Faul (1912) considers this progressive 
method of delimiting the spore the characteristic method for As- 
comycetes. He expresses the idea that astral rays would not 
naturally come together, but would rather tend to diverge. Fraser 
and Brooks (1909) report that vacuoles play an important part in 
