756 Wisconsin Academy of Sciences, Arts, and Letters. 
velopment, as mentioned above, were not followed out by Fa- 
mintzin and Woronin. 
Lister, in bis monograph (’94), added one point of interest 
concerning the mature spores of Ceratiomyxa, in that he show¬ 
ed that each contains four “nucleus-like bodies.’ 7 Famintzin 
and Woronin had already shown that there was but one nucleus 
in each newly-formed segment; and even in the young stalked 
structure (see their Figs. 15, 16, PL 2; Fig. 12, PI. 3), they 
figure but one. 
Jahn (’05) has quite recently asserted that these two succes¬ 
sive divisions in the young spore of Ceratiomyxa occur just 
after the stalk is fully formed. Jahn has also studied the 
later division, which occurs during the germination of the 
spore to form the eight swarm-spores. 
The most of the material used in this investigation was fix¬ 
ed in various, chromic-acetic-osmic acid mixtures, and sections 
were stained either withl the triple stain, or with iron-alum- 
haematoxylin. I am indebted to Miss A. F. Dean for some 
of the later stages of spore formation. The work has been 
done for the most part at intervals during the past three years 
while serving at Bonn and at Madison as a research assistant 
of the Carnegie Institution of Washington. 
A longitudinal section through a young fructification is 
shown in Figure 1. )This is the youngest stage which I have 
succeeded in obtaining, and it represents a mass of protoplasm 
about 175/X--200/A in thickness above the substratum. At this 
early stage, when the plasmodium has only just begun to creep 
out as rounded jelly-like masses, we see that it is made up of 
a very dense protoplasmic meshwork. As shown in the draw¬ 
ing, dejp, narrow furrows cut into the outer surface; while the 
inner portion appears to be full of irregular lacunae, which 
contain a slimy substance. Numerous nuclei also are seen, 
scattered irregularly throughout the protoplasm. 
From the dense reticulum making up the cushion-like mass 
shown in section in Figure 1, there are now sent up finger-like 
projections, which are destined finally to bear on their surface 
the exogenous spores. Figure 2 shows a cross section of one of 
these cylindrical outgrowths, when in a half mature condition. 
