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F. D. HEALD AND R. C. WALTON 
kept on top of the specimens to insure sufficient moisture for expulsion. 
The test was continued for ii days and shooting was recorded from 
all but one specimen. Expulsion was moderate except on two days 
from the same piece when the spots were very abundant. One 
peculiarity of the spore prints from inverted specimens is that the 
majority of the spots are not round and clearly defined as they usually 
are when the spores are shot upward (fig. i). The spot is generally 
Fig. I. A characteristic spore print of Endothia parasitica on an object slide, ob- 
tained when expulsion of the ascospores was taking place under optimum conditions. 
elongated, denser at one end, and fades oui: at the other somewhat 
like a comet's tail (fig. 2). The explanation for these is probably the 
fact that many of the long perithecial necks are not in a vertical posi- 
tion but grow obliquely. When expulsion starts it is natural to 
suppose that the spores are shot out more forcibly and at that time a 
more or less distinct spot is formed. However, as shooting continues, 
the spores are ejected with less force and they fall short of the original 
spot and form the "comet's tail." When the, necks point upward, 
