Sands—Spore Formation in Microsphaera Alni. 749 
getter, so that fusion is impossible, shows that he is here 
thinking not of adjacent but of opposite rays. The rays which 
fuse, of course, are those going to the same side of the future 
spore. 
The figures of the beaked nucleus with its aster within the 
plasma membrane of the spore, which F anil regards as con¬ 
clusive evidence that the rays take no part in forming the 
spores, may be explained, as noted, as polar views of spore 
formation by astral rays. This can be readily seen by com¬ 
paring Faull’s figures (5, Figs. 27, 28, 29, 34, 35) with an ob¬ 
lique view of a spore of Phyllactinia during the formation of 
the plasma membrane as described by Harper (13, PL 7, Fig. 
81). Further, the mildews regularly show the presence of 
more or less numerous rays which lie inside the plane of fu¬ 
sion and so exist as free, separate fibers within the plasma 
membrane after the spore is delimited, but this, of course, is 
no evidence that the plasma membrane was not formed by the 
fusion of other rays of the original aster. In some cases the 
plasma membrane retains a ribbed appearance such as Moves 
(20) describes in the formation of the “ Schwanzmanchette” 
in the spermatogenesis of the guinea pig. Traces of the fibers 
may persist even after the nuclear beak is withdrawn 1 (Fig. 
15). Faull assumes that the enclosed rays are either the en¬ 
tire original aster or are newly formed, a conclusion which is^ 
of course, unjustified. His figures of this stage (5, Figs. 26,. 
30, 31) agree entirely with the same stages in Microsphaera 
(Figs. 13, 14, 15). That the rays do actually fuse is proved 
by plasmolysis such as is found in shrunken material where 
the spore is pulled away from the cytoplasm. A careful study 
of Faulks paper leads inevitably to the conclusion that the ap¬ 
parent disagreement of his conception of spore formation with 
that here described is due not so much to a difference in the 
figures actually observed, as to a failure on his part to analyze 
carefully the results of his observations. 
Finally, it may be noted that the stages studied give no evi¬ 
dence of the existence of a series of “synkaryons” in Micro¬ 
sphaera 9 such as Maire describes for Galactinia succosa (14, 
