296 BOTANICAL. GAZETTE [OCTOBER 
and then is formed progressively until it cuts out the spore. This 
membrane is apparently not formed by a fusion of the astral rays, 
for although it appears at their outer limit, after it is completely 
formed the rays are still present within the spore and are appar- 
ently as numerous as ever, and in shrunken material both the 
centrosome and astral rays may be drawn completely away from 
the spore membrane. Moreover, in Lachnea there do not appear 
to be enough fibers to fuse together to form a membrane, unless, 
as pointed out by Fautt (12), they become flattened out very 
considerably, and there is no evidence that such is the case. Where 
there aré a large number of fibers, as in Phyllactinia (HARPER 23), 
the fusion would be a much simpler matter, but that they are very 
numerous where the membrane appears, and disappear as it is 
formed, is not sufficient evidence that they fuse. It would be 
necessary to see the actual fusion to prove that the spore is cut 
out by a membrane formed of fused fibers. What part, if any, 
the centrosome and fibers take in the formation of the membrane 
is doubtful. The appearance of the membrane just outside of 
them suggests that they may have something to do with its position. 
On the other hand, sometimes even before the membrane is com- 
pletely formed the centrosome may be within it and not in contact 
with it. Stages showing a spore partly cut out are relatively rare, 
which indicates that when the process is once begun it takes place 
rapidly. Miss Fraser (14) says that Fauir’s account of the 
cutting out of the spores ‘does not seem to satisfactorily explain 
either the persistence of the astral rays or the formation of the 
nuclear beak.”” In this connection it may be noted that in Lachnea 
the astral rays usually persist after both the first and second 
division, until the daughter nuclei are completely reorganized, and 
that beaks are frequently formed on the nuclei, although these are 
not so prominent as those on the nuclei of the spores. 
During the early stages of the formation of the membrane, it 
appears to be simply a differentiated part of the cytoplasm, and it 
is difficult to determine exactly when a distinct wall is formed, but 
the wall appears to be produced on the site of the original mem- 
brane. After the wall has been formed around the spore, it begins 
to thicken (fig. 51). This process frequently commences in the 
