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1909] ATKINSON—FUNGUS PARASITES OF ALGAE 335 
of its parent cell. If the zoosporangium is located at the periphery 
of the zygospore near the middle, the tube is quite short. In the case 
of the zoosporangia which are located at the ends of the zygospores, the 
length of the exit tube is considerably longer, even when it is directed 
from the start perpendicularly to the wall of the parent spirogyra cell. 
In many cases, however, the exit tube from the zoosporangia which 
lie at the ends of the zygospore starts out nearly parallel with axis 
of the spirogyra cell, or at some angle between this and the perpendicu- 
lar. In such cases:the exit tube may be very long and tortuous, 
frequently passing into the adjacent spirogyra cell and finally emer- 
_ ging through the wall of the latter. 
The protoplasm, with numerous small highly refringent granules 
and a number of vacuoles, presents practically the same appearance 
as in the case of the other species. It passes ina rapid stream through 
the exit tube and collects in an irregularly spherical mass at the 
extremity, from which in some cases it soon becomes free and floats 
to a short distance. In ten minutes from the passage slight rotary 
movements begin, the mass turning a short distance in one direction, 
and then in a moment in the other direction, the movement becoming 
faster and repeated at shorter intervals. a 
In some cases the cilia can be seen as delicate rays, even before 
the simultaneous constriction of the mass begins and they are slowly 
lashing. In other cases they are observed very soon after the con- 
striction of the mass begins which outlines the surfacgof the individual 
Zoospores. No inclosing membrane was observed, and it seems 
possible that it should exist if the cilia can extend for such a distance 
‘Tom the mass. As the division proceeds the reniform shape of the 
Individuals becomes more and more pronounced, and the movements 
“come more and more violent. The individuals divide the time in a 
quivering motion followed by the oscillatory movements and the 
gliding over one another until they are apparently separate, now 
®ne pulling off a short distance, then returning, and so on, until they 
make their escape one after another or several at a time. After 
“sparating from the group, movement in space is rather slow, as if 
they were uncertain how to use the freedom gained. The individual 
scillates and glides around in various curves, then becomes nearly 
Stationary and quivers for a moment; then, one end remaining 
