128 ERYTHEA. 
back showing neither distinct midvein nor evident reticula- 
tion: seed 1 only in each capsule. 
Common on wooded hills of Napa and Sonoma counties, 
California; perhaps one of several wholly distinct plants lat- 
terly confused with the Patagonian P. circinata. The calyx 
is a remarkable one, yet not at all as in var. calycosa, Gray. 
ZOOSPORES IN SPIROGYRA CONDENSATA. 
By L. B. Brripeman. 
Through the kindness of Mr. W. E. Loy of the San Fran- 
cisco Microscopical Society, I obtained a specimen of 
Spirogyra condensata apparently producing zoospores. 
The specimen was gathered by him the 26th of last March 
from a small way-side rill near Petaluma, California. On his 
first examination he observed several cells containing motile, 
globular green bodies; in one cell he counted twenty-four,— 
usually the number was less. I did not see the specimen 
until the next day, and at no time found as many zoospores 
as did Mr. Loy, eight being the highest number seen in @ 
single cell, and usually there were but three or four. Where 
these smaller numbers occurred only a part of the contents of 
the cell was used in their formation. 
The process of formation, judging from different stages 
observed in several cells, appeared to be as follows: 
The contents, which were of a healthy chlorophyll-green 
color, lose their characteristic spiral appearance and fill the 
cell with a structureless mass in which soon appear one or 
more denser portions. Around these the protoplasm, with 
its contained chlorophyll grains, is gathered and becomes 
rounded into as many zoospores as there are denser centers. 
These begin to revolve slowly in the parent cell, through the 
wall of which they finally escape into the surrounding water 
where their motion becomes more lively. After “swarming” 
a short time—from five to ten minutes in the ones I 
observed—the zoospores come to rest. At this instant the 
