1 38 Johnson . — Observations on Phaeozoosporeae . 
Reproductive organs. The arrangement of the reproductive 
organs is almost exactly the same as in C. Cabrerae. The 
sporangia and paraphyses are densely crowded together, at 
right angles to the surface of the stalked receptacle. The 
paraphysis is simple or branched. The sporangia are sessile 
or more usually inserted on the paraphyses, one paraphysis 
having several sporangia on it at different levels. The spo- 
rangia rarely reach to the terminal capitate cell of the para- 
physis, so that, in nature, the only part of the receptacle 
visible from the outside is the free ends of the paraphyses. 
Each sporangium is unilocular, and contains a large number 
of zoospores which appear quite like one another. I frequently 
kept a plant (it is only when it is quite young that it is not 
fertile) for 12-24 hours in a darkened bottle through which 
a steady stream of fresh sea-water was running. On examin- 
ing the plant under the microscope the zoospores were to be 
seen escaping in large numbers. They have the usual phaeo- 
phycean characters, are motionless at their escape, and collect 
in groups on the surface of the receptacle. In a few seconds 
the zoospores of a group separate and move off suddenly in 
all directions. I kept the zoospores under observation for 
many hours at a time, at nearly all hours of the day and night, 
and under various conditions, but saw no indication in them of 
any tendency to fuse with one another. Apparently each one 
is capable of independent germination. It should not be for- 
gotten that the conditions under which zoospores of deep-sea 
plants are examined in a laboratory are very different from 
those under which they live in nature, 30-40 feet below the 
surface of the water. A method of observation in which the 
natural conditions of light, pressure, temperature are carried 
out, as far as possible, is necessary before negative evidence 
can be fully relied on. The zoospores are very sensitive to 
light and quickly arrange themselves in a row, away from the 
light if at all bright h 
I was interested to find more than one plant in which the 
1 This is a further illustration of the observations of Strasburger and others on 
the movements of zoospores of Algae. 
