140 Johnson— Observations on Phaeozoosporeae. 
like, plurilocular. Each compartment of the chain is described 
and figured as containing only one large zoospore 1 . I have 
examined a very large number of plants of A. villosa and have 
never found the state of matters as just described to hold 
good. I have always found each compartment of the chain, 
on its stalk of 1-3 cells, to contain 10-20 zoospores which 
even before their escape are to be seen in very active motion. 
It was possible to see all stages in the mode of escape of the 
zoospores. The compartments open independently of one 
another, not necessarily simultaneously or successively, and 
the zoospores almost immediately after their escape swim off. 
The zoospores are all alike and, though more pear-shaped, 
are very similar to those of Sporochnus pednnculatus . They 
show the same sensitiveness to light. Beyond one or two 
doubtful cases which could be explained in other ways I saw 
no signs of any tendency on the part of the zoospores to fuse 
with one another, though zoospores from different plants were 
placed together. Each zoospore appears to be capable of 
independent germination. Not unfrequently the greater part 
of the whole branchlet falls off, leaving only the base on 
which the fertile filaments are inserted. Occasionally the 
sporangia are intercalary, i.e. in addition to the sterile stalk- 
cells there are several vegetative cells at the apex of the 
fertile filament (Fig. 10). It seems to me that if these 
observations are trustworthy, the description of the reproduc- 
tive organs in A. villosa should be altered. We should no 
longer speak of the sporangiferous filament as a stalked 
plurilocular sporangium with one zoospore in each com- 
partment, but as a stalked chain-like sorus of unilocular, 
plurisporous sporangia. Falkenberg 2 contends, in opposition 
to Thuret, that the sporangia are plurilocular, basing his 
opinion on (1) the independent opening of the several com- 
partments of the chain, (2) the origin of the fertile cells from 
one mother-cell. On the other hand, it should be noted 
1 MM. Crouan figure the compartments plurisporous (Florule du Finistere, 1867, 
c. 30, 190), without discussing the question of the nature of the sporangia. 
2 Falkenberg, op. cit. p. 226. 
