MINUTE PARASITIC ALQ.E. 
09 
but in a little time the small plants grow into unmistakable adult 
plants^ producing zoospores. As might be expected, plants thus 
circumstanced exhibit a wonderful variety of cell outline ; at times 
they scarcely show even a trace of the figure-of-eight form, and 
remain for the most part irregularly spherical. When the plants 
are much crowded in the frond of Schizonema, they will often 
assume an irregular hexagonal form ; sometimes the diatom 
frustules will be almost completely pressed into the upper portion 
of the frond, then the lower portion will in turn become filled with 
the green parasite, so as to appear as if one solid tissue of nearly 
uniform-sized green cells ; the more completely these filled the 
frond, the brighter the green colour seemed to be. The species 
became more and more common as the spring season advanced ; 
but during the month of January there were difficulties in pro- 
curing fresh specimens. ***** 
When the Schizonema fronds grew quickly, the zoospores of 
Chlorochytrium were well off, for the newer portions of the fronds 
were then ready to form a resting place for them ; and hence it was 
not until later in the season, and when the first growth of the 
Schizonema was over, that any great or undue crowding of the 
parasitic Algse took place, nor all this time did I find it occurring in 
any other of the Algse than the Diatoms ; but once their fronds got 
fully formed, the lower portions thereof soon became more or less 
densely beset with other (epiphytic) Diatoms, species of Epistylis 
crowded amongst these ; numbers of a pretty stipitate Khizopod 
form, probably the Lecythia elegans of Strethill Wright, occurred ; 
and more notable than any of these was a fine species of Yagini- 
cola, possibly a variety of Vaginicola crystallina, which was found 
in abundance. Against one and all of these the zoospores of the 
Chlorochytrium would ever and anon impinge, and in several 
instances I observed and noted that the spores attached themselves 
to the stipes of the Vaginicola and Epistylis. Such specimens 
continued to grow, assuming a nearly spherical form, and differen- 
tiating green chromules, but never increasing to anything like the 
size of those which had entered into the mucus exudation that 
makes up the tube of the Schizonema. In many specimens 
thus located I have traced the growth to the stage in which it 
was quite easy to count the number of the within-contained zoo- 
spores.” 
Other details are given of the occurrence of this same parasite on 
other Marine Alg^e. 
The second paper contains much interesting matter, inasmuch as 
it evidently opens the question of the fructification of the Ectocarpi, 
since it is not impossible that some minute parasites, such as 
members of the Chytridiaceie, may have been confounded with 
supposed forms of fruit, and hence a careful revision will prove 
desirable. The species described in this paper is referred, with 
some hesitation, to the genus Rhizophydium, and is thus 
described 
