1900] CHLOROCYSTIS COHNIT 103 
Chlorocystis, but a careful examination will at once reveal the 
difference. 
In shape Chlorocystis Cohnti is usually spherical, although it 
may be slightly elliptical. It measures from 16-26 in the 
mature condition. Even though thé plants are frequently 
crowded together in irregular masses, they never lose their 
characteristic outline. 
The question as to the degree to which Chlorocystis may 
infest the host plant is one upon which my observations do not 
agree with those made previously. Both Lagerheim (12) and de 
Wildeman (4) describe the plant as being completely surrounded 
by the cells of the host, except for a small colorless portion which 
projects beyond the surface, through which the zoospores escape. 
Wright in his original description conveys the same idea, 
although he Says, ‘‘sometimes zoospores attach themselves in 
such quantities to Schizonema that there is no room to force 
themselves into the frond,” and at such times they are said to 
show but little evidence of penetrating the host. Chlorocystis 
Sarcophyci (16) is described as being completely embedded within 
the tissue of Sarcophycus. As may be seen from fig. 2, the 
plants as I found them were not always included within the host, 
but were quite as often merely attached to the surface of the 
Enteromorpha. While, as will be described later, the zoospores 
upon germination may send out processes which penetrate 
between the Enteromorpha cells and during further develop- 
ment may be more or less surrounded by these cells, the fact 
remains that many of the plants pass their entire existence with- 
Hive having at any time been within the tissues of the host. The 
crowded condition of which Wright speaks is not necessary to 
Pring this about, for the epiphytic habit is just as apt to occur 
‘Mong single individuals entirely separated from one another, as 
ae they are grouped together. Even when the lower half of 
a rts cell is below the Enteromorpha (fig. 5, 9), a 
Siac — pressure will usually free it, leaving a round ees 
ers ee it has crowded the host cells apart. At no time 
ells observed completely covered by the Enteromorpha, 
