106 BOTANICAL GAZETTE [avcust 
Near the center of the cell is a well-defined nucleus, from 
which the protoplasm radiates in fine strands. There are usually 
several small non-contractile vacuoles present and the whole cell 
contents is often quite granular. 
Two sizes of zoospores are formed. The larger ones, which 
are spherical, measure 6-7 w in diameter (figs. zo, 72), while the 
smaller are only 2.6-3.5 « and are somewhat pyriform in outline 
( figs. 11, 13). The method of the formation of the zoospores 
is identical in both cases, except that there are more successive 
divisions in the formation of the smaller spores, thus producing 
a greater number. In the original description of the genus by 
Wright, it is stated that the zoospores are formed in a very fet 
hours by free cell formation. By Reinhardt (14) this simulta 
neous formation is considered one of the points of distinction 
between Chlorocystis and Chlorocytrium. De Toni also use 
this distinction to separate the two genera. That the zoospores 
in Chlorocystis are formed by free cell formation is undoubtedly 
wrong, and all of my observations go to substantiate those of 
Lagerheim (12) and de Wildeman (4), who both state that the 
Spores are formed by successive divisions. All stages im this 
process may be observed (figs. 6, 7, 9), and nothing comparable 
to the description by Wright has ever been seen. Also the 
statement made by the discoverer of the genus that the eal 4 
spores are at first colorless and that the protoplasm seemed 
project itself to one pole and there form a single cilium is o 
borne out by my observations. Both kinds of zoospores ha 
each four cilia, with a single chromatophore lining the base ® 
the cell. In the large zoospores the pyrenoid is easily madt 
out, and in the hyaline end of both the large and small spores ® | 
found a lenticular or spherical red spot. ; 
When the zoospores are fully formed and ready to escapes® | 
circular piece about 10 # in diameter is cut out from the top Zz 
outer side of the cell. This may be entirely loosened, or fre: ‘ 
quently it simply turns back, remaining attached at one - 
(Jig. IT) very much as in some of the Chytridinee. It see 
probable that the zoospores do not always escape in this manne : 
