682 Blackman .— The Primitive Algae 
described as a species of Tetraspora , which it superficially 
resembles, and it reproduces by zoospores. 
The individual cells are non-motile, and the mucilage may 
serve to float them by entangling air, or to protect them from 
small larvae. In Fig. 14, a, a vegetative cell with two band- 
phaeoplasts and a globule of leucosin is shown, and in b a 
zoospore which has the very unusual equipment of three 
cilia, two long and one short, and also has its chromatophores 
at the anterior end. 
Here again the essential non-motility is held by Scherffel 
to put this among the Algae, but Lagerheim and most autho¬ 
rities place it among the Flagellata on account of its naked 
cells and probable longitudinal division. The absence of 
cilia, eye-spot and vacuoles, however, seems to me to indicate 
a long established abandonment of the Flagellate type. The 
characters which Klebs so successfully drew up to differentiate 
between Flagellates and green Algae are not equally decisive 
between Flagellates and brown Algae, which indeed is only 
natural as they are independent evolutions. All speculators 
have so far tried to use the same sets of characters on both 
phyla. I would suggest that'this should be abandoned, and 
that it should be recognized that on the brown phylum the 
evolution of colonial aggregates of increasing solidarity has 
gone ahead of the evolution of a type of individual cell which 
is definitely algal, compared with the relation of these two 
characters on the green phylum. Thus the majority of uni¬ 
cellular motile green organisms are Algae, while the majority 
of brown are Flagellata. Organisms of the Volvox , Pandorina , 
and Tetraspora type of aggregation are found to be algal (in 
cell-type) if green, and Flagellate when brown. This seems 
tenable and removes the difficulties of a rigid system, but 
shows how unreal and unimportant is the separation of 
the kingdoms. Rising higher on the phylum we come to 
organisms which have sufficient plant-characteristics to leave 
no room for discussion. 
Phaeococcus (Borzi (’ 93 )) consists of spherical cells walled and 
non-motile, of which four are imbedded in a gelatinous matrix 
