1 14 Chodat. — On the Polymorphism of the Green 
whole by forming a macro-zoospore (as in Palmellaceae) or by 
transformation into a Palmella- stage. The first modification 
takes place generally in the erect filaments, the second is more 
commonly found when the plant is in the rhizome stage. 
Each of these cells can form a globular sporangium with 4-8 
quadriciliate zoospores ; in other cases subdivisions are 
effected, as in Tetraspora , and these can gradually pass into 
a Gloeocystis- condition or Protococcits-Q.o\\d\\Aon for the same 
reasons as above indicated in the Palmellaceae. In the 
Protococctis- stage (sporangium-condition) the zoospores can 
be transformed into spores which by mutual pressure become 
more or less polyhedric. After the destruction of the cell- 
wall these daughter-cells may remain united together and 
constitute multicellular bodies, from which zoospores or spores 
similar to those of the mother-cell escape. 
But I have also observed the same thing in the erect 
filaments and also in the gelatinous condition. In all the 
lower Chaetophoraceae, Ctenocladns , Chaetonema 1 , Endoclo - 
nium , similar conditions also exist. In the genera Chaetophora 
and Draparnaldia this is less marked and confined to special 
developments. 
This polymorphism, which shows us so clearly the rela- 
tion of this group to the Palmellaceae, is of the greatest 
interest, and is- similar to, though not identical with, the 
following, studied by me in Pleurococcus vulgaris . 
This plant is apparently well known. It grows on the bark 
of trees, on wet stones, on turf in mountainous places or on 
bare wood in damp places, and is of a characteristic green 
colour. In opposition to Gay, Artari, and Klebs, who believe 
in thq fixity of the form of this Alga, I have arrived at the 
conclusion, after three years of continuous research, that its 
variability under different circumstances is very great. Under 
this name we must include not only the common form without 
a pyrenoid, but also the similar one with a pyrenoid (PI. 
1 Huber, Sur un etat particulier de Chaetonema , Bull. Herb. Boiss., 1894, 
p. 164. 
