Elizabeth Acton. 
98 
in the dish and was found to be identical with it. Text-fig. 1 
shews portions of the thallus taken from the dish and from the 
“ Cladophora balls.” 
A 
6 
Text-fig. 1. A, portion of thallus from pie-dish. B, portion of thallus 
rom “ Cladophora balls.” x 370. 
In the “ Cladophora ball” the appearance of the alga seems to 
vary according to the extent of decomposition of the old cell-wall. 
A young thallus which has not completely covered the cell on 
which it is growing usually shews numerous lateral branches given 
off dichotomously and close together as in Text-fig. 2, D. As the 
thallus grows the branches become closely crowded, the cells 
become more regular and the original portions of the thallus often 
die away. It then appears to consist of almost parallel filaments 
of short, barrel-shaped cells running lengthways in the wall and 
partially embedded in it. Owing to the death of the younger 
portions of the thallus these filaments become disconnected. See 
Text-fig. 1, B. Frequently the alga obtains entrance to the interior 
of a cell and there develops irregularly as in Text-fig. 2, A. 
As decomposition advances in the cell-wall, the latter breaks 
up into pieces and many of the cells embedded in its surface die away. 
Some of the cells which remain, however, put out branches which 
penetrate deeply into the wall. The cells of these branches are 
extremely long and thin and appear finally to lose their chlorophyll 
(Text-fig. 2, B). It is possible that these penetrating branches act 
as rhizoids which absorb nourishment from the decaying wall. The 
surface cells connected with them are often large, with dense cell- 
contents and probably separate eventually from the penetrating 
branches and function as reproductive bodies. Text-fig. 2, C shews 
