380 
Fig. 17 
Fig. 22. 
23. 
24. 
25. 
26. 
30. 
STUDIES IN VEGETABLE BIOLOGY. 
PrarE LV. (continued ). 
. Very young zoosporangium, the wall of which has already broken 
down; its only gonidium has lost its cilia, if, indeed, it ever 
possessed them. 
. Small eciliate zoosporangium, the stalk covered with fine mud-particles 
and apparently breaking down. 
. A zoosporangium with its wall covered with tiny mud-particles ; cilia 
present in spite of this. 
. Palmella state ; still attached to its Cladophora cell. 
. The Palmella mass. 
Pare LVI. 
Gelatinous matter, formed by the breaking down of a zoosporangial 
wall, investing b, Botryocystis cells ; g, aG/eocystis cell; x, undivided 
cells ; and y, cells which have undergone simple division. 
Top of an attached zoosporangium with Gleocystis cells; x, cells still 
undivided. 
Peculiar Gleocystis condition of a young zoosporangium. 
À zoosporangium with several holes (a) in its wall through which 
ecenobia would seem to have passed; b, an opening by means of 
which the cenobium, c, has made its escape. 
A free biscuit-shaped two-celled cenobium with the cells lengthily 
ciliate, and in all respects similar to those of the preceding 
figure. 
. A larger free cenobium. 
. A large rapidly-moving ecnobium, apparently formed by breaking off 
of the distal portion of a zoosporangium: a, front; b, side 
view. 
- Apparently the last stage in the liberation of zoospores: the gonidia 
of the three groups a, b, and c were moving together in each 
case ; the connecting substance could not be seen. 
A zoosporangium whose proximal half has been evacuated by zoospores, 
with one exception : such a condition as this might be the forerunner 
of the large coenobium of fig. 28. 
31, a-c. Conjugation of zoogametes ; also zygote, X 600. 
[PosrscnrPT.— Since this memoir was written, Messrs. Bennett and Murray 
have published their useful * Handbook of Cryptogamic Botany,’ a work in which 
many reforms of nomenclature are carried out. Although I fully approve of this 
course, revision of the nomenclature of this memoir has been deemed inadvisable, 
as involving too much alteration of the type. I cannot, however, follow the 
authors in their classification of Volvox and its allies, which they place in a 
class Cenobiem, together with Hydrodictyes, Pediastrex, and Sorastre®, 
the rel 
ations of the last three groups being too obscure in my judgment to 
justify the proposed grouping: besides which I think that penetration of the 
cell-wall by cilia isa fact sufficiently striking to warrant the separation, as a 
class, o 
f all Algz so constituted.-—S, L. M.] 
