340 
POPULAR SCIENCE REVIEW. 
filaments become at certain times disjointed at their extremi- 
ties, the portions assuming the globular form. Indeed, this is 
the case with any portion of it at any stage ; and although at 
certain times these do not always resemble the cells of chloro- 
coccus, yet in the main the resemblance is very complete. 
Again, the Mosses produce forms in many of their stages 
similar to those already pointed out. 
The Mosses are provided with filaments similar to the Con- 
ferv8B (hence called confervoid filaments), which may indeed 
spring from almost any part, but generally just above the 
radicles at base of stem. These spread from the parent to a 
great distance almost indefinitely, and branching, frequently 
produce an appearance of a conferva, so much so that they 
have been classified under the algae, till Kiitzing separated 
them. The branches, during active growth, frequently crowd 
each other so much that the ends are pressed upwards, and a 
dark green velvety mass covers the ground on which they 
rest. The terminal cells of these are constantly thrown off 
(fig. 5a), and are capable of subdivision. Although they are 
rather different from Chlorococcus and more like a form to 
be mentioned hereafter, in the first generation, they shortly 
assume the characters of that growth. When the filaments 
are produced in drier situations, as on branches of trees, they 
are more tapering, and the end cells are thrown off, as in fig. 6, 
and begin to divide (a, a), and ultimately to assume the exact 
appearance of the before-named Chlorococcus. The component 
cells of any part of a moss, indeed, may, under certain condi- 
tions, be thrown off, and then it will divide in the same manner. 
These remarks will thus show that although it may be pos- 
sible that such a distinct growth as Chlorococcus may exist, 
yet that inasmuch as we already know that a form like it may 
have at least three distinct origins, and perhaps many more, 
it may naturally be asked, how is it possible for any one to 
assert, that with so extensive a distribution as the mosses, 
lichens, and Prasiola, the specimen we are observing is in truth 
a distinct growth? 
But Chlorococcus is only but one of the so-called Palmellacege. 
There are, of course, many other forms, some of which are 
imitated by the further changes which may be observed to 
take place in the cells of lichens and mosses. The Cup-moss, 
Gladonia ]?yxidata,^’ is a good example to observe. • 
At fig. 7 is shown what is called Gleocapsa,^^ where the 
green contents of the cell are surrounded by a thick colourless 
transparent layer of mucus-like matter, instead of the ordinary 
thin hard cell-wall. The one figured has many layers ; some 
have only one. This feature has been used to distinguish the 
genus, and to divide it into different species. If this Gleocapsa 
