Classification of Green Algce . 71 
cell-walls are formed in vegetative division, which 
occurs in all directions in space. Zoospores are 
formed, 8 or more from a single cell. Akinetes also 
occur. Gametes unknown. 
The affinities of the following genera are doubtful:— 
13. Dictijosphaerium. Nageli. 
Colony a globose mass of few or many spherical cells 
which are united in fours by the thong-like remains of 
the successive mother-cell-walls. The cells are at 
some distance from one another, the interspaces 1 eing 
filled by their respective mucilaginous envelopes. 
Under certain conditions the cells may exist free, 
singly. 
14. Tetracoccus. West, 1892. 
Colony of irregularly clustered groups lying in an 
indefinite free-floating mucilaginous mass and each 
composed of four cells, lying in one plane and united 
by delicate filaments. 
15. Ineffigiata. West & West, 1897. 
Colonies of 2-8 rather large cells, very various in 
shape and bearing irregular spines by which they are 
aggregated. 
16. Botryococcus. Kiitzing. 
Colony a free-swimming or attached botryordal mass, 
consisting of a cluster of oval cells each with a dense 
mucilaginous investment. 
17. D act \jlo coccus. Nageli. 
Colony consisting of a very few apiculate thin-walled 
cells which are loosely united to one another at their 
points of contact. No obvious mucilaginous invest¬ 
ment. 
Fam. III. Pleurococcaeege. 
Plant-body either unicellular or a mucilaginous indefinite colony 
or a true ccenobium; very rarely a filament (Stichococcus), never 
ciliate or motile. Cells of various shapes but frequently not far 
removed from the chlamydomonad-type of organisation. 
Reproduction typically taking place solely by vegetative division . 
Zoospores and gametes typically absent. 
[Certain genera placed in this family are known to produce zoospores, 
and in other cases they probably occur, but this has not been allowed to 
prevent their inclusion in any group to which they seem to belong 
naturally.] 
*Glococystiacece 
Body a mucilaginous colony, fixed or free-swimming, of definite or 
