4. _Confervaceae_.--Plants growing in the sea or in fresh water,
filamentous, jointed, without evident gelatine (forming merely a
delicate coat around the separate filaments) Filaments very variable in
appearance, simple or branched; the cells constituting the articulations
of the filaments more or less filled with green, or very rarely brown or
purple granular matter; sometimes arranged in peculiar patterns on the
walls, and convertible into spores or zoospores. Not conjugating.

5. _Zygnemaceae_.--Aquatic filamentous plants, without evident gelatine,
composed of series of cylindrical cells, straight or curved. Cell
contents often arranged in elegant patterns on the walls. Reproduction
resulting from conjugation, followed by the development of a true spore,
in some genera dividing into four sporules before germinating.

6. _OEdogoniaceae_.--Simple or branched aquatic filamentous plants
attached without gelatine. Cell contents uniform, dense, cell division
accompanied by circumscissile debiscence of the parent cell, producing
rings on the filaments. Reproduction by zoospores formed of the whole
contents of a cell, with a crown of numerous cilia; resting spores
formed in sporangial cells after fecundation by ciliated spermatozoids
formed in antheridial cells.

7. _Siphonaceae_--Plants found in the sea, fresh water, or on damp
ground; of a membranous or horny byaline substance, filled with green
or colorless granular matter. Fronds consisting of continuous tubular
filaments, either free or collected into spongy masses of various
shapes. Crustaceous, globular, cylindrical, or flat. Fructification: by
zoospores, either single or very numerous, and by resting spores formed
in sporangial cells after the contents have been impregnated by the