34 
GENERA. 
FIRST CLASS. — SECOND ORDER. 
Dynamena. Not much branching. Cells opposite. 
Sertularia. Stem or branches flexible. Cells al- 
ternate. 
Idia. Branches pinnated and alternate. Cells al- 
ternate,, nearly awl-shaped, and curved. 
Clytia. Stem filiform, twining or climbing. Cells 
campanulated and pediculated; pedicles long and 
curved. 
GENERA. 
FIRST CLASS.— SECOND ORDER. 
Laomedea. Plant-like. Cells dispersed ; peduncu- 
lated, or almost sessile. 
Thoa. Stem formed of numerous interwoven tubes. 
Ovaria in clusters. 
Salacia. Cells long, cylindrical, and in united for- 
mation to the number four; side and verticillated 
openings. 
