Spirogyra decimina (O.F.Müll.) Dumort.

IV i
B ...

Spirogyra decimina submarina n. var.Collins, Tufts Goll.stud.
Sci.Ser. 2; 110. J1 1909.

Filaments 27-32 u. diaip.,cells 3-6 diam. long; chromatophores
2 or 3, making 1-J--3 turns in the cell, spores ellipsoid,2-3 diam.,
long, 31-37 X 56-120 u; fertile cells swollen just enough to hold
the spore. Mass., Conn.

Perhaps a good species, hut having so many resemblances to
S. decimina as to indicate that the differences may he due to
the station, salt marsh and "brackish pools, an unusual one for
a Spirogyra. The principal distinctions are in the slender fila-
ments, longer cells, longer spores and somewhat swollen fertile
cells•