sensibly extended itself, It now occupies a broad space around
the margin, and resembles a floating bed of opaque bituminous-
like scum.
From its characters, this Alga certainly belongs to A g a r d h ’s
genus Lyngbya. But that naturalist remarks, that the filaments
of Lyngbya differ from those of Calothrix in being
much larger, and more nearly approaching to the genus Conferva.
Lyngbya 'prolifica forms an exception to this observation,
for the filaments are of extreme tenuity.
Fig. 1. A mass o f filaments, natural size. Fig. 2. Filaments. Fig. 3. For-
timi o f a filament; magnified.
