484 
to be quite normal. Intermixed with these cell-filaments consisting 
of one row of cells, occur some filaments in which the cells are 
divided into two rows (Schizogoninm- stage fig. 99, n), and this division 
is continued on the same plane so that it forms a complete plate 
(Prasiola - stage fig. 99, b and f). These plates are sometimes fairly 
broad much more so than fig. 99, f, but plates, as large as those oc¬ 
curring in the land-form of Prasiola crispa , were not met with. I 
have only observed these Prasiola - like cell-plates in the material 
from Hojvig, in which there further occurred some filaments re¬ 
sembling the fragment illustrated in fig. 99, a. As may be seen from 
this figure, the cells have become divided in more than two direc¬ 
tions, thereby reminding one of the genus Gayella founded by 
Rosen vinge. Typically developed Gayella -specimens did not 
occur in this gathering, consequently, it was very interesting that 
a gathering from Svino contained some well-developed Gayella- 
filaments exactly agreeing with Rosenvinge’s description. Fig. 99, d, 
shows a filament which has begun to develop into Gayella , the 
cells being divided in more than two directions; and fig. 99, o, p 
show the transverse section of thinner Gayella- filaments. In the 
latter gathering there also occurred cell-filaments exactly agreeing 
with, e. g. fig. 99, e; and fig. 99, h represents a fragment of such a fila¬ 
ment bearing one rhizoid. Finally in fig. 99, / and m are shown 
two fragments of filaments whence proceed several rhizoids side by 
side, corresponding with Rosenvinge’s fig. 45, G. 
It is on account of the interesting way in which the filaments 
consisting of a single row of cells pass by such very gradual stages, 
on the one hand into the form Prasiola , and on the other into the 
form Gayella , that it appears to me to be impracticable to maintain 
the genus Gayella ; the latter must therefore be regarded only as a 
phase in the development of Prasiola crispa subspec. marina co- 
ordinately with the already accepted Ulothrix radicans- stage and 
Schizogonium-Prasiola - stage. 
With regard to the contents of the cells, the star-like chromato- 
phores, etc., they exactly agreed with Gays’s description in »Algues 
vertes« (pp. 80—86) and Wille’s (1. c.). 
In »Deuxieme Memoire sur les Algues marines du Groenland« 
(p. 116), Rosen vinge points out the following characteristic of 
Gayella: — »Les couches interieures des membranes qui entourent 
les cellules, donnent la reaction de cellulose avec la chlorojodure 
de zinc, la membrane epaisse exterieure des filaments reste au con- 
