numbers (figs. 107 I, 108 A). More than two cells may sometimes fuse together. The 
cells of the basal layer are low, and the same may also be the case with the under- 
most cells in the erect filaments, while those of the middle and the upper part 
of the filaments may reach a length of up to 2,5 times the breadth. The erect 
filaments have almost the same breadth in their whole length, frequently, however, 
they are a little thicker towards the base, and the uppermost cell may be a little 
thicker than the second from the top. The filaments are rather firmly connected, 
but not or only to a slight degree united by a gelatinous collode. In the undermost 
partofthe frond 
fusions may 
sometimes take —— = 
place between == 7 
contiguouscells 
of different fila- 
ments, as in the 
following spe- 
cies. The sur- 
face is cove- 
red with a ra- 
ther firm out- 
er wall. Each 
cell contains a Fig. 107. 
calotte - shaped Cruoriopsis danica. A—H from M. A—D, vertical sections of frond, in Ba young hair, in C, 
chromatophore a more developed hair, in D, fully developed erect filaments, a little swollen at the top, E, 
P unripe sporangium. F, new sporangia formed within emptied sporangial walls. G, H, ripe 
and a small sporangia. I, K from MK. I, basal layer from the face showing fusions. K, erect filament 
ending in hair. 390:1. 
nucleus, little 
susceptible to staining reagents. The frond is, at all events in some cases, poly- 
stromatic to the border (fig. 108 F). 
Here and there some of the erect filaments terminate in hyaline hairs; these 
occur in varying quantity, usually solitary. They are fairly rich in protoplasm. 
The subjacent cell is somewhat lengthened, conical (fig. 107). 
The sporangia arise from the terminal cell of erect filaments. They reach the 
surface of the frond and are originally, like the vegetative cells, covered with a thick 
outer wall (fig. 108). The first wall is inclined, the two following perpendicular to 
it (figs. 107 G, 108 E). After evacuation of the sporangium a new one may some- 
times be formed from the subjacent cell within the emptied sporangial wall (fig. 107 F). 
In specimens dredged in the Little Belt in July 1915 I found very short-celled fila- 
ments which were supposed to be auxiliary-cell filaments, though carpogonia were 
not found. They arose from erect filaments, which in a smaller or greater extent 
of their length consisted of low, disc-shaped cells, the undermost and one, or more 
rarely two or three, of the uppermost cells showing the ordinary length. The short 
cells were of a feebler colour than the other cells; they resembled the auxiliary- 
D. K. D. Vidensk. Selsk. Skr., 7. Reekke, naturvidensk. og mathem. Afd. VII. 2. 24 
