— 365 
The cells contain one nucleus and nu- 
merous ribbon-shaped or irregular chromato- 
phores (Fig. 301 B, comp. NESTLER fig. 1). 
For the nuclei see SCHILLER (1911). The 
gland cells are borne on the inner (upper) 
side of the pinne, resting on a single cell. 
Their number is rather variable, owing to 
unknown causes. They are normally present; 
in single cases, however, I have sought them 
in vain. In the Skagerak they were never 
missing, and they were met with, partly 
even abundantly, in specimens growing near 
the southern limit of the species (fig. 300); 
they further occurred in numbers in slight and 
in great depths (e. g. Groves Flak, 32 m). The 
function of the gland cells is unknown. NEST- | 
LER is inclined to suppose them to be absorb- Fig. 301. 
ing organs; SCHUSSNIG supposes that they Antithamnion Plumula. Antheridial bushes. 390 : 1. 
function in the same manner as air-bladders. 
The tetrasporangia are borne on the upper side of the pinnæ usually in small 
elusters. Often a single sporangium is found terminal on a short stalk-cell, but this 
cell usually bears further one or two or 
three younger sporangia or rudiments of 
sporangia, and the stalk may sometimes 
consist of two or three cells (figs. 299, 300). 
Besides the sporangia borne in clusters 
sessile sporangia may occur too, princip- 
ally on the outer part of the pinnule. 
Sporangial clusters opposed to a pinna 
may sometimes be met with; they re- 
present a pinna reduced to a cluster of 
sporangia (figs. 299, 300). At the end of 
the period of growth the sporangia may 
even become terminal on the long shools, 
when their growth is ceasing (fig. 300). 
The ripe sporangia were 42—45,5 w long, 
29—40 w broad in specimens from the Ska- 
gerak; in a specimen from the Little Belt 
they were only 35—38 w long, 27—30 u 
broad. They open by a slit. 
The antheridia (fig. 301) have a similar 
Fig. 302: 
Antithamnion Plumula. Procarps. In A the carpogonial Woke > — 
branches are shaded. A 300 :1. B 390 : 1. position to the tetrasporangia. They are 
D. K. D. Vidensk. Selsk. Skr., 7. Række, naturvidensk. og mathem. Afd, VII. 3. 47 
