241 
this species consists of three cell-layers, the middlemost of which is composed of 
high cells, must refer to the fertile part of the crust (comp. fig. 159 D); but the 
author says that she has observed three layers also at a great distance from the con- 
ceptacles. Possibly, the specimens referred to this species by Mme Lemoine do 
not all belong to it. In Calc. Alg. Med., 1915, p. 19, the same author mentions spe- 
cimens of this species from the Mediterranean consisting only of two layers of cells, 
the upper being the cortical cells; these specimens thus agree with the Danish ones. 
The conceptacles 
of sporangia are usually 
densely crowded. They 
are low conical or, when 
very densely placed, de- 
pressed, with almost 
level surface (figs. 156 
—158). The orifice is 
rather narrow, almost 
cylindrical, not enlar- 
ged upwards, clothed 
with unicellular hairs 
of varying length. In 
rare cases I found the 
hairs long and protru- 
ding outwards in a ver- 
tical direction (fig.158 D), 
as drawn by ROSANOFF 
in fig. 11, pl. I, I. c., but 
usually they are shorter, Fig. 158. 
directed inwards hori- Melobesia Lejolisii, from TG, north of Læsø. A, frond seen from above, at left a 
% trichocyte. B, vertical section of antheridial conceptacle, not yet ripe. C, vertical 
zontally and not PLO- section of antheridial conceptacle provided with a spout. D, vertical section of 
truding (figs. 156 E; 157 sporangial conceptacle with well developed peristomial hairs. Æ, the same spor- 
angium as seen in D, from a following section. B and C 650:1, the rest 350:1. 
A, comp. ROSANOFF’s i 
fig. 8). The last quoted figure of ROSANOFF certainly represents a normal, fully de- 
veloped state. FosLıE, who did not find any protruding crown at all in examining 
numerous specimens, thought that this- might perhaps be owing to the fact that he 
had only had dried material for examination, “or it may be that the cells of the 
corona have a short phase of development and are soon falling to decay”. My 
investigations do not favour these suppositions; it must be supposed, that the de- 
velopment of the hairs is variable according to the various conditions. — The roof 
of the conceptacle is rather thin, consisting of about 2 (1—3) cell-layers, only a 
little thicker, if at all, near the orifice. The floor of the conceptacle consists of a 
single cell-layer; more rarely this cell-layer is absorbed (fig. 157 A). In some cases 
a sterile columella was observed in the centre of the conceptacle (fig. 157 C), but 
D. K. D. Vidensk, Selsk, Skr., 7. Række, naturvidensk. og mathem. Afd. VII. 2. 31 
