In specimens collected in June I 
- found such cavities about 6 cells in 
diameter and not so deep but that 
the sporangia reached the border of 
the aperture (fig. 123 A). The spor- 
angia in these young conceptacles are 
of different age. Besides fully devel- 
oped or two-parted sporangia young 
ones are found, but also aborted 
. sporangia occur, having sometimes 
the character of paraphyses (fig. 
Fig. 122. 
Hildenbrandia prototypus, vertical section of old crust showing i 
two conceptacles and limiting lines between the productions of 123 A, B), The production of Spor- 
three years: 1, angia continues a very long time, 
usually apparently a year (or more ?), while the crust grows gradually in thickness. 
When the sporangia have been emptied, new ones are produced on the same place 
from the cells forming the bottom of the cavity, within the emptied sporangial 
walls or between them, and at the same time the formation of sporangia extends 
at the sides and upwards on the lateral walls of the 
cavity, the cells of the vertical cell-rows limiting the 
cavity at the sides producing sporangia directed obliquely 
or horizontally towards the centre of the cavity, which 
gradually takes a nearly orbicular outline. The spor- 
angia-producing cells divide into a small stalk-cell and a 
greater outer cell, the sporangium. The stalk-cells of 
the lateral sporangia seem usually to decay, and the re- 
placing sporangia must therefore be produced by the 
cells of cell-rows situated within the stalk-cells. In such 
a manner the conceptacle increases in transversal out- 
line, new vertical cell-rows being gradually engaged in 
the production of sporangia. The parts of the cell-rows 
which are active in this manner are consumed by this 
production, and the continuity between the upper part 
forming the roof of the conceptacle and the under part 
is thus abolished. The upper part of these cell-rows 
therefore finally decays, at least in those situated nearest 
the aperture, where the regular arrangement of the cells 
is disturbed; the cell-walls swell, and the contents be- 
come discoloured and degenerate (fig. 125 A). In the Fig. 123. 
peripheral part of the roof, the undermost cells of the Hildenbrandia prototypus, vertical 
interrupted vertical cell-rows often undergo a growth in os of young conceplacles. A 
and B from specimen collected in 
a transversal direction, in consequence of which the June (near Refsnæs), C, from ae 
a collected in January (Store Belt). 
cell-rows become bent inward below (fig. 122). The above 560 : 1. 
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