311 
occur rather frequently, in branches of different order (fig. 216 B), principally in the 
most vigorous main axes, which may bear branches on all sides. J. AGARDH states 
that the lower branches are given off on all sides, and that I have also found in 
some cases; but in other cases, the main stem was pinnate from the base, and the 
same was found in a young plant (fig. 218). 
The descending filaments constituting the cortex of the stem and the main 
branches are produced from the base of the cells of the axes and from the base of 
the branches given off from them; they may completely hide the original cell-filament 
of these axes. Here and there adventitious filaments are given off from the descending 
filaments, principally from 
the base of the branches 
(fig. 219). 
All cells contain a 
single nucleus and nume- 
rous chromatophores which 
in the young cells are small 
lengthened discs (fig. 217), in 
the older ones long bended, 
partly branched ribbons. 
All the fructiferous 
specimens bear heaps of 
paraspores agreeing with 
the description of Kyrın, 
1. c. They are more or less 
obliquely ovate and contain 
an indefinite number of SER 
Reo 10-72 res De Callithamnion Hookeri. With a nes (Kerteminde). A, nearly 
ling the tetraspores; they are ripe heap. B, younger stage. C—G, still younger stages, the heaps of para- 
placed on the upper pinne spores partly replaced by vegetative branches. 200 : 1. 
or pinnulæ, usually on their 
upper side in a number of one or two on the first or on the first and the second 
joint, more rarely in a number of three or four. In the latter case they are not 
always placed on the upper side of the branch but partly on the flanks or on the 
under side, and not rarely it happens that two heaps are placed on the same joint 
and then one under the other (fig. 221 B) or beside the other (fig. 220 B) or in oblique 
direction under the other, or they may be opposite, on the upper and under side 
of the cell (fig. 220). One of the heaps may be replaced by a vegetative branch. 
The position of the heaps of paraspores is the same as that of the tetrasporangia 
which in the plants from the Atlantic shores are placed not only on the upper side 
of the pinnules but also “utroque latere inordinate” (J. AGARDH, I. €. p. 52, comp. 
Harvey l.c. pl. 279, fig. 4, Kirzine |. c. pl. 94 fig. b). 
The fact that the heaps of paraspores have a position similar to that of the tetra- 
40* 
