271 
complanated, especially in the upper end of the shoots (Plate IV fig. 6 ). In speci- 
mens from deeper water it sometimes happens that some of the branches assume 
a special character, growing out as slender, unbranched, irregularly curved organs 
taking not the upward direction but growing in a transversal direction or more 
downwards. They resemble either rhizomes or tendrils but have usually not the 
function of either of these organs (Plate IV fig. 7). It may however happen that 
the end of such a branch fixes itself on any solid substratum, f. inst. molluses, 
Furcellaria, Zostera, developing an adhesive disc similar to the primary crustaceous 
frond. It is connected with the ultimate joint by a genicle. Such adhesive discs 
may also develop at the end of ordinary fronds coming accidentally in contact 
with any solid body (fig. 195). These discs have the power 
of producing new articulated fronds, in a similar manner to 
the primary ones (fig. 195 B). 
The age of the articulated fronds is not known. They | 
reach a length of up to 16 cm, usually however only 10 cm. \ | ) 
Supposing that a long pinnated shoot is produced every year, | N 
it seems probable that the age of the erect fronds does not \ W 
exceed 3 or 4 years. N SAR = 
The joints consist of a central tissue of elongated cells Fig. GE 
and a cortex not sharply limited from it, the cell-rows at the  Gorattina officinalis. A, ad- 
hesive disc developed at the 
periphery of the central tissue bending outwards and consisting 
of cells becoming gradually shorter outwards. The cells of 
the central tissue are usually 5—8 times as long as broad; 
they are disposed in transversal zones, their end-walls being 
situated about at the same level, the limiting lines being, 
however, convex upwards (comp. Mrs. WEBER, Siboga pl. XVI 
end of an ordinary shoot on 
coming in contact with a 
shell. B, adhesive disc devel- 
oped from the ultimate joint 
of a shoot coming in contact 
with a rhizome of Zostera; 
scars after articulated fronds 
developed from the dise but 
fallen off are visible. 3:1. 
fig. 15, 1904). The cells are as usual connected with primary 
pits at the end walls, while secondary pits do not occur"), but lateral fusions 
between the cells of the central strand are very numerous and more than two cells 
frequently fuse together. As mentioned above, p. 211, I found these fusions followed 
by a fusion of the nuclei in a tetraspore-bearing plant. 
In a female specimen with ripe cystocarps collected in winter at Frederikshayn 
similar cell-fusions were found, but the behaviour of the nuclei was different, those 
of the central tissue having divided in two to four, while such divisions were not 
observed in the tetraspore-bearing plants. It was therefore not easy to decide 
whether fusion of the nuclei took place in the female plant. It should be of much 
interest to decide whether there is such a constant difference between the tetraspore- 
bearing and the sexual plants. 
The cortex of the joints is covered with a continuous layer of low cover-cells 
(comp. Solms, Corall. p. 29). 
1) PILGER states, however, that the longitudinal walls in the central tissue of Corallina are pro- 
vided with pits (1908. p. 252). 
