314 
distinct, straight, not bent in zigzag, corticated below. The thickness is 130—150 x 
below, over the cortication about 75 uw. The cells are 1'/;—5 times as long as broad. 
From the cells of the cortical filaments growing down in the outer walls small 
adventitious filaments are given off (fig. 224), probably more numerous in larger 
specimens. The lateral branches are as a rule much shorter than the main axes 
the result being that the outline of the 
main branches become narrow, hastate or 
pyramidate. 
The branches are given off on all sides, as 
a rule one from each joint; they are usually 
placed in a spiral line, however not in the 
whole length of the shoot, the angle of diver- 
gence is about 1/3 or 7/4, the spiral turning to 
the right or to the left in different shoots 
(fig. 227). In a long branch the branches were 
arranged from the base in a spiral turning to the 
right with an angle of divergence of 1/3, then 
irregularly, after that in a spiral to the right 
with an angle of divergence of 1/3 and finally 
secundate. The ramification of the lateral 
branches is usually similar to that of the main 
branches. The first branches of the second order 
are frequently alternating to the right and to 
the left or irregularly arranged, and it is only 
at a higher level that the regular spiral ar- 
rangement commences. In the main branches 
this ramification may be repeated several times, 
but the branches become gradually feebler and 
ae the later branches have limited growth, are 
Callithamnion En Part of tetrasporiferous divaricate and more irregularly branched, often 
plant. 62:1. secundate, bearing only branches on the upper 
side (fig. 228). As will be seen, this description 
agrees with that of Kyrın. Secundate pinnulæ are also mentioned and figured by 
Harvey (Phye. Brit. Pl. 129), but as many and as regularly arranged secundate pin- 
nulæ as in Harvey's figs. 2 and 3 I have never seen in the Danish specimens. 
In the main branches dividing walls of the apical cell are inclined, and the 
axis is at first bent in zigzag but later it becomes straight. In the unbranched or 
feebly branched pinnule the dividing walls are transversal. 
The cells contain a single nucleus in the young and the later age, and numerous 
long ribbon-like, more or less branched chromatophores. 
Characteristic of the species is the great development of hyaline hairs at the 
tip of the branchlets, as already figured by Kirzine and Kyrın. The hairs are rather 
rs 
