the plants exhibits consider- 
able differences. The maxi- 
mal total length observed 
in the North Sea and Skage- 
rak is only 12 cm while 
in the Limfjord and most of 
the other inner waters it is 
usually 18 cm, and greater 
maximal lengths are obser- 
ved in Eastern Kattegat (24 
cm), the Little Belt (23 cm), Ole D 
Fig. 482. the Great Belt (28cm) and the OS 
Phyllophora membranifolia. A, cortical : € 
cells, transverse section of frond. B, me- western Baltic Sea (21 cm). Fig. 483. 
dullar cell. 840 : 1. Only in the true Baltic is the Phyllophora membranifolia. Hya- 
La i line hairs on carpophores. Prins 
maximal length much less, Frederiks Grund, Vejle Fjord. 
Bm (12 cm) and Bb (5.5cm). The specimens occurring in Sb are 835 : 1. 
often very long and narrow with fairly slender stems (fig. 481). 
The anatomical structure of the thallus has been treated at length by Darsi- 
SHIRE, Whose description (1895) may here be referred to. WILLE has pictured a 
longitudinal section of the end of a frond showing the structure of the “Spring- 
brunnentypus” (1887, pl. 5, fig. 65). 
The cortical cells contain, according to DARBISHIRE, each one chromatophore 
that may easily be observed in the outermost cells where it lines the outer and 
lateral walls. In the inner cortical cells it is much branched and appears as much 
bent ribbons that perhaps partly are sepa- 
rate chromatophores. In the inner cells a 
great number of rod-shaped or ribbon-like 
plastids are present which stain intensively 
with hematoxylin. A single nucleus in the 
vegetative cells may also be ascertained by 
this reagent (fig. 482). Hyaline hairs have 
only been observed in carpophores from a 
specimen gathered in Vejle Fjord in August 
(fig. 483). 
Secondary pits are produced in consider- 
able number between the elongated cells of 
Fig. 484. the medullary tissue with the effect that 
Phyllophora membranifolia, Longitudinal section of several pits are to be found in the same wall 
medullar cells Dreh Pi pits. (fig. 484). A plug Re Gale de geen fim the 
middle of each pit. 
As shown by Jønsson (1891, p. 19) and DARBISHIRE (1895), the lower portion 
of the stem has a thick cortex produced by secondary growth in thickness. The 
