EAST 
produced from the central cells, further occur on the creeping shoots and the under- 
most part of the long upright shoots, but they may also arise at the base of the 
normal branches in the upper part of the plant. They usually appear on the inner 
side of the branch, most frequently between the 2nd and the 3rd or between the 
3rd and the 4th joint. 
The upper trichoblast-bearing end of the shoots is curved, each trichoblast 
causing the axis to change direction. Later on, when the longitudinal growth takes 
place, the shoots are strengthened and each trace of bending is effaced. The number 
of pericentral cells is 11—13 in the long 
shoots, lower in the short shoots (about 9). ( 
The older joints, in particular of the longer 
shoots, usually show a more or less marked 
torsion, the pericentral cells being spirally 
curved, an appearance already observed by 
the first observers of the species. The torsion 
is undoubtedly caused by the pericentral 
cells growing more in length than the central 
cell. The coherence between the first and 
latter and between the ends of the pericentral 
cells in consecutive joints must, however, 
oppose resistance to this torsion, and this 
resistance may sometimes cause that the 
pericentral cells have a sigmoid curvature Be 
= 5 5 Polysiphonia atrorubescens. Male trichoblasts with ste- 
(fig. 385 C). The torsion may go to the rile branches. 200 : 1. 
right or to the left, and the direction 
may change in various joints of the same shoot. — Cortication does not occur. 
The antheridia have been met with only once in a specimen from Hirshals 
(July 1914). The male trichoblasts may have the same appearance as in most other 
species, the antheridial body occupying the main axis of the trichoblast except the 
two first joints, the upper of which bears a sterile branched branch to the right.” 
But the fertile part of the trichoblast, which is always curved inwards, often bears 
sterile branches on the flanks in varying number (1 to 3 or more), issuing from the 
inner central axial cell-row (fig. 389). The antheridial bodies may then be a little 
irregular in shape and sometimes slightly branched. It also happens that the lower sterile 
branch is transformed into an antheridial body. The sterile branches of the antheridial 
bodies occurred in so great a number that they seemed to be a normal appearance. 
The ripe cystocarps are nearly globular, about 400 « in diameter, with a short 
stalk, the ostiole is small, situated in a slight depression and surrounded by small 
cells. The outer cells of the cystocarpial wall are connected with secondary pits, the 
formation of which is easily studied in this object. 
1 According to THURET (Et. phyc. p. 86) the male trichoblast in this species bears no sterile 
branch on the coast of France. 
D. K. D. Vidensk. Selsk. Skr., 7. Række, naturvidensk. og mathem. Afd. VII. 3. 56 
