426 
filaments become connected with 
each other and with the pericentral 
cells by secondary pits (fig. 368 B). 
Two pits in the same wall may even 
occur. 
The antheridia occupy the main axis 
of the male trichoblasts except the 
two lowermost cells. and the second 
cell bears a sterile branch on its right 
side. A torsion takes place. however, 
in the second joint with the con- 
Fig. 370. 
Polysiphonia violacea. Ripe # 5 
cystocarp. 76:1. sequence thatthe sterile branch issues 
on the outer side of the trichoblast 
and thus serves to protect the antheridial body (fig. 369). 
As regards the development and the structure of the 
cystocarps reference may be made to Yamanoucut (1906). A 
ripe cystocarp is shown in fig. 370. 
In the tetrasporiferous shoots a considerable number 
of joints, usually without interruption, contain each one 
sporangium. As the sporangia always arise to the left of the 
trichoblast of the same joint, the sporangia are thus arranged Fig. 371. 
in a spiral. The fertile joints have 6 pericentral cells, two of  Polysiphonia violacea. Branch 
which are cut off from the cell which gives rise to the spor-  “ifh !etrasporangia. 20:1. 
angium and which corresponds to the second pericentral 
cell in the sterile joints (figs. 372, 373. comp. fig. 366). One of these secondary peri- 
central cells does not reach the base of the joint, and a small peripheral cell (p) 
is here later cut off from the inner cell which is thereafter divided by a horizontal 
wall in a short stalk-cell (s) and the mother-cell of the sporangium. The stalk-cell 
is then connected through pits with 
the central cell, the sporangium, the 
two secondary pericentral cells and 
the small peripheral cell, p. 
P. violacea which is one of the 
most common species of Algæ in the 
Danish waters is very variable. The 
single characters distinguishing the 
different forms, as the length of the 
joints, the degree of cortication, the 
degree of branching of the trichoblasts 
Fig. 372. 
Polysiphonia violacea, A, tetrasporiferous joint; b basal cell of and the frequency of the secondary 
trichoblast; Ps small peripheral cell. B, transverse section of axillarv shoots are evidently depend- 
tetrasporiferous joint. 390:1. C, similar after evacuation; s, 5 aoe = A 
split through which the tetraspores have escaped. 230 : 1. ent on the outer conditions. P. fibrillosa 
