us 
production ceases and then the rhizoids appear 
and the shoot becomes pointed. Such spiny 
shoots have been met with in specimens from 
the different Danish waters from the North 
Sea to the Belts, gathered in July to November. 
The form described and figured by Kürzıng 
under the name of Polysiphonia asperula (l. c.) 
shows these spinous shoots in great number 
also in the upper part of the plant. The rhizoids 
mentioned ought perhaps rather to be compared 
with the unicellular hyaline hairs occurring in 
other Florideæ; they are like these separated 
Fig. 407. 
Brongniartella byssoides. Shoot with antheridia- g R 
bearing trichoblasts. June. 350: 1. from the pericentral cell by a wall. As I have 
had no occasion of examining them in a living 
state, it cannot be said with certainty whether they contain chromatophores or not. 
The antheridia-bearing trichoblasts are simple with a two-celled stipe without 
sterile branch (comp. Kürzıng Tab. phyc. 14, Pl. 23 and 
THuRET 1878). They are borne on short branches which also 
bear sterile trichoblasts but are usually unbranched (fig. 407). 
I always found them on particular individuals, but BurrHam 
found them intermixed with eystocarps on different branches 
of the same plant, and in another plant he found antheridia 
combined with tetrasporangia (1888, p. 263). LyNGBYE found 
these organs in specimens gathered at Gjerrild 1825 and men- 
tions them in his herbarium as corpuscula antheræformia. 
The procarps arise as usual in the second joint of 
a trichoblast. The third joint remains short and the fourth 
bears a branch on the right side. The ripe cystocarp has 
a cylindrical spout consisting of parallel cell-rows. The 
sterile part of the trichoblast is kept till the maturity of 
the cystocarp. (fig. 408). 
The tetrasporangia arise in shoots with more or less 
limited growth of the two last orders of ramification. In 
transversal sections of tetraspore-bearing joints I found 
7 pericentral cells whereas sterile joints of the same 
shoot often showed only 6 or 5 (fig. 403). A small peri- 
pheral cell under one of the secondary pericentral cells 
was not met with. The sporangia apparently always arise 
Fig. 408. 
Brongniartella byssoides. Ripe 
to the right of the trichoblast borne on the same joint. cystocarp. July. 130: 1. 
The different organs of fructification were always found 
in distinct individuals. Antheridia were met with in June to September, carpogonia 
in June to July and even later, cystocarps in August to October and tetraspor- 
