443 _ 
joints; the antheridial bodies are usually pointed (comp. Harvey |. c. and BurrHam) 
and terminate in a short row of sterile cells, but that is not always the case (comp. 
Kyrın 1923 p. 122). A sterile branch given 
off from the second joint is in many spec- 
imens normally present, in other specimens 
it is normally wanting, and the trichoblast 
is then unbranched. For the rest various 
arrangements may occur, as shown in fig. 399. 
As regards the development of the spermatia 
see KyLiN (1. c.). 
The development of the cystocarp from 
the second joint of the female trichoblasts 
and the position of the branches of the upper 
sterile part of these trichoblasts in relation 
to that of the sterile trichoblasts have been 
mentioned by me in 1884. The development 
of the procarp and the cystocarp has recently 
been very carefully studied by Kyrın (1923 
pp. 118—121). The ripe cystocarps have a 
conical upper part, tapering towards the 
orifice (fig. 400). 
The tetrasporangia are, in the shoots 
Fig. 398. 
Polysiphonia nigrescens. Transverse section of stem, 
at the level of the transverse wall between two 
central cells. p, callus plate of the pit between the 
central cells. c, intercellular “euticular” bodies. 200 :1. 
bearing a trichoblast on each joint, seated to the right of the trichoblast (or branch) 
borne on the same joint. When the internodia consist of more than one joint, the 
D 
Fig. 399. 
position of the one following 
next to a trichoblast seems 
usually to be determined 
by the position of the follow- 
ing trichoblast. The tetra- 
sporangia are covered in 
the front with two peri- 
(a) 
= central cells between which 
m 5 Sra split is formed through 
a eZ NAG which the spores escape at 
[ E Of F 
maturity. On the flanks the 
sporangium is coyered by 
two other pericentral cells. 
Polysiphonia nigrescens. Male trichoblasts, differing from the ordinary type, No short peripheral cell is 
dorsal view. A without branches, B—F with one or two branches, sterile 
or fertile. A 230:1. 
produced as in several other 
species. A cruciately divided 
sporangium was once observed amongst numerous sporangia divided in the ordin- 
ary tetrahedrical way. 
