553 
of Phyllophora Brodiwi partly beset with Ceralocolax Hartzii bearing ripe tetra- 
sporangia were placed in a glass vessel with sea-water and kept there for a long 
time. Three months later a number of young plants of Cerato- 
colax had arisen on other fronds or other shoots of Phyllophora, 
undoubtedly from tetraspores set free from the nemathecia, eo 
comp. fig. 541. In the middle of September these specimens 0 O00 Q 0) 
contained no organs of reproduction. In April 1930 the tips of 
the branches of one of them were globular and turned out to be 9@ @ ge 
nemathecia, being composed of radiating cell-rows. Some of the v® = 
cells of the latter were 4-parted, but the sporangia were not = 
quite normal, probably owing to the unfavourable conditions of the Fig. 540. 
3 “9 atts Ceratocolax Hartzii. Sup- 
culture. It must then be concluded that plants arisen by germina- sea antheridia. Au- 
tion of tetraspores are able to produce tetrasporangia directly. gust. Formalin. 625 : 1. 
The tetraspores seem to be the only reproductive cells 
which reach normal development, at any rate in the Danish waters. They are pro- 
duced in spring, particularly in March to May. The sex organs are abortive and 
cystocarps are never produced. The specimens gathered after June never contain 
nemathecia but only sex organs, at least procarps, and might therefore be designated 
as gametophytes, but sex organs may also appear in the spring months, particularly 
in May, simultaneously with the nemathecia. It is pos- 
sible that there exist distinct sexual and asexual indi- 
viduals, resp. gametophytes and sporophytes, bul at any 
rate in some cases procarps and nemathecia were found 
with certainty in the same individual, and this is perhaps 
a normal occurrence. It seems that sex organs normally 
arise in specimens first producing tetrasporangia, but 
this point deserves further investigation. 
The Danish specimens have here been referred to 
the same species as the Greenland ones though there 
are or seem to be some differences. In specimens from 
East Greenland the parasite was found penetrating 
deeply into the frond of Phyllophora, deeper than in the 
Danish specimens, but I have later found Greenland 
Fig. 541. specimens where the connection between the two orga- 
Ceratocolax Hartzii. Nearly 4months nisms was much as in the Danish specimens. Another 
eae denied heen difference is that sex organs have not been observed in 
deposited in May specimens of the Greenland specimens, but that may perhaps be due to 
Phyllophora Brodiei, one of which insufficient investigation. Finally the sporangia seem to 
bore a nemathecium-bearing Cera- 5 . . 
tocolax. Drawn in September. 2:1. be larger in the Greenland specimens than in the Danish 
ones; in the former I found them 22—26 w long, 12-16 u 
broad, while in the latter they were only 9—19 w long, 8-11 # broad; but the 
dimensions of the sporangia seem to be variable. 
D.K. D. Vidensk. Selsk. Skr., 7. Række, naturvidensk. ogmathem. Afd. VIT. 4. 71 
