130 
the middle of the cell a body staining in hæmalum is visible, probably a pyre- 
noid. The branches are given off at a certain distance from the acroscopic trans- 
verse wall, sometimes from the middle of the cell or even, though rarely, a little 
under the middle. All the vegetative branches are given off in a plane parallel to 
the surface of the host, while the extremely short fertile branchlets break through 
the cuticle in a direction perpendicular to that plane. These branchlets consist of 
a short partly immersed stalk-cell and an entirely free sporangium, but sporangia 
arising directly from the endophytic filaments also occur. In the fertile part of the 
plant a sporangium is usually given off from each cell in the endophytic filament 
(fig. 55 A). After the evacuation a new sporangium may be formed within the 
empty sporangial wall, but it may also occur that a new lateral sporangium is 
given off from the stalk cell besides the emptied terminal one. 
The species appears to be nearly related to Acrochetium endophyticum BATTERS 
(Journ. of Botany Vol. 34 1896 p. 386) living in “the cortical layer” of Heterosiphonia 
coccinea. As far as can be seen from BATTERSs’ description this species is distin- 
guished from Ch. emergens mainly by longer erect filaments, which are composed 
of from one to three cells. 
Locality. Sk: Mellegrund off Hirshals (XO), 11,5 to 15 meters, with ripe sporangia in August. 
21. Chantransia immersa sp. nov. 
Thallus endophyticus; fila omnino immersa, intercellularia, varie ramosa, 
ramis sparsis vel ex una cellula pluribus egredientibus. Cellule nunc cylindricæ 
plerumque tamen medio vel supra medium inflate, 8—10 „ late, 40—53 y longe, 
nunc, pr&cipue superficiem hospitis versus, breviores plus minus rotundatæ, usque 
ad 15 4 late. Chromatophorum unicum stellare pyrenoide centrali et ramis longis 
sursum et deorsum protractis munitum. Cellule ultimæ breves obovate vel ro- 
tundatæ, in superficie hospitis prorumpunt, cellulas periphericas illius plerumque 
non superantes, nonnunquam pilum hyalinum gerentes. Sporangia, transformatione 
cellularum ultimarum orta, obovata, 15—17,5 » longa, 11—12 „ lata, monospora, 
post evacuationem sæpe sporangio novo e cellula suffultoria formato repleta. 
This species occurs in Rhodomela subfusca and in species of Polysiphonia. As 
the endophytes are essentially identical in structure, they are referred to the same 
species, but as their behaviour to the different hosts is somewhat different, two 
forms may be distinguished. 
Forma Rhodomelæ. In Rhodomela I have only found the endophyte growing 
in tumours and occurring in fairly great quantity at Frederikshavn in July 1895 
and 1896. These tumours are irregularly roundish and somewhat remind one in 
form and size of Harveyella mirabilis. I conclude that they are occasioned by this 
endophyte, but it deserves notice that these tumours also contained an endophytic 
Ectocarpus or Streblonema and the very common endophyte Bolbocoleon piliferum. 
The Chantransia grows intercellularly through the whole tumour, the filaments 
running mainly in a radial direction. The swellings have essentially the same 
