227 
Meer., 1904, p. 32 Taf. II figs. 15—23; Lemoine, Répart. du Maërl pl. I fig. 14. It is 
“flabellate, the branch-systems spreading like a fan in all directions from the centre 
of the frond almost in one plane. Sometimes it forms rather thick and compressed 
fronds” (Foslie, Remarks p. 69). 
3. F. palmatifida Foslie, Some new or cril. Lith., 1898 p. 6, Remarks p. 69; 
Lemoine, Répart. du Maërl pl. I fig. 3, Structure, p. 104. — “With branches more 
distant and palmate” (Foslie, 1905). 
4. F. subsimplex (Batt.) Foslie, Norw. Lithoth. 1895 p. 62 pl. 16 figs. 38—42; Le- 
moine, Rép. du Maërl pl. I fig. 10, Structure p. 104. Frond “simple or feebly branching” 
(Foslie Remarks). 
There are no distinct limits between these forms, which occur together at 
the same locality. 
The structure has been mentioned by Mme Lemoine (Structure p. 105), whose 
description may here be referred to. It will suffice to add some small remarks. 
According to Mme Lemoine there is always at the periphery a 
cortex composed by 5 or 6 layers of cells which are rectangu- 
lar, while the other cells are ovoid. I have certainly observed 
such a cortex in some cases, but it does not occur normally; 
the outer tissue, in the sections examined by me, more fre- 
quently consisted of cells of the same shape as those of the 
inner tissues (fig. 144). Transverse fusions between the cells are 
very frequent. The size of the cells is somewhat variable, generally (I ar 
they are 9—13 y long, 5—7y broad. Starch grains were found in Fig. 144. 
great quantity in all cells except the outermost. On being treated Lithothamnion calcareum, 
with acetic acid and iodine in potassium iodide the starch grains er 
swelled and filled the cells with a homogenous violet-brown mass. an fusions. 
In a specimen from Trindelen (ZB, July) empty concep- : 
tacles were found, the kind of which could not be determined; they were almost 
entirely immersed. Possibly they were antheridial conceptacles. 
The species has been found in 17 to 30 meters depth, on gravelly or stony 
bottom, generally associated with other Lithothamnia, in particular Lith. glaciale, 
and with Corallina officinalis. 
Localities. Kn: ZB, near Trindelen, 28—30 meters. — Ke: IL and IP, Fladen; IK, Lille Mid- 
delgrund. — Km: Læso Rende, clayey bottom, small fragments (C. H. Ostenfeld). 
Subgenus Phymatolithon Foslie. 
In 1898 Fosrie (Syst. Surv., p. 4) established the genus Phymatolithon, founded 
on Lithothamnion polymorphum, and distinguished from the genus Lithothamnion 
chiefly by immersed conceptacles and the roof of the sporangial ones being de- 
pressed or cup-shaped. Later on he has referred L. levigatum and another species 
to the same genus. I must, however, agree with Mme Lemoine, who observes (Struct. 
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