Lithothamnion Philippi. 
Subgenus Hulithothamnion Fosl., char. mut. 
Conceptacles of sporangia superficial or more or less immersed; 
the roof plane or vaulted. 
1. Lithothamnion læve (Strömf.) Fosl. 
FosLıE in K. Rosenv. Deux. Mém., 1898, p. 14; Rev. Surv., 1898, p. 15; Remarks, 1906, p. 16 and 131; 
Algol. Notiser V, 1908, p. 6; K. RosEnvinGeE, Mar. Alg. N. E. Greenl., 1910, p. 100, fig. 1; Lemoine, 
Struct., 1911, p. 74, figs. 36 and 37. 
Lithophyllum leve Strömfelt, Isl., 1886, p. 21, tab. I fig. 11—12. 
Lithothamnion Lenormandi (Aresch.) Rosanoff, f. lave (Strömf.) Foslie, Contrib. IL, 1891, p. 11. 
Lithothamnion tenue K. Rosenvinge, Gronl. Havalg., 1893, p. 778, figs. 4—7 (Alg. mar. Gr. p. 58). 
Lithothamnion Strömfeltii Foslie, Norw. Forms, 1895, p. 145. 
This species, very common in the Arctic Sea, has been found in two localities 
in the sea north of Sealand, the most southerly stations known in Europe. The 
specimens from the Kattegat were mentioned by FosuiE in 1906 (Remarks p. 131). 
I have examined the structure of the specimen from the Sound which was preser- 
ved in Juer’s liquid. The species is easily distinguished from L. Lenormandi by 
its smooth surface and the large conceptacles. i 
The thallus in the Danish specimens is thin. The filaments of the hypothallium 
are, as pointed out by Mme Lemoine, loosely connected. When seen from the surface, 
they show here and there transversal fusions. The cells are 21—33 long, 7,5 —9,5 u broad. 
According to Mme Lemoine, the undermost cells of the hypothallium form rectangular 
cells directed towards the sub- 
stratum, thus constituting “une On SSeS 
= S ære Seer s 
rangée de rhizoides obliques”. S SEX) SELON: ) 
I have not been able to see ox YO OD RSIS > 
( œ = 
anything of this kind in the IL CCS eg 
specimen examined. The fil- eee == Se 
aments of the perithallium are A ==> 
composed of a small number 
of roundish cells, 7 » thick or 
a little more, up to 104. These I 
dimensions, which I found in © SE ©) 
é Ne OC Bog 
specimens from both localities, © OO Å 
are in accordance with FosLIE's ao Q 
\ u 
statement (Remarks p. 18), ) SO = 
while Mme LEMOINE gives the © SENG 
thickness as only 4—5 47. The Ss 
7 This indication is not in accor- Fig. 129 
ae = g. 129. 
x nce my ith the figures of NEE LEMOINE, Lithothamnion leve, A and B, vertical sections of crust. C, Hypothal- 
in which the cells are thicker. lium seen from below. From Hellebæk. 350: 1 
