217 
Lithophyllum Lenormandi (Aresch.) Rosanoff, Rech. anat. p. 85, pl. V, fig. 16 et 17, pl. VI, fig. 1, 2, 3, 5 
8. 1, 4, J, 0. 
(Fig. 5 is said in the text to represent L. Lenormandi, while in the explanation of plates it is attri- 
buted to L. lichenoides). Hauck, Meeresalg. p. 267, Taf. III fig. 4; Strémfelt, Algveg. Isl. kuster, p- 21, 
tab. I, fig. 9—10. 
Lithothamnion squamulosum Foslie, Norw. Forms of Lithoth p. 155, Tab. 19 fig. 24—26. 
Squamolithon Lenormandi (Aresch.) Heydrich, Die Lithoth. von Roscoff. Ber. deut. bot. Ges. 1911, 
p- 26, Taf. II. 
This widely spread species has been met with in almost all the Danish waters. 
It is particularly characterized by its thin reddish-violet crust with a lobed, whitish 
border, by its hypothallium composed of densely joined filaments, and at all events 
in the typical species, by the 
densely crowded concep- 
tacles. 
As pointed out by Mme 
Lemoine, the hypothallium 
is composed of more densely 
joined filaments than in the 
other crustaceous species. 
According to this author, the 
number of horizontal fila- 
ments in a vertical section 
is usually 7—8; in thicker 
crusts it may be greater (fig. 
133 B), in thinner it may be 
only 3—4 (fig. 133 A, C). In Fig. 133. 
z S Lithothamnion Lenormandi. A, vertical\section of border of frond, not 
horizontal Sealens through decalcified, made by grinding. B and C, vertical sections of thick and thin 
the hypothallium transverse crusts, made by microtome through decalcified fronds. D, horizontal sec- 
fusions are frequently seen tion of hypothallium showing fusions. A 195:1. B—D 350:1. 
(fig. 133 D). Mme LEMOINE states that the filaments of the hypothallium “se relèvent 
d’une façon très brusque pour constituer les files du périthalle”. This, however, is, 
in my opinion, not characteristic of the species, as will be seen in my fig. 133. 
The cells of the hypothallium which, according to Mme LEMOINE, are 3—4 4 thick, 
I generally found somewhat thicker, 3,5—6 », in specimens from the Limfjord 5—6 y, 
the length 12—185y. The cells of the perithallium I found 4—6y thick, 4—13 4 
long. In the perithallium also numerous transverse fusions occur, but as the cells 
are closely joined, the fusion canals are very short. 
The sporangial conceptacles are very crowded, in particular in f. typica; they 
measure 200—300 in diameter. The flat roof is, according to Fos.ir, intersected 
by 25 to 35 muciferous canals, which is in accordance with my observations; I 
have, however, met with up to 45 canals. Transverse fusions between the cells of 
the roof are frequently met with. The sporangia which are otherwise always tetra- 
sporic, are also normally so in the Danish waters. Conceptacles with disporic 
Sporangia only, however, not infrequently occur (fig. 134 A). It might be suggested 
D. K. D, Vidensk. Selsk. Skr., 7. Række, naturvidensk, og mathem. Afd. VII, 2, 28 
