cells of the hypothallium and the undermost part of the perithallium often contain 
a number of distinct starch grains. In the cells of the perithallium a nucleus and 
a small number of disc-shaped chromatophores 
could be distinguished. (fig. 130). 
In the Danish specimens, only conceptacles 
of sporangia were met with. Their diameter is 
A å somewhat smaller than in the Greenland speci- 
mens; in the plants from Hesselø it is 500—650 x, 
Lithothamnion læve. A, cells from the peri- in those from Hellebæk 600—800 pL The roof 
SCPE A ER aE CE consists of narrow filaments of cells which are 
grains. 730 :1. longer than in the vegetative frond, and connected 
with numerous transverse fusions, while 
the cells are only rarely fusing in the 
perithallium. The sporangia I found al- 
ways disporic when fully developed, 
126—129 » long, 67—72 x broad, thus 
somewhat smaller than in the specimens 
from Greenland. The species has otherwise 
been found with two and with four spores 
in the sporangia. Foslie has (1908, p. 7) 
given all the localities where it has been 
found with two-cel- 
led sporangia only 
and those where it 
has been met with 
only with four-celled 
sporangia. Both are 
found in a number 
aa Rot localitieseingihe 
A arctic regions and Fig. 132. 
Fig. 131. ; Lithothamnion læve 
Lithothamnion læve. A, vertical section of conceptacle at the Norwegian Tetraspore. 
of sporangia. B, part of a similar section. 200: 1. coast as well. 390 : 1. 
Localities. Ks: A, S.E. of Hessele, 28m on stone and shell. — Su: Hellebæk Aug., on Mylilus 
Modiola, Henn. Petersen. 
2. Lithothamnion Lenormandi (Aresch.) Foslie. 
Foslie, Norw. Forms, 1895, p. 150; Heydrich, Lithoth. von Helgoland, 1900, p. 78, Taf. II, fig. 23—25; 
Foslie, Remarks, 1905, p. 12; Mme Paul Lemoine, Struct. anat., 1911, p. 811; Deux. exped. antarct. 
franc. 1913, p. 10. 
Melobesia Lenormandi Aresch. in J. Agardh. Sp. G. o. II p. 514. 
* Mme Lemoine cites the fig. 7 of my paper, "Grønlands Havalger” as representing Lith. Lenor- 
mandi; however, it does not represent this species but L. tenue Rosenv. (= L. lœve Strömf.). 
