216 



Fig. 130. 



Lilhnthainnion Iccve. A, cells from the peri 

 thallium showing cliromatophores and nucleus 

 B, cells from tlie liypotliallium sliowinjA slarch 

 firains. 730:1. 



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 cliromatophores 

 could be distinguished, (fig. 130). 



In the Danish specimens, only conceptacles 

 of sporangia were met with. Their diameter is 

 somewhat smaller than in the Greenland speci- 

 mens; in the plants from Hesselo it is 500 — 650 /j, 

 in those from Hellebsek 600—800 /i. The roof 

 consists of narrow filaments of cells which are 

 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 /i long, 67- 72 /^ 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 

 of localities in the 

 arctic regions and 

 at the Norwegian 

 coast as well. 



A 



Fig. 131. 



Litliothamnion Iceve. A, vertical section of conceptacle 

 of sporangia. B, part of a similar section. 200: 1. 



Fig. 132. 



Lithothaninion Iceoe. 

 Tetraspore. 

 390: 1. 



Localities. Ks: A, S.E. of Hessele, 28m on stone and shell. 

 Modiola, Henn. Petersen. 



Sii: Hellebsek Aug., on Mi]lihis 



2. Lithothamnion Leuormaiidi (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. 81'; Deux, exped. antarct. 



franc. 1913, p. 10. 

 Melobesia Leiiormandi Aresch. in J. Agardh. Sp. G. o. II p. 514. 



' Mme Lemoine cites the fig. 7 of my paper, "Gronlands Havalger" as representing Lith. Lenor- 

 mandi, however, it does not represent this species but L. tenue Rosenv. (= L.lieve Stromf.). 



