No. 3J REMARKS ON NORTHERN LITHOTHAMNIA. 47 



deeper into the sublitoral region. It is often covered by Phyma- 

 tolithon investiens. At Galten in West-Finmarken and inside Tamso 

 in the Porsangerfjord I have seen large masses of sterile specimens 

 probably of the species in question quite overgrown with the said 

 species. It was in these places coarser and less typical than it is, 

 when growing freely. Cp. under the said species. The alga is 

 fructiferous in the months of May — September. 



Area: Norway: From Porsangerfjord as far as Tromso(!); 

 Iceland (Jonsson!). 



12. Lithothamnion breviaxe Fosl. 



Norw. Lithoth. (1895), p. 16, partim, pi. 2. 



Syn: Lithothamnion i'ruticulosum Fosl. in Rosenv. Deux. Mem. Alg. Mar. 

 Gronl. (1898) p. 10? 



Frond resembling Lithoth. TJngeri in habit and in structure; 

 conceptacles of sporangia convex, but little prominent, or subpro- 

 minent, 300 — 450 \i in diameter;' sporangia bisporic, 120—160 /j- 

 long and 40—60 //• broad; conceptacles of cystocarps conical, 

 rather low, 400 - 500 ;j. in diameter. 



As remarked 1. c. p. 17, I found only a few sporangia, when 

 I described this species. They were found in a small fragmentary 

 specimen, which was in habit resembling those pictured 1. c. I 

 have, however, afterwards succeeded in finding sporangia in a part 

 of the specimen pictured 1. c, fig. 2. These sporangia are two- 

 parted. I, therefore, still concider this alga as an independent spe- 

 cies, but with a limitation different from that stated 1. c, i. e. 

 bearing the same relation to L. TJngeri as L. tophi forme is bearing 

 to L. soriferum. 



In old specimens of this species, or particularly in such ones 

 which are attacked by boring mussels, the branches of the last 

 order — like the case of L. TJngeri — will become rather straight 

 and coalescing, though always short. 



L. breviaxe has hitherto been found in a depth of 3 — 5 

 fathoms in places fairly sheltered. It bears sporangia in the months 

 of June — August. 



As to the geographical distribution of the species, I want to 



