KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND. 20. N:0 5. 93 



Geogr. Distr. The Atlantic region of the Polar sea. Within the arctic region it 

 has not as yet been found. 



Locality. The Norwegian Polar Sea: Tromso amt near the town of TromsO, the 

 only place where it is known to occur. Here it has been found by M. Foslie. 



Lithothamnion Norvegicum Aresch. (nob). 



Descr. Lithothamnion calcareum var. norvegicum Aresch., Obs. Phyc. 3, p. 4 — 5. 

 Fig. Lithothamnion norvegicum tab. nostra 5, fig. 9 — 10. 



Remark on the determination of the species. J. E. Areschoug 1. c. has described, 

 under the preceding combination of names, a plant from the southwest coast of Norway, 

 that has also been found in the Polar Sea. On pi. 5, I have given figures of one 

 specimen from the south of Norway (fig. 9) and of another from the Polar Sea (fig. 10). 

 Judging from the fact that no overgrown sporangia are to be found on sections of 

 older frondal portions, the plant with regard to the inner structure belongs to that 

 group of Lithothamnia which possesses external conceptacles of sporangia. Areschoug 

 considers this plant to be a local form of Melohesia (Nidlipora) calcarea Ell. et Sol., 

 occurring on the coasts of England and figured by Harvey (Phyc. Brit.) and Johnston 

 (Brit. Spong. Lith.) It is certainly possible that this may indeed be the case, but the 

 statement of Areschoug »forma M. calcarea quam depinxit et descripsit Harvey (est 

 forsan maxima et magnopere evoluta) a nostra valde ab'horrens» being clearly quite 

 correct, and the Norwegian specimens being unlike those figures of Nullipora calcarea, 

 much differing from one another and possibly designating different species, which 

 Johnston gives, I consider myself entitled to regard the above-mentioned plant, found 

 on the coast of Norway, as a distinct species separated from Melobesia calcarea Harvey 

 and Nullipora calcarea Johnston. 



Hah. It grows, spreading stratiformly, in 10 — 15 fathoms water. Cf. Areschoug 

 1. c. Only sterile specimens are known. 



Geogr. Distr. This species belongs only to the Atlantic region of the Polar Sea, 

 and seemingly only to its most southerly part. It has not been found to the north 

 of Nordlanden. 



Locality. The Norwegian Polar Sea: Nordlanden at Lodingen (Foslie). 



Lithothamnion glaciale nob. 



L. fronde demum crustam formante validam circum lapides vel conchas e£fusam e roseo flavescentem, 

 plus minus lobatam, ramos simplices, conicos, obtusos vel subcylindricos, usque 7—8 mm. altos, inferne dia- 

 metro usque 5 mm., scabriusculos undique emittentem; conceptaculis sporangiferis demum innatis, minutis, con- 

 vexiusculis at parum prominentibus, creberrimis, nullo ordine in crusta ramisque dispositis; sporangiis binas 

 sporas foventibus, 80 — 136 /.i. longis, 40 — 60 f.i. crassis; Tab. 2 et 3. 

 Syn. Lithothamnion calcareum Kjellm., Vinteralg. p. 64. 



» » Kleen, Nordl. Alg. p. 11. 



» fascioulatum Aresch. Obs. Phyc. 3, p. 5 (saltem ex parte). 



» » Dickie, Alg. Sutherl. 1, p. 142. (?) 



» » Gobi, Algenfl. Weiss. Meer. p. 22. 



» » Kjellm. Spetsb. Thall. 1, p. 3, Algenv. Murm. Meer, p. 7 et alibi. 



