KUNGL. SV. VET. AKADEMIENS HANDLINGAR. BAND 61- NCO II. 17 



M. macrocarpum Skottsb. Ant. Meeresalg. I, p. 49, fig. 48 — 51. — Fig. 7 a, b — d. 



South Georgia: Bay of Isles, on drifted specimens of Desmarestia ligulata 

 (25. 4. 09, gt.). F a 1 k 1 a n d Islands: Westpoint Isl. on Macrocystis (5. 12. 07, sp.?). 



This seems to be a characteristic species. The new material is quite satisfactory ; 

 it differs in the scarceness of sterile filaments, which are not longer than the game- 

 tangia. No hairs were observed. There is only one large chromatophore in each cell, 

 not several as indicated before. The gametangia are large, often more or less club- 

 shaped, with rather irregular divisions, the ripe ones measure 60 — 108x18 — 36 [i. 

 Fig. 7 a gives an idea of the variation in shape and size. 



The plant from Westpoint (fig. 7 b-d) is doubtful. Of all the species observed 

 by the writer it agrees best with M. macrocarpum. The disc produces long assimi- 

 lators with long cells, each containing a single chromatophore, and numerous ovoid 

 sporangia (?); but not a single ripe one was found. Some, however, seem to be 

 empty. The cells of the disc are different in outline from those in macrocarpum. 



Distribution: Fal kl., S. Georgia. 



M. densum Skottsb. Ant. Meeresalg. I, p. 50. — Fig. 7 e — 1. 



Discus basalis margine irregulariter soluto cellulis 9—12 ( — 18) X 4 — 6 (— 8) ;i, 

 chromatophoris ut videtur singulis. Fila erecta ad 400 \x longa et 4 — 6 »j. crassa, in- 

 terdum nulla. Pili 4— 6»j. crassi. Sporangia non visa. Gametangia 40— 75 x (4 — ) 

 6 — 7 [J-, uniseriata. 



F u e g i a: Orange Ba}% on Lessonia nigrescens (St. 45, 11.3. 09, gt.). South 

 Georgia: Bay of Isles, on Desmarestia ligulata (St. 52, 25. 4. 09, gt.). 



Having studied my new material, I am inclined to believe that M. densum of 

 1907 comprised two species, one with broader gametangia, biseriate in the central 

 parts. I retain the name densum for the plant described and figured here. The 

 specimens from St. 45 are a trifle smaller, with the cells of the disc not more than 

 6 [t across. I have not found any hairs on the sp. from St. 52. As limited here, M . densum 

 very much resembles M. Corunnae Sauv. : the gametangia measure 25— 100 X 4.5— 7 ^ 

 and the hairs 4 — 5. 6 [t in that species. The shorter or almost missing pedicel of 

 the gametangia and the irregular margin of the disc are characteristic of M. densum. 

 It is possible that M. inconspicuum Reinsch, Siidgeorg. p. 405, pl. XVI fig. 1, from 

 South Georgia, is the same, but this cannot be decided. M. paradoxum Reinsch 1. 

 c. fig. 2 is even more dubious. 



Distribution: Fuegia, Falkl., S. Georgia. 



M. fuegianum -no v. spec. — Fig. 7 m. 



Discus basalis cellulis brevibus sat irregularibus, 6;j. diam., chromatophoris ut 

 videtur singulis. Fila erecta sat longa et numerosa, ad 9jj. diam. Pili 6 — 7^ diam. 

 Sporangia ignota. Gametangia numerosissima, breviter pedicellata, 30 — 75x7 — 10 ;j-, 

 medio fere semper biseriata. 



Fuegia: Orange Bay, on Lessonia with the preceding (St. 45, 11. 3. 09, gt.). 

 — In the microscopic slides this was discovered mixed with the former, which it 



K. Sv. Vet. Akad. Handl. Band 61. N:o IX. 3 



