251 



to me that some of the first were cystocarpic ones. As shown in fig. 170 the 

 antheridial conceptacles occur in the same fronds as the cystocarpic ones. The 

 latter were rather small in these specimens. 



The specimens growing on Corallina officinalis, collected north of Lseso (ZC\ 

 7658a, fig. 171), are more vigorous than the specimens previously mentioned. The 

 structure of the frond is the same, but the conceptacles reach greater dimensions. 

 They may be hemispherical, 160 — 185 /j. in diameter, or they may be lower, fre- 

 quently fusing together, when the conceptacles are densely placed. The ostiole was 

 provided with small papillae directed inwards in the conical space of the orifice. 



When seen 

 from above, the 

 ostiole appea- 

 red surrounded 

 by a rosette ex- 

 actly like that 

 shown in fig. 

 168 D. The re- 

 mains of a col- 

 umella were 

 found in the 

 case represen- 

 ted in fig. 171 A. 

 The sporangia 

 were always Fig. 171. 



tetraSDOric Melobesia FosUei growing on Corallina officinalis from ZC, north of Lseso A, vertical section 



r ' of frond with two conceptacles, one hemispherical, the other depressed. B, vertical section 



44 — 50 fJ. long, of frond with antheridial conceptacle. C, vertical section of cystocarpic conceptacle. 

 ,1 i£. u J A and C 260:1. B 420:1. 



11 — 16/i broad. 



— The antheridial conceptacles are slightly prominent; the spermatangia are pro- 

 duced on the flat bottom of the conceptacle from small cup-shaped cells; they (or 

 the spermatia) are linear clavate, slightly curved, measuring 7 a in length, about 

 2 // in their broader end. — The cystocarpic conceptacles have the same shape 

 and size as the sporangial ones and are, as those, provided with short horizontal 

 papillse in the ostiole, principally in its under part. 



I have been much in doubt in determining the specimens referred to this 

 species. Some of them, those from Bragerne, Skagerak, have been referred to M. 

 Lejolisii by Foslie (Remarks, p. 106) and I have also been much inclined to con- 

 sider them as a more or less reduced form of this species. However, I have judged 

 it better to describe it as a new species, considering, besides other characters, 

 especially the higher conceptacles of sporangia, the formation of the spermatia 

 taking place in our species at the bottom of the conceptacle from short cells, while 

 in M. Lejolisii they are produced at the end of long sterigmata, and the long curved 

 spermatia, while those of M. Lejolisii are much shorter. The antheridial concep- 



32* 



