193 



time were unknown to me in Cr. codana, present, however, such differences that it is 

 impossible to identil'y our species with that of Crouan, the nemathecial filaments of the 

 latter being forked, fastigiate, and the sporangia being terminal on undivided erect 

 filaments and reaching the surface of Ihe nemathecium, in which respect 1 found 

 the specimens of Crouan corresponding to his description and figures. 



Our species is apparently related to Cr. Nordstedtii, wliich shows resemblances 

 in the structure of the frond and of the sporangial nemathecia, but there seems to 

 be a difference in the superposed fronds arising only by splitting of the frond in 

 Cr. Nordstedtii, while in C. codana they seem to arise principally as excrescences 

 from the surface of the frond. The first-named differs further, according to Mrs. 

 Weber-van Bosse, by the want of principal rows of cells thicker than the others 

 in the basal layer and by the presence of pluricellular rhizoids besides the uni- 

 cellular ones. The sexual nemathecia are unknown in C. Nordstedtii. 



It is highly probable that this species has been met with earlier, but con- 

 founded with Cr. armorica; this, however, cannot be stated without examination of 

 the corresponding specimens. 



Locality. Ku : TR, near Trindelen, 23,5 meters, September. 



2. €ruoriella Diibyi (Crouan) Schmitz. 



Fr. Schmitz, Syst. Ubersicht, Flora 1889, p. 20; id. in Kolderup Rosenvinge, Granl. Havalger, 1893 p. 783; 



Fr. Schmitz und V. Hauptfleisch in Engler ii. Prantl, 1897, p. 536. 

 Peyssonnelia Dubiji Crouan, Ann. sc. nat. Ille ser. t. 2. 1844, p. 367, pi. 11; id., AJg. mar. du Finistere 



(Exsicc.) 2e vol. no. 236, Brest 1852; id. Floriile du Finistere, 1867, p. 148, pi. 19; Harvey, Phycol. 



brit. I, 1846, plate 71; J. Agardh, Sp. II, 1852, p. 501; III, 1876, p. 384; Hauck, Meeresalg., p. 3,'); 



Batters, Mar. Alg. Berw., 1889, p. 90; Kuckuck, Bemerkungen, II, 1897, p. 393, fig. 18 (antheridia). 



The purple-coloured crusts are 1 to 3 (4) cm in diameter. In a dried state 

 they show characteristic radial folds. The outline of the frond is undulate; the 

 course of the cell-filaments in the marginal part is not regularly radiating, owing 

 to its composition of coalescing lobes, the growth being usually arrested in one of 

 the meeting lobes (fig. 115 C). From the underside of the frond, which is covered 

 with a layer of chalk, a varying number of rhizoids are given off; when fully de- 

 veloped they are separated by a wall from the producing cell (fig. 115 A). 



The thickness of the frond is variable. As shown in a vertical section, it is 

 divided immediately behind or at a small distance from the border by horizontal 

 walls (fig. 115 A). The cells of the undermost layer, which produces the rhizoids, 

 are usually somewhat lengthened in the radial direction. Two erect cell-rows are 

 frequently given off from one cell in the basal layer or the subbasal layer (fig. 115 B) \ 

 the cells are therefore greater in the under part of the frond than in the upper. 

 Each cell contains a nucleus and apparently a vaulted chromatophore in the upper 

 part of the cell. To judge from the figure given by Kuckuck (1. c. p. 394, Fig. 18 B) 

 the chromatophore is either divided into ribbonlike branches or there are several 

 bandlike chromatophores ; they are not mentioned in the text. The cells, particu- 



D. K. D. Vidcnslc. Selsk. Skr., 7. Riukke, naturvidensU. og matlicm. Afd. VII. '2. 25 



