— 113 — 



3 jul in diam. Réfringent, proteid-containing cells occur, but spar- 

 ingly, in the lower parts. Hairs common. Tetraspores in verti- 

 cillate rows are observed in some specimens from Iceland. 



The Færoes: 



Syderö: Tveraa, 10 /ö 1896 (upper litt, zone; exposed coast). 

 St. Dimon: 12 /e 1896 (in pools above upper water mark). 



12 / 6 1896 (in a Gjov). 

 Strome: Kalbakbotn, 6 / 5 1898 (shallow water, sheltered coast). 



Velbestad, 3 U 1898 (upper litt, zone, exposed coast). 



Kviyig, 29 /ö 1898 (pools in the upper litt, zone; exp. coast). 

 Østero: Skaâlefjord off Glibre, 10 / 5 1898 (epiph. on Halidrys, sheltered). 



Ejde, (sheltered coast). Strender, 10 l 6 1898. 



Glibre, (forms great bushes in the upper littoral zone ; also epiphytic). 

 Iceland: 



S. le: Vestmannaeyjar, u Iô 1897 (upper littoral zone in small bushes; 

 sheltered coast). 



Stadur ( 12 / 6 1896, leg. Ostenfeld upper littoral zone). 

 Eyrarbakki, 31 / 5 1897?" 

 SW. Ic: Grötta, 17 k 1908? (exposed coast in the zone of Gorallina- 

 Gigartina) HafnarfjörÖur, 7 /s 1890 (Hj. Jensen). 

 This species seems to be confined to the littoral zone. 



Ceram. rubrum (Huds.) Agardh. Pl. I, fig. 5a; PI. III & IV; 

 Pl. V, figs. 25, 27—30; Fig. VI. 



In my paper 1908 I demonstrated why C. rubrum is changing 

 in form from the Baltic Sea into the North Sea and Skagerak. 

 The forms, which are the predominant here, the forma proliféra 

 and pedicellata-virgata, are so to say the starting forms from which 

 the forms in the Limfjord, Kattegat, the Belts and the Baltic Sea 

 are to be derived, formed by the influence of the decreasing con- 

 tents of the chloride of sodium in the waters in question (cf. Plate 

 III, which gives an idea of the modifications of f. proliféra and ped. 

 virgata). In the above-named paper I defended the idea that all 

 these variations were forms of one single species induced by diffe- 

 rent external conditions. With regard to these and other forms of 

 this species I am now in the main point of the same view, not to 

 establish species upon the different forms but rather to consider 

 them all as occasioned by different external conditions. I admit 

 however that it is possible that within this species there may exist 

 types (races or small species) about which the variations are grouped. 

 As to the Danish forms it is probable that forma proliféra and 

 pedicellata- virgata are the best developed representatives of two types 

 whose variations in the southern waters resemble each other. But as 



Botanisk Tidsskrift. 31. Bind. S 



