KONGL. SV. VET. ARADEMIENS HANDLINGAB. BAND. 20. N:0 5. 245 



Gen. Chorda (Stackii.) Lamour. 



Ess. p. 46; Stackh. Ner. Brit. p. XVI; ex parte. 



Chorda filura (L.) Stackh. 

 1. c. Fuous filum L. Spec. PI. p. 1162. 



f. typica. 



Descr. Chorda filura Akesch. Obs. Pbyc. 3, p. 1.3. 



Fig- » » Haiiv. Phyc. Brit. t. 107. 



Exsicc. B a AiiEscH. Alg. Scaiid. exsico. N:o 92. 



f. subtomentosa Aeesch. 



Obs. Phyc. 3, p. 13. 

 Descr. Chorda filum /? subtomentosa Aeesch. 1. u. 

 Exsicc. » » var. tomentosa Abesch. Alg. Scaud. exsicc. N:o 168. 



f. crassipes nob. 



f. thallo 20 — 40 cm. alto, diametro 1 — 2 ram., flavesceiiti-olivacen apicem versus valde, at basira versus 

 obsolete attenuate, parte basali partem apicalem crassitudinc multo superante. Tab. 26, fig. 16. 

 Syn. Chorda filum Akesch. Phyc. Scaud. p. 365 et 1. c. 



» » J. G. Ag. Spetsb. Alg. Till. p. 28; Gronl. Alg. p. 110. 



» » Croall, Fl. Disc. p. 457. 



» « Gobi, Algenfl. Weiss. Meer. p. 74. 



» » Harv. Fl. West. Bsk. p. 49. 



» » Kjellm. Spetsb. Thall. 2, p. 27; Algenv. Murm. Mcer. ji. 41. 



» » Kleen, Nordl. Alg. p. 34. 



» » Post, et Eupr. 111. Alg. p. II. 



Fucus filum Gdnn. Fl. Norv. 2, p. 10. 

 » )) ScoRESBY, Account. 1, p. 132. 



» B Wg. Fl. Lapp. p. 505. 



Scytosiphou filum J. G. Ag. Spetsb. Alg. Progr. p. 2; Bidr. p. 11. 



Remark on f. crassipes. This form differs pretty much in habit from typical 

 Chorda filum. It tapers rather imperceptibly towards the callus and on that account is, 

 immediately above it, very much thicker that at the extremity and almost as thick 

 as at the middle, while the thallus of the typical form is almost as much attenuated 

 towards the base as towards the tip. Besides, it is smaller and of a lighter and clearer 

 colour than common Ch. filum. In inner structure, however, it accords very nearly with 

 it. I have not observed any hairs in f. crassipes. Its being a deep-water form explains 

 its lighter colour as well as the absence of hairs. 



Habitat. In the Arctic Sea proper this species is always sublitoral, in the Nor- 

 wegian Polar Sea it is usually so; but it occurs here also in rock-pools within the 

 litoral zone. Generally it lives at inconsiderable depths on gravelly bottom, particularly 

 when the ground is composed of broken Lithothdmnia, one to three fathoms below low- 

 water mark. I have dredged f. crassipes in the lower part of the sublitoral region in 

 15 — 20 fathoms. The present species is gregarious and flourishes both in exposed and 



