KONGL. ÖV. VET. AKADEMIENS HANDLINGAK. BAND. 20. N:0 5. 267 



length of 30 cm. In the interiör of Altenfjord it was in general low but bushy. Though 

 being often pretty gregarious, it occiipies only inconsiderable spaces. In August and 

 September it is richly provided with zoosporangia on the north coast of Norway. 



Geogr. Distrib. Known only from the Atlantic region of the Polar Sea, at several 

 places abundant. The most northern point where it has been taken is Gjesvajr about 

 Lat. N. 71°. 



Localities: The Norwegian Polar Sea: Finmarken at Gjesva3r, Talvik, and Svaer- 

 holt, at the two first-named places rather abundant, but local. 



Gen. Dictyosiplion (Grev.) Aresch. 

 Bot. Not. 1873, p. 164; Grev. Alg. Brit. p. 55; cliar. niut. 



Dictyosiphon corymbosus nob. 



L. fronde fusco-flavescente, solido; axi piimario distincto, ramis suboorymbosis, elongatis, siraplicibus vel 

 parce raraulosis; zoosporangiis srepe confertis, a superficie thalli visis vulgo ellipsoideis. 



f. ahbreviata nob. 



f. ramis vi.\ semipedalibus, crassitudinem setre excedentibus. 



Tab. 26, fig. 12—15. 



f. elongata nob. 



f. ramis usque ultra pedalibus quara iu prfecedente tenuioribus. 



Syn. Dictyosiplion hippuroides Kjellm. Algenv. Murm. Meer. p. 46; ex parte. 



Description. This alga is attached by a callus and the frond becomes from half 

 a foot (f. ahbreviata) to more than one foot (f. elo7igata) long. It resembles D. fwni- 

 culaceus in colour and by its branching reminds one much of Coilonema chordaria f. 

 bahusiensis. The main axis is distinct and beset in its whole length with rather nu- 

 merous secondary axes of the first order, from half a foot to one foot long, usually 

 unbranched, sometimes bearing one or two branches of the second order. Branches of 

 a higher order than the second are rare. The secondary axes of the first order are 

 almost corymbose. The principal axis is markedly attenuated towards the base, the 

 secondary axes not at all or exceedingly little, by which marks the present species is 

 distinguished in habit from species of Coilonema. The branches taper perceptibly to- 

 wards the tip, more in f. elongata, less in f. abbreviata. With regard to structure 

 this species is most nearly allied to D. liii^jniroides. The cortical layer is composed 

 of small angular cells which in optical longitudinal section are squarish or irregularly 

 four-sided, in the lower part of the frond rectangular. The latter are arranged in 

 rather regular, longitudinal rows. The endochrome of the cortical cells is less plentiful 

 and lighter in colour than in D. hippuroides. The thick central layer is composed of 

 elongated cells of varying width with comparatively thin walls. In full-grown individuals 

 there is to be found in the centre of the frond a small number of fine cell-rows 

 resembling those of D. hip)p>ur oides : fig. 13. Hairs are rarely found. The zoosporangia 



