KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND. 20. N:0 5. 221 



an older specimen with almost complete lamina; this is — measured dry — 90 cm. 

 long and 20 cm. broad. In some fragmentary specimens the breadth amounts to nearly 

 25 cm. Even in older specimens with ripe zoosporangia the lamina is thinly mem- 

 branaceous, densely wavy, rather brittle when dried. In drying it assumes a dark- 

 brown colour with a soot-brown tinge. 



The casta is prominent, sometimes almost planely convex, usually biconvex, ellip- 

 tical in transverse section, in older individuals about 7 mm. broad, 3 mm. thick (tab. 

 25, fig. 23, 24). 



The sporophylls are linear spade-shaped, with short pedicels, when sterile thinly 

 membranaceous, about 10 — 20 cm. long and scarcely 2 cm. broad near the rounded 

 top. The sorus occupies half or two thirds of the length, being surrounded upwards 

 by a narrow margin. The soriferous part is comparatively thin, membranaceously 

 pergameneous. The sporophylls are developed in rather little number (20 — 30) at the 

 same time in the same individual, and are somewhat thinly arranged, those which are 

 first developed every time being thinner than the later. 



The zoosporangia are cylindrically club-shaped, 35 — 60 /u,. long, 10 — 12 /u. thick. 

 The paraphyses are club-shaped with a distinct pedicel somewhat enlarged downwards. 

 The outside of the membrane is much thickened. The length of the pedicel is usually 

 45 |M., that of the head of the club 60 ,«., the thickness of the latter about 10 ^. 



In anatomical structure the present species is most closely allied to the preceding 

 one. It agrees with this also with regard to the shape of the cauloid part, the sporo- 

 phylls, and the costa, but differs decidedly and, as far as I can see, constantly as to 

 the shape of the lamina. Even in young individuals that shape of the lamina which is 

 charateristic of the present species, is found well marked and it remains the same 

 through all its ages. The only difference in this respect I have been able to detect is 

 the base's becoming more cordate as the plant grows older. 



Thus this Alaria appears to show that at least in certain groups of this genus 

 more importance may be attached to the shape of the lamina in distinguishing the 

 various species than I myself and several algologists have been inclined to suppose. 



Habitat. At the only place where this species has been hitherto met with, it 

 grew on the exposed coast within the sublitoral zone in 4 — 5 fathoms water, on rocky 

 and stony bottom, constituting here together with other Laminariacew a formation of 

 considerable extent and richness. The plant when collected in the middle of September 

 bore scarce zoosporangia. 



Geogr. Distrib. Known only from the Siberian Sea. 



Locality: Irkaypi on the north coast of Tshutshland. 



Alaria elliptica nob. 



A. stipite brevissimo, tereti; rhachide compressa, apicem versus incrassata; lamina elliptica, basi distincte 

 decurrente, usque 40 cm. lata, fere papyracea, undulata; costa elevata, in sectione tiansversali elliptica; sporo- 

 phyllis lanceolato-spathulatis, infra apicem rotundatum 2 — 3,f) cm. latis, papyraceis, parte sorifera submembranaceis, 

 margine crispatis; soro dimidiam partem occupante; Tab. 23 et 25 fig. 25, 26. 



