KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND. 20. N:0 5. 135 
Geogr. Distrib. It is known only from the Atlantic region of the Polar Sea, 
reaching its maximum of frequency at Nordlanden. Its northernmost locality is Gjes- 
ver about Lat. N. 71°. 
Delesseria Montagnei novum nomen. 
Delesseria denticulata Mont. Syll. p. 408. Cfr. Ann. d. Se. 9, p. 62 
Descr. Wypoglossum denticulatum Kurz. Tab. Phye. 16, p. 6. 
Fig. » » » » » be te Lo. 
Syn. Delesseria alata # angustifolia Lynas. Hydr. Dan. p. &. 
Remark on the species. In the collections of Greenland algw belonging to the 
Copenhagen Museum there is a pretty great quantity of specimens, evidently gathered 
at different occasions and by different persons, of a Delesseria bearing the name of D. 
alata. Some of these agree very well with the above-quoted figure in Kirzinc, others 
approach more nearly to D. alata. However, they all differ from the latter species 
by their more spreading branches which are never so obliquely cut out at the base 
and consequently more regularly linear or elongated-cuneiform than in D. alata. Besides, 
the branches, especially those of the last order, are always distinctly, sometimes den- 
sely, serrate. Thus there can be no doubt, I think, that the specimens from Greenland 
are not to be referred to D. alata, but to D. denticulata Mont., which must be regarded 
as a species distinct from /). alata and most nearly related to D. spinulosa Rupr. J. G, 
Aa. known from the Pacific, if it be not indeed quite identical with this. It is difficult 
to draw any definite limit between them. Monracne has himself declared that his 
species is identical with D. spinulosa. Ruprecut states that D. spinulosa is closely 
allied to D. alata f. denticulata, but differs from it by the narrowness of the branches of 
the frond which are crispy at the margin, by the more spreading lower secondary axes 
which spring out almost at right angles, by some difference in regard to the lateral 
nerves which I do not quite understand, and by the tetraspores being developed some- 
what farther down from the tips of the axes. With regard to the breadth of the frond, 
the specimens from Greenland vary much, from 4 mm. to 1,;5—1l mm. and even less, 
in case D. alata ( angustifolia Lyncs., as is most probable, is a slender form of the 
present species. Broader specimens from Greenland often have a distinetly crisp mar- 
gin. The branches are in general very much expanded, so that the lower ones, in 
several specimens of D. denticulata, form a right or nearly right angle to the main axis. 
In D. denticulata the development of tetraspores both begins and extends farther down 
than in D. alata. Cp. Ruprecut, Alg. Och. p. 244. 
J. G. Acarpn has some doubts about the identity of D. spinulosa and D. denti- 
culata, chiefly because the latter, as figured by Ktrzinc, wants the microscopic lateral 
nerves, which are to be seen in J. spinulosa. But it should be remarked that it is 
stated expressly in the diagnosis that accompanies the figure in Kirzine |. c. p. 6, 
»segmentis.... a costa ad margines venis obliquis percursis», and that the lateral nerves 
in the specimens of JD. denticulata from Greenland are always, especially in broader 
sterile individuals, distinctly apparent on microscopical examination, sometimes even 
