8 
green Algæ were especially mentioned, amongst others a new species Spirulina 
subsalsa. 
Orstev’s dissertation’, published three years later, in which the distribution 
of the marine Algæ in the Sound is discussed, is of greater importance. In this 
paper, which deals with the geographical, geological, botanical and zoological con- 
ditions of the Sound, all the species of Algæ are mentioned, which were found there 
by the author, but the single species are not described in detail, which is the rea- 
son why it is not always possible to know the meaning of a name given by the 
author. A number of species, considered by him as new, are however described 
in the comments under the text, but mostly so briefly and incompletely, that the 
plant cannot be recognised; and the result has been, that none of the genera and 
species, given by ØRSTED, have been maintained. Some of them have later been 
published in Flora Danica. The systematic value of the paper in thus very small, 
but its importance for our subject lies in this that it is based upon systematic 
investigations by means of dredgings, with the result, that for the first time the 
Alsæ are not only discussed in regard to their horizontal distribution but also 
in regard to their vertical. It cannot be determined what new species have been 
added to the flora by ØRSTED's work without examining his specimens. 
Already several years before the appearance of OrsTED’s work, LyNGBYE in 
1836 had written a treatise of a somewhat kindred character, but, on account of 
special conditions, it was not published before 18807. In floristic regard it is not 
of so much importance in enriching the flora, as in its being based upon investi- 
gations in the southernmost part of the Kattegat off Gilleleje, a region not investi- 
gated before, and especially by its containing more exact data on the distribution 
of the Algz in relation to the depth. Neither his nor ØRSTED's divisions into re- 
gions of depth need be mentioned here. 
Since ØRSTED's work there has not until the end of the 19th century appea- 
red any noteworthy, floristic or systematic contribution to the Danish literature 
on the Danish marine Algæ. In Flora Danica marine Algæ from Denmark were 
included up to 1861, but very few new species were added beyond those mentioned 
by Lıesman and ØRSTED. Helminthocladia purpurea*, found by Miss CAROLINE 
ROSENBERG, is perhaps the most interesting addition. During the same period pub- 
lications which partly deal with the algal flora in Danish territory have appeared 
À. S. ØrsTED, De regionibus marinis, elementa topographiæ, historiconaturalis freti Øresund. 
Hauniæ 1844. 
* H. C. LYNGBYE, Rariora Codana (Opusculi posthumi pars). Vidensk. Meddelelser fra den naturh. 
Foren. i Kjøbenhavn, 1879—80, p. 215. 
° In “Nomenclator Flore Danice” published by Jou. LANGE in 1881 a systematic summary, pre- 
pared by myself, was given of all the Algæ mentioned in this work with data on their occurrence. 
This general summary, which in regard to the determination of the species, is essentially based upon 
the references available in the literature and consequently in part out of date, comprises the following 
Danish marine Algæ: 47 Rhodopyceæ, of which two are however incorrectly named as Danish, 38 
Pheophycee (1 incorrectly named Danish), 18 Chlorophyceæ and 7 Cyanophyceæ. By accident the Cha- 
raceæ were omitted in this work. 
