10 
whieh have been collected in Danish waters by others in earlier and more re- 
cent times. 
Other collections. LyNGBYE's herbarium of Algæ, kept in the Botanical Mu- 
seum of Copenhagen, is of the greatest importance for the study of the Danish 
marine Algæ, as it contains the original specimens of LYNGBYE's Hydrophytology. 
The specimens in this herbarium have not been particularly well prepared, but 
they are furnished with exact indications of the place and time of collecting; most 
of them originate from the neighbourhood of Hofmansgave on Fyen. 
The Botanical Museum’s Danish herbarium contains a considerable number 
of specimens of marine Algæ. The majority of these come however, like LYNGBYE’s 
herbarium, from the neighbourhood of Hofmansgave and have been collected mainly 
by Horman Bang and Miss CAROLINE ROSENBERG. The latter, who passed the greater 
part of her life (+1902) at Hofmansgave, has from there during a long series of 
years sent a large number of carefully prepared specimens of marine Alge, many 
of which have come to be housed in the Botanical Museum’s herbarium. As they 
have been collected at different seasons, they provide a good material for following 
the development of the single species during the course of the year. Further, spe- 
cimens are also present from HORNEMANN, LIEBMAN and ØRSTED, by which the 
determinations of the latter can be controlled, and also from J.VaHr, C. M. POULSEN, 
Jou. LANGE, CHR. THOMSEN (mostly from Samsø), J. P. JACOBSEN (mostly from the 
Limfjord), E. Rostrup, C. RascH and others. 
Since I began my systematic collections, some material collected by others 
has further been left to me. Dr. TH. MORTENSEN has thus placed at my disposal 
a valuable collection principally from the Limfjord procured at different seasons 
in 1894—95; and Dr. F. BorGesen has permitted me to examine the Algæ dredged 
on two expeditions with the fishery-inspection ship S. S. “Guldborgsund” in 1897 
and in 1898 in the Skagerak, Kattegat and the Baltic. Smaller collections have 
been given me by Dr. C. H. OsTENFELD, Mr. A. OTTERSTROM, Mag. OVE PAULSEN 
and Mag. HENNING E. PETERSEN. 
My own collections. I began my first collections of Danish marine Algz 
already towards the end of the seventies, but it was not until 1890 that I made 
extensive and systematic collections and they were carried on most energetically 
during the years 1891—1895, whilst later they have been continued almost every 
year though less extensively. My aim has been to make as uniform an investi- 
gation of the Danish waters as possible and also, as far as possible, to investigate 
them at different seasons; for that purpose I have made dredgings at more than 
700 different places and besides made collections at numerous harbours and at 
other places close to the land; I have made these collections during all the months 
of the year, chiefly however during May—September. The dredgings have almost all 
been made by means of a triangular dredge with sharp steel teeth (Reinke’s model), 
more rarely with a quadrangular dredge without teeth or with seine. The greater 
part of the material has been preserved as herbarium specimens, of which I possess 
