ET 
M. Fostıe (1900), Revised systematical Survey of the Melobesieae. Ibid. 1900. No 5. 
— (1905), Remarks on Northern Lithothamnia. Ibid. 1905. No 3. (Issued 1906). 
— (1909), Algologiske Notiser. VI. Ibid. 1909, No 2. 
F. Hauck, Die Meeresalgen Deutschlands und Oesterreichs. Leipzig 1885 (1882—1885). 
F. HeypricH (1900), Die Lithothamnien von Helgoland. Wissensch. Meeresunters. N. F. IV. Band. Abt. 
Helgoland. Kiel und Leipzig. 
Mme Pauz Lemoine (1911), Structure anatomique des Melobesiees. Application à la classification. Annales 
de l’Institut Océanographique. Tome II fase. 2. 
F. MINDER, Die Fruchtentwicklung von Choreonema Thureti. Freiburg i. Br. (s. a.) 
"R. Pırcer (1908), Ein Beitrag zur Kenntnis der Corallinaceae. Engler, Botan. Jahrbücher. 41. Bd. 
S. Rosanorr (1866), Recherches anatomiques sur les Mélobésiées. Mémoires de la soc. sc. nat. Cherbourg. 
Fr. Schmitz und P. HAUPTFLEISCH (1897), Corallinaceae. Engler u. Prantl, Nat. Pflanzenfam. I. 2. Leipzig, 
SoLMS-LAuBAcH (1881), die Corallinenalgen des Golfes von Neapel. Leipzig. 
H. F. G. STRÖMFELT (1886), Om algvegetationen vid Islands kuster. Göteborg. 
N. SvepeLius (1911), Corallinaceae. Engler u. Prantl, Nat. Pflanzenfam. Nachtr. zu I. Teil, Abt. 2. Leipzig. 
G. THuRET (1878), Etudes phycologiques. Publ. par les soins de M. le dr. E Bornet. Paris. 
When carrying out my systematic investigations in the Danish waters, I ar- 
ranged with M. FosLie, the well-known authority on calcareous algæ, that he should 
deal with the Melobesieæ-group of the family of Corallinaceæ, and forwarded to him 
accordingly, from time to time, such material as I had collected of these alge, 
which he also mentioned in various publications. Unfortunately, M. FosLır’s 
energetic work in this field was brought to a close by his unexpected and prema- 
ture decease in 1909. Since then, I have collected but few calcareous algæ, and 
nearly all the present specimens from Danish waters have thus been determined 
by FosLıe. As we know, this writer repeatedly altered his view concerning the 
limitation of these difficult species, and his last great work on Northern Melobesiez 
(Remarks 1905) bears evident witness to his indecision on this point. When, after 
his demise, I myself took up the task of dealing with this group, I considered it 
necessary to investigate all species by means of microtome sections, in order to 
obtain closer knowledge as to the structure of the frond and reproductive organs, 
being also further instigated hereto by the newly published works of PırgEr, Mme 
Lemoine and MINDER. In many cases, the results attained were disproportionate to 
the amount of time involved, partly owing to the fact that the great bulk of the 
material had only been preserved in a dried state, and also because suitable devel- 
opmental stages of the various sorts of conceptacles were in many cases lacking. 
With regard to distinction of species, for the Lithothamnia I have in the main fol- 
lowed FosLiE in his valuable work above-mentioned; on the other hand, closer in- 
vestigation has led me to distinguish several new Melobesia species. 
With regard to structure and development of the frond and reproductive 
organs, I may refer to the works above quoted by RosAnorr, SOLMS, PILGER, Mme 
Lemoine, MINDER and SVEDELIUS, as also to what is stated below with regard to 
the various species. It will here suffice to mention certain particular features. 
The frond is in all cases composed of branched cell filaments, the cells of 
which are connected up by pits of the structure characteristic in Floridez, in the 
middle of the transverse walls. These pits are however, very thin, and are often 
D. K. D. Vidensk. Selsk. Skr., 7. Række, naturvidensk. og mathem. Afd. VII. 2 27 
