In Notes on two Lithothamnia from Funafuti 1 ) I mentioned 

 two specimens from this atoll, where borings have tåken place to 

 ascertain the structure of coral-reefs together with other investiga- 

 tions so as to get a general view of the present flora and fauna 

 of the said atoll. 



Afterwards Dr. G. Murray was so kind as to send me a 

 collection of calcareous Algæ for determination lately received from 

 Funafuti. This collection contains a rather considerable number 

 .of specimens collected in different localities, but comprehends only 

 4 species 2 ), showing this group of Algæ scarcely being represented 

 by any great number of species. On the other hand, each of those 

 species themselves appear in considerable numbers. The same 

 proportion is generally met with in northern seas, where the cal- 

 careous Algæ in the sublitoral region frequently grow in banks, 

 little by little increasing both in vertical and horizontal direction 

 and thereby, to a certain degree, correspond with the reef-building 

 in southern seas, where such banks as far as known seldom appear. 

 Here, on the contrary, not only crustlike species but even branched 

 ones most frequently grow in company with Corals, Sponges, etc, 

 and then act as a kind of mortar in holding together the reef-buil- 

 ding animals. 



From deep water around the atoll of Funafuti is only known 

 a solitary species, LitJiothamnion Philippii f. funafutiensis, which 



x ) Det kgl. norske Videnskabers Selskabs Skrifter. ' 1899. No. 2. 



2 ) There is a specimen in the collection which perhaps belongs to another 

 species than any of the above. It is however steril and at present not 

 determined, occupying the depressed central parts of a Coral (Porites) and 

 almost buried here. A. No. 25. 



