25 



In Norw. Lithoth. ] ) I placed among Lithothamnion coralloides Crn., then taken in a 

 rather wide sense, a form which I named f. australis, and which has afterwards been partly 

 ranked with Lithothamnion calcareum (Pall.) Aresch. The knowledge of L. coralloides, as well 

 as of L. calcareum, was then insufficiënt, and decided fertile specimens were not in hand. As 

 to the mutual relation of the tvvo species mentioned, I refer to Lithoth. Adriat. Meer, where 

 I have presumed that L. coralloides includes partly L. calcareum, partly L. fruticulosum, 

 in the sense taken by Crouan ), however, in the main only L. calcareum. Simultaneously with 

 Norw. Lithoth. I published a paper where I classified f. australis from the Gulf of California 8 ). 

 This form constitutes the basis of Lithothamnion australe, entered into Rev. Syst. Surv. 

 Melob. '). The said form from the Gulf of California is here named f. amcricana. 



The question whether the forms from the East-Indian Archipelago, named above, actually 

 belong to the same species as the American form is not to be settled at present, the material 

 partly in the main consisting of sterile specimens, partly being too small. There are several 

 specimens in the collection in hand which are in almost full conformity with the said American 

 form. It is, however, to be observed that specimens of rather widely different species may 

 often resemble each other in habit as well as in structure, and accordingly cannot be defined 

 with certainty, when sterile. Besides it cannot — as yet — be ascertained to what extent 

 there is a connection — as to this group of the algal flora — between the East-Indian 

 Archipelago and the Pacific coast of America. I have, below, in treating of Lithothamnion 

 ertiöesceus, mentioned some instances that seem to be inclicative that the distribution of some 

 species has a very wide range. At any rate, however, I do not find reason for the present to 

 classify the forms in question as independent species (one or more), but I provisionally place 

 them with L. australe. 



The form tualcnsis mostly forms small shrub-like masses which appear to have developed 

 themselves freely at the bottom, and generally are i — 2 or up to 3 cm. in diameter. It is 

 subdichotomously or — oftener — repeatedly irregularly branched. The branches are partly 

 somewhat crowded, partly — and more commonly — rather spreading, more or less curved, 

 with short axes, frequently about 1,5 mm. thick, either slightly tapering or now and then 

 slightly enlarged towards the tip, with rounded ends (PI. II, fig. 10 — 17). This form comes 

 near to L. fruticulosum, and particularly old specimens approach to certain forms of this 

 species. Future investigations will ascertain the relations between them. I here place the form 

 under L. australe, to which it — judging from the material in hand — is most closely allied. 

 Among the specimens brought home a comparatively great number prove to have been wholly 

 or partially dead, when collected. On these were often developed crusts of other calcareous 

 algae, or new crusts of the same form, together with animals and other extraneous objects, 

 had caused a very irregular development. Such specimens frequently show an appearance rather 



1) M. Foslie. The Norwegian Fovms of Lithothamnion. — Det Kgl. Norske Videnskabers Selskabs Skrifter 1S94. Trondhjem 

 1S95, p. 62. 



2) P. L. et H. M. Crouan. Florule de Finistère. Paris, 1867, p. 151. 



3) M. Foslie. New or critical Lithothamnia. — Det Kgl. Norske Vidensk. Selsk. Skrifter 1895, Trondhjem 1895, p. 8. 



4) M. Foslie. Revised Systematical Survey of the Melobesieae. — Det Kgl. Norske Vidensk. Selsk. Skrifter, 1900, N". 5, 

 Trondhjem 1900, p. 13. 



SIBOGA-EXPEDITIE LXI. 4 



