110 M. FOSLIE. [1905 



and f. lacunosa only on other algae. As a matter of fact, both 

 Melobesia farinosa and Lithophyllum pustulatum have been found 

 on substrata quite as different. In f. typica the cells are on an 

 average a little larger than in the specimens hitherto known of f. 

 lacunosa (which are very few), but they do not, however, exceed 

 the maximum measures stated for this form. Cortical cells gene- 

 rally seem to be wanting. I have only found a few inconsiderable 

 ones, which resemble the smallest cortical cells in M. Lejolisii. 

 The reproductive organs in both forms coincide with each other. 



As to the questionable synonyms recorded, it is to be obser- 

 ved that I have earlier supposed that Melobesia incequilaterata 

 Solms might belong to Lithoth. membranaceum or to Melobesia 

 farinosa. Cp. Rem. Melob. Herb. Crouan, p. 7. The said alga, 

 of course, cannot be identified with certainty, as the specimens 

 which underlie the description and the pictures 1. c. are sterile and 

 quite young. However, I do not think it precluded that it should 

 be identical with M. minutula, as it is indicated to want cortical 

 cells, and such ones seem to be of rare occurrence in M . minutula. 

 Besides the cells in a vertical section are often horizontally elongated. 



The same is the case of LitJwcystis Allmanni Harv. The 

 magnified crust 1. c. fig. 2 greatly recalls M. minutula f. typica. 

 The description, on the contrary, is only in part consistent with 

 the species in question. 



As to Lithothamnion Van Heurckii, Dr. H. Van Heurck, 

 on my application, most kindly sent both specimens and prepara- 

 tions of this alga to me to be examined. It proves to be com- 

 pletely consistent with M. minutula f. typica in structure as well 

 as in the form and the size of the conceptacles. The frond 1. c. 

 is stated to be „ compose d'une couche de cellules quadratiques, 

 ayant de 6 a 8 ou de 8 a 8 /j. de diametre, et est pourou de cel- 

 lules corticales tres plates, qui sont completement enfoncees dans 

 les grandes, et qui couvrent la moitie de la grande." According 

 to my measures the cells are of about the same size as those of 

 the Danish specimens above mentioned of M. minutula f. typica, 

 though in part oftener elongated in the direction of the radius, up 

 to about 18 fi long, and the length being up to IV2 tne breadth. 



