24 



appear to be smaller than northern ones, and, being more densely 

 branched, even to f. typica. It seems not to be any well defined 

 form, although it deserves to be specially mentioned. 



As quoted above, I consider the typical L. fasciculatum Hauck 

 to be one of the most extreme forms of the precent species, the 

 above f. flexuosa. I have seen 3 authentic specimens determined 

 by Hauck as ,,L. fasciculatum." The one of these agrees with 

 specimens in my collection referred to f. typica. The two others 

 accord with the form flexuosa, smaller but otherwise fully resembling 

 the specimen represented pi. 7, fig. 1. This form apparently gets 

 much larger with us than in the Adriatic Sea, attaining a diameter 

 of up to 15 cm., or more, and as a rule freely developed on the 

 bottom. I very seldom met with it fastened to or encompassing 

 shells. The branches are less crowded than in f. typica, in the 

 lower or central portion rather coarse, or forming smaller lobes, 

 and more or less anastomosing, though far less than in the named 

 form. They are rather spreading in the peripherical portion, much 

 bent and about 2 mm. in diameter, cylindrical, or sometimes slightly 

 tapering towards the obtuse ends, which, however, now and then 

 may be a little roundish-thickened. PI. 7, fig. 1 — 2. It sometimes 

 is rather rubbed in the part turning towards the bottom, and now 

 and then in part hollow. PI. 7, fig. 3 represents a transition to 

 f. typica, partly with ' the upper branches somewhat denudated. 

 The form occasionally is provided with an apparently coarse hypo- 

 thallus. Cp. pi. 8, fig. 1 . This is, however, produced by epiphytic 

 Lithothamnia, mostly L. flavescens. The specimen that Hauck 

 delineates 1. c. t. V, fig. 3 looks coarser than the specimens which 

 I have seen from his herbarium, on the one side resembling and 

 probably identic with f. flexuosa in the sense here taken, but on 

 the other side reminding one of certain forms of L. tophiforme. 

 A similar, but larger, form is represented on pi. 8, fig. 2. This 

 also is coarser than typical f. -flexuosa, closely related to or pro- 

 bably identic with the latter, but on the other hand it coincides in 

 several particulars with L. tophiforme. I met with this form in 

 one locality growing in company with f. typica, typical specimens 

 of f. flexuosa and L. tophiforme. In another locality I found the 



