No. 3] REMARKS ON NORTHERN LITHOTHAMNIA. 109 



with specimens carrying antheridia of M. farinosa, partly even 

 with M. Lejolisii, when growing on the same substratum as either 

 of these species. It bore ripe sporangia at the end of July. 



Among some Melobesiae from the West coast of Sweden, 

 which Professor Kjellman kindly sent to me for examination, 

 the species in question was found, but also here very scarcely. 

 Thus a few crusts occurred on a piece of a leaf of Laminaria, 

 taken at Koster, not far from Hvaloerne, which were partly repre- 

 senting typical f. lacunosa, partly a transition to f. typica. The 

 species here appeared associated with or partly overgrown by a 

 Melobesia perhaps belonging to M. farinosa f. borealis. Cp. above 

 under the latter. The alga here carried conceptacles of 80 — 100/*. 

 in diameter with ripe, bisporic sporangia at the end of May, 

 30—35 /J. long and 20—25 fi broad. A similar form of the spe- 

 cies occurred very scarcely on a piece of the leaf of Laminaria 

 hyperborea labelled „Bohuslan" without any further statement of 

 locality. Here it was partly overgrown by a form of M. Lejolisii 

 which very nearly approaches f. limitata, and which carried con- 

 ceptacles of about the same size as those mentioned above, with 

 ripe carpospores. 



In the same locality at Hvaloerne in which f. lacunosa was 

 found, I afterwards met with the form which I have above deno- 

 minated f. typica. It occurred very sparely on chitine tubes of 

 hydroids attached to other algae. It was sterile, when collected. 

 The same form, however, was found in fertile state among some 

 Melobesiae from Denmark which Dr. K older up Rosen vinge 

 kindly sent to me for examination. It also here appeared on 

 hydroids attached to Polysiphonia elongata, collected at Tonneberg 

 Banke. This form stands in the same relation to the f. lacunosa 

 above mentioned as M. farinosa f. typica to f. callithamnioides. 

 Therefore, it seems to me that both forms ougth to be considered 

 as belonging to one and the same species, even though they are 

 sometimes somewhat diverging from each other. The form last 

 met with must have to be considered as the typical form of the 

 species. No particular stress needs to be laid on the fact that this 

 form has hitherto been found only on chitine tubes of hydroids, 



