171 



neous objects. Besides, it is furnished with numerous and shallow 

 little holes, that I suppose to be scars atter emptied conceptacles 

 of sporangia. Some of them are effaced by local formations of 

 tissue. These scars are rather more numerous, smaller and more 

 shallow than the holes after the emptied conceptacles in L. lævi- 

 gatum, and, therefore, it seems as if the conceptacles have been 

 less, or, perhaps, not immersed. The colour is vinaceous or pinkish 

 vinaceous, partly with a yellowish tinge. 



I do not éxactly know the structure. The cells of the upper 

 layers of tissue appear on a vertical section to be about 8 ;i long 

 and 6 jj. thick. 



Relation to other spedes. As remarked, it shows greatest 

 affinity to L. lævigatum. However, it differs in some particulars, 

 and if the above named scars really are those after conceptacles 

 of sporangia, it probably is a well defined species. 



Habitat. The specimen was found in a muen exposed loca- 

 Iity on a depth of about 6 fathom. It was tåken in the beginning 

 of August, probably bearing sporangia earlier in the summer. 



Occurrence. Only found on the outer side of Kjelmo (Syd 

 varanger) in- East-Finmarken, a solitary specimen. 



Lithothamnion orbiculatum Fosl. mscr. 



L. fronde crustacea; crusta orbiculari vel suborbiculari, dia- 

 metro 3 — 6 mm., arcte adnata, sublævi, in media parte circa 

 0.2 mm. crassa, limbo tenuissimo, margine leviter undulato-crenato; 

 conceptaculis sporangiferis convexiusculis, parum prominentibus, 

 diametro a superficie visis circa 250 ji ; sporangiis circa 80 fi longis, 

 20 fi latis. Tab. 22, fig. 10—11. 



Syn. Lithothamnion polymorphum Aresch. Obs. Phyc. 3, p. 5; ex parte? 



Remark on the species. In I. E. Areschougs herbarium 

 in the Riksmuseum at Stockholm is a piece of a stone, to which 

 some specimens of an undescribed and chanacteristic Lithothamnion 

 are fastened, the above L. orbiculatum, collectéd about 40 years 

 ago at Christiansund, N. by F. L. Ekman. It has probably been 

 referred to L. polymorphum, as it in the named herbarium was 



