29 



conceptacles are numerous, and in one of these I found a solitary 

 sporangium, about 100 [i long and 50 p. broad, but I was not 

 able to determine the partition. 



Prof. Kjellman records I.e. a Lithothamnion under the name 

 of L. Ungeri, which he, among others, got from me, gathered at 

 Tromso. He identifies this plant with L. byssoides Unger, Leitha- 

 kalk p. 19—20, t. 5, fig. 1—8. In Contrib. 1. c. I followed Kjell- 

 man and quoted the plant under the same name from East-Fin- 

 marken, by comparison of specimens determined by Kjellman 

 himself. However, I then perhaps referred to it some specimens 

 now considered to belong to another species. Later I have had 

 the advantage of seeing Unger's description, and I also brought 

 together greater and better materials as then for the classification 

 of these much varying algae. Two fragmentary specimens that I 

 got back from Prof. Kjellman denominated as above agree with 

 the form typica of the present species, the one, however, showing 

 transition to f. corymbiformis and provided with an apparently 

 coarse hypothallus like the above mentioned specimen figured pi. 

 8, fig. 1, but also this infested with an epiphytic Lithothamnion. 

 He remarks, that the conceptacles of sporangia never grow down 

 into the frond. I, however, found in the named specimens older 

 grown-in organs of this kind, but they are scarce, which, as 

 quoted above, is often the case in f. typica. It may be that 

 Kj ell man's plant includes also another species, or, more likely, 

 the overgrown conceptacles escaped his observations. The speci- 

 mens then known were sterile. I on the other hand do not coin- 

 cide with Kjellman, that this form may be considered identic 

 with the named species described by Unger 1. c. This appears 

 to be a smaller plant, with thinner branches, but otherwise cer- 

 tainly somewhat reminding one of L. fruticidosum f. typica. I 

 think it identic with L. gracilescens described below. 



Relation to other species. This species apparently has origi- 

 nated in more southern wathers than for inst. L. glaciale, and it 

 is not unlikely that several other Lithothamnia have issued from 

 it, as L. crassum, or vice-versa, L. breviaxe, L. divergens, L. 

 apicidatum, L. dirnorphum and perhaps also L. mamillosum, and 



