No. 3] REMARKS ON NORTHERN LITHOTHAMNIA. 1 1 1 



As far as I have seen, the cortical cells show the same state of 

 things as in the species mentioned. As to reproductive organs the 

 following statement is found 1. c. : „Les tetraspores, divisees trans- 

 versalement en deux, se trouvent dans les conceptacies soriformes 

 de 80 a 100 p. de diametre, qui renferment 7 — 8 tetrasporanges 

 et ont autant de pores (fig. 2 et 3); ces conceptacies sont parfai- 

 tement spheriques." I have not had the opportunity of ascertaining 

 the correctness of this statement, as most of the conceptacies I 

 have examined were empty. I have found two conceptacies with 

 a single orifice. But I have not been able to determine whether 

 they represent conceptacies of sporangia. I should think it likely 

 that the species is identical with M. minutula f. typica. 



The species in question on one hand approaches M. farinosa. 

 Particularly f. lacunosa bears a considerable resemblance to f. calli- 

 thamnioides of the latter species. On the other hand the species 

 is more closely connected with M. Lejolisii. and when the con- 

 ceptacies are a little lower than typically developed ones, M. mi- 

 nutula is hardly distinguishable from stunted forms with small 

 conceptacies of the said species. The basal cells, however, in a 

 transverse section are more frequently horizontally elongated, and 

 comparatively more so, in M. minutula than in M. Lejolisii; the 

 cortical cells are few, and the alga is not incrusted or but little 

 incrusted with carbonate of lime. Cp. under M. Lejolisii. 



Area: South coast of Norway: Hvaloerne, f. typica, f. la- 

 cunosa {}); West coast of Sweden: Koster, f. lacunosa (Bovallius 

 and Kj ell man!); Denmark: Tonneberg Banke, f. typica (Rosen- 

 vinge!); Jersey (Van Heurck)? Ireland: Dublin Bay (Allmann, 

 Harvey)? The Mediterranean (Solms Laubach)? 



Lithophyllum Phil. 



Wiegm. Arch. Jahrg. 3, Bd. 1 (1837), p. 387; Fosl. Syst. Surv. Lithoth, 

 (1898), p. 5, Rev. Syst. Surv. Melob. (1900), p. 10; De Toni, Syll. Alg. IV (1905). 

 p. 1778; char. mut. 



