22 M. F0SL1E. [1905 



carps and apparently also of antheridia in a specimen from East- 

 Greenland. They are convex or subhemispheric conical, 300 — 450 

 and 200 — 250 p. in diameter, occurring in the central part of a 

 thin crust richly furnished with conceptacles of sporangia. 



This species is characteristic and easily recognizable, when 

 bearing conceptacles of sporangia fully developed. Otherwise it 

 may be confounded principally with Lithoth. loeve, but also with 

 other species. Even specimens with young conceptacles may be 

 hardly distinguishable from a Lithoth. loeve faintly developed, the 

 more so because both species are for the most part growing gre- 

 gariously and often sharing substratum and coalescing or one 

 sometimes growing over the other. Old specimens of the species 

 with an uneven surface or specimens growing on an uneven sub- 

 stratum may even be confounded with stunted forms of Lithoth. 

 glaciate which have not developed branches, but only show a 

 surface more or less uneven or finely rugged. This is, by way 

 of example, the case at Heklahavn on the east coast of Greenland, 

 where L. foecundum, L. Iwve, and such a stunted form of L. 

 glaciate are growing gregariously. The same sometimes seems to 

 be the case on the coast of Iceland. Sterile specimens will besides 

 bear a considerable resemblance to young Ph. investiens or some- 

 what faded forms of Ph. polymorpJium f. sublosvis, or of Ph. 

 Icevigatum which bear the peculiar sterile conceptacles mentioned 

 under these species. 



There is a possibility that L. foecundum is referable to the 

 genus Phymatolithon, but this can not at present be decided. 



The alga occurs within the sublitoral region in a depth of 

 5—20 fathoms both on the open coast and in sheltered places 

 where the tidal waters run rather strongly. It grows sporadically 

 in small numbers of individuals together with other calcareous 

 algse, often sharing substratum with Lithoth. Iwve. It has been 

 ibund furnished with sporangia in June, July, August and October, 



Area: Norway: Near Tamso in Porsanger Fjord and at 

 Berg near Tromso(!) 1 ) N. and E. Iceland (Jonsson!); Newfound- 



: ) Specimens from other localities on the northern coast of Norway are un- 

 certain. Therefore, I do not record them here, but only such ones of which 



