No. 3] REMARKS ON NORTHERN LITHOTHAMNIA. 87 



of Norway, occurring in the sublitoral region at a depth of 3 — 15 

 or up to 20 fathoms. On some banks it nearly suppresses the 

 other calcareous algse occurring. Thus at Galten in West-Finmarken 

 was found a bank where Ph. investiens at the depth of 6 — 8 

 fathoms seemed to cover all other larger calcareous algae there 

 occurring, particularly a species which is likely to belong to Li- 

 thoth. Ungeri and L. soriferum or L. tophiforme. I did not 

 succeed in getting any specimen of the latter which was not almost 

 completely covered with Ph. investiens. Inside Tamso in the 

 Porsanger fjord is found a bank of calcareous algae which is about 

 10 km. long. In the parts of this bank which I examined, Ph. 

 investiens also occurred abundantly at the depth of 10—15 fathoms, 

 covering now a coarse form probably of L. Ungeri, now L. sori- 

 ferum, and perhaps other species. On Ph. investiens there was 

 in part a very rich vegetation of Ptilota. Besides there are both 

 at Tamso, in the Altenfjord, and in several other places found 

 rather considerable numbers particularly of young specimens oiL. 

 glaciate covered with Ph. investiens. On the contrary, it appa- 

 rently can not get the upper hand in banks of older and well 

 developed L. glaciate or L. fomicatum. The alga bears mature 

 reproductive organs in the months of June and July. 



Area: Norway: From Lebesby in East Fm mar ken to Lyngo 

 near Tromso(l); East Greenland? 1 ) 



Subgen. Clathromorphum Fosl. mscr. 



Gen. Clathromorphum Fosl. Syst. Surv. Lithoth. (1898), p. 4; Rev. Syst. Surv. 

 Melob. (1900), p. 9; De Toni, Syll. Alg. IV (1905), p. 1726.2) 



A sterile crust of Lithoth. glaciate from Heklahavn, picked up from a depth 

 of about 10 fathoms (H a r t z), is in part loosely covered with another 

 crust, which perhaps belongs to this species. Cp. Rosenv. 1. c. 

 In Rev. Syst. Surv. Melob. p. 10 I still kept Clathromorphum as a sepa- 

 rate genus, but remarked that it is perhaps to be considered as a subgenus 

 of Phymatolithon. I have not yet succeeded in finding unquestionable 

 cystocarps, and as the sporangia show a close relation to Phymatolithon, 

 I now think it most correct to admit it as a subgenus of the latter. 



