103 



rated both in structure, the sporangia and other essential charac- 

 teristics. 



Habitat. With us the plant grows in the upper part of the 

 sublitoral region, on a depth of 3 — 8 fathoms. It apparently pre- 

 fers protected places, in somewhat exposed localities descending 

 farther down than in the former. On the Greenlandic coast it 

 descends to a depth of 16 fathom. It bears sporangia in July, 

 August, September and December. 



Occurrence. Mehavn in East-Finmarken, Bergsfjord in West- 

 Finmarken, scarce ; Skorpen in Kvænangen, apparently rare ; Rissen 

 in the Trondhjem Fjord, rare; Drobak (Gran) and Nesodden 

 (Schreiner) in the Christiania Fjord, apparently pretty plentiful. 



Geogr. Distribution. Greenland (Rosenvinge); the Atlantic 

 coast of North America (Collins). 



Lithothamnion colliculosum Fosl. 



Contrib. II, p. 8. 



f. densa Fosl. mscr. 



f. crusta 0.5—1.5 mm. crassa; tuberculis usque ad 4 mm. altis, 

 1 — 2 mm. crassis, dense dispositis. 

 Fig. Lithothamnion colliculosum Fosl. 1. c. t. 3, fig. 1 et tab. nostr. 17, fig. 8 — 10. 



f. laxa Fosl. mscr. 



f. crusta usque 3 mm. crassa; tuberculis tenuioribus, usque 

 ad 2 mm. altis, laxe dispositis. Tab. 17, fig. il. 



f. rosea (Batt.) Fosl. mscr. 



Descr. Lithothamnion roseum Batt. in Grevillea, vol. 22, p. 20. 



Fig. „ colliculosum f. rosea tab. nostr. 17, fig. 12 — 16. 



Syn. Lithothamnion fasciculatum Farl. New Engl. Alg. p. 182; ex parte 

 sec. spee. 

 „ colliculosum Batt. in Grevillea, vol. 21, p. 23; Journ. 



of Bot. 1892, p. 8; saltem ex parte sec. spee. 



Remark on the form of the spedes. The plant recorded by 

 B at ters 1. c. under the name of L. roseum is supposed by him 

 perhaps to be the tetrasporic form of L. colliculosum. It is in fact 

 so closely related to this species, that it in my opinion cannot be 

 considered more than a denominated form, or not unlikely being 



