59 



Habitat. The species lives in the upper part of the sublitoral 

 region, on a depth of 3—8 fathom. It chiefly is met with in the 

 fjords, preferring somewhat sheltered places, and is to be found 

 best developed on hard bottom. It partly grows scattered partly 

 forming smaller banks together with other species. Specimens 

 collected in July, September and October have been very scantily 

 provided with conceptacles of sporangia, some of which with ap- 

 parently ripe sporangia. Specimens bearing cystocarpic conceptacles 

 have been taken in July. 



Occurrence. The typical form found at Bejan, local but abundant, 

 and together with it some specimens of f. parvicocca. A form 

 closely related to the former has been collected at Munkholmen 

 near Trondhjem, scarce, and at Christiansund, N. (Ekman). The 

 form connata is known from Drobak in the Chris tiania Fjord 

 (Gran), apparently scarce; Storfosen near Bejan, scarce; and a 

 form most nearly connected with this at Roberg in the Trondhjem 

 Fjord, scarce. Typical specimens of f. patula have been collected 

 at Skorpen in Tromso Amt, Skjorn and Bejan in the Trondhjem 

 Fjord, local but pretty plentiful, and especially at the two last 

 named places together with transitions to f. typica and f. connata. 



Lithothamnion gracilescens Fosl. mscr. 



L. fronde libera vel interdum lapidi.bus afflxa, subglobosa, dia- 

 metro usque 6 cm., obscure rosea, irregulariter ramosa; ramis e 

 centra solido, exiguo, undique egredientibus, teretibus, subcylindricis, 

 superioribus plerumque nodulosis, fasciculos plus minus remotos 

 formantibus, apicibus obtusis; conceptaculis sporangiferis convexius- 

 culis, parum prominentibus, infra apices ramorum crebris, a super- 

 iicie visis diametro 350 — 400 /a ; sporangiis quatemas sporas foven- 

 tibus, 120 — 150 \i longis, 45 — 60 /* latis; conceptaculis cystocar- 

 piferis conicis, diametro 300—350 \i. Tab. 15, fig. 20—27. 



Syn. Lithothamnion byssoides linger, Leithakalk p. 19, t. 5, fig. 1 — 8. 



Description of the species. The plant forms spheroidical or 

 somewhat irregular masses attaining a diameter of about 6 cm., 

 in general freely developed on the bottom, but now and then fastened 

 to or nearly encompassing small stones. The colour is a dark 



