1\~0. 3] REMARKS ON NORTHERN LITHOTHAMNIA. 43 



10. Lithothamnion grande Fosl. mscr. 



Frond freely developed at the bottom, subspherical or hemi- 

 spherical, repeatedly subdichotomously branching, the branches 

 erect, but curved, fastigiate, 1,5 — 2,5 mm. in diameter; concep- 

 tacles of sporangia convex, but little prominent, 300 — 400 [i in 

 diameter; spoiangia two-parted, 100 — 140 //. long and 50 — 70 ft 

 broad. 



This species forms spherical masses of 10 — 15 cm. in diameter, 

 or subhemispherical ones of up to about 35 cm. in diameter by a 

 thickness of about 14 cm., and of up to about 5 kilogrammes in 

 weight. The branches are 1 — 1,5 or up to 2 cm. long, curved, 

 those of the last order sometimes rather straight, often carrying 

 wart-like processes and more or less anastomosing. 



in structure the alga coincides in the main with L. fomicatum. 

 So it does also as to the conceptacles, which are more or less 

 crowded in the upper part of the branches. Grown in organs of 

 that kind occur sparingly in the peripherica! portion of a branch. 



L. grande approaches L. fomicatum in habit, but is di- 

 stinguished by its curved branches as contrasted with the straight 

 branches of L. fomicatum. On the other hand, it coincides in 

 ramification with L. TJngeri and L. hreviaxe, particularly coarse 

 specimens of the former species, but differs by its two-parted 

 sporangia, and from the latter by its longer branches and as it 

 seems frequently less prominent conceptacles. Besides it sometimes 

 approaches old specimens of L. coll iculo sum, but the branches of 

 the latter are mostly thicker and straight, and this species never 

 grows as large as L. grande. 



Of the occurrence and frequency of the species little is known. 

 A solitary live specimen has been taken in the Langesundfjord, 

 .a few dead specimens at Mandal and in the Sandsund at Rdvasr. 

 A single specimen not certainly belonging to this species, has been 

 picked up from a depth of 15 fathoms in the Hardanger Fjord. 

 The other specimens in hand few, but well developed, have come 

 from localities unknown on the west coast of Norway. 



Area: Norwa} 7 : the west coast (sent in to the Bergens Mu- 

 seum from localities now unknown); Sandsund at Rovrer (brought 



