169 



peripherical portion always being sterile. They are immersed, and 

 at first appear from the surface of the frond as minute, lighter 

 points, which soon become decorticated, at first in the centre, for- 

 ming depressed-circular points not perceptible to the naked eye, 

 later getting larger and at length forming sharply defined cup- 

 shaped deepenings, the roof of the conceptacles, about 150 — 200 p 

 in diameter and intersected with 40 — 55 muciferous canals. The 

 edge of the roof forms a not or scarcely not elevated, narrow 

 border. In this state the conceptacles much resemble in shape 

 the conceptacles of antheridia in L. polymorphum, but are smaller, 

 and those only traversed by a single canal. At maturity the roof 

 gets thinly decorticated and the border disappears, by and by dis- 

 solved or settling more or less down into the conceptacle. When 

 emptied the conceptacles leave globular and rather deep, distinct 

 holes of the same diameter as above quoted. So far as I have 

 seen the conceptacles never grow down into the frond and the 

 holes become frequently effaced by a new thickening layer of the 

 frond. On the other hand the roof apparently does not always 

 get fully dissolved and also local formations partly efface the holes 

 partly are formed upon the settled roof and even raised above the 

 surface of the frond as small, convex excrescences reminding one 

 of conceptacles, but very easily falling away. Such formations 

 sometimes even appear to be formed upon the roof of not fully 

 developed conceptacles, but I do not know whether they then 

 perhaps prevent the farther development of the reproductive organs. 



I have examined rather numerous sporangia, most of which 

 appeared to be mature and were two-parted. I, however, found 

 two irregularly three-parted sporangia, but never four-parted, so 

 that I suppose mature and typically developed ones always to be 

 bisporic. They are 120—150 fi long, 40—60 \i broad and about 

 15 — 20 ii thick. Occasionally may be found very broad ones, or 

 up to 100 /x. , 



Habitat. With us this species has been found fastened to 

 smaller stones on a depth of 5—6 fathom. Otherwise it fastens 

 itself to rocks, stones and other hard objects. It apparently deve- 

 lops sporangia all the year. In specimens collected in the middle 



