55 



partly and most often occur in small numbers, partly not, and 

 especially in the most extreme form of this type the overgrown 

 as well as superficial ones appear to be very scarce. Also in 

 Adriatic specimens of the two last named forms older grown-in 

 organs of this kind seem to be scarce. Now and then occur 

 apparently two-parted overgrown sporangia in this species, but these 

 probably have not been fulfy developed before they together with 

 the conceptacles grew down into the frond. 



The cystocarpic conceptacles are in the present species conical, 

 low, seldom somewhat acute, about 400 — 500 fi in diameter at 

 the base. Some other conceptacles, only 200 — 300 {i in diameter 

 at the base and in shape coinciding with the former, probably are 

 those of antheridia. I have not seen the carpospores, nor the 

 spermatia. These organs are on the whole scarce in the specimens 

 that I have collected, and scattered in the branches without any 

 order. Also in this respect the form flexuosa in part rather differs 

 from the typical development, as I found the conceptacles of cysto- 

 carps in some cases to be more acute than ever in f. typica or 

 in other and more typical specimens of f. flexuosa as weil as in 

 Adriatic specimens of the latter, somewhat reminding one of these 

 organs in L. tophiforme. 



Bemark on the synonomy. I suppose that Gunnerus referred 

 to his Apora polymorpha all the Lithothamnia then known to him. 

 Among the 4 specimens mentioned under L. boreale apparently 

 from his own collection 1 ) are two which, no doubt, belong to the 

 present species, the one nearly according with the cited figure in 

 Act. Nidros., referrible to the form fastigiata. 



The figures that Johnston 1. c. gives of YåsL.polymorphum 

 are much differing from each other and most probably designate 

 different species, and even still more judging from his list of syno- 

 nymes. Thus the plant that he delineates 1. c. pl. 24, flg. 2 very 

 much reminds one of f. intermedia of the present species, to which 

 it probably belongs. The other forms referred by him to the same 

 species will be mentioned under L. crassum and L. incrustans. 



As remarked below under L. crassum Phil. I consider L. 



!) Cp. Witt r up, Catal. p. 88. 



