F. Børgesen: Rhodophyceæ of the Danish W. Indies. 



87 



outwards, about 200// long and 170// broad, but both larger and 

 smaller ones occur. 



In a young growing tip Setchell found the '■''punctum 

 vegetationis'''' convex projecting. As to this Setchell remarks: 

 "Whether this is normal or not, it is strikingly different from 

 the depressed punctum vegetationis as observed in all other species 

 of Scinaia examined." In my specimens this is not the case; 

 the tips of the plants in a turgescent state certainly appear to 

 be convex projecting but when somewhat magnified the growing 

 region is clearly found to be sunk. 



It can not be denied that these differences in my plants 

 from the typical Scinaia complanata are very essential. Even if I 

 left out of consideration the fact that in Setchell's plant the 

 growing point is not sunk, 

 which as pointed out by 

 Setchell himself, is very 

 probably not normal, the 

 terete thallus in my 

 plant is a very strik- 

 ing character. And the 

 axial strand being di- 

 stinct through the whole 

 thallus is of course also 

 important and to these 

 characters may yet be 

 added the narrow thallus. 



On account of these 

 differences we apear to be entitled to consider these narrow 

 forms as a variety to which I propose the name intermedia, this 

 variety appearing to me to be a connecting link between Scinaia 

 complanata and Scinaia furcellata. 



In his newly published highly interesting paper on Sci- 

 naia furcellata, Svedelius^) describes for the first time mono- 

 spores as occurring in this species. As is well known tetraspores 

 are never met with in Scinaia and the discovery of the mono- 

 spores is therefore highly interesting. I have been looking care- 

 fully for these organs in my specimens but without success, 

 only antheridia were present. Also I did not succeed in finding 



Fig. 94. Scinaia complanata (Collins) Cotton, 

 var. intermedia nov. var. a, part of the epi- 

 dermal cell-layer seen from the inner side 

 showing the arrangement of the assimilating 

 cells, c, transverse section of the same tis- 

 sue, b, epidermal cells and antheridia seen 

 from above, [a and b about 250 : 1, c about 

 150:1). 



^) SvEDELius, Nils, Zytologisch-entwicklungsgeschichtliche Studien über 

 Scinaia furcellata. Ein Beitrag zur Frage der Reduktionsteilung der 

 nicht tetrasporenbildenden Florideen. (Nova Acta Regiae Soc. Scient. 

 Upsaliensis, Ser. IV, Vol. 4, No. 4. 1915). 



