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



333 



not in series". In F alkenhergia vagabunda the sporangia are formed 

 directly from a pericentral cell and no covering cells are present. The 

 contents are firstly divided in two parts and these two parts are 

 again divided into the four spores (cfr. Falkenberg, 1. c, p. 691). 

 While the form first discovered by me and mentioned in my 

 paper quoted above was rather a small one, the filaments reaching 

 only a diame- 

 ter of about 

 30—40 |a, I 

 have later on 

 found a much 

 more robust 

 form in w^hich 

 the filaments 

 often had a 

 diameter of 50 

 to 60 |a. In this 

 form the seg- 

 ments were 

 now and then 

 very swollen 



in their middle, the whole filament in this way getting a moniliform 

 appearance (Fig. 332 b)*). 



This species occurs in shallow water near the shore in sheltered 

 as well as in more exposed places. It is, as mentioned above, found 

 epiphytic on or intertwisted among other littoral algæ as Gelidium, 

 Chamædoris annulata, Heterosiphonia Wiirdemauni, Dasya ocellata 

 etc. often forming together with these large spongy tufts. 



At the islands it seems to be a common species. 



Geogr. D i strib.: Mediterranean Sea, Canary islands, Bermudas, Bar- 

 badoes. 



Cottoniella nov. gen.**) 



Thallus ex filamentis infra decumbentibus rhizoideis substrato 

 adfixis, dein assurgentibus, erectis compositus, structura dorsiven- 



Fig. 333. F alkenhergia Hillebrandii (Bornet) Falkb. 

 ,4, part of the thallus (25:1). B and C, summits of fila- 

 ments, in B with a new branch (150:1). Z), part of a fila- 

 ment (120:1). £", tran.sverse section of the thallus (150:1). 

 F and G, hapters (65:1). 



*) According to Yendo (Bot. Magaz., vol. XXX, p. 62) our form is very 

 hke the Australian F. rufolanosa {Bdir\.) Schmitz; most probably this 

 plant and F. Hillebrandii are forms of the same species. 

 **) I have great pleasure in naming this interesting plant after my Eng- 

 lish colleague and friend, Mr. A. D. Cotton of Kew. 



