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



19 



The chromatophores have the form of irregularly bent filaments. 



This species seems to come quite near if it is not indeed 

 identical with the form described and figured by M me Weber in 

 "Liste des Algues du Siboga", I, p. 128 and here designated 

 Ectocarpus elachistæformis Heydr. prox. The way of growing, the 

 shape and size of the sporangia, the breadth of the assimilating 

 filaments all seem exactly the same. 



Fig. 11. Ectocarpus elachistæformis Heydr. 



Parts of thallus with plurilocular sporangia. 



(a, b, about 200 : 1 ; c, 150 : 1). 



The only differences I have found were that the length of 

 cells in the upper part of the assimilating filaments attain a 

 greater length than in my plant (more than double), and that 

 "le sommet de ces derniers [filaments longs] se transforme en 

 longues cellules hyalines : le pseudo poil", while those in my plant 

 all contain chromatophores. The shape of the chromatophore is 

 not mentioned by M mc Weber. 



Judging from the description and figure of Heydrich his 

 plant shows the following differences. 



2* 



