F. Borgesen: Phæophyceæ of the Danish W. Indies. 13 



• This species was found in the littoral and upper sublittoral 

 region, growing epiphytic upon other algæ or on stones etc. It 

 has been collected in much exposed as well as in more sheltered 

 localities. 



St. Croix: Christiansteds Harbour, Northside. St. Jan: Cruz Bay. 



4. Ectocarpus Rallsiæ Vickers. 

 Vickers, A., Liste des Algues marines de la Barbade (Ann. Sc. Nat., 

 Botanique, 9^me Serie, vol. 1, 1905, p. 59) ; Phycologia Barbadensis, Part 

 II, pl. 32. 



Amongst Eet. Mitchellæ I found a small Ectocarpus which 

 seems to agree with the figure of E. Rallsiæ, given by M Ue Vickers, 

 1. c. As M lle Vickers' description is rather poor I give here a 

 further description from my plant. 



The basal part consists of creeping, irregularly bent filaments 

 (Fig. 7 d) twisted together. Underneath the filaments are fastened 

 to the substratum by means of short rhizoids. 



From their upper side the erect filaments spring up. These 

 are composed of cells from nearly as long as broad, to about 5 

 times the length of their own diameter. Long and short cells 

 are found intermingled owing to the fact that intercalary division 

 may take place everywhere in the filaments (Fig. 7 b); in their 

 upper end the filaments terminate in very long, colourless hairs. 

 The diameter of the filaments reaches a length of about 27/7. 



The ramification is not very great and rather irregular. Some- 

 times several branches are crowded together, sometimes the fila- 

 ments for a long while remain unbranched. Some of the branches 

 are short, others long and terminating in a long hairs. 



Several small discoid chromatophores are found in each cell. 



The plurilocular sporangia are fusiform with attenuated apex, 

 sessile or often pedicellate. They are rather variable in size, the 

 length varying from 80// — 120 p. or more and their diameter 

 from 27//— 40//. 



The unilocular sporangia (Fig. 7 b) are oval-ovate, reaching a 

 length of about 70 // and a breadth of about 45 p. 



Far up in a long hair in the end of a filament (Fig. 7 d) I 

 noticed a series of short cells with chromatophores etc. ; these 

 cells were certainly actively dividing, also producing a branch 

 from one of the cells. If this phenomenon is a common event 

 I think it may be of some importance, as a method of propa- 

 gation, to a plant living as it does intermingled between larger 

 algæ. 



