F. Børgesen: Rhodophyceæ of the Danish W. Indies. 277 



case in Polysiphonia*). When fully developed they are urceolate 

 in shape (Figs. 273, 276), with a broadly hemispherical base tape- 

 ring gradually upwards, the apex prolonged into a rather long 

 neck. They are about 250 // long and 190 ju broad. As to their 

 shape they agree very well with Kützing's figure, 1. c, fig. c. 



This plant is evidently in several respects nearly related to 

 P. sertularioides**) but this specias has branches in the axils of 

 the trichoblasts as described by Kny***) and Falkenberg, 1. c, 

 p. 122, pi. I, figs. 1 — 16, so that Polysiphonia macrocarpa, owing to 

 the lack of axillary branches, (provided that my plant is rightly 

 referred to this species) is easily separated from it. 



It has been found with tetraspores, antheridia and cystocarps 

 in the months of January and February. 



St. Croix: Christiansted's Lagoon, Salt River, Krause's Lagoon. St. 

 Thomas: Bovoni Lagoon. St. Jan: Coral Bay. 



Geogr. Distrib. : Atlantic coast of Europe and Africa from Great 

 Britain to Morocco. West Indies. 



6. Polysiphonia fenilacea Suhr, J. Ag. 



J. Agardh, Spec. Alg , vol. II, pars III, p. 980. 



Polysiphonia breviarticulata Harv., Nereis Bor.-Am., p. 36, tab. XVI B. 



This plant was found growing among other algæ forming, 

 together with these, entangled masses. It is a very coarse and ro- 

 bust plant. 



It has creeping basal filaments (Fig. 277 a) fastened to the 

 surrounding algæ by means of numerous hapters. The hapters 

 are commonly short, but vigorous, with thick walls, and end in 

 a small lobed disc. The diameter of the cylindrical stem of the 

 rhizoids often reaches a length of more than 100 ^u. The basal 

 filaments are about 800 p. thick, sometimes even 400 /i or more. 

 The peripheral walls are very thick (lat. about 8^«); also the walls 

 between the cells are proportionally substantial. The cells are 

 about 130 /i broad and 100/.« long. The hapters often issue in 

 pairs side to side, a single one from each of the pericentral cells 

 below. 



On their upper side these filaments carry the erect branches 



*) Comp. Rosenvinge, L. Kolderup, Bidrag til Polysiphonias Morfologi, 



Bot. Tidsskr , Bd. 14, 1884, p. 23. 



**) Cfr. Bornet, Ed. Les Algues de P. K. A. Schousboe, p. 306. In Sylloge 



De-Toni has P. macrocarpa as merely a synonym of P. sertularioides. 



***) Kny, L , Über Axillarknospen bei Florideen, p. 105, pi. II, figs. 1 — 4. 



