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



327 



original specimens in Harvey's Herbarium, must be considered as 

 the var. üjpica. The other more slender and softer plant I propose 

 to call var. laxa. 



Falkenberg suggests, not having made any observations regard- 

 ing the localities in which the two forms grow, that the var. typica 

 ought to originate from shallow water while the var. laxa on the 

 other hand ought to be a deep sea form. My 

 observations have not quite verified this 

 supposition. To be sure the var. typicais often 

 found in shallow water in exposed places 

 with strong light, but I have also dredged 

 this form once in a depth of ten meters and 

 another time in about twenty meters. As 

 to the var. laxa this was once found in shal- 

 low^ water in a lagoon growing in the shade 

 of the mangrovesand therefore at a place where 

 it might be exspected to occur, but another 

 time it was gathered in shallow water behind 

 Long Reef at Christianssted, a rather exposed 

 place with strong light. 



The specimens with tetraspores were ga- 

 thered in the month of January. 



HeterosiphoniaWurdemannii^ often found 

 upon other larger algæ. Between its branches 

 Falkenbergia Hillehrandii is often entangled. 



Heterosiphonia is most probably a com- 

 mon species along the shores of the islands ; 

 I have gathered it only at the shores of St. 



Croix. 



St. Croix: Ghristianssted's Lagoon, Long 

 Reef, White Bay, Casavagarden. 



Geogr. Distrib.; West Indies, Key West, Cadiz, Mediterranean Sea 



Fig. 328. Heterosiphonia 



Wurdemanni (Bail.) 

 Falkb. var. laxa n. var. 

 a, stichidium with ripe 

 tetrasporangia ; in the 

 basal part they are emp- 

 tied, ft, ends of ramuli 

 transformed into rhi- 

 zoids. c, transverse sec- 

 tion of the thallus. 

 (About 180:1). 



Dictyurus Bory. 



Dictvurus occidentalis J, 



Ag. 



Agardh, J., Nya alger från Mexico (Öfversigt af Kungl. Vet.-Akad. 

 Forhandl., 1847, p. 17); Spec. Alg., vol. 11,3, p. 1243. Kützing, F., Spec. 

 Alg., p. 673; Tab. phycol., vol. XII, t. 64. 



Unfortunately all the material preserved in spirit of this 



