380 Dansk Botanisk Arkiv, Bd. 3. Nr. 1. 



granatens Turner, Fuci, pi. 215), and partly to the var. aeruginosa 

 (Turn.) J. Ag. (= Fuciis æruginosus Turner, Fuci, pi. 147;. 

 Besides I have some few specimens approaching the var. poly- 

 carpa (Grev.) J. Ag. and some others most likely referable to 

 the var. angustissima Harv. These last mentioned specimens are 

 quite terete at their base, but in the upper part the thallus is 

 a little flattened being at the same time more or less bi-trifurcate. 

 Some of these specimens were lying loose upon the bottom. 



Gracilaria lacinulata occurs in shallow water near the shore, 

 partly in sheltered places, partly in more exposed. 



St. Croix: Longford, Christianssted's harbour, White Bay, Salt River, 

 Buck Island. 



Geogr. Distrib.: Warmer Atlantic coast of Europe and America, 

 Mediterranean Sea. 



9. Gracilaria dentata J. Ag. 



Agardh, J., Spec. Alg., vol. II, p. 603; Epicr., p. 424. 

 Sphærococcus oligacanthus Kütz., Tab. Phycol., vol. XVIII, pi. 87. 

 Sphcerococcus rangiferinus Kütz., ibd. pi. 86. 



The specimens found seem to agree very well with J. 

 Agardh's description. They have a thicker, more firm and cartila- 

 ginous thallus than that of Gracilaria lacinulata. The thallus 

 is several times bi-tripartite, in the upper end flabellate. Along 

 the margin the specimens are more or less dentate. Some of the 

 specimens lack the dents. These bear a close resemblance to some 

 specimens in my collection from Jamaica, gathered some years 

 ago at this island by Mr, 0. Hansen and determined by the late 

 Major Reinbold to be a form intermediate to the var. polycarpa 

 of Gr. lacinulata. 



Transverse sections of the thallus show that the cells in the 

 present plant are much smaller than those of Gr. lacinulata, 

 about 200 fi lat. The cells become smaller outwards and are sur- 

 rounded by the cortical layer which consists of a few layers of 

 cells, oval of shape. 



The Fucus denticulatus of Vahl (in Skrivter af Naturhistorie- 

 Selskabet, 5te Bind, 2. Hefte, p. 45) is most probably this species. 

 But as his diagnosis is rather short and as I have seen no spec- 

 imens from Vahl's time, I do not think it right to reestablish 

 his specific name. 



