— 204 — 



a new species, which he has called Halophila Aschersonii^) yet 

 closely related to H. Engelmanni, which is known from Florida. 



A good many algae are growing in connection with these 

 Phanerogams, partly creeping species belonging to the genus Can- 

 lerpa, in their mode of growth imitating the sea-phanerogams, 

 partly species belonging to the genera Penicillus, Udotea and 

 Halimeda, which by means of numerous fine rhizoids growing out 

 from the base of the stem-like part of the thallus, are fastened 

 into the mud and the sand. Both these peculiar forms of algae 



Fig. 1. Seagrass formation on the shore at Fair plane on the south coast of 



St. Croix. (F. B. phot.) 



are, as I have pointed out in earlier papers, characteristic of the 

 warmer seas^). 



On the south coast of St. Croix just west of Krausse's lagoon, 

 outside the coast of Fair plane, I have noticed a singularly beautiful 



^) Gfr. Ostenfeld. C. H., Halophila Aschersonii, n. sp. (Botanisk Tidsskrift. 



Bind 24, Kobenhavn 1902). 

 '-) Borgesen, F., A contribution to the knowledge of the marine Algte 



vegetation on the coasts of the Danish West-Indian Islands (Botanisk 



Tidsskrift, Bind 23, 1900, p. 49). 



— — , An ecological and systematic account of the Gaulerpas of the Danisli 



West Indies (Kgl. danske Vidensk. Selsk. Skrifter, 7. Rtekke. naturv. og 



mathem. Afd. IV. 5. Kobenhavn 1907). 



