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home here; with its rhizomes fine as thread it creeps all around 

 the roots of the mangrove and often forms pure societies covering 

 the root with a soft dark green sheath a few inches thick. Bryopsis 

 species f. i. pennata and plumosa are likewise to be found here in 

 abundance. Botrijophora occidentalis also covers the mangrove 

 roots in the same manner; Ørsted has collected it in Krauses 

 Lagoon on the southside of St. Croix. I have not seen this species 

 in a fixed position. Furthermore Codiiim tomentosum and other 

 Ghlorophyceæ. Of Florideæ the dark coloured Acanthophora 



Fig. 4. 



Caulerpa verticillata J. Ag. 

 A little magnified {Vj 2 : 1). F. B. del. 



Thierii often forms unmixed thick colonies; the beautiful rose- 

 coloured Çeramium nitens likewise is seen in abundance. Further- 

 more of Florideæ elegant species of Dasya and Bostrychia, Bryo- 

 thamnion trianguläre, Callithamnion and Polysiphonia species and 

 many others. Here may also no doubt be found several Myxo- 



wickeln, Rhizome hervorbringen, während in sehr dicht gewachsenen Rasen 

 die Individuen von unten her absterben". This last supposition is quite 

 correct as my figure shows. 



