Before concluding these introductory remarks I wish to express my 

 thanks to the many botanists who in different ways have helped me in 

 the working out of this paper. 



1 am especially obliged to Mrs. and Mr. Gepp in London who have 

 not only been of great help to me during my visits to the British Museum 

 (Natural History) but have also, when preparing their monograph of the 

 Codiaceae, had my material of Penicillus, Udotea and Rhipilia for deter- 

 mination. 



Also my thanks are due to Mr. Frank S. Collins in Maiden, Prof. 

 V. G. Farlow in Cambridge and Dr. Howe in New York for sending me 

 collections of marine alg* from the West Indies and surrounding islands, 

 which have been of much value to me. 



Furthermore I am much obliged to the late Dr. Bornet, M. Paul 

 Hariot, Prof. Mangin, Prof. O. Nordstedt, Prof. Okamura, Major Rein- 

 bold, Dr. L. KoLDERUP Rosenvinge, Mme Weber-van Bosse and Profes- 

 sor WiLLE either for lending me specimens for comparison or determining 

 species for me. 



Finally, I would express my indebtedness to the Direction of the 

 Carlsberg Fund for the grant in aid of the many drawings and repro- 

 ductions. As to some of the last mentioned I would also thank Det Kgl. 

 Danske Videnskabernes Selskab and Naturhistorisk Forening 

 for permission to reprint here some drawings used in some of my earlier 

 papers. 



INTRODUCTION TO THE PHyEOPHYGEyE PART 



As in the case of my Chlorophycese paper the present communication 

 is based upon material collected during my three stays at the islands. 



With regard to the collecting of the algae, reference should be made to 

 the introduction to the Chlorophycese section for information as to the loca- 

 lities visited and for physiographical details. Here also a Chart showing 

 the coral reefs, depths etc. in the sea nearest the islands is published. 



Concerning the brown algae from the islands I have already published 

 some papers on the subject, namely : 



x,^3?wo crustaceous brown algai from the Danish West Indies (Nuova Notarisia, Serie XXIII 

 Lugllo 1912). 



The species of Sargassum found along the coasts of the Danish West Indies with remarks 

 upon the floating forms of the Sargasso Sea (Mindeskrift for Japetus Steenstrup, Kobenhavn 1914). 



For the sake of completeness I also give here the contents of these 

 paper so far as they treat with the fixed alga? living at the shores of the 

 islands. 



If we compare the brown algal vegetation of the West Indian islands 

 with that found in northern seas we see clearly the well known fact that 

 the northern brown algal vegetation reaches a Juxuriancy which greatly 

 surpass that in the tropics. The group of brown algae which in the islands 

 is most vigorously developed is the Fucacese represented by Sargassum and 

 Turbinariii, and where these are growing in full vigour this tropical Fuca- 

 ce«-Formation is not much inferior to that found in the northern sea, e. g. 

 at the shores of the Faeroes'). But this fucaceous vegetation is also the 

 most vigorously developed and as is well known the corresponding vege- 

 tation in the northern seas is much behind the vegetation of the Lamina- 

 riaceae. 



^) Comp. F. BORGESKN The Algpe-vegetation of the Faeroese coasts, 1905. (Botany of the FsDroes 

 Part III. 



