INTRODUCTION 



J\s was the case with the parts of "The marine Algae of the 

 Danish West Indies" published earlier, this third part, containing 

 the Rhodophyceee, is based especially upon materials collected during 

 my three stays at the islands. 



With regard to West Indian Red Alga? I have already published 

 some papers on the subject, namely: 



Some new or little known West Indian Florideae, I. (Botanisk Tids- 

 skrift, 30. Bind, Kebenhavn 1909). 



Some new or little known West Indian Florideee, II. (Botanisk Tids- 

 skrift, 30. Bind, Kobenhavn 1910). 



For the sake of completeness I have included here the principal 

 contents of these papers. 



The Red Algse are common in the literal region and also in 

 the upper sublitoral, but they occur especially in deep water, 

 and where I succeeded in dredging in such places I always had 

 good results. 



Thus they occurred abundantly in the Sound between 

 St. Thomas and St. Jan. Strong currents run here in the 

 narrow channel and steadily renew the water. The depth varies 

 from 10 to about 20 fathoms, seldom more. The bottom is suitable 

 for dredging ; it consists of smaller and larger stones, pieces of 

 corals etc. Upon these a very rich vegetation of algae is present, 

 mostly consisting of Red Algae. Also north of St. Jan, in the 

 narrow sound between this Island and Tortola, a flourishing algal 

 vegetation is found, including especially many Red Algae. 



1 



