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



At St. Thomas I have dredged in the sea around Water Island. 

 At a depth of about 10 fathoms and upon sandy, loose bottom 

 a vegetation of Udotea and Halimeda was found, together with 

 several Florideæ. 



At St. Croix the dredgings were mostly not successful on 

 account of the coral reefs which almost entirely surround the 

 island. Only in the sea near Buck Island have more successful 

 dredgings been undertaken. 



I much regret that I have not succeeded in dredging in deeper 

 water than about 20^ — 25 fathoms ; as pointed out in the intro- 

 duction to the Chlorophyceæ section, my attempts at this were 

 negative, the dredge being immediately lost in the rocky bottom. 



But it is not only in deep water that the Red Algæ occur; 

 also in shallow water near the shore they are often found in great 

 numbers. In connection with this may also be borne in mind 

 the rich algal vegetation upon the roots of the mangroves and 

 among which the red algæ are very prominent, i) 



With regard to the physiographical details, coral reefs, depths 

 etc. and also to localities visited, reference should be made to the 

 introduction to the section on the Chlorophyceæ ; in this part' 

 moreover a chart is published showing the coral reefs, depths etc. 

 in the sea surrounding the islands. 



^) Compare my treatise : "The algal vegetation of the lagoons in the Danish 

 West Indies" in "Biologiske Arbejder tilegnede Eng. Warming den 

 3. November 1911", p. 41. 



