any case at the Faeroes, I have found some few FlorLdese only at this 

 depth; the Chlurophi/rese here stop in the uppermost part of the sublittoral 

 region, except only Gomontia and Ostreobium. 



As many of the tropical Chlurophycese furthermore are incrusted bj'^ 

 chalk, they also contribute greatly to the deposits in the sea not only in 

 bays and lagoons but also in the more open sea, and even the gravel 

 along the shores is much mixed with remains of these algae, sometimes 

 almost consisting of these alone. 



On account of the numerous coral reefs surrounding St. Croix it has 

 often been difficult to dredge off the shores of this island; nevertheless, 

 successful dredgins have been undertaking e. g. in the sea round Buck 

 Island, in White Bay and off Frederikssted. At St. Thomas and St. Jan I 

 have often dredged in the sea round Water Island especially in Gregorie 

 Channel, further in the Sound between St. Thomas and St. Jan, where a 

 very rich algal vegetation was found. On the whole the sea round St. Jan 

 has appeared to be very rich both on the north side where I have dredged 

 along most of the coast until near the east end and on the south side 

 until near Rams Head. 



In the sea surrounding these islands no very great depth occurs, the 

 deepest part is about 21) fathoms. But on the other hand rather deep 

 water, up so ten fathoms or more comes often quite near the steep, rocky 

 coast; this applies especially to the exposed north side of these islands. In 

 the larger and smaller bays we have shallow water with sandy or muddy 

 bottom often covered with mangroves f. i. the extensive mangrove growth 

 in the Bovoni Lagoon at the east end of St. Thomas. 



St. Croix on the other hand has the greater part of the coast sur- 

 rounded by coral reefs and shallow water, the only exception from this 

 being the northwestern rocky coast, where the great oceanic depths come 

 quite near. But the sea is most often very turbulent and 1 have therefore 

 not been able to dredge there. 



An opportunity of trying to dredge in greater depths and on the 

 whole of examining to what depth the algas are able to grow, was afforded 

 me when the Ministry of Marine gave me permission to go out with the 

 cruiser »Ingolf«. but the result was negative, as the dredge immediately 

 caught in the rocky bottom and was lost. 



When mentioning some of the most important external conditions 

 under which the alga^ live at the shores of the Danish Islands 1 may yet 

 point out that the tide is nearly wanting and in every case of no practical 

 significance to the algae ^ . 



The greater part of my collection has been dried but of nearly all the 

 gatherings 1 have also had material preserved in alcohol or formaline and 

 the examination has nearly always been based upon this. 



Of earlier contributors to our knowledge of the algae of the Danish 

 West Indies Rector Hans West may first be mentioned. West collected 

 algae and sent them to Professor Martin Vahl who has described several 

 of them in his paper: »Endeel kryptogamiske Planter fra St. Croix« (Skriv- 

 ter af Naturhistorie-Selskabet, 5te Bd., 2det Hefte, Kiobenhavn 1802). 



Later, Professor Orsted has made rich gatherings at the islands and 

 some of his specimens have been determined by J. Agardh. 



And furthermore Baron Eggers, C. O. E. Hansen Ganneskov, Johs. 

 H. Krebs, Holger Lassen, Dr. Tii. Mortensen, Professor Warming and 

 .several others have collected algae at the shores of the islands. 



In West's book; )^Bidrag til Beskrivelse over St. Croix« etc., Kioben- 

 havn 1793, a few alga? are named, and in John Knox' »A historical ac- 

 count of St. Thomas, W. I.« etc. New York 1852, some few alga) are also 

 mentioned in the plant list p. 230. This list is reprinted in B.V.Petersen, 

 »En historisk Beretning om de dansk-vestindiske 0er, St. Croix, St. Thomas 

 og St. Jan«, Kjobenhavn 1855. Finally in Millspaugii »Flora of the island 

 of St. Croix« some few algae, determined by Prof. Farkow , are mentioned. 



') Regarding the external conditions of life to the algse compare also my above quoted paper 

 concerning the C'aulerpas and as to the algal vegetation in the iagoons also ray treatise in 

 >Biologiske Arbejder tilegnede Eug. Warming*, Kobcnhavii 1911, p. 41. 



