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the Phæophyceæ in general are but faintly represented, whilst the 

 Ghlorophyceæ on the contrary are dominating in shallow water. 

 These general characters as described for instance by Warming 

 in „Plantesamfund" and by Schimper (1. c.) quite correspond with 

 my own observations in the Danish West-Indies. 



The tidewater is inconsiderable on the shores of the Danish 

 islands, and the litoral region 1 ) therefore is not developed at all or 

 at all events only very slightly so. In contradistinction to northern 

 shores such as for instance those of the Faroe Islands where a 

 very abundant litoral vegetation occurs, the West-Indian rocks 

 immediately above the sea are sterile, and only on exposed loca- 

 lities, for instance the west coast of St. Croix, a faintly developed 

 litoral vegetation is to be found on moist rocks, rising scarcely 

 more than one or two feet above the sea , and at all events not 

 higher than to be within the reach of the constant squirting from 

 the nearly always rather restless sea; should it happen to become 

 calm, most of the species growing here would quickly become dry 

 and be killed by the rays of the tropical sun. It is essentially a 

 vegetation of Ghlorophyceæ composed of several different species, 

 but none of them are sufficiently predominant to justify spea- 

 king of different societies of this or that species. Of species which 

 I have found on such localities, just above the surface of the sea, 

 may be mentioned: Viva Lactuca var. rigida, Enteromorpha sp., 

 Struvea delicatula, Anadyomene stellata, Neomeris dumetosa, Sipho- 

 nocladas membranaceus, Padina Pavonia, Sargassum sp., Bostrychia 

 and Laurencia species etc. These however are without exception 

 nearly all species that otherwise have their home in the upper 

 sublitoral region and which are only able to exist here on account 

 of their constantly being kept moist by the squirting of the sea or by 

 growing in cracks or recesses of the rocks, protected against the 

 rays of the sun. This is all the information I am able to give 

 about the litoral vegetation ; we shall now occupy ourselves a little 

 with the sublitoral Alga vegetation, and then first with the litho- 

 phile Algae. 



On rocks and coralreefs in shallow water a motley collection 

 of Algae is to be found. Besides the above mentioned species 

 which occur in the litoral region, but all have their real home 

 here, we also find here Caulerpa racemosa Forsk, with the varie- 



3 ) From ordinary low water mark upward. 



