336 THE ALGAE 



Myelophycus and Ishige followed by a belt of Sargassum thunbergii 

 and Hijikiafusiforme. 



In the South Pacific there has been intense activity in recent 

 years, and one of the principal features to emerge is that the major 

 belts are primarily dominated by animals. One reason for this is 

 that, apart from Hormosira, the predominant fucoids are all genera 

 that require total or ahnost total submergence, only being really 

 exposed at low water of spring tides. Various examples from the 

 South Pacific and South Atlantic are illustrated in Table 8. 



Table 8 



New Zealand Tasmania Victoria 



Supra- 



littoral Littorinids 



fringe 



Littorinids Littorinids 



S.W.Africa Chile 

 Littorinids Littorinids 



Chamaesipho- C] iamaesipho- Chamaesipho- Balanus 

 Chthalamus Chthalanius Chthalamus 



Mid- Hermella, 

 littoral Saxostrea or 

 serpulid 

 Corallines, 

 Hormosira 



Galeolaria 

 Corallines 



Algae or 

 Galeolaria 



Pjoira 



Pomato- 

 ceros 

 Corallines 



Chamae- 

 sipho- 

 Balanus 



Serpulids 



Corallines 



Sub- Ecklonia, Lessonia, Sarcophycus Laminaria 



littoral Carpophyllum Xiphophora Cystophora 

 or or 



Durvillea Sarcophycus 



Durvillea, 

 Lessonia 



The occurrence of the large brown algae reflects exposure to 

 wave action. Sarcophycus or Durvillea are found in the most ex- 

 posed situations, whilst Ecklonia, Hormosira and Cystophora are 

 typical of the more sheltered locahties. Xiphophora and Lessonia 

 occupy regions of moderate exposure. Transitional stages from the 

 types of zoning that have been described above from the colder 

 waters of the earth to those that are found in the warmer waters are 

 represented by examples from Florida and North CaroHna. In the 

 latter place it is only the summer flora that is warm temperate, the 

 winter flora being cold temperate (WiUiams, I945)-^ Along this 

 coastline the supra-Uttoral fringe is represented by a *black zone' 

 dominated by Myxophyceae and marine hchens. The upper part of 

 the mid-Httoral is dominated by barnacles (Chthalamus, Tetraclita\ 



1 A similar combination of floras exists in the Chatham Islands off New 

 Zealand. 



