) 
OLIvER.— Marine Littoral Plant and Animal Communities. 519 
The large-brown-algae formation appears to be best represented in tem- 
perate seas. In Tasmania and the southern coasts of Australia Durvillea 
Transeau) In warmer waters the principal algae are smaller and the 
species fewer. In Queensland species of Sargassum are dominant (Johnston, 
1917, p. 55) ; in Tahiti the outside reef supports a low growth of Sargassum 
and Turbinaria. 
Durvillea Association. 
"This association is characterized by the presence of the large kelp 
Durvillea antarctica. This alga stands out above the others like a lofty 
tree in a forest, forming a tier of vegetation by itself. Below is a growth of 
Marginaria, Lessonia, and other algae equivalent in size and appearance to 
h 
granules, which are most dense along the outer edge. Beneath this follows 
à layer, twice as thick as the palisade layer, of interwoven branched 
