OLIVER.— Marine Littoral Plant and Animal Communities. 525 
on the projections and in the hollows. In the lower portion of the associa- 
tion occur Scytothamnus australis, Colpomenia sinuosa, and, in shady places, 
Shag Point.—Between tide-marks at Shag Point are some fairly wide 
stretches of nearly level rocks. Just within the outer edge with its forma- 
tion of brown algae there are regular meadows of small algae 4 cm. to 
occur, all, however, of low growth. Standing out among the close growth 
are Colpomenia sinuosa and Adenocystis utricularis, both possessing hollow 
thalli, generally full of water. In crevices are found larger algae, such as 
Cystophora dumosa. 
and ; 
usca occur on the rock-surface under the algae. In such situations 
Acantho- 
Small-brown-algae Subformation. — 
. Hormosira Banksii, when dominant, usually forms a nearly pure associa- 
tion, as far as algae are concerned, on level rocks between tides in harbours. 
Such an association is well developed at Waitangi, Chatham Island, and 
near Purau, in Lyttelton Harbour. Hormosira can endure long exposure 
