OF SOUTH AUSTRALIA. 
15 
are massive and incrusting Nullipores. ’ 7 Madame Weber van Bosse 
similarly emphasises the great part filled by seaweeds in reef -building, as 
observed by her in the Siboga expedition to the Dutch East Indies. But 
it is not merely as adjuncts to the corals, for Lithothamnion and other 
stony seaweeds, Nullipores par excellence, build up reefs independent of 
the corals. Thus Madame Weber says, “Near the coast of Haingsisi, an 
island near the N.W. point of Timor, the whole reef which stretched from 
the shore into the sea was literally covered with knolls of Lithothamnion 
erubescens , up to 9 cm. in diameter. The living ones were red all round, 
the dead or dying totally or partially white. As far as the eye can reach, 
the bank is covered by the pretty beautifully pink-coloured knolls, heaped 
up close together.” And again, “Another remarkable bank was one south 
of the island Saleyer, marked on the charts as a ‘ coralbank. ’ It was found 
to be an enormous bank of Lithothamnion, that gave a red colour to the 
bottom of the sea 8 to 10 metres deep, intersected by white bands consisting 
of heaped up dead joints of Halimeda There is an extensive Litho- 
thamnion reef at Lord Howe Island. 
Thus the algae perform geological work in the building of protecting 
fringing reefs and of the gigantic breakwater, the Great Barrier Beef 
itself. Then the reefs break down and out of their detritus islands are 
formed, or the land is added to, and footing is provided for plants and 
birds and insects. Geologists meet with stony algae in layers of enormous 
thickness in various parts of the world, thus demonstrating that the rock- 
building work of the algae has been continued through the ages. 
An instance nearer home is provided by the Blue-Green Algae which are 
playing an important part. in the formation of the “biscuits” and other 
limestone structures on the south-east coast of South Australia, described 
in Sir Douglas Mawson’s previously referred to account. 
USES OF SEAWEEDS TO MAN. 
Food. — Primitive races having access to sea shores make seaweeds an 
important part of their food. In Hawaii a long list of species eaten by 
the natives was recorded by American biologists. In earlier days in 
Tahiti Professor Tilden found the natives still existing under the effects 
of a diet consisting largely of sea-foods, including raw seaweeds, vegetables 
and fruits, and the people were vigorous in body and mind, handsome and 
healthy, and their teeth were perfect. Dr. Olive Wood made a collection 
of seaweeds edible in Tonga. She writes that inland native women in a 
state of pregnancy will go and reside on the coast in order to gather a 
particular seaweed, which is beneficial to them in their condition. In Japan 
there is a flourishing industry, with fleets of boats in which to gather the 
kelps, shops and markets in which the dried weeds are sold in bundles, and 
an export trade to China. Bundles of seaweeds are sold for the making 
of soups and to furnish vegetable dishes. In Wales, Scotland, and Ireland, 
