The South Australian Naturalist. 
13 
the boring mollusc can pierce the hardest timber, and even marble 
as in the case of the porphyry columns of the Serapeum, at 
Naples, was lucidly explained. The tiny soft-bodied creature, 
using its foot like a bradawl, can bore its way into the toughest 
wood or the hardest rock. The pelecypoda (axe footed) supplied 
an example of the mollusc^s method of obtaining nutriment from 
the surrounding water. Making a burrow in the sand, it projects 
its two syphons above the opening. The water, containing car- 
bonate of lime, various salts, and organic matter, enters through 
the lower syphon, circulates through the body of the mollusc, and 
when all the nutrient matter has been absorbed is ejected, 
through the upper tube. In this way these tiny creatures serve 
a most useful purpose in purifying the water of the ocean. The 
building up of the shell with the solids obtained in the water was 
next explained from the protoconch (first shell), in which the 
minute organism finds its earliest shelter, to the successive whorls 
needed to accommodate the rapidly growing body. The maternal 
care is of a limited nature, and quickly at an end. Capsules 
containing from 10 to 20 eggs, and supplied with a store of albu- 
men as food for the young, are deposited on a convenient rock, 
and there the mother’s care is at an end. 
EXCURSION TO WATERFALL GULLY, SEPTEMBER 
6. 1924. — Under the leadership of Mr. W, H. Selway, a party 
visited Waterfall Gully. Eucalypts, casuarinas, banksia. and 
acacias were observed, also many aliens that have taken kindly 
to their new home. Wild flowers were very abundant. Two 
species of orchids were found. The fairylike Drosera (sundew), 
a most remarkable carnivorous plant, had its hairy, disc-like 
leaves well supplied with the flies and gnats whose curiosity had 
led them to an untimely end. Birds were not numerous, but 
several species were distinguished — the honey-eater, the mis- 
chievous Rosella, the purple-crowned lory, the graceful little blue 
wren, the robin. The sweet notes of the harmonious thrush were 
blended with the harsh cry of the noisy minah. The Australian 
brown fly catcher was also seen. 
EXCURSION TO LONG GULLY, OCTOBER 4, 1924.— 
One of the most pleasant trips of the year was that made to Long 
Gully, under the leadership of Professor T. G. B. Osborn. The 
members remarked on the extraordinary profusion of wildflowers, 
due to the bountiful rains during September. Attention was 
drawn to the striking variations of native flora according to situa- 
tion and aspect. On the wettest part, along the exposed ridge, 
the stringybark (E. obliqua) dominated the landscape. With 
