Thr South Australian Naturalist. 
101 
WOl 
EXCURSION TO HENLEY BEACH, JULY 10. 
•cfe The Section visited ITenley Beach on Juh' 10th and al- 
eh' though the tide was high some interesting creatures were found 
ill and menibers of the Shell Club spoke of their habits and named 
the shells taken. A sponge had a line specimen of Modiola 
0 l 7 alis attached by its byssus of silky threads and the use of 
[his to mussels and other sedentary bivahes was pointed out. 
ivlilUube making gasteropod Vcrmettis siptio had firmly attached its 
h strange shell to the modiola and the animal must get its food in 
ep, practically the same way as a bivalve does, by siphons. The 
eel: sponge was also inhabited by scores of another bivalve, Vulsella 
nhella, and as, it is very frequently found in this way the 
question arises as to the reason of this strange association. Species 
ipolyioa and serpulae were also firmly fixed to the modiola 
and the leader of the party spoke of the food which all the crea- 
tures living in apparent harmony required, and the amount of 
energy exerted in getting that food which consists of microscopical 
)lant and animal organisms. A common serpxda, a worm which 
makes a shelly tube, often attaches it to jetty piles in such masses 
s to prevent the teredo or “ship worm” entering, or if it had 
already entered it prevents the teredo, which is a bivalve mullusc, 
from obtaining food by closing the hole through which it must 
protrude its siphons. A few species of Echinoderms were taken, 
their wonderful structure spoken of and members were asked 
[0 make a more scientific study of them as there is much need 
and the work would be most interesting. 
o : 
EXCURSION TO LARGS BEACH, AUGUST 7, 1926. 
On Saturday an investigation was made by a party of field 
naturalists of the sea life on the beach between Largs and the 
Outer Harbour. Interesting discoveries rew'ardcd the seachers, 
Dut the best find was a perfect specimen of Fusus Australis picked 
up by Mrs, Kelsey. 'The creature tenanting this shell is red as a 
red runner, and there are four species found in South Australian 
nters. Air. Trigg discoursed on specimens of the Murex. It is 
one of the most numerous of molluscan families. Some 2S0 species 
have been identified and the Investigation of the group affords am- 
pe scope for the energies of young and enterprising members. It 
takes first ^place among the mollusca in numbers and variety of dec- 
oration. Tryon has divided the family into the muricidae and the 
purpurinae. The most striking character of the former is found 
’0 the number of varices or seams that diversify the surface of the 
melL Besides the more marked, several secondary varices are to 
be noted. These are highly decorative in color and form, but, 
contrary to the ordinary case, these ornaments indicate not 
