66 The South Australian Naturalist. , 



Mussels, etc.), and Scaphopoda (Tooth Shells). The lecturer 

 stated that the science which treats of shells is called Conch- 

 ology, and that which treats of the animal which makes the 

 shell. Malacology. Members were urged to collect and study 

 shells, as they were easily obtained and kept, as moth, rust and 

 other plagues did not attack shells, many of which were so 

 beautiful in colour and shape. Some are quite four feet across, 

 and others no larger than a pinhead ; many simple in form 

 (as the limpet), others most complicated (nautilus) ; some 

 could be gathered in drayloads, some were, from their rarity, 

 worth more than their weight in gold. They are found all over 

 the world, in sea, river and lake, and many thousand species 

 of land shells are known. Nearly 1,000 species have been taken 

 in South Australia, and about 300 could be got on the beach 

 between Brighton and the Outer Harbour. The composition of 

 shells makes them most suitable for petrifaction, hence we 

 know that Molluscs were among the first creatures which lived 

 on the earth, as even in the Cambrian rocks nearly 400 fossil 

 shells have been found. In the Tertiary rocks of South Aus- 

 tralia many fossils are to be got, and members of the Society 

 could do valuable work in collecting them. 



The lecturer gave useful hints on collecting shells, and 

 asked members to avail themselves of every opportunity of 

 watching live Molluscs in rock pools, on reefs, and in glass 

 jars, and let others know of what they observe. Get on reefs 

 at low tide, and there get perfect specimens, under rocks, on 

 weed, in sponges, on echinoderms, or boring in the mud, sand, 

 or rock. Examine drift wood for the Teredo, or "Ship Worm,*' 

 which is really a species of Mollusc which, with a bivalve shell, 

 bores into timber and destroys the piles of jetties and wharfs, 

 also wooden ships unless sheathed with copper. 



By means of the episcope, shells, and pictures of shells with 

 animals which make them, were shown, and proved interesting 

 and instructive. Cephalopods were dealt with first. The name 

 means ''head-footed," and refers to the tentacles attached to 

 the head, by which they progress along the bottom of the sea. 

 They are the most highly-organised of the Mollusca, most of 

 them being very active, with the senses of seeing, hearing, and 

 smelling w^ell developed. Many species have finlike append- 

 ages by which they swim, and others progress by inflating the 

 body with water, which they can eject forcibly through a 

 siphon on the underside of the body. The tentacles are fur- 

 nished with wonderful suckers (acetabula), varying in number 

 and shape in different species, but all perfectly under control. 

 All except the pearly nautilus have an inkbag, which is con- 



