Aquatic JLitt 



107 



South Australian Society 



At a meeting of the South Australian 

 Aquarium Society held on Tuesday, Au- 

 gust 3, 1920, Mr. W. J. Kimber delivered 

 an address on "Fresh-water Mollusca." 



The lecturer remarked that the fresh- 

 water mollusca fauna of Australia is 

 poor ; in the United States of America 

 200 species of Unia have been named, 

 whilst in all Australia there are but 



wide distribution of some species being 

 thus accounted for. The development 

 of the shell was dealt with and Mr. 

 Kimber spoke of the usefulness of mol- 

 luscs in aquaria. Our small fresh-water 

 limpet has about 4400 teeth placed in 

 200 rows and with these teeth the exces- 

 sive growth of algae is rasped off the 

 glass. Although water snails are gen- 

 erally herbivorous they relish flesh and 



EXHIBITED BY 

 MR. 6.WHILLIKER. 



A Newspaper Cartoonist's Impressions of the Philadelphia Exhibition 



three. He mentioned the extraordinary 

 number of eggs deposited at one time by 

 some species of Mollusca. The fresh- 

 water mussel lays about 200,000 eggs, 

 but this is not large as compared with 

 the millions laid by the oyster. Mol- 

 lusca's eggs form the principal food of 

 some fishes and of the great quantity 

 deposited comparatively few survive. 

 The larvae have interesting habits, some 

 even attaching themselves to fishes, being 

 thus transferred for long distances. Au- 

 thentic records have been made of the 

 transportation of small bivalves on the 

 legs of birds and of water-beetles, the 



the larger species have been known to 

 feed upon their brethren and even to de- 

 vour small fishes. The bivalves feed by 

 continuously filtering the water and re- 

 taining the nutrient matter. 



Many parasites of higher forms of 

 life utilize molluscs as intermediate 

 hosts. Thus some parasites of sea-birds 

 live in the branchial cavities of sea-snails 

 in the first stages of development, and 

 the live fluke, which has caused the 

 death of over three million sheep in the 

 Commonwealth, uses a water-snail as its 

 first host. The dreaded disease BiUiart- 

 cia is similarly propagated. — Herbert M. 

 Hale, Honorary Secretarv. 



