IS 



(luirfv l<> the Molhtsca. 



The purple dye obtained in ancient times from several species 

 of marine Gastropods is well known, and various savage tribes at 

 (lie present day employ dyes obtained from these animals. 



There are many Mollusca which are directly or indirectly 

 harmful to man. Some of these are illustrated in the two exhibits 

 of ' Marine Boring Animals ' and ' Biology of Waterworks ' in 

 the Central Hall and are described in the Guide-books to these 

 exhibits. 



The importance of slugs and snails to gardeners and other 

 cultivators is well known. 



Pearl Oyster (Maryaritif< fa marijarilij'rra). Case 147. 



Some molluscs play an important part in the transmission of 

 diseases. Certain freshwater Snails act as the intermediate hosts 

 of Trematode parasites which infect man or domestic animals. 

 Fasciola hepatica, the liver-fluke which causes liver-rot of sheep 

 in Europe, passes part of its life in the body of the Pond-Snail 

 Limnaea truncatula ; and species of Schistosoma, Trematodes that 

 cause serious disease in man in tropical and sub-tropical 

 countries, similarly undergo part of their development in fresh- 

 water molluscs (Hypsobia nosophora in Japan and Isidora contorta 

 and Planorbis boissyi in Egypt). 



