li 



Helix pulchella Linnaeus stagnalis 



Helix rotuutlata Linnaeus jiereger 



Helix hortensis Bithinia tentaculata 



Helix hispida Bulimus acutus 



Clausilia nigricans Azeca tridens 



Planorbis spirorbis Zua lubrica 



Planorbis albus Valvata piscinalis 



Planorbis nautileus Cyclas cornea 



Cyclostoma elegans 

 making a total of 1 7 species. 



A great deal more might be said about these interesting creatures. We 

 might speak about the medium that some of them are in spreading the sheep 

 fluke, which has proved so deadly a parasite to numbers of sheep ; or enlarge upon 

 the teeth — odontophores as they are called, agents in reality for rasping food— or 

 many subjects. Like all the Great Creator's works, mollusks show an immense, 

 an overpowering amount of skill. The study of them is a source of great 

 pleasure. They iierform the part allotted to them in keeping up the balance 

 of life. 



