DIAGRAMS, 



PAGE 



BRITISH CUTTLE FISHES 26 



BRITISH CUTTLE FISHES .*..... 27 

 PARTS OF A MULTIVALVE SHELL . . . . -30 

 PARTS OF A BIVALVE SHELL . . . . . -31 

 LEFT VALVE OF Unio pictorum . . . . -32 

 PARTS OF AN OYSTER (Ostrea edulis) . . . .40 



PARTS OF A UNIVALVE SHELL (Nassa reticulata) . . 52 



VARIETIES OF THE MOUTH 53 



LIVING SHELLS 56 



