CONTENTS. 



PAGE 



I. INTRODUCTION vii 



II. LIST OF FAMILIES 1 



Sub-Braiich Mollusca vera . . . ... 1 



Class Cephalopoda 1 



Order 1. Dibranchiata 1 



" 2. Tetrabranchiata 2 



Class Gasteropoda, or Cephalophora . .4 



Sub-Class Dioeca 4 



Order 3. Pectinibranchiata .... 4 



" 4. Heteropoda 10 



" 5. Rhipidoglossa ...... 10 



" 6. Docoglossa 11 



" 7. Polyplacophora . . . . .12 



Sub-Class Pulmonifera 12 



Order 8. Pulmonata 12 



Sub-Class Opisthobranchiata 14 



Order 9. Tectibranchiata 14 



" 10. Nudibranchiata . . . . .15 



Sub-Class Pteropoda .17 



Order 11. Tbecosomata ..... 17 



" 12. Gymnosomata 17 



Sub-Class Prosopocephala . . . . . .17 



Order 13. Solenoconchse . . . . .17 



Class Conchifera ........ 18 



Order 14. Dimyaria 18 



" 15. Metarrliiptae 21 



" 16. Heteromyaria 21 



