CONTENTS, 
CHAPTER I. 
INTRODUCTION ; OBJECT AND NATURE OF ZOOLOGICAL 
CLASSIFICATION ; CLASSES OF THE MOLLUSCOUS 
PAGE 
ANIMALS . : : - : s : : 1 
CHAPTER II. 
BIVALVES :— 
I. STRUCTURE AND PHYSIOLOGY OF THE CONCHIFERA 10 
II. DESCRIPTION OF SPECIES . ; ‘ ; « 20 
FAMILY MYTILIDZ . : : 5 : Bane, 
»»  UNIONID# (FRESH-WATER MUSSELS) . 25 
- CYCLADIDE . : f F x oe ee 
CHAPTER III. 
WATER-BREATHING SNAILS . : ; : 7 34 
I. STRUCTURE AND PHYSIOLOGY OF THE GASTERO- 
PODA Bae) ae fs 2 5 : P é 44 
