CONTENTS 



CHAPTER PAGE 



I. INTRODUCTION 1 



II. THE CELL AND PROTOPLASM .7 



III. THE PROTOZOA 11 



IV. THE SPONGES 19 



V. THE CCELENTERATES 29 



VI. THE WORMS 44 



VII. ANIMALS OF UNCERTAIN RELATIONSHIPS .... 66 



VIII. MOLLUSKS 72 



IX. ARTHROPODS. CLASS CRUSTACEA 93 



X. ARTHROPODS. CLASS INSECTS 114 



XI. ARTHROPODS. CLASS ARACHNIDA 133 



XII. ECHINODERMS 140 



XIII. THE CHORDATES 151 



XIV. THE FISHES 154 



XV. THE AMPHIBIANS 174 



XVI. THE REPTILES 184 



XVII. THE BIRDS 201 



XVIII. THE MAMMALS 225' 



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