x CONTENTS 



CHAPTER VI 



PAGE: 



THE FROG (continued] : THE VASCULAR SYSTEM THE CIRCU- 

 LATION OF THE BLOOD 78 



PRACTICAL DIRECTIONS 9$ 



CHAPTER VII 

 THE FROG (continued] : THE MICROSCOPICAL EXAMINATION 



OF THE SIMPLE TISSUES 104 



PRACTICAL DIRECTIONS 119 



CHAPTER VIII 



THE FROG (continued) : THE MICROSCOPICAL EXAMINATION OF 



THE COMPOUND TISSUES -GLANDS SECRETION AND 



ABSORPTION 126 



PRACTICAL DIRECTIONS 136 



CHAPTER IX 

 THE FROG (continued) : RESPIRATION AND EXCRETION . . 141 



PRACTICAL DIRECTIONS 152 



CHAPTER X 

 THE FROG (continued): THE NERVOUS SYSTEM 154 



PRACTICAL DIRECTIONS 175 



CHAPTER XI 



THE FROG (continued): THE ORGANS OF SPECIAL SENSE . 179 



PRACTICAL DIRECTIONS IC)I 



CHAPTER XII 

 THE FROG (continued) : REPRODUCTION AND DEVELOPMENT . 193 



PRACTICAL DIRECTIONS 2IO 



CHAPTER XIII 

 THE FROG (continued) : MEANING OF THE TERM SPECIES THE 



PRINCIPLES OF CLASSIFICATION -EVOLUTION -ONTO- 

 GENY AND PHYLOGENY -HEREDITY AND VARIATION 



STRUGGLE FOR EXISTENCE -NATURAL AND ARTIFICIAL 



SELECTION ORIGIN OF SPECIES 2T5 



