CONTENTS 

 CHAPTER VI 



PAGE 



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

 LATION OF THE BLOOD 78 



PRACTICAL DIRECTIONS 98 



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 AB- 

 SORPTION 126 



PRACTICAL DIRECTIONS 135 



CHAPTER IX 



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



PRACTICAL DIRECTIONS 152 



CHAPTER X 



THE FROG (continued] : THE NERVOUS SYSTEM 1 54 



PRACTICAL DIRECTIONS 175 



CHAPTER XI 



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



PRACTICAL DIRECTIONS I9 1 



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 ONTOGENY 

 AND PHYLOGENY HEREDITY AND VARIATION. STRUGGLE 

 FOR EXISTENCE SELECTION ORIGIN OF SPECIES .... 215 



