^ CONTENTS 



CHAPTER VI 



THE FROG (continued) : THE VASCULAR SYSTEM— THE CIRCU- 



I.ATiriN OF THE BLOOD 



I'RACTICAL DIRECTIONS 



PACE 

 98 



CHAPTER VH 



THE FROG (continued) : t'he microscopical i.;xamin'ATIO-\ 



OF THE simple tissues . I°4 



practical directions . ^'9 



CHAPTER VHI 

 THE FROG (continued): THE microscopical examination of 



IHE COMPOUND TISSUES— GLANDS — SECRETIO-X AND AB- 

 SORPTION . 



126 

 PRACTICAL DIRECTIONS 135 



CHAPTER IX 

 THE FROG (continued): respiration and excretion . 141 



I'RACTICAL directions . . 1 52 



CHAPTER X 



THE FROG (continued): the nervous system , 154 



PRACTICAL DIRECTIONS . 175 



CHAPTER XI 



THE FROG (continued) : THE ORGANS OF SPFXIAL SENSE 1 79 



PRACTICAL DIRECTIONS I9I 



CHAPTER XII 



THE FROG (continued) : REPRODUCTION AND DEVELOPMENT. I93 



PRACTICAL DIRECTIONS 2IO 



CHAPTER XIII 



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

 PRINCIPLES OF CLASSIFICATION — EVOLUTION — ON TOC.ENV 

 AND PHYLOGENY — HEREDITY AND VARIATION — STRUGGLE 

 FOR EXISTENCE — SELFXTION- ORIGl N (IF SPECIES . 215 



