Page 



4. HOW THE ANIMALS HAVE CHANCED . 93 



I ntegument 96 



Respiration 100 



Body Fluids . 111 



Metabolism 1 22 



Locomotion 125 



Nervous System 127 



Excretion 1 29 



Reproduction . . 1 30 



Food 136 



AccI i ma t i za t ion 1 37 



Parasites 140 



Conclusion 141 



5. WHAT ANIMALS HAVE ATTAINED ON LAND 145 



B I BLIOCRAPHY 149 



I N DEX 1 93 



[xii] 



