CHAPTER X. 

 HEREDITY AND DESCENT. 



Heredity and Variation 



Evolution 



Sexual Selection ... 



80 

 81 

 82 



Part II. 



CHAPTER XI. 

 PROTOZOA. 



Amoeba 



Paramoecium 



Vorticella ... 



Gregarina ... 



The Protozoa 



The Gymnomyxa and Corticata 



85 

 89 

 92 

 94 

 97 

 98 



CHAPTER KH. 

 FOR ITER A. 



Sycandra ... 

 The Porifera 



103 

 107 



