CONTENTS. 



CHAPTER PAGE 



I. Introduction 7 



II. First Parents ii 



III. SpIROGYRA 21 



IV. The Division of Labor 26 



V. Fish Life 38 



VI. Crustaceans 47 



VII. Metamorphosis of Insects 54 



VIII. Reproduction of Insects 63 



IX. Flowers and Insects : 74 



X. Plant Life 88 



XI. Bird Life 98 



XII. Skin Changes 106 



XIII. Periodic Activity 116 



XIV. The Mammal ... 124 



XV. Varfability and Inheritance . . . . 136 



XVI. Nutrition and Reproduction . ... 143 



XVII. Value of Sexual Reproduction 153 



XVIII. Individuality 160 



XIX. Male and Female 169 



XX. Maturity 178 



XXI. Human Life 189 



XXII. Man and the Community 198 



XXIII Conclusion 210 



