CONTENTS. 



CHAPTER PAGE 



I. INTRODUCTORY 1 



II. AMCEBA 18 



III.- THE GENERAL STRUCTURE OF ANIMALS ... 23 



IV. ORGANS OF DIGESTION 102 



V. THE BLOOD AND THE BLOOD-VASCULAR SYSTEM . 181 



VI. ORGANS OF RESPIRATION 210 



VII. ORGANS OF NITROGENOUS EXCRETION . . .247 



VIII. ORGANS OF SPECIAL SECRETIONS .... 265 



IX. PROTECTING AND SUPPORTING STRUCTURES . . 274 



X. ORGANS OF MOVEMENT .370 



XL VOCAL ORGANS 387 



XII. THE NERVOUS SYSTEM AND ORGANS OF SENSE . 393 



XIII. ORGANS OF REPRODUCTION 472 



XIV. THE DEVELOPMENT OF THE METAZOA . . .525 



