CONTENTS 



CHAPTER I PAGE 



Introduction ___-_____---------- 17 



Zoology, a Biological Science, 19; The Subdivisions of Zoology, 19; 

 Classification of the Animal Kingdom, 22; Balance in Nature, 24; 

 Vital Relations of Animals and Plants, 26; Zoology as Related to 

 Man, 29; Agriculture and Zoology, 29; Fisheries and the Application 

 of Zoology 30, 



CHAPTER II 



History of Zoology _________________ 31 



CHAPTER III 



Protoplasm and the Cell _______________ 39 



Living Matter, or Protoplasm, 39; The Cell Principle, 39; General 

 Characteristics of Protoplasm and the Material of the Cell, 41 ; Funda- 

 mental Properties or Activities of Protoplasm, 42; Physical Nature of 

 Protoplasm, 43; Chemical Nature of Protoplasm, 44; Structure of a 

 Typical Animal Cell, 47; Cell Division, 50. 



CHAPTER IV 



Metazoan Organization _______________ 54 



Cellular Differentiation, 54 ; Cellular Organization, 55 ; Development of 

 Sexual Reproduction, 61. 



CHAPTER V 



The Bullfrog as a Typical Vertebrate Animal (Class Amphibia) 



(By Ottys Sanders) _________----- 64 



Habitat of the Bullfrog, 64; External Structure, 65; Digestive System 

 and Digestion, 67 ; Circulatory System, 70 ; The Veins, 73 ; Respiratory 

 Organs and Respiration, 80; Excretory System and Excretion, 81; 

 Skeletal System, 83; Muscular System, 88; Nervous System, 90; The 

 Sense Organs, 93; Reproductive Organs, 95; Embryology, 96; Eco- 

 nomic Importance of Amphibia, 102; Classification of Amphibia, 103; 

 A List of Families of the Amphibia in the United States, 104; Order 

 Caudata (Tailed Amphibians), 104; Order Salientia (Tailless Am- 

 phibians), 105. 



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