CHAPTER IX 

 THE ANIMAL KINGDOM 



IT is common phraseology to speak of the great 

 province embracing all animals as "The Animal 

 Kingdom." Linnaeus employed the designations 

 "Animal Kingdom," "Plant Kingdom" and "Min- 

 eral Kingdom" to indicate the three kingdoms of 

 nature; and the title of Cuvier's general zoology was 

 The Animal Kingdom Arranged According to its 

 Organization. 



One phase of zoology has for its aim to give a 

 descriptive inventory of the animal kingdom. We 

 should remember, however, that this is merely one 

 aspect of zoology. In early times, it was the dom- 

 inate feature of zoological study, but it is now subor- 

 dinate in importance to those phases of the subject 

 that deal with structure, development, physiology, 

 habits, etc. The orderly arrangement of animals into 

 natural groups of different rank should be the out- 

 come of a study of their structure and life histories. 



In the time of Linnaeus, the classification of 

 animals was based on observations of the external 

 resemblances and differences and, later, the internal 



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