160 PHILOSOPHY OF 'ZOOLOGY. 



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PART IV. 



CLASSIFICATION OF ANIMALS. 



IF we employ the twofold method of classification recomk 

 mended in the preceding part of this work, we shall be at 

 no loss to obtain the first divisions of the animal kingdom, 

 VERTEBRAL and INVERTEBRAL, however great difficulty may 

 be experienced in the construction of the subordinate groups. 

 These two divisions depend, the one on a positive, the other 

 on the negative character, and possess the advantage of be- 

 ing easily recognized. In this respect, and indeed in every 

 other, they have the decided superiority. Any other basis of 

 division hitherto employed is faulty, in not including a num- 

 ber of common properties, in effecting unnatural separation 

 among kindred tribes, or in being founded on characters 

 which are merely modifications of some positive quality. 

 Without wasting the time of the reader, in dwelling on 

 the defects of these different systems, we shall proceed at 

 once to an exposition of the characters of the method em- 

 ployed. 



