THE CLASSIFICATION OF ANIMALS. 231 



CHAPTER XXI.* 



THE CLASSIFICATION OF ANIMALS. 



The Kingdom of Nature is a literal Kingdom. Order 

 and beauty, law and dependence, are seen everywhere. 

 Amidst the great diversity of the forms of life, there is 

 unity; and this suggests that there is one general plan, 

 but carried out in a variety of ways. 



Naturalists have ceased to believe that each animal or 

 group is 'a distinct, circumscribed idea. "Every animal 

 has a something in common with all its fellows : much 

 with many of them; more with a few; and, usually', so 

 mucli with several, that it differs but little from them." 

 The object of classification is to bring together the like, 

 and to separate the unlike. But how shall this be done ? 

 To arrange a library in alphabetical order, or according to 

 size, binding, date, or language, would be unsatisfactory. 

 "We must be guided by some internal character. We must 

 decide whether a book is poetry or prose; if poetry, 

 whether dramatic, epic, lyi'ic, or satiric ; if prose, whether 

 history, philosophy, theology, philology, science, fiction, 

 or essay. Tlie more we subdivide these groups, the more 

 diflicult the analysis. 



A classification of animals, founded on external resem- 

 blances — as size, color, or adaptation to similar habits of 

 life — would be worthless. It would bring together Fish- 

 es and Whales, Birds and Bats, Worms and Eels. Nor 

 should it be based on any one character, as the quality 

 of the blood, structure of the heart, development of the 

 brain, embryo-life, etc. ; for no character is of equal value 

 in every tribe. A natural classification must rest on those 

 * See Ajuieiidix. 



