174 



BIOLOGY FOR BEGINNERS 



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 Onycophora 



.Ancestral arthropod 



FIG. 56. A scheme to show how the arthropods have developed from their 

 ancient ancestor. The branches are not intended to represent actual relation- 

 ships but to indicate the lines of specialization which have been followed. 

 From Pearse. 



We do not have to learn these apparently difficult names. What 

 we ought to try to understand is the method of classification, be- 

 cause it is used in all animal and plant groups and is so well il- 



