CHAPTER II 



VARIETY AND UNITY IN LIFh 



"L'especc, c'est iin etre qui dans ses generations successives 

 presente toujours les memes caracteres d 'organisation; il faut ajouter 

 dans les memes localites, et les memes circonstances exteriem-es. " — 

 Rambur, 1842. 



"That mystery of mysteries as it has been called by one of 

 our greatest philosophers " — this is Darwin's phrase regarding 



the problem before us, the 

 origin of species — the origin 

 or cause of variety in the 

 life of the globe. 



That variety exists, that 

 there are many kinds and 

 types, grades and grada 

 tions in animal and vege- 

 table life is evident to all. 

 Birds and trees, beetles 

 and butterflies, fishes and 

 flowers, ferns and blades of 

 grass, all these are objects 

 of constant recognition. 

 The green cloak which 

 covers the brown earth is 

 the shield under which 

 myriads of organisms, 

 brown and green, carry on 

 their life work, and still 

 farther below the level of 

 our ordinary notice exists 

 a range of hfe scarcely less 



Fig. 1. — Long-horned boring beetle from 

 Central America (one-half natural size).i 



^This figure and the others in this chapter are introduced simply to 

 Illustrate graphically the variety of animal form. 



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