Chap. II.] VAK1ATI0N UNDEB NATURE. 51 



CHAPTER II. 



Variation under Nature. 



Variability — Individual differences — Doubtful species — Wide rang- 

 ing, much diffused, and common species, vary most — Species of 

 the larger genera in each country vary more frequently than 

 the species of the smaller genera — Many of the s; ecies of the 

 larger genera resemble varieties in being very closely, but un- 

 equally, related to each other, and in having restricted ranges. 



Before applying the principles arrived at in the last 

 chapter to organic beings in a state of nature, we must 

 briefly discuss whether these latter are subject to any 

 variation. To treat this subject properly, a long 

 catalogue of dry facts ought to be given ; but these 

 I shall reserve for a future work. Nor shall I here 

 discuss the various definitions which have been given 

 of the term species. No one definition has satisfied all 

 naturalists; yet every naturalist knows vaguely what 

 he means when he speaks of a species. Generally the 

 term includes the unknown element of a distinct act of 

 creation. The term " variety" is almost equally 

 difficult to define ; but here community of descent 

 is almost universally implied, trough it can rarely be 

 proved. We have also what are called monstrosities ; 

 but they graduate into varieties By a monstrosity I 

 presume is meant some considerable deviation of 

 structure, generally injurious, or not useful to the 

 species. Some authors use the term " variation" in a 



