204 CLASSIFICATION. [Chap. XIV. 



sub-family, distinct from that containing the next two 

 genera on the right hand, which diverged from a common 

 parent at the fifth stage of descent. These five genera 

 have also much in common, though less than when 

 grouped in sub-families ; and they form a family distinct 

 from that containing the three genera still farther to 

 the right hand, which diverged at an earlier period. 

 And all these genera, descended from (A), form an 

 order distinct from the genera descended from (I). So 

 that we here have many species descended from a single 

 progenitor grouped into genera; and the genera into 

 sub-families, families, and orders, all under one great 

 class. The grand fact of the natural subordination of 

 organic beings in groups under groups, which, from its 

 familiarity, does not always sufficiently strike us, is in 

 my judgment thus explained. No doubt organic beings, 

 like all other objects, can be classed in many ways, 

 either artificially by single characters, or more naturally 

 by a number of characters. We know, for instance, that 

 minerals and the elemental substances can be thus 

 arranged. In this case there is of course no relation to 

 genealogical succession, and no cause can at present be 

 assigned for their falling into groups. But with organic 

 beings the case is different, and the view above given 

 accords with their natural arrangement in group under 

 group ; and no other explanation has ever been 

 attempted. 



Naturalists, as we have seen, try to arrange the 

 species, genera, and families in each class, on what is 

 called the Natural System. But what is meant by this 

 •m ? Some authors look at it merely as a scheme 

 for arranging together those living objects which are 

 most alike, and for separating those which are most 



