204: CLASSIFICATION. [Chap. XIV. 



sub-family, distinct from that containing the next two 

 genera on the right hand, which diverged from a com- 

 mon 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 far- 

 ther 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 subordina- 

 tion 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 or- 

 ganic 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 spe- 

 cies, genera, and families in each class, on what is called 

 the Natural System. But what is meant by this sys- 

 tem? 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 unlike; 



