THE PHENOMENA OF ORGANIC NATURE. 133 



I drew your attention, on a previous evening, to the 

 facts which are embodied in our systems of Classifi- 

 cation, which are the results of the examination and 

 comparison of the different members of the animal 

 kingdom one with another. I mentioned that the 

 whole of the animal kingdom is divisible into five sub- 

 kingdoms ; that each of these sub-kingdoms is again 

 divisible into provinces ; that each province may be 

 divided into classes, and the classes into the successively 

 smaller groups, orders, families, genera, and species. 



Now, in each of these groups, the resemblance in 

 structure among the members of the group is closer in 

 proportion as the group is smaller. Thus, a man and 

 a worm are members of the animal kingdom in Virtue 

 of certain apparently slight though really fundamental 

 resemblances which they present. But a man and a 

 fish are members of the same Sub-kingdom Vertebrata, 

 because they are much more like one another than 

 either of them is to a worm, or a snail, or any member 

 of the other sub-kingdoms. For similar reasons men 

 and horses are arranged as members of the same Class, 

 Mammalia; men and apes as members of the same 

 Order, Primates ; and if there were any animals more 

 like men than they were like any of the apes, and yet 

 different from men in important and constant particu- 

 lars of their organization, we should rank them as 

 members of the same Family, or of the same Genus, 

 but as of distinct Species. 



That it is possible to arrange all the varied forms of 

 animals into groups, having this sort of singular subor- 

 dination one to the other, is a very remarkable circum- 

 stance ; but, as Mr. Darwin remarks, this is a result 

 which is quite to be expected, if the principles which he 



