444 THE EVOLUTION OF LIFE. 



sumption that the groups within groups which constitute the 

 animal and vegetal kingdoms, have arisen by direct descent, 

 multiplication, and divergence — that is, by evolution. 



§ 124. Strong confirmation of this inference is yielded by 

 the fact, that the more marked differences which divide 

 groups are, in both cases, distinguished from the less marked 

 differences which divide sub-groups, by this, that they are 

 not simply greater in degree, but they are more radical in 

 hind. Objects, as the stars, may present themselves in small 

 clusters, which are again more or less aggravated into clusters 

 of clusters, in such manner that the individuals of each 

 simple cluster are much closer together than are the simple 

 clusters gathered into a compound cluster : in which case, the 

 trait that unites groups of groups differs from the trait that 

 unites groups, not in nature but only in amount. But this is 

 not so either with the groups and sub-groups which we know 

 have resulted from evolution, or with those which we here 

 infer have resulted from evolution. In both cases the highest 

 or most general classes, are marked off from one another by 

 fundamental differences that have no common measure with 

 the differences that mark off small classes. Observe the 

 parallelism. 



We saw that each sub-kingdom of animals is distinguished 

 from other sub-kingdoms, by some unlikeness in its main 

 plan of organization; such as the presence or absence of a 

 peri-visceral cavity. Contrariwise, the members of the 

 smallest groups are united together, and separated from the 

 members of other small groups, by modifications which do 

 not affect the relations of essential parts. That this is just 

 the kind of arrangement which results from evolution, the 

 case of languages will show. 



On comparing the dialects spoken in different parts of 

 England, we find scarcely any difference but those of pro- 

 nunciation: the structures of the sentences are almost uni- 

 form. Between English and the allied modern languages 



