290 



HABIT AND INTELLIGENCE. 



[chap. 



Analogy 

 of Imman 

 kindreds. 



akin by descent do not necessarily resemble each other the 

 most. Thus the Cirrhipedes are nearly akin to the Crus- 

 tacea, though in their mature state they do not resemble 

 them ; and if they had lost their metamorphoses, their 

 kindred to the Crustacea would never have been suspected. 

 Tliere may be, and probably are, many such cases in the 

 organic kingdom of real affinity without visible resem- 

 blance; and this possibility almost indefinitely increases 

 the difldculty of ascertaining the true classification by 

 descent : just as in human kindreds there is such a thing 

 as family likeness, but the degree of likeness is no measure 

 of the nearness of kiudred ; brothers are sometimes met 

 with who have no family likeness to each other, and 

 cousins sometimes resemble more than brothers. But in 

 human genealogy we have records or tradition, w^hile we 

 have to make out the facts of organic genealogy as we best 

 can, from the resemblances between the variou.s gTOups. 

 There is this further parallelism between human and 

 organic genealogy, that in men there are some kinds of 

 characteristics, such as the form of the features, which are 

 original and not acquired, and are consequently in some 

 degree an index to the man's kindred ; while there are 

 others, si;ch as peculiarities of voice and of manner, and to 

 a certain extent complexion, which are much more capable 

 of alteration by the action of circumstances, and conse- 

 quently are no index of kindred. Just so, in organic 

 genealogy there are some kinds of characteristics which 

 are subject to alteration to suit special habits of life, and, 

 as has been already stated, are thus merely adaptive 

 characters, and are of mu.ch less value as indications of 

 the real affinities of the organism than those which are not 

 so alterable. 



I have shown in this chapter why, as I believe, the 



branches of the organic tree should diverge and re-diverge. 



"VVliy is But why should they ascend ? Why is there organic pro- 



oi-ffani.^ gress ? The laws of habit and variation may account for 



progress ? variety, for divergence and re-divergence ; but why is it 



that groups, after being formed, generally produce members 



