GEEMINAL SELECTION 131 



many secondary sexual characters, whose resemblance to the excessive 

 developments artificially produced in our domestic poultry is so very 

 striking. Here, too, we shall have to regard germinal selection as the 

 root of the variations of plumage and other distinguishing characters, 

 which have evolved by intra-germinal augmentation into the magnifi- 

 cently coloured crests, tufts, and collars, into the long or graduated, 

 multiplied or erectile tail-feathers of the birds of Paradise, pheasants, 

 and humming-birds. The conception of sexual selection formu- 

 lated by Darwin will be so far modified, that we are no longer 

 compelled to regard every minute step in this cumulative process as 

 due to the selection of the males by the females. A preference of the 

 finest males may still take place, and is probably general, since only 

 thus could the distinguishing male characters become common pro- 

 perty, that is, be transmitted to all or the majority of the ids 

 of the germ-plasm, but the increase of the individual determinants 

 which are in the act of varying goes on in each individual id, quite 

 independently of this personal selection. 



As it is not a single id with its determinant a in ascending varia- 

 tion that controls the organ A, but as it always requires a majority of 

 the ids a, this must be secured here by personal selection just as it is 

 in ordinary natural selection. If the handsomest males are the suc- 

 cessful competitors, then a majority of the transformed ids a' will 

 be transmitted to a number of their descendants, and the oftener this 

 happens the larger will the majority be, and the less becomes the 

 danger that it will be dispersed again by reducing division and amphi- 

 mixis. Personal selection is thus in no way rendered superfluous by 

 germinal selection, only it does not produce the augmentation of the 

 distinguishing characters, but is chiefly instrumental in fixing them in 

 the germ-plasm ; it collects, so to speak, only the favourably varying 

 ids, and, where complex variations depending on the proper variation 

 of many ids are concerned, it combines these. How very great the 

 influence of personal selection may be in this case of secondary sexual 

 characters we see clearly from the soberly coloured mates of the 

 brilliant males, for here natural selection has been operative in 

 conserving the coloration inherited from remote ancestry. 



But if the question be asked, how the first onajority of deter- 

 minants varying in the same direction is brought about, there are two 

 possibilities : first, by chance, and secondly, by influences which cause 

 particular determinants of all the ids to vary in almost exactly the 

 same manner. We shall find illustrations of the latter among climatic 

 varieties ; but the cases of the first kind are the more important, for they 

 form the foundation and the starting-point for processes of selection 



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