RECOGNITION-MARKS 165 



after the Origin of Species, expressed this objection very 

 forcibly. After describing many of the wonderful forms and 

 ornaments of the humming-birds, he says : 



" Mere ornament and variety of form, and these for their own 

 sake, is the only principle or rule with reference to which Creative 

 Power seems to have worked in these wonderful and beautiful 

 birds. ... A crest of topaz is no better in the struggle for existence 

 than a crest of sapphire. A frill ending in spangles of the emerald 

 is no better in the battle of life than a frill ending in spangles of the 

 ruby. A tail is not affected for the purpose of flight, whether its 

 marginal or its central feathers are decorated with white. . . . Mere 

 beauty and mere variety, for their own sake, are objects which we 

 ourselves seek when we can make the forces of nature subordinate 

 to the attainment of them. There seems to be no conceivable 

 reason why we should doubt or question that these are ends and 

 aims also in the forms given to living organisms." 



In a criticism of the Duke's book (written in 1867) I 

 adduced sexual preference by the female bird as sufficiently 

 explaining these varieties of plumage and colour, but I have 

 since come to doubt the validity of this, except so far as the 

 plumes are an indication of sexual maturity ; while I see in 

 the need for outward marking, whether for purposes of 

 recognition or as preventing intercrossing between incipient 

 species, a sufficient cause for all such conspicuous indications 

 of specific diversity as are found pervading the whole vast 

 world of life. It now only remains to point out how these 

 markings have been produced, even under conditions which 

 some writers have considered must render their production 

 for this purpose impossible, and therefore as constituting a 

 valid objection to the whole theory of recognition-marks. 



An Objection to Recognition- Marks answered 



In a book on Darwinism and Lamarckism, the late 

 Captain Hutton, a well-known New Zealand naturalist, 

 objected to the validity of recognition-marks as a cause for 

 the development of specific characters, that there are, all 

 over the Pacific, numerous cases of small fruit-pigeons of the 

 genus Ptilopus, which each have distinctive markings, and 

 are almost always confined to one island or a small group of 

 islands. In most of these cases there is no other pigeon or 



