PDF - Wallace Online

TROPICAL NATUREdevelopment; the forms and colours, ofthese wonderful littleif we consider all these varied and complex influences,bir(jswe shall be less surprised at their strange forms, their infinitevariety, their wondrous beauty. For how many ages thecauses above enumerated may have acted upon them wecannot say ;but their extreme isolation from all other birds,no less than the abundance and variety of their generic andspecific forms, clearly point to a very high antiquity.The Relations and Affinities of Humming-birdsThe question of the position of this family in the classof birds and its affinities or resemblances to other groupsis so interesting, and affords such good opportunities forexplaining some of the best established principles of classificationin natural history in a popular way, that we propose todiscuss it at some length, but without entering into technicaldetails.There is in the Eastern hemisphere, especially in tropicalAfrica and Asia, a family of small birds called sun-birds, whichare adorned with brilliant metallic colours, and which, in shapeand general appearance, much resemble humming-birds. Theyfrequent flowers in the same way, feeding on honey and insects ;and all the older naturalists placed the two families side byside as undoubtedly allied. In the year 1850, in a generalcatalogue of birds, Prince Lucien Bonaparte, a learnedornithologist, placed the humming-birds next to the swifts,and far removed from the Nectarinidse or sun-birds ;and thisview of their position has gained ground with increasingknowledge, so that now all the more advanced ornithologistshave adoptedit. Before proceeding to point out the reasonsfor this change of view, it will be well to discuss a few of thegeneral principles which guide naturalists in the solution ofsuch problemsḢowto Determine doubtful AffinitiesIt is now generally admitted that, for the purpose ofdetermining obscure and doubtful affinities, we must examineby preference those parts of an animal which have little or nodirect influence on its habits and general economy. The valueof an organ, or of any detail of structure, for purposes of