HUMMING-BIRDS. 157 



This somewhat technical discussion will, it is hoped, 

 enable the general reader to understand some of the 

 more important principles of the modern or natural 

 classification of animals, as distinguished from the 

 artificial system which long prevailed. It will also 

 afford him an easily remembered example of those 

 principles, in the radical distinctness of two families 

 of birds often confounded together, the sun-birds of 

 the Eastern Hemisphere, and the humming-birds of 

 America; and in the interesting fact that the latter 

 are essentially swifts profoundly modified, it is true, 

 for an aerial and flower-haunting existence, but still 

 bearing in many important peculiarities of structure the 

 unmistakable evidences of a common origin. 



