PLAN OF THE WORK. 
     
    
   
   
    
     Nomenclature—The nomenclature of the American Ornithologists’ 
     
     Union’s * Check-List of, North American Birds has been adopted. The 
     
     number preceding the name of each species is its permanent number 
     
     in the Union’s “ Check-List.” 
     
    

    
     Definition of Terms—The accompanying figure with its named 
     
     parts will explain the meaning of the terms used in the following de- 
     
     scriptions of birds. The words, upper parts and under parts, men- 
     
     tioned so frequently, refer respectively to the whole upper or under 
     
     surfaces of the body of the bird from the base of the bill to the root of 
     
     the tail, but are not applied to either wings or tail. 
     
    

    
     There are infinite variations in the markings of feathers, and those 
     
     figured present only the patterns most frequently met with. The 
     
     shaft of the feather is the midrib, to either side of which the ,vanes 
     
     or webs are attached. 
     
    

    
     The Keys—It is of the utmost importance to thoroughly under- 
     
     stand the use of the keys. At first sight they will, no doubt, ‘appear 
     
     confusing, but in reality they are exceedingly simple. The system 
     
     upon which they are arranged may be mastered in a few minutes, and 
     
     you will then be surprised at the ease. and rapidity with which, even 
     
     in large families, you can “run a bird down.” 
     
    

    
     The Key to Families—Strictly speaking this is not one key but a 
     
     series of keys, one under each order. 
     
    

    
     The orders are placed in a natural sequence—that is, we begin with 
     
     the oldest or lowest forms of birds. Loons, Grebes, etc., and end with 
     
    
   
   
    
       
     
    
   
   
    
     * The American Ornithologists‘ Union is the leading society of its kind in 
     
     this country. Its membership includes the foremost ornithologists of the world, 
     
     and is divided into four classes: 1. Honorary members, limited to 25 in number. 
     
     2. Active members, limited to 50 in number, who must be residents of North 
     
     America. 3. Corresponding members, limited to 100 in number; and 4. Asso 
     
     ciate members, who must be residents of North America, and are not limited as 
     
     to number. The total membership of the Union in December, 1894, was 616. 
     
     Annual meetings are held, usually in Washington, New York, or Cambridge. 
     
     The Auk, the official organ of the Union, is a quarterly journal under the editor- 
     
     ship of Dr. J. A. Allen, at the American Museum of Natural History. 
     
    
   
   
    
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