INTKODUCTION. xi 



VI. STEGANOPODES. Hind toe lengthened and incumbered, and united to the inner 

 toe by a complete web (small only in Tachypetidce) . Bill extremely variable, but 

 usually with a more or less extensible naked gular sac between the mandibular rami. 

 Nostrils obsolete. Habits altricial, youiig dasypa3dic in Tachypetidce, Phalacrocoracidce, 

 Plotida, and Phaethontidce, gymnopfcedic * in Pelecanidoe and Sulidce. Palate saurogna- 

 thous. Carotids double. 



VII. LONGIPENNES. Hind toe small or rudimentary, and elevated, sometimes almost 

 obsolete ; anterior toes fully weighed. Bill more or less compressed (nearly cylin- 

 drical only in some Stercorariidce), the nostrils linear, never tubular. Habits altri- 

 cial, young dasypa^dic. Palate schizognathous. Carotids double. Eggs, two or more, 

 colored. 



VIII. TUBINARES. Hind toe absent or very rudimentary ; anterior toes fully webbed. 

 Bill variable, but usually nearly cylindrical or compressed (rarely depressed), the ter- 

 minal portion strongly hooked. Nostrils tubular. Habits altricial, young dasypsedic. 

 Palate schizognathous. Carotids double. Eggs, never more than one, white. 



IX. PYGOPODES. Legs inserted far backward, the tarsi extremely compressed. Anterior 

 toes fully webbed or else strongly lobed and with broad flat nails {Podicipidce). Bill 

 extremely variable. Habits prcecocial in Podicipidce and ColymhidcE, altricial in Alcidce ; 

 yoimg dasyptedic. Palate schizognathous. Carotids double, except in Podicipidce and 

 some Alcidce (e. g., genus Alle). 



The above arrangement is not strictly natural, but the division of Water Birds into " Waders " 

 and " Swimmers " is adopted for the convenience of the student. The Orders most nearly related 

 are the Herodiones and Steganopodes, Limicolce and Alectorides, Phoenicopteri and Anseres, and Longi- 

 penncs and Tiibinares. Of the Pygopodes (which as here defined is certainly not a properly 

 limited group) the Alcidce present many points of true relationship to the Tubinares and Longi- 

 pennes, while the latter are not far removed from the Limicolce. The Podicipidce also appear to 

 resemble in some respects (perhaps only teleological) the Steganopodes. 



1 Young birds are gymnoppedic when naked or very incompletely covered with down when hatched ; 

 e. g., the young of all Passeres, Woodpeckei's, Pigeon.s, etc. 



