50 NORTH AMERICAN BIRDS. 



Order TUBINARES. — The Tube-nosed Swim- 

 mers. (Page 1.) 



Families. 



a 1 . "Wings very long ; nostrils opening in anterior end of horizontal nasal tubes. 

 b 1 . Nasal tubes widely separated by the intervening culmen ; size very large 

 (equal to a large goose or larger) ; wing very narrow, with very nu- 

 merous (39-50) remiges Diomedeidae. (Page 50.) 



P. Nasal tubes united, and resting upon the basal portion of the culmen ; size 

 and other characters extremely variable, but usually medium-sized or 

 small, and remiges never more than 39 (usually 30, or less). 



Procellariidse. (Page 53.) 

 a 2 . Wings very short, and general appearance decidedly Auk-like ; nostrils opening 

 upwards, as parallel longitudinal slits, at very base of culmen. 



Halodromidse. (Extralimital.) 



Family DIOMEDEIDAE.— The Albatrosses. (Page 50.) 



Nest a mound-like heap of grasses, etc., with depressed top, built upon the 

 ground in open situations, on oceanic islands. Egg single, ovate, or elliptical ovate, 

 white, sometimes speckled or sprinkled on larger end with reddish brown. 



Genera. 



a 1 . Sides of lower mandible without longitudinal groove ; wing three or more times 

 as long as the short, rounded tail. 

 b 1 . Upper division of the bill much broadest at base, where joined closely to the 



lateral division Diomedea. (Page 50.) 



b 2 . "Upper division of the bill narrow, and of equal width from the middle of 

 the culmen to the base, where widely separated from the lateral division 

 by the interposition of a strip of naked skin extending from the nasal 



tubes to the forehead Thalassogeron. (Page 52.) 



a 2 . Sides of lower mandible with a distinct longitudinal groove, extending the entire 

 length of the lateral division ; wing only about twice as long as the gradu- 

 ated or wedge-shaped tail Phcebetria. (Page 53.) 



Genus DIOMEDEA Linnaeus. (Page 50, pi. XIII., figs. 1, 2.) 



Species. 



a 1 . Culmen very concave; feathers, at base of upper mandible extending in an angle 

 nearly or quite to the base of the nasal tube, those at the base of the lower 

 mandible forming a still more decided angle. (Subgenus Diomedea.) 



