AVE S. 



77 



Genus Pelecanus, Lin. Pelican, 



Beak exceedingly long, straight, depressed and terminated 

 by a kind of nail ; the lower mandible has flexible branches 

 sustaining a naked membrane, which can be dilated into a 

 more or less voluminous sac ; nostrils linear, hardly percep- 

 tible ; eyes heavy and naked like the throat. 



Genus Tachypetes, Vieil. Frigate-Bird. 



No remarkable pouch ; tail forked ; feet short ; toes semi- 

 palmate ; wings very long ; mandible short and curved at 

 the point. 



Genus Sula, Briss. Booby. 



Beak straight, the edges provided with teeth ; nostrils pro- 

 longed by a line which extends to near the point ; throat 

 naked (as well as the circumference of the eyes), and little 

 extensible ; nail of the middle toe indented like a saw ; wings 

 moderate. 



FAMILY IV. LAMELLIROSTRES. 



Beak thick, clothed with a soft skin rather than with true 

 horn, the edges furnished with small laminaB or teeth ; tongue 

 wide and fleshy, and the edges notched ; three toes before 

 united by membranes, one behind free ; wings of moderate 

 length ; habitation more frequently upon fresh waters than 

 upon the sea, 



Genus Anas, Lin. 



Beak large and broad, the edges furnished with a row of 

 projecting laminse, placed transversely, which seem intended 

 to let the water escape when the bird seizes its prey. Three 

 remarkable subgenera. 



Subgenus Cygnus, Meyer. Swan. 



Beak as broad before as behind ; neck very long ; nostrils 

 in the middle of the length of the beak. 



Subgenus Anser, Briss. Goose. 



Beak moderate and narrow before ; legs longer than in the 

 Anas proper. 



