oj the United States* fe9 



ORDER ANSERES. 



Family Longipennes. 



* Nostrils immarginate. 

 Genus 61. Rrinco-ps Lower mandible much longer than the 

 upper, truncated. 



62. Sterjna Bill subulate, straightish, compressed, 



acute. 



63. L*rus. Upper mandible hooked, without a cere : 



lower gibbous below the point. 



64. Lestris Upper mandible hooked, covered at 



base by a cere : lower gibbous below the point. 

 ** Nostrils tubular. 



65. Procellaria Hind toe only a sharp nail. 



66. Diomedea Feet three-toed ; no hind nail. 



Family Lamellosodentati. 



67. Anas. Bill depressed, obtuse; teeth lamelliform. 



68. Mergus. Bill slender, hooked ; teeth subulate. 



Family Steganopodes. 

 * Bill entire. 



69. Pelecanus. Bill much depressed. 



70. Phalacrocorax. Bill compressed, hooked, not 



seamed above : tibiae wholly feathered. 



71. Tachypetes. Bill compressed, hooked, seamed 



above : tibiae wholly feathered. 

 ** Bill serrated. 



72. Sula. Bill stout, straight, compressed ; face 



naked. 



73. Phaeton. Bill cultrate : face feathered. 



74. Plotus. Bill subulate : face naked. 



