116 
BIRDS. PALMIPIDES. 
PALMIPIDES. 
WATER BIRDS. 
!► Hind toe united with the front toes hj a continuous membrane. Nasal- 
openings indistinct. 
Phalacrocorax. 
Sula. 
II. Hind toe separate. 
a. Margin of the mandibles with corneous teeth ; the sides of the tongue, 
with tufts of pectinated bristles. 
b. Bill broad. Teeth in the form of transverse plates. 
c. Trachea of the male with a capsular enlargement at the bron- 
chial extremity. 
d. Hind toe bordered with a membrane. 
e. Base of the bill enlarged. 
Oidemia. 
Somateria. 
ee. Base of the bill plain. 
Clangula. 
Nyroca. 
dd. Hind toe not bordered by a membranei 
e. Bill wide at the extremity. 
Tadorna. 
Spathulea. 
' ee. Bill nearly of equal breadth throughout. 
Anas. 
cc. Trachea of the male simple at the bronchial extremity. 
Cygnus. 
Anser. 
hb. Bill narrow ; margins with reflected teeth ; the upper mandible^ 
hooked at the end. 
Mergus. 
aa. Margin of the bill and tongue destitute of teeth or bristles. 
b. Wings short. Brachypter-®. 
c. Bill compressed and obliquely furrowed. Tridactyle. 
Alca. 
Fratercula. 
cc. Bin conical, subcompressed, and destitute of furrows.^ 
d. Webs scalloped. A hind toe with a broad web. 
Podiceps. 
dd. Web entire. 
€. Tridactyle. 
Colymbus. 
ee. Tetradactyle. 
/. Upper mandible notched at the point* 
Uria. 
Upper mandible plain. 
Cephus. 
Mergulus. 
