90 Birds of Colorado 
b! Bill shorter ; culmen less than the middle toe and claw. 
a® No frontal shield. 
a’ Larger; wing over 4; nostrils about the middle of 
the bill. Porzana, p. 95. 
b? Smaller; wing under 3; nostrils nearer the base of 
the bill. Creciscus, p. 96. 
b? A frontal shield on the front part of the head. 
Gallinula, p. 97. 
b. Toes with w series of lateral marginal lobes; a frontal shield 
present. Fulica, p. 97. 
Family GRUID. 
The Cranes are large birds with long legs and necks ; 
the bill is long and generally exceeds the length of the 
head ; part of the face is generally naked and often 
wattled or papillose ; there are twelve tail-feathers and 
eleven primaries, and the trachea or windpipe is generally 
convoluted and packed away in a hollow space formed 
between the walls of the keel of the sternum ; the legs 
are long, the tarsi scutellate in front, the toes short 
and webbed at the base; the hallux very short and 
elevated above the other toes. 
The Cranes are externally not unlike the Storks, with 
which they were formerly often associated, but they 
differ very essentially in internal structure. Externally 
they may be distinguished by the grooving of the bill, 
in which are situated the nostrils, and by the elevation 
of the hallux above the toes. 
Genus GRUS. 
The characters of the family, to which may be added—plumage 
white or grey in the adult, rusty in the young; head more or less 
bare of feathers and not crested. 
All the three North American, species have been taken in Colorado. 
Key oF THE SPECIES, 
A. Plumage white, primaries black. G. americana, p. 91. 
B. Plumage slaty-grey. 
a. Larger; wing 21—22. G. mexicana, p. 92. 
b. Smaller; wing 18—19, G. canadensis, p. 91. 
