INTRODUCTION. 3 
R shows on the bill the culmen, or crown, of the = 
upper mandible. 
S is the naked skin at the base of the bill, 
called the cere. 
T shows the position of the lores between the y "SS 
= U 
eye and bill. 
U indicates the gape, the angle at the junction of the upper and lower 
mandibles: the feathers in this locality are called rictal. 
V is the commissure, or the folding edges of the mandibles. 
In addition to these parts, there are the flanks or sides 
of the bird; the pectus, or breast; the flexure, or bend of 
the wing; the iris, or irides, the colored circle which sur- 
rounds the pupil of the eye; and the toes and tibia: the 
former are sometimes palmated, as with the swimmers, or 
natatores; and the latter is that portion next above the 
tarsus on the leg. , 
