INTRODUCTION. 



The shape and size of the bill vary greatly, as will be seen by the following 

 illustrations representing fifteen of the principal types among our birds : 



' ' -o. \ 



Bit! of Humming-bird 



l of Whi/ipoorii'il! 



Bill of Mr ik;- 



Bill of' i'ong Sparrow 



BUI of Least Bittern 



Bill of Dv.ck 



Bill of Heron 



Cere. A membrane (usually hard), which covers the base of the upper mandible. 

 (Hawks, Parrots, Jaegers.) 



Nasal Fossa, or Nasal Groove. Groove in which the nostrils open. 



Gonys. Lower outline (middle) of the under mandible, A to B. 



Culmen, The ridge of the upper mandible. 



Unguis. The iiaiK on the end of the upper mandible. Very pronounced in some 



families of Water Birds, --Ducks, Pelicans, and Petrels. 

 flandibles. Some authors use the word ma.viila for the upper half of the bill, and 



mandible, for the lower. I prefer, however, to describe the two halves of the bill 



as upper and lower mandible. 



