146 



ELEMENTS OF OEFITHOLOGX. 



and is called the culmen. The lower line coincides with its 

 lowest margin, that which encloses the under mandible. This 

 lower line is the maxillary tomium. The culmea may be in the 

 form of a sharp elevated ridge like a knife, when it is said to 

 be " oultrate" the mandible which bears it being "heeled"; the 

 apex of the upper mandible may be hamulate or unguiculate. 

 The maxillary tomium may bear tooth-like processes or be 

 notched like a saw, when it is said to be serrate. If it has a 



Kg. 143. 



J ' 

 Paets'of a Bill. 



, Side of maxilla or upper mandible ; b, culmen ; c, nasal fossa ; d, nostril ; 

 e, tomia or inferior margin of upper mandible ; /, gape, or whole com- 

 missural line ; a, rictus ; h, commiasural point or angle of the mouth ; 

 i, ramus of under jaw ; 7, tomia of under mandible ; i, angle of gonys : 

 the hindermost point of junction of the two rami which form the lower 

 mandible is the " gonys proper," but the term is extended to apply to 

 the -whole line of union of the rami from the gonys proper to the tip 

 of the under mandible corresponding to the culmen or median ridge 

 and upper outline of the uppe^ mandible ; I, m, side of under mandible ; 

 n, tips of mandibles. 



single notch or tooth-like process (as in the Hawk) it is called 

 dentate. If it forms a sharp edge like that of a knife it is 

 (like a sharp culmen) termed cultrqte, and if it is at the same 

 time much curved it is falcate, or " like a sickle." An upper 

 mandible provided with a series of transverse plates or ridges 

 within it (like that of the Duck) is called lamellate. 



The nostrils are almost always conspicuous one on either 

 side of the upper mandible. As a rale they each open at the 

 bottom of a depression, which when rounded is termed the 



