PARTS OP A BIRD. THE HEAD. 
21 
scrupulous accuracy, the several parts of a complicated 
machine, without giving any intimation of the effects 
that machine was intended to produce. 
(25.) The external anatomy of a bird relates to all 
those parts which are wholly or partially exposed to 
sight : under this head, therefore, we comprise its ge- 
■ neral shape, and the proportion of its parts ; the struc- 
ture of the mouth, bill, tongue, wings, tail, and feet ; 
and the manner in which these are diversified. It will 
be our first object to give a short explanation of the 
terms employed to designate the parts of a bird : we 
shall then point out in what manner they vary in the 
different types ; and trace, as far as possible, the relation 
between these variations of structure, and the habits of 
the birds themselves. 
(26.) The three primary parts of a bird, as of all 
vertebrated animals, arc its head, body, and limbs, under 
which all the subordinate parts may be classed. These 
latter are so numerous, and would require such elaborate 
definitions if we employed words only, that it becomes 
desirable to give the annexed sketch (fig. 9.), to which 
the reader can refer when perusing the following short 
vocabulary of terras, essential to be understood by every 
student. ^ ■' 
(27.) The HEAD is composed of the skull and bill 
and joined to the body by a neck. Commencing with 
the BILE, we see that it is composed of two pieces, cor- 
responding to the jaws of quadrupeds : that which is 
above is called the upper mandible (a) (or maxilla) ; that 
beneath, the lower, or mamlibula (6). The upper man- 
‘lible contains the nostrils {nares, c), the form of whose 
apertures is various : its highest part is the culmen, or 
eel ; the corresponding ridge of the lower mandible 
e gonyft (e); both these Latin tcrmsj by common 
cpusent, are used in our vernacular descriptions, although 
may be applied to the culmen, and keel to the gonyx. 
“■'^RniNs of both mandibles are those lateral edges 
liV ''^i. when the bill is closed (/) : in some birds, 
e t e todies, flycatchers, and humming birds, the mar- 
c 3 
