﻿PARTS OF 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, are 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«X> t0 which 

 the reader can refer when perusing the following short 

 vocabulary of terms, 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 bill, 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 mandibula (b). The upper man- 

 dible contains the nostrils {nares, c), the form of whose 

 apertures is various : its highest part is the cnlmen, or 

 keel (d) ; the corresponding ridge of the lower mandible 

 is the gonys (e): both these Latin terms, by common 

 consent, are used in our vernacular descriptions, although 

 ridge may be applied to the culmen, and keel to the gonyx. 

 The margins of both mandibles are those lateral edges 

 which meet when the bill is closed ( / ) : in some birds, 

 like the todies, flycatchers, and humming birds, the mar- 

 c 3 



