or THE BILL. 23 



Sub-sect. 2. Of the Members ; tJieir parts and organs. 



1. The Bill. 



§ 42. The Bill is hand .ind mouth in one : the instrument of prehension. 

 As hand, it takes, holds and carries food or other sul:)stances, and in many 

 instances, feels; as mouth, it tears, cuts, or crushes, according to the nature 

 of the substances taken; assuming the functions of both lips and teeth, 

 neither of wliich birds possess. An organ thus essential to the prime func- 

 tions of birds, one directly related to their various modes of life is of the 

 utmost consequence in a taxonomic point of view ; yet, its structural modi- 

 fications are so various and so variously interrelated, that it is more impor- 

 tant in framing families and genera than orders ; more constant characters 

 must be emploj'ed for the higher groups. The general 



§ 43. Shape of the bill is referable to the cone; it is the anterior part of 

 the general cone that we have seen to reach from its point to the liase of the 

 skull. This shape confers the greatest strength combined with the greatest 

 delicacy; the end is fine to apprehend the smallest olyects, while the base is 

 stout to manipulate the largest. But in no bird is the cone expressed with 

 entire precision ; and in most, the departure from this figure is great. The 

 bill ALWAYS consists of two, the upper and the lower 



§ 44. Mandibles (fig. 5), which lie, as their names indicate, above and 

 below, and are separated b}^ a horizontal fissure — the mouth. Each mandi- 

 ble ALWAYS consists of certain projecting skull-bones, a i, c d o r 

 sheathed with more or less 7/0)-)i?/ integument in lieu of \ \ \ \.,: ...••■"^^./ 

 true skin. The frame-work of the Upper mandil)le is \ \/\V'U-^T^i,' / 

 (chiefly) a bone called the intermaxillary, or better, z^^ij^^l^S<" w 



iu this case, the preniaxiUary. In general, this is a ' """>/-- — ^ "^ T^^V '' 



three-pronged or tripodal bone running to a point in / /•-,. / j \n. 

 front, with one, the uppermost prong, or foot, im- / / ,/ ■ i \ 

 planted upon the forehead, and the other two, lower "rig. s. Vaits of a Bin. 

 and horizontal, running into the sides of the frc)nt of «, sirie of upper man. i iwe ; s.cui- 



,, 1 11 rni /I' 1 1 o j_i TT 1 Ti 1 • men; c, nasal fossa; rf, nostril; <?, 



ihe skull. Ihe scatiold ot the Under mandible is a (soebeiow);/, gape, or wiioie com- 

 missural line; f7, rictus; /(, comniis- 



compound bone called inferior maxillary; it is U-, or f^SmSs'orundef'faw-'j'^mni'al',;- 

 V-shaped, with the point or convexity in front, and iti'';sSd have S'S^?S 



,, • . • ^ •ir'jii n ^ indicate the correspondinK tomia 



the pronf>'s runnuii? to either side oi the base of the -^i" "pp^i- anmdibie); ;j, ant^-ie or 



■*■'-' •— j^'-onys; /, gonvs; m, side of under 



skull behind, to bo there movably hinged. These two '"^""^i""'; «, tips of mandibies. 

 bones, with certain accessory bones of the upper mandible, as the palate 

 bones, etc., together Avith the horny investment, constitute the Jaws. BotJi 

 jaws, in birds, are movable; the under, by the joint just mentioned; the 

 ujDper, either by a joint at, or by the elasticitj^ of the bones of, the forehead ; 

 it is moved by a singular muscular and bony apparatus in the palate, 

 further notice of which would involve anatomical details. When closed, 

 the jaws meet and fit along their opposed edges or surfaces, in the same 

 manner, and for the same purposes, as the lips and teeth of man or other 



