20 cassell's book of birds. 



The parts of the Neck are thus designated : — The back of the neck is called the upper neck, or 

 nucha ( 2i ), beneath which is the lower neck or auchaiium. The under-side of the neck is divided into 

 three regions ; first, there is the chin (/), or that small space just beneath the lower mandible ; to the 

 chin succeeds the upper throat ( 8 ), between which and the broad part of the body is the lower throat ( 51 ). 



The Body presents the following regions : first there is the breast ("), which extends over the 

 space which covers the breast-bone. To this succeeds the belly (' :o ), which is terminated by the vent 

 or crissum ( M ). Immediately behind the vent are the under-tail covers ( s2 ), which are frequently of a 

 different colour from the surrounding feathers. 



On the upper aspect of the body we have the interscapular region, sometimes called the back ( 21 ), 

 to which succeeds the lower back ( M ), which terminates at the rump, or that part where the upper- 

 tail covers ( il ) are inserted. 



Last of all comes the Tail, composed of long stiff feathers, called the tail-feathers ( 31 ), con- 

 cerning which it is only necessary to observe that the two middle tail-feathers are the intermedial, while 

 those on the sides are the lateral tail-feathers. 



The Wing of a bird will be found to present a structure worthy of our highest admiration. The 

 object aimed at in the arrangement of its different parts is evidently to obtain a very large and firm 

 expanse of surface, by employing the smallest possible quantity of material. For the purposes of 

 flight it is obviously necessary that the superficial extent of the wings shall be sufficiently ample, not 

 only to sustain the weight of their possessor in the thin and yielding element in which it flies, but, by 

 the vigour of their stroke and the violence of their impulse, to propel the bird with a rapidity 

 proportioned to the occasion, and, moreover, by the lightness of their touch and the accuracy 

 of their movements, to steer and steady its course through all the varied evolutions whereby it is 

 enabled to capture prey, or sportively display the wonderful activity conferred upon the feathered 

 tribes. 



We have already seen, while examining the construction of the skeleton, that the bony frame- 

 work of the wing essentially resembles that of the human arm, and that the limb when stripped of its 

 feathers is no more adapted for flying than our own. The needful expansion is obtained altogether 

 by the addition of the quill feathers, which, as explained in a preceding page, combine in their struc- 

 ture all the qualities requisite for the intended purpose, lightness, firmness, strength, elasticity, and 

 extent of surface : the central part of the arm or wing forms merely a basis of support, into which the 

 quills and other appendages to the wing are securely implanted. It will therefore be easily under- 

 stood that the importance of the individual quills as instruments of flight will depend very much 

 upon the position they hold in the wing, of which they form so considerable a portion, and, 

 consequently, that they have received names expressive of their relative efficiency. Those that are 

 affixed to the bones representing the hand (Fig. 12, /, q q), by the length of their stroke, and the 

 peculiarity of their arrangement, are obviously of primary importance, both from their size and the 

 situation they occupy, and have consequently been named the " primaries" or the " primary quills" 

 (Figs. 2, f; 13 s5 ); they might be called with equal propriety the "hand-quills" a term more 

 particularly expressive of the parts to which they are attached. Upon the relative length and other 

 proportions of the primary quills the shape and mechanical power of the instrument principally 

 depend ; if the first primary be the longest, the termination of the wing is sharp and pointed 

 (acuminate), as in most birds that are remarkable for the swiftness of their flight ; whereas if the 

 second, third, or fourth of these quills should exceed the others in this respect, the wing becomes 

 more and more rounded (obtuse), and the perfection of its action visibly deteriorated. 



The "Secondary Quills," or "Secondaries" (Figs. 2, c ; 13, 84 ), are exclusively sustained by the 

 bones of the fore-arm (Fig. 12, m, n) ; from their situation being much nearer to the shoulder-joint 



