• tympaniform mcmbiane and the reed-(haped apertiire, or 

 litis, upon which the produAioii of the voice effentially 



B I R 



force through the bronchix, a lirely vibration is excited in 



the " " ' ' ' - > - 



glotti: 



depends. . . 



The magnitude, figure, and proportions of the inferior 

 arynx vary more or lefs in almoft every fpecics, which Cu- 

 vier has taken great pains to point out. 



The trachta is commonly enlarged, at its bifurcation, by 

 the cxpanfion and union of its la!l cartilaginous rings, which 

 is dcficined to afl'ord llrergth to the voice. 



In the Jan and i\iejirigin^ lirch, the lall rings of the tra- 

 chea are united ii:to a fiugle piece, of which the bafc is wide, 

 and furni(hed with two points that are joined by a tranl- 

 verfe olTeous bar in fuch a way, that the tracliea commu- 

 nicates by two openings with cuch of the bronchia;. 



In the piinot, the lall rings of the trachea are united, and 

 form a lube a httle comprefted on the fides. The very lall 

 ring is almoll fquare ; it is alfo flattened before and behind, 

 and furiiilhed pollcriorly with two points. There is no par- 

 tition within. The fides of the bronchix, oppofite to each 

 othtr, are membranous. The firrt femi-ring is larp;e, flat, 

 and fi'.aped like a crefcent ; the ftcond, third, and fourth 

 femi-rings unite in one piece; and the fifth, fixth, and fe- 

 yenth are confolidated into a fimilar plate. The edges of 

 both, however, prcfent the marks of tlitir original parts. 



In the noilurnal iiri/j of prey, the laft ring of the trachea 

 is divided by a bone. 



In ihe fco!opas ruJlicoLi, the four lafl cartilaginous lings 

 of the trachea are incomplete pofteiiorly, and the tympani- 

 form membrane is continued up between them. 



The male birds of the duel kind, and the genus mcrgus, 

 have the latl rings of the trachea united, and forming a car- 

 tilaginous or bony fack, called by authors the ampulla, or 

 the labyrinth. This part, in the mallard, forms two dilata- 

 tions ; the one on £he right is fmall, and refemblcs a trun- 

 cated cone, with a prominence from the bafe behind. The 

 left is a large veficle irregularly rounded, and produces at 

 the lower part a pyramidal projeAion. Its right furface is 

 a little flattened below, and its inferior border is indented. 

 The cavity is interrupted by projections, or fepta, in luch a 

 manner, that the air cannot pafs from the left bronchia into 

 the trachea, b\it through the capfule, although on the right 

 fide it may. The entrance to the bronchia; is provided with 

 a thick membrane, under which there are fome glands re- 

 Icmbling \.\\<z fynoviat, that fecrete a mucous fluid. 



The form and internal partitions of the ampullar of the 

 drakts of other fpecics and the merganfers, are different in 

 every inllance. Their deviations are delcribed at length by 

 Cuvicr. See Memoire fur le larynx inferieur des oifeaux, 

 Magazin Encyclopedique, tom. zd. 



Two fpecies of vulture (V. papa and V. aura) were ob 



ferved by Cuvier to be deprived of the organ of voice, glottis. 



B I R 



may alfo bring the trachea forwards. Thefe were the only 

 mulcles obfervcd by Cuvier in the ^nlliniP, and moft of the an- 

 feres. It is probable, that no others are to be found alfo 

 in t\\eJlru!iAous birds. 



The feconJ kind of mufolcs are confined to the inferior 

 larynx ; they are fliort, and fituated upon each fide of the 

 bifurcation of the trachea ; and, except in the parrot tribe, 

 are all conftriftors, or intended to render the tympaniform 

 membrane tenfe, and thus exalt the tones of voice. 



In moll birds, which do not fing, there is but a fingle pair 

 of contlridors, one on each fide, which arifes from fome of the 

 lall rings of the trachea, and is inferted into fome of the 

 firft fcm:-rings of the bronchia. Thefe mufcles are longed 

 in the ti^c^urtial l/lrd.r of prey, extending from the bafe of the 

 trachea to the fevtnth lemi-ring. The conftriftor is attached 

 to the fifth femi-ring in the cuchow, the heron, and bittern. 

 The latter birds owe their ilrength of voice to the elafticity 

 of the femi-rings, and the extent of the tympaniform mem- 

 brane. The gocit-fucker, ling-Jifier, and pelican, have the 

 conftriilor miilcle affixed to the fecond femi-ring of the 

 bronchia ; and the woodcock, pbalarope, coots, and the plovers, 

 and recurvirujira, and probably all the weak billed gralU, 

 have it inferted into the firll femi-ring. 



The larynx of Jinging birds, and fome others, is pro- 

 vided with five conlltitiors on each fide, which Cuvier 

 has named, according to their fituation and direction. 



1. The anterior longitudinal conjlrt&or. 



2. The p'l/lcrior longitudinal conJlriSor, 



3. Tht fmall longitudinal conflridor. 



4. The oblique canflri&or. 



5. The tranfverfe confiriSor. 



Tlicfe almoft uirrourid the bifurcation of the trachea, to 

 which they have all the lame attachments, as near as may 

 be. The two firll are inferted into the third femi-ring ; the 

 two next into the fecond femi-ring ; and the laft is aflixedto 

 the firft femi-ring, and particularly to a little cartilage that 

 is joined to it. 



Cuvier has obfervcd the five pair of conftriftors in all the 

 finging birds, in thefare, in aU the pa^eres, except thefival- 

 loiv and goat fucker, and in the crow, raven, jay, and many 

 of the pie kind. 



The moft complicated inftrument of voice, amongft 

 birds, is that of the parrot tribe. It pofTcffes three pair of 

 mufcles ; but one pair is intended to relax the opening of 

 the glottis. 



The principal conflridor arifes from the laft ring but one of 

 the trachea, defcends almoft perpendicularly upon the lax- 

 ator, and then goes on to be inferted into the union of the 

 fifth, fixth, and feventh femi-rings of tlie bronchia. Its at- 

 tachment being joined to the femicircular plate, it urges the 

 upper part of the plate inwards, and thus contrads the 



there being neither the tympaniform membrane, nor any 

 contraflion, or projeding elaftic parts at the entrance of the 

 bronchise into the trachea. 



The voice of birds is modified, and the tones rendered 

 more acute or grave, by means of two dcfcriptions of muf- 

 cles. The firft are common to all fpecies, and have been 

 long known and delcribed. They were called by Vic 



The auxiliary conjlridor occ\\\Ae?,, for a certain diftance, the 

 anterior part of the trachea, and fends off a tendon, which 

 is loft in the preceding mufcle ; its operation, therefore, is 

 exaftly the fame. 



The laxator is placed under the two other mufcles ; it 

 arifes along the fide of the trachea, and expands upon the 

 inferior concave edge of the laft ring; in diawing which 



d'Azir the inferior or external luryiigeal. They are two flelhy outwards, the mufcle enlarges the glottis. 



cords, and arifc from the triangular proceffes of the fternum, 

 to which the fuperior ribs are joined within the cheft, and 

 proceed to the fide of the trachea, above the bifurcation, 

 along which they afccnd for its greateft length. Their ef- 

 feft IS to deprefs the inferior larynx, and contraft the bron- 

 chia, and thereby relax the tympaniform membrane, and 



Sec Plate XI. in the Anatomy of Birds. Fig. 8. fliews 

 the external appearance of the inferior larynx in the oavl ; a 

 the lower part of the trachea ; b the two bronchix ; c the 

 external laryngeal mufcles, which are common to all birds ; 

 (/ the conftridor. Fig. g. of the fame plate exhibits the 

 organ of voice in the thruflj ; a the anterior longitudinal 



deepen the tone of voice, and in fome circumftances they conftridor ; b the tianfverle conftridc 



partially expofed 

 under 



