202 



GENERAL ORNITHOLOGY. 



Fro. 07. — 1, 2, left hand, two tracheal rings, sepa- 

 rate, as iu fig. IIG, /-,■ ], 2, right hand, the same put 

 together, as in fig. 'Jit, a. (After Macgillivray. ) 



partly over each other on alternate sides is something like that upon which a cooper fastens 

 the ends of any one barrel-hoop without any nailing or tying. The rings are in some birds 



(icrfectly cartilaginous : in most they become 

 osseous. The trachea is moved by lateral 

 muscles, which not (mly shorten the tube by 

 appro-vinuitiug th(! rings, but also drag the 

 whole structure backward, by their attach- 

 ment to the clavicle and sternum. The strip, 

 or two striiis, of muscle lying upon each side 

 of the trachea, ia the contractor tracliecc (fig. 

 101, 1, ss, ss) ; the most anterior, when there 

 are two, as soon as it leaves the tube to go to the clavicle, becomes the ctcido-trachealis, or 

 cleido-hyoid, fig. 101, ', /, /; the other is similarly the stcrno-tracheidis. The latter may be a 

 direct coutinuation of the contractor, as in fig. 101, 1, the loose strips under q, or apparently 

 arise separately from the side of the lower end of the tube, as in fig. 101, 1^, e. (Otlier muscles 

 are to be described with the larynx superior and inferior.) The trachea is long in birds, pro- 

 ixirtionate to the extension of the necli ; it is very flexuons, following with ease the bends of 

 the neck in which it lies so loosely. Its cross section is oval m- circular; but all that relates 

 to the configuration and course of the pipe requires special descrijition, — so variable is the 

 organ in different birds. It is subject to dilatations and contractions in any part of its extent, 

 and to deviations from its usual direct course t!> the lungs. IMinur modifications must be 

 passed over. The most remarkable expansions of the lower part of the tube occur in tnany 

 sea-ducks and mergansers {Fidigulinai and Mcr/jiiue), and scane otlier birds ; several lower rings 

 of tlie trachea being emn-mously enlarged and welded together into a great bony and mem- 

 branous box, of wholly irregular, unsyniinetrical cont<iur. Such a structure, represented in 



tigs. 3 and 98, is termed a traclieal tympanum, or ?«?»/- 

 rinth. It is not a part of the voice-oi-gau proper, but 

 may act as a reverberatory chamber to increase the v<il- 

 ume of the sound, without however modulating it. Being 

 chiefly developed in the male, it is a kind of secondary 

 sexual organ. The vagaries of the wind-pipe are still 

 more remarkable. Very generally, in cranes and swans, 

 the trachea enters the keel of the stei-num, which is exca- 

 vated to receiv(^ it, and where it forms one or more coils 

 before emci'ging to pass to th(! lungs. This curious wind- 

 ing is carrie<l to an extreme in our Gri(S americana, the 

 whooping crane, in wliich the wind-pipe is about as long 

 as the whole bii-d, and about half of it — over two feet of 

 it! — is coiled away in the bi'east-bone (fig. 99). The 

 same thing occurs in G. canadensis to a less extent (fig. 

 100). In a Guinea-fo«'l, Guttera cristata, a loop of the 

 tiachea is received in a cup formed by the apex of the 

 clavicles. In various birds, as some of the curassows ( Cra- 

 cida'), the capei-caillie {'Letrao nroijaUus), agoose, Anseranas semipalmata, and the female of the 

 curious snipe, Rhynchcea australis, the trachea folds between the pectoral muscles and the skin. 



Fig. 08. — Bony labyrinth at the bot- 

 tom of the trachea of the male of CJangpJa 

 Ulantlira, seen from behind, nat. size. Dr. 

 R. \V. Shufeldt, U. S, A. 



The Larynx (the Gr. name, Xapt/y^, larurj:i) is the peculiai-ly modified upper end of the 

 trachea I fig. 101, 1, and 3 to 12). In niaininals it is a complicated voice-organ, containing the 

 vocal chords and other consonantal apparatus; in birds the construction is simpler, as the 

 larynx merely modulates the sound already produced in the lower (.'ud of the tube. It lies in 



