CLAMATORES. 169 



SECTION II. CLAMATORES. SONGLESS BIRDS. 



Inferior larynx provided, with less than five pairs of muscles. The stcrno-trachcalis 

 has its origin above the. broncho-trachealis. 



Birds in this Section lack the complicated singing apparatus found in those which are 

 placed under Oscincs. These last named birds have five pairs of vocal muscles in addition 

 to the stcrno-trachcalis which may be considered as a sixth pair, for they not only support 

 the trachea but, by drawing it downward, thus relaxing the tympaniforui membrane, aid 

 in producing sound. 



I have given life-sized drawings of the inferior larynx of a Crow in Plate VI, figs. 1 

 to 4, in order that students may understand the various parts. Fig. 4 shows a view from 

 the lower side; 0, is a portion of the trachea and B, the bronchial tubes which extend to 

 the lungs. The muscles which are deeper in color, are as follows: Bt, broncho-trachealis; 

 Bp, broncho-trachealis posticus. Fig. 3 exhibits a side view with the same figures ap- 

 plied to the same parts as far as explained. The broncho-trachealis is better defined and 

 its division into the broncho-trachealis anticus, B, and posticus, Bp, is very clearly seen. 

 The broncho-trachealis brevis is given at Bb, the bronchialis posticus at BB, which with 

 the bronchialis anticus, BB.\, make up the number of vocal muscles; their counterparts 

 being on the opposite side. It is observable that the sterno-trachealis has its tracheal or- 

 igin below the division of the broncho-trachealis; the other extremity being attached to 

 the costal process of the sternum, seen in fig. 5, Cp. The exact point from which this 

 muscle emerges from the trachea is of great importance in determining in which section 

 of the order Insessores any particular species is to be placed, for, in all birds which only 

 have the power of modulating their voices to a limited extent, this muscle will be found 

 to originate on the trachea quite above the broncho-trachealis. This will be further il- 

 lustrated in a future plate in which I purpose giving drawings of the larynx of some mem- 

 ber of Section II. 



The other accessories for producing melodious sounds are the tympaniform membrane 

 which stretches across the under side of the upper portion of the bronchial tubes, fig. 2, 

 M, and the scmilunar membrane, shown in fig. 1, which is a section of the larynx, at S. It 

 is supported by the os transversale, T, a slender bone which crosses the interior of the tra- 

 chea. The office of the laryngeal muscles is to tighten these two membranes, which then 

 vibrate and produce sound. 



FAMILY I. TYRANNID^J. THE TYRANT FLYCATCHERS. 



Bill, more or less Irianyu/ar inform, wider than hiyh at base, and the upper mandible /' abruptly curved at tip which it 

 notched. Nasal and loral rcyion at base uf upper mandible provided with stiff bristles which also very often occur on the chin. 

 Sternum, broad with hiyh keel. 



i- a largo family with dull colors, occasionally relieved by yellow below or by bright markings on tlie crown. 

 The dill r. nr, , between the various genera are slight, although constant. I have made some change" in the arrangement 

 of the genera, ba-eJ mainly upon anatomical characters. The tympaniforui membrane is always present bat, although I 

 have found the os transversalo in all that I have examined, yet I hove never seen the semilunar membrane. The coracoids 

 are short, but are set on at an angle causing t'.ia farcular to b3 wall arched, an 1 in tjr-nin vl prJSJ-H is short. 



BIRDS OF FLORIDA. 22 



