EXPLANATION OF PLATES, 



495 



Plate XII. Respiratory and Vocal Organs of Pigeons, Grouse, 

 and Parrots. Full size. 



Fig. 1. Trachea of Wood Pigeon, Co- 

 lumba Pahcmbus, vieived from before. 



a, the tongue. 



b, b, processes of hyoid bone. 



c, d, e, trachea. 



f, thyro-hyoid muscles. 



ff, g, contractor or lateral muscle, with 



their sterno-tracheal slips. 

 h, h, single pair of inferior laryngeal 



muscles. 



Fig. 2. Lateral view of Inferior Larynx 

 or Syrinx. 



a, sterno-trachealis. 



b, tensor of the membrane of the sy- 



rinx. 



c, membrane of the syrinx. 



Fig. 3. Last entire Ring, not divided. 



Fig. 4. Glottis, vieived from behind. 



a, tongue. 



b, b, processes of hyoid bone. 



c, aperture of glottis. 



d, trachea. 



e, e, lateral muscles. 



Fig. 5. Bones of the Larynx. 



a, thyroid. 



b, its posterior prolongation. 



c, cricoid. 



d, arytenoid. 



Figs. 6, 7. Rings of Trachea. 



Fig. 8. Trachea of the Broivn Ptarmigan, 

 Lagopus scoticus. 



a, the tongue. 



b, b, apo-hyal and cerato-hyal bones. 



c, trachea. 



d, d, cleido-tracheal muscles, 



e, e, sterno-tracheal slips. 



f, inferior larynx, entirely destitute of 



muscles. 



g, g, bronchi. 

 h, h, lungs. 



Fig. 9. Trachea of Psittacus ochroce- 

 phalus. 



a, glosso-hyal bone. 



b, basi-hyal bone, 



c, uro-hyal bone, 



d, d, apo-hyal bones. 



e, e, cerato-hyal bones. 



f, thyroid bone. 



g, its appendages. 

 h, cricoid bone. 



i, arytenoid bones. 



j, k, trachea. 



k, inferior larynx. 



I, I, sterno-tracheal slips. 

 m, m, outer muscles. 



n, n, inner muscles. 



Fig. 10. Inferior Larynx, viewed later- 

 ally. 



a, rings of trachea, 



b, last entire ring. 



c, dimidiate terminal ring. 



d, first bronchial ring. 



Figs. 11, 12, Muscles of the Larynx, 



I I, thyro-hyoidei, 



12, thyro-cricoidei. 



Figs. 13, 14. Muscles of the Syrinx. 



13, inner muscle. 



14, outer muscle. 



