32 PRACTICAL ORNITHOLOGY. 



Plate XII, Fig, 8, represents the trachea of a Brown Ptar- 

 migan, Lagopus scoticus. It tapers considerably toward the 

 lower extremity, and is composed of about seventy rings. Like 

 that of the Pigeons, it keeps on the left side of the neck, as is 

 in fact the case in all birds which have the crop large, but in 

 this, as in the other representations, it is straightened. The 

 thyroid, cricoid, and arytenoid cartilages present nothing re- 

 markable in their form or arrangement. The rings of the tra- 

 chea, however, are extremely thin, broader in front than at 

 the sides, and having a transverse vacuity there. The lowest 

 complete ring is very similar to that of the Wood Pigeon, 

 being formed of an upper curved ring, a lower ring also 

 curved, and an anterior and a posterior erect bony slip con- 

 necting the rings, the interval between which is filled by mem- 

 brane. As in the Pigeon, there is no transverse dissepiment in 

 this ring, beyond which are two half rings belonging to the 

 trachea. The bronchi, g <7, are very wide, and composed of 

 about fifteen half rings. The muscles of the upper larynx are only 

 three, the thyro-hyoideus, the thyro-arytenoideus which opens 

 the glottis, and the crico-arytenoideus which closes it. The la- 

 teral muscles of the trachea are two, the cleido-trachealis, d d ; 

 and the sterno-trachealis, e e ; but the syrinx or lower larynx 

 is totally destitute of muscles, and in this respect differs from 

 that of any bird which w^e have yet examined. In other 

 gallinaceous birds, the trachea is less flattened or perfectly 

 tubular, with strong bony rings ; but in all, the lower larynx 

 is destitute of muscles. The lungs, h h, are seen covered by 

 the strong fibro-membranous expansion, to which are attached 

 on each side three muscular slips, i,j, k, arising from the ribs. 



Thus, it appears that in reference to the complexity of its 

 muscular apparatus, the trachea of the Cantatores, Vagatores, 

 and Deglubitores, occupies the highest place, there being five 

 pairs of muscles appropriate to the larynx, two pairs to the 

 tube of the trachea, and four pairs to the lower larynx. The 

 Gemitores or Pigeons have three pairs for the larynx, one 

 pair for the tube of the trachea, and a single pair for the lower 

 larynx. The Rasores have three pairs for the larynx, and two 

 pairs for the tube of the trachea, but none for the lower larynx. 



