

KAVEN. 69 



bird, by any one who is inclined to follow me in the ex- 

 amination. 



The organ of voice in birds may be considered as consist- 

 ing of four parts : the glottis, or superior larynx, the tube 

 of the trachea, the inferior larynx, with its muscles, and the 

 bronchise ; and the variety of modulation birds in general 

 are known to possess has its corresponding variety of forms 

 and appendages. The glottis, or superior larynx, opens 

 into the mouth at the root of the tongue. The orifice, 

 figure 1, letter 5, in the first group of illustrations, is long 

 and narrow, encircled by two pair of muscles, figure 2, 

 5, #, and figure 3, , #, which govern the size of the aper- 

 ture, and constitute one of the accessory means by which 

 the sound of the voice is regulated. Birds have no epi- 

 glottis, or covering over this aperture, to prevent any 

 particles of food passing into the windpipe ; but the sur- 

 face near the opening is furnished with numerous papillae, 

 pointing backwards, which assist in directing and convey- 

 ing food towards and into the O3sophagus. 



Figure 1 is a representation of the glottis with its sur- 

 rounding membranes. Figure 4 is a representation of the 

 cartilages forming the superior larynx, all the softer parts 

 having been removed. The letters a refer to the principal 

 cartilage, which, when in its natural situation, lies upon 

 the pharyngeal portion, and between the cornua of the os 

 hyoides, or bone of the tongue. This cartilage appears to 

 perform the double office of the thyroid and cricoid car- 

 tilages in the higher animals. In substance it is uniformly 

 thin, its shape nearly triangular when laid flat, one angle 

 placed forward, the lateral angles curving upwards to sup- 

 port the base of the arytenoid cartilage on its own side. 

 The letters 5, 5, refer to the arytenoid cartilages, supported 

 at their base by the lateral angles of the cricoid cartilage, 



