( 378 ) 



XV. Observations on the Trachece of Birds ; icitli Descriptions 

 and J\epresentatio)ts of several not hitherto Jigured. Bij William 

 Yarrell, Esq., F.L.S. 



Read February 6, 1827. 



The various qualities and powers of voice exhibited by birds 

 in general, and the diversity of structure known to exist in the 

 trachete or windpipes of different species in some particular 

 families, have justly excited the attention and remarks of several 

 writers. Dr. Latham, in the 4th volume of the Transactions of 

 this Society, has furnished descriptions and illustrations of the 

 peculiarities of this part in some of those species most remark- 

 able for their deviation from the common form ; and to his paper 

 I shall occasionally take the liberty to refer. 



To other sources ornithologists are indebted for delineations 

 not included in the essay before mentioned : and the present 

 communication, accompanied by drawings of several tracheœ 

 not hitherto figured, will, 1 trust, be considered an acceptable 

 addition on this interesting subject. 



The peculiarities in the form, as well as in the composition, of 

 the several parts of the windpipes of birds, having already been 

 described under the different names of the glottis, or superior 

 larynx ; the tube ; the bone of divarication, with its cross-bone 

 forming the lower end of the tube; and lastly, the bronchia, by 

 which the bone of divarication is connected with the lungs ; — I 

 shall proceed at once to the descriptions of those new forms of 

 trachea3 which are the subject of the present communication. 



The 



