Mr. YaAnnELL on the Organs of Voice in Birds. 309 
of the lower portion of the trachea of a Condor Vulture without 
muscles or any true bone of divarication, the bronchial rings 
almost completing the circle, with little flexibility, and the voice 
of the.bird monotonous. The want of muscles of voice will be 
more immediately apparent by comparing this representation 
with those of Tas. XVIII. all of which exhibit various mus- 
cles attached. The Spoonbill is another instance of a bird 
without any true muscles of voice. Tan. XIX. is a representa- 
tion of part of the inside of this bird with the convolutions of its 
singular trachea in situ: the insertion of the bronchiz into the 
lobes of the lungs is shown, but no ossification at their junction 
with the tube of the trachea will be observed, nor any muscles 
by which variations in the length of the trachea or bronchiz can 
be effected. "The convolutions of the trachea of the Spoonbill 
have been described, but I am not aware that they have been 
figured. 
The next division, or those birds possessing one pair of mus- 
cles of voice, is by far the most numerous, including as it dan 
the genera Falco and Striv, some of the Insessores, all : 
Rasores, Grallatores, and Natatores, with a few exceptions 
only, which will be pointed out. I refer particularly to the ` 
British species of these different orders, as it is with them I am 
best acquainted. 
The single pair of muscles with which these idi are pro- 
vided, arise from the whole outer surface of the cricoid carti- 
lage ; Eee a they form a sheath round the upper ] art of 
st panoan ih nts end side, uniformly atta | 
and not quitting it till arrived at or near Fie Rens oF divarica- 
tion; when, separating from the tube, they pass outwards and 
downwards in distinct slips on each side to be inserted upon ae 
each inner lateral edge of the sternum. "This P "t 
