Cassoioary of' New Holland. 137 
glottis, and compressing the chest. On doing this, and calling 
into action the abdominal muscles, the air must of necessity be 
forcibly driven into the bag of the trachea ; and may, by retain- 
ing the glottis shut, be alternately circulated between the lungs, 
air-cells, and bag of the trachea, giving the bird an additional 
advantage in running. It may not be altogether uninteresting 
to add, that the contents of the stomach shewed that these birds 
had been chiefly fed on animal fat, 
Edinburgh, } 
April 1823. I 
Art. XXII . — Additional Observations on the Structure of the 
Trachea in the Cassowary Emeu qf New Holland. By Dr 
Knox, 
In the preceding paper, I have detailed, at considerable length, 
the peculiarities in the internal structure of the Cassowary of New 
Holland, and of the Indian Emeu or Cassowary, describing, at 
the same time, though somewhat briefly, a very remarkable ap- 
pendage of the trachea in the former bird, which had escaped 
the notice of preceding comparative anatomists. Since that time, 
frequent inquiries have been made, in relation to this peculiar 
structure ; more particularly as to its nature, supposed, functions 
and importance ; but chiefly as to its analogies with the append- 
ages found in the tracheae of several other birds, of the duck and 
merganser kind. Now, these inquiries convinced me, that the 
subject had been viewed verj^ incorrectly, even by those who 
were good anatomists, but who had not themselves examined the 
anatomy of the windpipe of birds, and had merely read accounts 
of the appendages sometimes connected with them ; and this is 
the excuse I offer, for again recurring to this subject. I shall 
now briefly point out (what ought to have been done formerly) 
the total dissemblance between the appendage of the trachea in 
the Cassowary of New Holland, and those found in any other 
animal. 
With a view to be better understood by those gentlemen who 
are not quite conversant with anatomical subjects, I shall re- 
fer to specimens of the trachea of the peacock, singing swan 
