139 
Cassowary of New Holland. 
form the very important function, of enabling the bird to swim, 
and so preserve life amidst the extensive marshes composing 
central New Holland, and to escape also from those sudden in- 
undations to which Australasia is generally exposed. It is to be 
hoped, that the observations of naturalists will soon decide on 
the correctness of this theory. In the mean time, we may re- 
mark, that the muscular bag of the trachea may be extremely 
useful to the bird in running, altogether independent of the 
function I have assigned to it ; for it is evident, that, by its means, 
and the precaution of shutting the glottis, the bird will be ena- 
bled to cause the air of one inspiration to pass and repass the 
lungs, without being necessitated to allow it to escape, in order 
again to perform the act of inspiration. 
It is now, I think, made evident, that the appendage of the tra- 
chea in the Cassowary of New Holland has not the most distant 
resemblance to those found in other birds ; and that in thus dif- 
fering so singularly and mysteriously from the analogous struc- 
ture of birds of the Old and New Continent, it fully confirms 
the opinions of some naturalists, that the living productions of 
Australasia will, when properly examined, be found to present 
peculiarities altogether wonderful, and perhaps yet, for a long 
period, quite inexplicable. 
Explanation o /* Plate IV. 
Fig. 1. Represents the windpipe of the Indian or Galeated 
Cassowary, reduced to gth of its natural size, 
a, marks the tongue, 
5, the cornua of the os hyoides, 
c, the trachea, which is quite simple in this bird. 
Fig. 2, The trachea of the New Holland Cassowary or Emeu, 
reduced to Jth of its natural size. 
The letters «, and c, refer to the same parts in 
all the figures ; d marks the singular muscular bag 
appended to the trachea, and which seems peculiar 
to this bird. 
Fig. 3. Represents the windpipe of the Golden-eyed DucTc, re- - 
duced to ^th of its natural size. 
