Page 629. 
450 ON THE TRACHEZ 
an inch long and arrow-head shaped. The sub-equilobed liver has a 
gall-bladder. 
In Vanellus cayennensis there is an exaggerated development of 
the intrinsic muscles of the trachea a short way above its bifurcation 
in both sexes that is quite worthy of special note, because the amount 
of muscular fibre there present is proportionately as much as in any 
bird with which I am acquainted. 
There is nothing peculiar about the windpipe itself or the bronchi, 
which are represented in the accompanying figure (p. 451). The 
uppermost two bronchial semirings are not like those which succeed 
them, but are like halves of tracheal rings. The third and fourth 
semirings are closely united, whilst those which follow are not modified 
in any way. : 
The sterno-tracheal muscles are powerful, and besides springing 
directly from the side walls of the windpipe opposite the spot where 
they run off, their upper fibres are continuous up the trachea itself in 
front of and in contact with the intrinsic muscles. These latter, one 
on each side as usual, meet in the posterior middle line of the trachea, 
but are not unusually near in front; they are of considerable size 
throughout. Near their lower ends they increase immensely in bulk 
to form, combined posteriorly, a large subglobose mass which is 
situated opposite the twenty-four lowermost rings of the trachea, 
which are considerably shallower than those above them and conse- 
quently occupy a much less space than if they were of the same depth, 
as is the case in Tantalus loculator. There is a consolidation of the 
last few rings in adult birds, with which the first two bronchial semi- 
rings fuse to form a compound three-way piece, and it is to the lower 
elements of this that the powerful lateral muscles are attached (as 
well as to the third and fourth bronchial semirings slightly) by a 
broad fibro-tendinous continuation of their muscular substance, which 
fixes itself on each side along nearly the whole length ‘of the semirings, 
especially the second, of which the extremities are alone free. 
So far as I can find out by watching the living birds, there is 
nothing peculiar in their note to lead one to surmise so large a mus- 
cular supply for their lower larynx. They make a powerful screech, 
with no modulation in it; and it can hardly be possible that the extra 
muscular development has not some other function to perform. What 
that may be it is not easy to surmise. 
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