ON THE TRACHEA OF THE GALLINZE. 479 
-In the middle of the upper border of the penultimate ring an- 
teriorly a white line is seen sending a limb down on either side, beyond 
the ring itself, on to the next, at the lower margin of which it ceases 
at the root of the obtuse median process. Such an appearance 
indicates that in the older bird fusion of the two rings will occur at 
the spot, as an inspection of the part in the adult verifies. From the 
above description it will be also seen that the pessulus—a slender 
cylindroid bar, expanded and flattened at each end—is anteriorly 
attached to the last, and posteriorly to the penultimate ring of the Page 356. 
trachea. The last tracheal ring, it must not be forgotten, is incom- 
plete behind. 
The first bronchial semiring—for in no Gallinaceous birds are any 
of the bronchial rings complete—articulates at both its extremities 
with the last tracheal, anteriorly along the side of the oblique median 
process, posteriorly with the lower angle of its square-cut termination. 
Both ends are slightly expanded and obliquely truncated, their acute 
upper angles being their articulating spots. The lower margin of the 
last tracheal ring being concave downwards and slightly uptipped 
laterally, whilst the first bronchial semiring descends slightly from 
its attachments outwards, a considerable membranous interannular 
interval is left. The second bronchial semiring is simple, free, and 
slightly expanded posteriorly. In front the third was bifurcated in 
both bronchi, on one side each branch being further subdivided. The 
depth of the bronchial interannular membranes is about the same as 
that of the semirings themselves. 
_Between the membranous inner wall of one bronchial tube and 
the same part of the other there is a dense fibrous band of union, a 
short distance below the bifurcation of the windpipe, and generally on 
the level of the two or three semirings below the second. This band 
is, I believe, always to be found in birds (it will be termed the 
bronchidesmus in this communication) developed to a greater or less 
extent. Being of fibrous tissue and connected with the membranes of 
the neighbourhood, anatomists have removed it whilst dissecting the 
organ for examination. Its importance, however, is more considerable 
than might be at first imagined; and I only regret that in many of 
the subjoined descriptions I took no note of it. In birds like the 
Tetraonide the bronchidesmus is so strong that it cannot escape 
special observation. 
The adult female presents no modifications of importance. The 
penultimate and last tracheal rings are relatively a little smaller and 
have blended in front in the middle line, whilst all trace is lost of the 
shape of the posterior termination of the pessulus. The articulating 
surfaces of the first bronchial semiring have become slightly more 
considerable. 
