Page 369. 
Page 370. 
492 _ ON THE TRACHEA OF THE GALLINZE. 
are conspicuous. Anteriorly the rings above the antepenultimate are 
separated by an interval which slightly reduces the lowest of them, 
and that only, towards the middle life. There is a median semifusion 
in front, of considerable breadth, between the antepenultimate and 
penultimate rings, below which a broad cordiform cartilage represents 
the fused mid-anterior elements of the penultimate and last rings, with 
which the anterior extremity of the first bronchial ring is blended, 
and the second articulates, in such a way as to form lateral extensions 
of its apex. The line constituting the actual angle between the con- 
tiguous sides of the bronchi—produced, as just indicated, by the apex 
of the cordiform cartilage, together with the inferior margins of the 
lateral expansions, composed of the anterior ends of the first and 
second bronchial semirings—is less concave downwards than in Lago- 
pus (in fact almost straight), and much less so than in the other 
Gallinew. It has, in Tetrao, a very, slight descending protrusion in the 
actual centre—the apex of the cordiform cartilage. Posteriorly each 
free end of the last tracheal ring expands and sends downwards and 
outwards a small process for the articulation and fusion with the 
similarly enlarged extremity of the first bronchial semiring. Upwards 
it blends with the base of the vertical posterior cartilage, which is 
considerably broader opposite the lowermost three tracheal rings than 
higher up. Into the middle of its base the narrow pessulus is seen to 
run. There is a great similarity between the depth and shape of all 
the interannular intervals in the bifurcating portion of the tube, the 
comparatively great depth of the intervals between the lateral parts of 
the last tracheal and the first bronchial semiring, observed in Thau- 
malea for instance, not being seen. The first and second bronchial 
semi-rings themselves, agreeing as they do with those of Lagopus in 
all respects, are of the same thickness as their neighbours both above 
and below—the result being simplicity of construction a little more 
apparent than real. Many of the bronchial semirings are bifid at their 
anterior extremities. 
In the male of Tetrao tetrix the trachea is most extraordinary. At 
first sight the deeply situated intrathoracic part appears to have no 
similarity with that of the female, there being developed, on each side, 
an immense irregular tumefaction, communicating with its fellow by 
means of a bridge of fatty tissue which covers the anterior portions of 
the lowermost tracheal rings. When preserved in spirit this tumefac- 
tion shrinks to a comparatively small size, to swell to its original 
bulk upon its immersion in water. This leads me to suppose that it 
is composed of “‘ mucous”’ tissue, like that of the umbilical cord, which 
it resembles in consistence. The ‘‘mucous” tissue in this case is 
entirely developed between the external fibrous covering of the wind- 
pipe and the middle ring-carrying layer, the rings themselves not 
