Page 378. 
Page 379. 
502 ON THE TRACHEA OF THE GALLINA. 
same direction, only the antero-lateral parts persisting as rudiments, 
not seen, therefore, in the back view of the organ. A short distance 
above the level of the apex of the anterior triangular cartilage, and 
some way below the first fairly normal tracheal ring, is a continuous 
filamentous transverse cartilage, with little extra pieces connected to 
it—incomplete in the middle line behind, supported by the mem- 
branous walls of the windpipe. This is evidently the atrophied fourth 
ring, counting from below. Above this an abrupt change occurs; 
the rings attain their ordinary depth, with only linear intervals 
between them. The fifth ring, again counting upwards, differs from 
those above it in being slightly incomplete behind, with downturned 
ends. The interval between it and the fourth is about equal to its 
own depth. It in front, and its superior two or three neighbours 
behind as well, is slightly V-shaped in the middle line*. 
The Cracide are particularly uniform in the manner in which the 
trachea bifurcates. In Mituwa tuberosa there are no tracheal inter- 
annular intervals of any kind. The pessulus is united with the pen- 
ultimate ring posteriorly and with the last ring in front, the latter 
ring being therefore incomplete behind, as in all the birds above 
described. Mid-anterior and posterior ossifications extend upwards 
from the attachment of the pessulus, generally sufficiently high to 
involve the four lowermost rings, which are therefore consolidated 
together in the median lines. The lower lateral borders of the last 
tracheal ring are slightly concave downwards; the medio-anterior 
descending process being small, whilst by its slightly truncated 
triangular apex it forms a small portion of the actual margin of the 
bifurcation. On account of the eonsiderable length of the slender 
first bronchial semiring, which is very concave upwards, the interval 
between it and the last tracheal ring is conspicuously large and fusi- 
form, one side of the small antero-median process and the outer border 
of the inferior angle of the corresponding truncated posterior termina- 
tion of the last tracheal ring being its articulating spots. The semi- 
ring is not of uniform thickness, small expansions, not unlike the 
‘“‘tubercles”’ of ribs, occurring at a short distance from both ends, 
which mark the points at whieh the next semiring meets it and 
ceases. The second semiring is simple, except that it is slightly 
enlarged at its posterior extremity. The interval between it and its 
neighbours is extremely narrow. 
The species I have examined are Craw globicera, C. carunculata, 
Pauaxis galeata, Mitua tomentosa, Penelope jacucaca, P. cristata, P. 
superciliaris, Pipile cwmanensis, and Aburria carunculata. In Penelope, 
* By Temminck (loc. cit., pl. ii. fig. 4) a different figure of the windpipe of 
G. bankiva is given. 
