ON THE TRACHEA OF THE GALLIN2. 495 
to form the considerable three-way piece, which is triangular in front, 
apex downwards, and horizontally oblong behind. Of the anterior 
Fig. 23. 
Baek view. 
Perdizx cinerea. 
triangle, which is ossified, the two sides are formed by the last ring, 
whilst the penultimate ring constitutes the base, the intervening 
interval being filled up with a thin cartilage. The apex of the triangle 
is continued downwards in cartilage, this latter being deeply notched 
in the middle line, at the same time that the anterior extremities of 
the first and second slender and upward-arched bronchial semirings Page 372. 
blend with it laterally. Laterally, the separation between the last and 
penultimate rings is feebly indicated, as it is posteriorly by the non- 
ossification of the latter, notwithstanding the blending of the two. 
Posteriorly the oblong ossified cartilage, with its unossified and 
slightly indented upper margin (the part formed by the penultimate 
ring), is joined by the slender pessulus in the middle of its lower edge, 
whilst it is with its lower extreme angles that the simple posterior 
extremities of the first bronchial half-rings blend, the same parts of 
the second semirings not participating in the fusion, and being 
almost if not quite free, as are those below it at both ends. All the 
upper bronchial semirings are slender, strongly convex upwards, and 
separated by intervals not greater than their depth. The interval 
between the last tracheal ring and the first semiring, to which it is 
united both in front and behind, is fairly deep and crescentic. The 
antepenultimate ring is very much slenderer than the one below it, 
from which it is separated by a large interannular interval, deeper in 
front than behind on account of the obliquity of its plane. Anteriorly 
it is very shallow and insignificant; and it gradually enlarges as it 
goes backwards. The ring above itis scarcely different, but slightly 
less oblique, the interannular interval between it and the fifth from 
