Page 371, 
494 ON THE TRACHEA OF THE GALLINA. 
only in a few details. All the rings and semirings are thinner, and the 
interannular intervals greater. The posterior vertical bar is undis- 
tinguishable. Anteriorly, however, the lowermost seven tracheal rings 
are not thinned in the middle line, where they, above the penultimate, 
articulate above and below to form what becomes almost an anterior 
vertical bar as well. The corresponding parts of the penultimate and 
last rings, considerably narrower than in 7’ tetriz, expand and con- 
solidate into an elongate lozenge, with a much shorter one above it, 
from the lateral angles of which the rings are continued, and from the 
inferior angle of the lower of which the articulating (and subsequently 
fusing) surfaces for the anterior ends of the first bronchial rings arise. 
The second semiring also articulates with the first, as in the allied 
birds, with, however, a considerably larger interannular interval than 
in T. tetriz. The lateral parts of the first semiring being markedly 
convex upwards, at the same time that the curved last tracheal ring 
sends down rather lengthy processes from its posterior extremities as 
well as the deep lozenge-shaped cartilage in front, the interval between 
_the two agrees with the section of a plano-concave lens. Some of the 
bronchial semirings are bifid at their extremities: and the bronchi- 
desmus is very strong. 
Tetrao cupido is intermediate in its tracheal bifurcation between 
Lagopus scoticus together with L. mutus on the one hand, and Tetrao 
urogallus with T. tetriz on the other. Its cartilages are considerably 
less yielding than those of either genus; and the lower tracheal rings, 
instead of fusing behind to form a continuous longitudinal bar sup- 
porting the remaining parts of the rings upon each side, remain sepa- 
rate, in close contact, for the posterior half of their circumference. 
The pessulus interpolates its considerable cuneate posterior end as 
high as the antepenultimate ring, which it splits up. The lowermost 
nineteen tracheal rings are considerably thinned in front, the upper- 
most being least so. Of these, the antepenultimate ring, as well as 
the one above it, give indications of being bent downwards in the 
middle line in front. This angulation is more marked in the penulti- 
mate ring, and most so in the last ring, where a mid-anterior rhombic 
cartilage exists, of exactly the same shape as in Lagopus scoticus. The 
first and second bronchial semirings agree precisely with those of the 
last-named species, convexly upwards as they are curved; and, as in 
all the species of Lagopus and Tetrao, the bronchidesmus is strong, at 
the same time that the bronchial semirings almost completely encircle 
the tubes, leaving a very narrow membranous unsupported wall. The 
bronchial tubes are comparatively lengthy. 
In Perdiz cinerea the intrathoracic portion of the trachea is quite 
different from the same in Caccabis or any of the birds above described. 
The last and penultimate tracheal rings are much developed, and blend 
