Ee ee 
=— 
NN  — ———————<<— 
ON THE TRACHEA OF THE GALLINZE. 491 
below the second are peculiarly lengthy; their extremities turn in- 
wards towards one another, and so slightly intrude into the mem- 
Fig. 17. Fig. 18. 
Front view. Back view. 
Lagopus scoticus. 
branous inner wall of each bronchus. One or more of the semirings 
may be bifid at their anterior ends. The bronchidesmus is particularly 
powerful in the Tetraonide, including Lagopus, and, as it were, pulls 
the two tubes into nearer relationship than would otherwise appear to 
be their tendency. 
Lagopus mutus agrees with L. oahiche: 5 in every respect. 
Tetrao urogallus and T. tetriz conform to a type which has several 
important differences from Lagopus scoticus, although in eommon they 
have the yielding cartilaginous (and never ossified) rings throughout 
the organ under consideration, as well as the great development in 
length of the bronchial semirings beyond the second. 
In the female of Tetrao tetriz the first feature that strikes the ob- 
server is the consolidation of all the intrathoracic tracheal rings along 
the mid-posterior surface into a vertical bar, rendered more than it 
would be otherwise conspicuous by the considerable thinning of the 
lateral third or more of each ring on each side, and the consequent 
formation of lateral interannular spaces slightly deeper than the rings 
enclosing them. In the adult bird no trace of the transverse lines of 
junction between the constituent transverse annular elements of this 
vertical posterior bar can be seen; in the young bird, however, they 
