ON THE TRACHEA OF THE GALLINA. 487 
just beyond it, the anterior extremity of the first bronchial semiring 
articulates by its triangularly expanded end, the lower angle of which 
is jointed with the not much specialized second semiring, which pos- 
-teriorly articulates by its somewhat expanded termination with the 
first semiring also. The hinder extremity of the first semiring fuses 
with the last tracheal, as does the posterior termination of the pes- 
sulus, to form a continuous cartilage along the back of the tube as 
high as the upper border of the antepenultimate tracheal ring. An- 
tero-laterally the annular interval between the penultimate and last 
rings is well developed, and bent downwards near the middle line on 
account of the presence of the process and notch above described. The 
interval between the last tracheal ring and the first bronchial semiring 
is very large and deep on account of the great size of the descending 
process of the former: The interval between the first and second 
semirings is ovate and slightly deeper than those which follow. The 
pessulus is narrow. 
Euplocamus prelatus, E. nychthemerus, and E. albocristatus differ 
from H. swinhoii in that anteriorly the median process from the lower 
border of the penultimate ring blends with the upper border of the 
last tracheal, as does the upper border, but by a more slender isthmus, 
with the antepenultimate. In EH. nychthemerus and E. albocristatus 
there is a further fusion of the anterior extremity of the first semiring Page 364, 
with the last tracheal at its (should be) articulating spot. 
The pessulus is broad; and the angle on each side of its posterior 
blending with the penultimate ring runs a short way into the latter so 
as to reduce its depth a little at the spot. The interannular intervals 
are the same as in EZ. swinhoti, except the one between the antepenul- 
Fig. 11. Fig. 12. 
Front view. Back view. 
Euplocamus albocristatus. 
