ON THE ANATOMY OF PASSERINE BIRDS. 377 
_ It may be mentioned that the second bronchial semi-ring is some- 
what expanded at its ends, intruding more into the membranous 
completion of the bronchial tube than do those which follow it. The 
damaged condition of my specimen makes it impossible to determine 
whether the antero-posterior bar, which is situated at the point of 
“bifurcation of the trachea, is formed by the last tracheal ring, or by 
the completion and junction of the first bronchial rings of either 
side. I am inclined to think it depends on the latter of these 
conditions. 
Chiromacheris manacus, according to the description given by 
Miiller, agrees exactly with this species, as far as its syrinx is con- 
Heteropelma vere-pacis.—It is Mr. Salvin whom I have to thank 
for a specimen of this species, as well as the next to be described, in 
spirit. Its voice-organ is most simple. The single, broad lateral 
muscle of each side of the trachea continues down to the middle of 
the second bronchial semi-ring, which is scarcely different from those 
below it either in bulk or appearance; and the one above it resembles 
it. There is, however, a considerable interval between it and the © 
third, whilst it almost touches the first. None of the lowermost 
tracheal rings are peculiar in any way. 
Hadrostomus aglaie is a bird in which the calibre of the lower end 
“ef the trachea is very inconsiderable, and the syrinx is correspond- 
ingly difficult to investigate. The tracheal rings are not modified, 
except the last, which is developed into a three-way piece from the Page 526. 
presence of a bar running from before backwards at the middle of the 
lower margin. The first bronchial half-ring is of the same flattened 
and deep nature as the tracheal rings, and, like them also, is not 
separated from the three-way piece by any interval. To its anterior 
end, on each side, as well as to the front of the three-way piece, the 
intrinsic muscle is attached, which descends, broad and thin, down the 
front of the lower part of the trachea, in contact with its fellow of 
the opposite side, there to terminate (vide Plate [27] LIII. fig. 8). 
The second bronchial semi-ring is not modified. It is separated 
by a short interval from the first, and by a strikingly considerable one 
from the third, which is the commencement of the normal bronchus. 
I could not find that the muscles of the syrinx sent any fibres to this 
second ring, as in Pachyrhamphus atricapillus, described by Miiller, 
although otherwise this structure is almost identical in the two birds. 
If they are present they must be extremely feeble; and the relative 
distances of the upper bronchial semi-rings favours the view that 
some special arrangement exists. 
The account, above given, of the voice-organs in the aberrant 
Passeres in question, is entirely confirmatory of the results arrived at 
