ON THE ANATOMY OF PASSERINE BIRDS. 361 
wished to know the nature of the syrinx of that bird, of which 
Sundevall*, in 1872, remarks, “ musculi laryngis inferioris ignoti.” 
Through the kind permission of Dr. Giinther I have had the Page 513. 
opportunity of dissecting two specimens of each of two species of 
the genus Pitta, namely P. cyanura and P. angolensis, from the 
National Collection; and Mr. Sharpe had previously very liberally 
given me a specimen of the Javan species, the dissection of which 
had led me in my paper “On the Carotid Arteries of Birds” to 
remove it from the Oscines,f as Cabanis had done from its wing- 
characters. Two specimens of Pitta angolensis from Fantee, and 
three of P. cyanura from Java, have therefore formed the material 
_ for the present description. 
In Pitta angolensis the unmodified trachea terminates thoracically 
in a ring, split behind, and deep in front; which, from the fact that it 
presents irregularly placed fenestre on its anterior surface, arranged 
in a somewhat transversely linear manner, appears to have been 
formed by the fusion of two rings. This terminal segment of the 
trachea does not, as in the Oscines and several other Passeres, form a 
three-way piece, because there is no antero-posterior bar traversing 
its inferior margin in the middle line. Of this, however, there is an 
indication in the form of a median backward-directed process, whiclt 
advances a short distance into the inferior membraniform completion 
_ of the tube, from its anterior border. The tracheal ring last but one 
is complete, and has a slight median indentation in its inferior margin 
behind. These points are seen in Plate [26] LIII. figs. 1, 2, and 3. 
The first and second bronchial ring-segments are semirings—not 
modified into the somewhat separate, round-margined, slightly oblique 
semicircles of fibro-cartilage or bone which, as usual, are found nearer 
the lungs, but are like moieties of true tracheal rings, approximate, 
sharp-edged, and at right angles to the axis of the tube. They 
present no peculiar processes, and are slightly swollen at their 
anterior extremities. 
There is only a single pair of bronchial muscles, continued down 
from the sides of the windpipe; insignificant in size; quite lateral, 
and terminating by being inserted into the middle of the outer surface 
of the second bronchial semiring. 
Pitta cyanura differs from P. angolensis only in detail, not in plan 
of conformation. There are four instead of two syringeal bronchial 
semirings, to the middle of the last-of which the single extremely 
feeble lateral muscle is attached on each side. In it also the last two 
tracheal rings, and not the last only, are incomplete behind, the last 
* “ Method. nat. Av. disp. Tentamen,” 1872, p. 5. 
+ “ Proceedings of the Zoological Society,” 1873, p. 463. (Supra, p. 167.) 
