ee 5 (Sere 
ON THE TRACHEA OF CERTAIN DUCKS. 283 
the left, which is the larger and has semimembranous walls; the other 
slightly to the right, inferior in position to theformer. This latter is 
simply osseous, no fenestree being present in it; it intrudes upon the 
right: side as well as the left in front. The last 12 orso tracheal rings 
are considerably dilated and co-ossified, the two above-mentioned 
compartments being connected with the cavity formed by their fusion 
through a single left-sided orifice, the left bronchus springing from 
the membraniform cavity. 
The cxca are not quite equal in size, being 23 and 1? inches long; 
the whole intestine measured 4 feet. 
3. Meroprana Peposaca (Vieill.): Sclater, Rev. Cat. Vert. p. 255. 
Of this bird Mr. Sclater mentions* that “it has a large bulbous 
expansion in the windpipe.” This I have found in all the male 
specimens which I have examined. Its distance above the bifurcation 
of the bronchi is best estimated from the accompanying sketch (fig. 6, 
p- 282) which is of the natural size. A similar tracheal dilatation is 
to be observed in the male of Melanitta fusca, that in Clangula his- 
trionica being much less considerable. In a male, purchased on the 
6th of July, 1870, which died on the 7th of January last, the syringeal 
Fig. 7. 
a lel 
Lower part of trachea of Metopiana peposaca ¢ (side view). 
* “ Proceedings of the Zoological Society,” 1868, p. 146. 
