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Show 1882.] ON THE ANATOMY OF AN AUSTRALIAN DUCK. 455 6. Note on some Points in the A n a t o m y of an Australian D u c k (Biziura lobata). By W . A . F O R B E S , B.A., Prosector to the Society. [Eeceived May 16, 1882.] Two male specimens of Biziura lobata, the first the Society has received, were purchased of a dealer in February last ; both were in very weak condition when received, and, unfortunately not recovering, did not long survive. The trachea of this bird being, so far as I know, unknown, I take this opportunity of describing it, as well as of adding some notes on other points of its structure. The trachea is of nearly uniform calibre throughout, with no dilatation anywhere in its course; below it is perhaps a little narrowed as it approaches the bronchi, but in no degree laterally compressed, as it is, e. g., in such genera as Anser or Cereopsis. There is no syringeal bulla formed at its thoracic end, there being merely, as will be seen from the annexed drawing (fig. 1), a simple ossified box, Fig. 1. Lower part of the trachea of Biziura lobata. notched in front and behind, and with a narrow pessular bar below. This is formed by the few last tracheal and early bronchial rings co-ossified together, though not equally so on each side, or before and behind. The four or five preceding tracheal rings differ from those higher up the tube in being narrower and of more uniform breadth throughout, not being notched and incompletely ossified in the middle line, both before and behind, as these are. The bronchi are quite normal in structure, being non-dilated, and with partly ossified semirings of the ordinary form. In the non-development of a bulla, whether osseous or partly membranous, and in the perfectly simple character of its trachea, Biziura differs from all the forms of ordinary Ducks known to me, all the genera of these that have been as yet examined exhibiting, in the male sex, either one or other of (or, more rarely, both) these pecu- PROC. ZOOL. Soc-1882, No. XXXI. 31 |