1882.] ON THE ANATOMY OF AN AUSTRALIAN DUCK. 455 



6. Note on some Points in the Anatomy of an Australian 

 Duck [Biziura lobata) . By W. A. Forbes, B.A., Pro- 

 sector to the Society. 



[Received May 16, 1882.] 



Two male specimens of Biziura lobata, the first the Society has 

 received, were purchased of a dealer iii 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 dila- 

 tation anywhere in its course ; below it is perhaps a little nar- 

 rowed as it approaches the bronchi, but in no degree laterally com- 

 pressed, 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. 



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 semi- 

 rings 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 



