396 ME. W. p. PTCEAri ON THE 



Notes on a Skeleton of the Musk-Duck, Biziura lobata, with 

 Special Eeference to Skeletal Characters evolyed in relation 

 to the Diving Habits of this Bird. By W. P. Pyceaft^ 

 A.L.S., P.Z.S. 



[Eead 15th June, 1905.] 



(Plate 39.) 



The following notes on the skeleton of a Musk-Duck {Biziura 

 lolata), kindly submitted to me for examination by Prof. C. 

 Stewart, F.E.S., of the Eoyal College of Surgeons, will, it is 

 hoped, prove of some service, since no similar description has 

 hitherto been published, although several short incidental 

 references are to be found scattered here and there among the 

 papers of Beddard and others. 



The Musk-Duck {Biziura lolata) is a native of Australia and 

 Tasmania, and appears to frequent indifferently large lakes, as 

 well as the open sea. An expert diver, it seldom, if ever, it is 

 said, flies in the daytime, though it will do so at night. The 

 Musk-Duck is generally regarded as the close ally of the genera 

 Thalassiomis, Nomonyx, and Erisonatura — making 10 species in 

 all — mainly on account of the fact that all are remarkable for 

 the peculiar structure of the tail-feathers, which are long and 

 stiff", hence they are known as " stiff -tailed " ducks. The nearest 

 allies of this small group appear to be the Scaups and Pochards. 

 Of the Stiff'-tailed Ducks — the Erismaturinse of Count 

 Salvadori — Biziura is to be regarded as the most bighly 

 specialized member, adaptation tending to increase the diving 

 powers of this bird, having effected several noteworthy changes 

 in the skeleton. 



The Skull. 



This, in the specimen submitted to me, was not fully anchy- 

 losed, all the cranial sutures are obliterated, but the elements of 

 the Upper jaw remain distinct ; and these display one or two 

 features demanding notice. 



The nasal is a somewhat remarkable T-shaped bone. The 

 frontal process is very long, and extends backwards as far as the 

 middle of the orbit as a spatulate plate ; the premaxillary process 

 is rod-shaped, and extends forwards as far as, and beneath, the 



