454 MR. p. L. SCLATER ON AN AUSTRALIAN DUCK. [May 16, 



1879 (on Sept. 24, Oct. ]0, Oct. 11, Oct. 20, and Nov. 17, and one 

 in 1880, Jan. 30); singularly enough, all these ondissection turned 

 out to be males. The skin of one of them only was in sufficiently 

 good condition to be worth preservation. I now exhibit it, and a 

 drawing (Plate XXXIII.) taken from it by Mr. Smit. 



I also exhibit the trachea of four of these individuals, showing a 

 distinct bulla ossea, as is usual in the males of the Anatid8e\ 



Having been in error myself as to my first identification of these 

 Ducks, I fear I have also led Prof. Newton into an error upon the 

 same subject. 



In January 1871 I furnished Prof. Newton with what I believed 

 to be specimens (in the flesh) of a male and female A?ias enstanea 

 that had recently died in the Society's Gardens ". Prof. Newton, 

 trusting to Mr. Baker's determination that the presumed female was 

 really of that sex, read a paper upon these birds before this Society 

 in November of that year, in which he pointed out that the presumed 

 female possessed the extraordinary peculiarity of having a iw/Za ossea, 

 hitherto only known to occur in the male sex of the Anatidae, and 

 proposed in consequence the new generic term Virago for Anas 

 castanea^. But Prof. Newton having been kind enough to send me 

 up the skins of this presumed pair of birds for examination, 1 think I 

 may say that there is little doubt that Mr. Baker niust have made 

 an error in his determination of the sex of the supposed female, and 

 that that bird is in all probability a male of Anas gibberifrons. 



This hypothesis is rendered more probable by the existence of the 

 marked difference in the sternum between tlie two birds which Prof. 

 Newton has pointed out, and by the fact that Mr. Ramsay tells us 

 (Proc. Linn. Soc. N. S. W. iii. p. 154) that he has examined six 

 females of Anas castanea without finding any trace of the bulla ossea. 

 I fear therefore that the proposed generic term " Firago" will not 

 stand. 



I have not ascertained female specimens of Anas casfanea, and 

 cannot, therefore, say how that sex differs in plumage from^. gibbe- 

 rifrons. But it will be at once seen on comparison that there is a 

 considerable difference in the bills of the two species, that of A. 

 castanea being considerably longer and larger than that of A. gibbe- 

 rifrons, and that the presumed female ot A. castanea (the type of 

 Virago') agrees in this respect as well as in every other point with 

 the male oi A. gibberifrons. 



^ The trachea is very similar to that figured by Prof. Newton, P. Z. S. 1871, 

 p. 650, fig. 4. 



^ The male was purchased Juue 15, 1S70, and died Jan. 9, 1871 ; the 

 presumed female arrived Mav 11, 1S65, and died Jan. 7, 1871. 



^ See P. Z. S. 1871, p. 65U. 



