1878.] MR. P. L. SCLATER ON FULIGULA NATIONI. 479 



This species appears to be a true Fuliguline duck, the only known 

 representative of the group in South America. In colour it is quite 

 different from any other species of the genus known to me, being 

 immediately recognizable by its black dress and the transverse 

 white bar on the wing. 



The characteristic Fuliguline white spot between the rami of 

 the mandible is small in the male but quite distinct, larger in the 

 female. The white colour in the secondaries occupies rather more 

 than the basal two thirds, but does not extend onto the outer elon- 

 gated feathers ; it likewise pervades portions of both webs of some 

 of the inmost primaries. The hinder toe has a well-developed lobe, 

 almost as broad as in F. collaris. 



Prof. Nation has also sent to me the dried trachea of the male 

 specimen, for the preparation of a figure and description of which I 

 am indebted to Prof. Garrod. 



" In the trachea," Prof. Garrod remarks, " of this duck, as in the 

 males of the sea-ducks generally, there is a large dilatation at the lower 

 end, on the left side, composed of an osseous framework supporting 

 membranous walls. The outer one of these is traversed by an inter- 

 vening osseous bar (see fig. 2), which courses backwards and upwards 

 from its anterior inferior angle, and sends two small extra bars to the 

 supero-marginal rim, and so forms a pair of oval fontanelles, before 

 it terminates at the superior and posterior angle of the outer wall. 



" The wall of the tracheal box which faces inwards is ossified 

 through nearly its entire extent, a few small membrane-covered 

 fontanelles being found not far from its superior margin. In this 

 respect the species differs from Fuligula rufina, in which the wall 

 under consideration is almost entirely membranous, whilst it is almost 

 identical with F. marila. 



" The outer aspect of the terminal tracheal box is represented in 

 fig. 2. 



" Fig. 1 gives a front view of the trachea, which is seen to be con- 

 siderably and fusiformly dilated in its middle part, in very much the 

 same way as in Fuligula rufina, F. marila, Nyroca leucophthalma, 

 Clangula vulgaris, and Mergus serrator\ except that in the last- 

 named species the enlargement is situated somewhat nearer the 

 mouth. 



" In F. rufina the dilatation of the middle of the trachea is rather 

 more considerable and more localized to the lower portion of the 

 windpipe, whilst in F. marila it is more extended and not quite so 

 considerable in breadth. In fact F. nationi is almost exactly inter- 

 mediate between the two, tending, if at all, towards the latter 

 species. 



" In the South-American Metopiana peposaca the mid-tracheal 

 dilatation is much more decided and more limited, forming a nearly 

 globose cavity 2 like that in Melanitta fusca and Clangula his- 

 trionica." 



1 Vide Eyton, ' Monograph of the Anatidre,' 1838, p. 63. 



2 See P. Z. S. 1868, p. 146, and 1875, p. 154. 



