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Show 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 elongated 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 intervening 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 considerably 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 serrator1, 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 intermediate 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 cavity2 like that in Melanitta fusca and Clangula his-trionica." 1 Vide Eyton, ' Monograph of the Anatidae,' 1838, p. 63. 2 See P. Z. S. 1868, p. 146, and 1875, p. 154. |
