Summary.Unfortunately the Erismaturinæ are represented in the National Collection, in so far as skeletons are concerned, only by a single specimen each ofErismatura jamaicensisandE. vittataand a sternum ofNomonyx.This fact, and the still immature condition of the skull in the skeleton ofBiziuranow under consideration, makes any generalization as to the affinities ofBiziura, as indicated by osteological characters, a matter of difficulty. The generaErismatura, Thalassiornis, Nomonyx, andBiziurahave been placed together by Count Salvadori (Cat. Birds Brit. Mus. vol. xxvii.) in a separate subfamily—the Erismaturinæ. This he places between the Fuligulinæ on the one hand, and the Merganettinæ and Merginæ on the other.The osteological characters of these groups certainly do not seem to bear out this classification.The Erismaturinæ should be merged in the Fuligulinæ, since they are undoubtedly closely allied to the generaAythya, andFuligula, and more distantly toClangula.On the other hand, the generaTachyeres, Harelda, Histrionicus, ædemia, Heniconetta, Somateria, andErionettamight well be placed together in a separate subfamily—the Somateriinæ. They have much in common, and are quite distinct from the Fuligulinæ. It is open to question whether the Merganettinæ should be separated from the Merginæ.Biziurais primitive in some respects, in the skull for example, and highly specialized in others, as in the form of the pelvis and of the hypapophyses of the vertebræ.The remarkable gular pouch of this bird was figured and described by Forbes