Kagu close relationship between the kagu and sunbittern. The kagu and sunbittern, and possibly the adzebills, seem to form a distinct Gondwanan lineage of birds, possibly one order, possibly more, though the relationships between them and groups previously considered related, such as the mesites and the "core Gruiformes," are not yet resolved. It is notable, however, that the sunbittern and the mesites possess powder down too, whereas the "core Gruiformes" do not. While the kagu is the only living species in the clade Rhynochetidae, a larger species, the lowland kagu ("Rhynochetos orarius"), has been described from Holocene subfossil remains. The measurements
What is a Masterpiece? confluence of memories and emotions forming a single idea", that it has "a power of recreating traditional forms so that they become expressive of an artist's own epoch and yet keep a relationship to the past". The highest masterpieces are said to be "illustrations of great themes." Clark also implicitly excluded the erotic from considerations of what constituted a masterpiece, based on his perspective that a necessary condition is the balance between sense and form (works that are too sensual are, therefore, unbalanced and not to be categorised at masterpiece level). What is a Masterpiece? What is a Masterpiece? is