Toothed whale porpoise as a fish. Toothed whales, as well as baleen whales, are descendants of land-dwelling mammals of the artiodactyl order (even-toed ungulates). They are closely related to the hippopotamus, sharing a common ancestor that lived around 54 million years ago (mya). The primitive cetaceans, or archaeocetes, first took to the sea approximately 49 mya and became fully aquatic by 5–10 million years later. The adaptation of echolocation and enhanced fat synthesis in blubber occurred when toothed whales split apart from baleen whales, and distinguishes modern toothed whales from fully aquatic archaeocetes. This happened around 34 mya. Unlike toothed whales, baleen
Two Forms (Divided Circle) fire at her studio in St Ives in 1975. It includes two vertical bronze semi-circles forming a broken circle approximately across, each pieced pierced by one large hole. Both elements are welded to a bronze base. All three elements are hollow, and were cast in London by Morris Singer. Hepworth designed the work after being diagnosed with cancer in 1966. She wanted the viewer's body to be engaged with her work, saying: "You can climb through the Divided Circle – you don't need to do it physically to experience it." Hepworth also made a series of nine maquettes about tall,