Chordate of the three subdivisions of chordates, all have distinct skulls. They include the hagfish, which have no vertebrae. Michael J. Benton commented that "craniates are characterized by their heads, just as chordates, or possibly all deuterostomes, are by their tails". Most craniates are vertebrates, in which the notochord is replaced by the vertebral column. These consist of a series of bony or cartilaginous cylindrical vertebrae, generally with neural arches that protect the spinal cord, and with projections that link the vertebrae. However hagfish have incomplete braincases and no vertebrae, and are therefore not regarded as vertebrates, but as members of
What Have You Done What Have You Done "What Have You Done" is the first single from Dutch symphonic metal and rock band Within Temptation's fourth studio album "The Heart of Everything" (2007). The song features guest vocals from Life of Agony's lead singer Mina Caputo (then known as Keith Caputo) and it was released as the album's first single in early 2007 (see 2007 in music). It became their first charting single in Canada and in the United States. A new edit and version of the song was released in the US through iTunes on 26 June 2007. There are two music videos