connected anatomical structure extraembryonic structure A multicellular anatomical structure that is associated with an embryo and derived from the zygote from which it develops, but which does not contribute to the embryo proper or to structures that are part of the same organism after embryogenesis. CARO:0000042 MH: define as not part of embryo, or will not develop into embryo? MH: changed def to exclude cells so this class could be included in gross anatomical part. DOS: Changed to something that I think works for both vertebrates and invertebrates and that keeps the restriction to multicellular structures. Old def: "Anatomical structure that is contiguous with the embryo and is comprised of portions of tissue that will not contribute to the embryo.". One remaining question - perhaps zygote is too restrictive given that some organisms have parthenogenesis e.g. aphids? multi-cell-part structure gross anatomical part multicellular anatomical structure