By invertebrates are meant the non-vertebrate creatures of the kingdom Animalia (or Metazoa+b vmbnParazoa) in the biotic domain of Eukaryota. By phyletic definition, these many-celled, sub-vertebrate animals lack a vertebral column, spinal column, vertebrae, backbone, or long, full-length notochord -- in contrast, of course, to the vertebrates in the one phylum of Chordata.