Rachis Rachis Rachis is a biological term for a main axis or "shaft" (from the Greek "ράχις, backbone, spine"). In vertebrates a "rachis" can refer to the series of articulated vertebrae, which encase the spinal cord. In this case the "rachis" usually forms the supporting axis of the body and is then called the spine or vertebral column. "Rachis" can also mean the central shaft of pennaceous feathers. In the gonad of the invertebrate nematode "C. elegans", a "rachis" is the central cell-free core or axis of the gonadal arm of both adult males and hermaphrodites where the germ cells have
What Bird is That? of "What Bird is That?" It was published in 1984 and incorporated all of Cayley’s paintings created over many years for his vision of releasing a “big bird book” and included a revised taxonomy. In the 53 years since its first edition, more than a hundred new bird species had been identified in Australia. Scientific names had been changed and groups of birds had been reordered. Lindsey brought "What Bird is That?" up-to-date with the latest birding conventions of the time, as well as contributing a valuable supplementary list of birds and a scholarly catalogue of Cayley’s paintings. The "Signature