from The Century Dictionary.
- noun In ornithology: Properly, the aftershaft; the rachis accessoria; the stem or scape of the supplementary feather which grows upon many feathers of most birds.
- noun The whole of such a supplementary feather; a hypoptilum: more frequently but less correctly used in this sense. See
hypoptilumand aftershaft. Also written hyporrhachis.
from Wiktionary, Creative Commons Attribution/Share-Alike License.
- noun ornithology The
downylower barbsof a feather.
Sorry, no etymologies found.
As a consequence of duplication and direction, the same mechanisms that produce the main vane of the feather result in the division of the posterior new barb locus into two laterally displaced new barb loci, the creation of a second rachis ridge the hyporachis, and ultimately an entire second vane growing simultaneously from a single follicle.