from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. The downy lower barbs of a feather.
from The Century Dictionary and Cyclopedia
- n. In ornithology: Properly, the aftershaft; the rachis accessoria; the stem or scape of the supplementary feather which grows upon many feathers of most birds.
- n. The whole of such a supplementary feather; a hypoptilum: more frequently but less correctly used in this sense. See hypoptilum and aftershaft. Also written hyporrhachis.
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.