They consist of two principal parts: the axis, or spinelike central structure; and the barb, or side branch of the stem. All the barbs together form the vane or fringe. The axis consists of the barb-bearing shaft and the hollow quill, which is rooted in a small sac of the skin. They are similar in structure and origin to th
They consist of two principal parts: the axis, or spinelike central structure; and the barb, or side branch of the stem. All the barbs together form the vane or fringe. The axis consists of the barb-bearing shaft and the hollow quill, which is rooted in a small sac of the skin. They are similar in structure and origin to the scales of fish and reptiles. FTP, name these objects, which serve as sex differentiators, protect from water and cold, and aid the flight of birds.
They consist of two principal parts: the axis, or spinelike central structure; and the barb, or side branch of the stem.
{feathers}