pennaceous

1.Pennaceous feathers cover the bodies of birds, and their tightly closed vanes create the aerodynamic surfaces of the wings and tail.

羽覆盖鸟身体，这些紧紧靠拢羽片，为翅膀与尾部塑造出符合空气动身体表面。

2.In a pennaceous feather, the barbs grow helically around the tubular feather germ and fuse on one side to form the rachis.Simultaneously, new barb ridges form on the other side of the tube.

在羽上，羽枝以绕著管状羽芽生长，在管子一侧接合在一起成羽轴，同时在管子另一侧成新羽枝脊。