Pennaceous feathers are also known as contour feathers. This type of feather is present in most modern birds, and has been shown in some species of maniraptoran dinosaurs. Pennaceous feathers have a central shaft (or rachis) with vanes spreading to either side. These vanes are composed of a high number of flattened barbs, that are connected to one another with barbules. The barbules are tiny strands that criss-cross on the flattened side s of the barbs. This forms a kind of miniature velcro-like mesh that holds all the barbs together, stabilizing the vanes. Flight feathers (remiges and rectrices) are specialized types of pennaceous feathers, adapted for high loadings and often strongly asymmetric for improved flight performance[WP]. [ http://en.wikipedia.org/wiki/Pennaceous_feather ]