Avian feather morphogenesis: Fibronectin‐containing anchor filaments

During feather morphogenesis anchor filaments, continuous with the basement membrane, extend deep into the dermis. We find that these anchor filaments give intense fluorescence with antifibronectin (FN) antibody, using indirect immunofluorescence and immunoelectron microscopic techniques. These filaments are abundant in the dermis of the developing feather germ, yet are not present in the dermis beneath the epidermis of the elevated feather primordia. We suggest that these FN‐containing anchor filaments function in establishing the epidermal placodes of feathers and/or the organization of the feather dermis.