Avian scale development. IV. Ultrastructure of the anterior shank skin of the scaleless mutant

Scales do not form on the legs and feet of the scaleless mutant chicken, and consequently, the skin in these regions remains soft and pliable, similar to that covering the rest of the body. By 17 days of embryonic development, both the peridermal and subperidermal cell layers have developed along the surface of the anterior shank epidermis. Subsequently, the scaleless epidermis cornifies, producing an alpha stratum characteristic of the inner epidermal surface of normal scales. The cells of the alpha stratum elaborate lipid droplets, multigranular bodies, and peripherally located keratohyalin granules. The beta stratum found along the outer epidermal surface of normal scales never develops.