Morphological and biophysical identification of fibrous proteins in the amniote epidermis

Epidermal material from a variety of reptilian species, avian and mammalian scales have been examined by standard histological and x‐ray diffraction techniques. It has been found that morphologic and/or tinctorial properties are not good criteria for the identification of specific fibrous protein types. The distribution of fibrous protein types in reptilian epidermal material is very variable, especially in turtles. Lepidosaurian reptiles (the tuatara, snakes and lizards) are unique in showing an alternating vertical distribution of feather and α‐type proteins over the entire body surface. The protein distribution in crocodilian scales resembles exactly that found on avian scales. Mammals only possess the α‐type protein whatever the nature of the epidermal structure of modification.