Observations on the structure of vibrissa follicles in the marsupial Trichosurus vulpecula, with special reference to Keratinization

Abstract

The structure of active and resting vibrissa follicles from adult brush-tailed possums, T. vulpecula, has been examined with the light and the electron microscope. Particular attention is given to the structural changes which occur during keratinization of the vibrissa and hardening of the inner root sheath, and these changes are compared with those of pelage follicles in eutherian mammals. Keratinization in the various follicle layers is similar in these two follicle types. However, the stages of keratinization in vibrissa follicles are better defined than they are in the smaller pelage follicles of other species. A transition phase of hardening has been observed in the inner root sheath cells of vibrissa follicles. This phase appears to be very short-lived and has not been previously described in other follicles.