Abstract
Tylotrich follicles are present in the skin of the marsupial, the American opossum (Didelphis virginiana). Their morphology, ancillary structures, time of development, size and distribution of epidermal pads, are similar to tylotrich follicles found in eutherian mammals. The presence of tylotrich follicles in the marsupial suggests that they arose early in the evolution of mammalian skin.