[Possible extraepithelial precursors of Merkel cells in the sinus hairs in the cat].

Numerous Merkel cells are situated among the epithelial cells of the hair follicle of sinus hairs. Many of them are in contact with sensitive nerve terminals and differ from the epithelial cells by the presence in the cytoplasm of specific granules concentrated in the region of contact with nerve terminals. In the connective tissue of sinus hairs of 8-9 weeks old embryos and newborn kittens there were found the cells surrounded by the basal membrane and differing from the Schwann's cells of palisade system and flesh nerve fibers. These extraepithelial cells have common structural features with the Merkel cells situated in the epithelium and are the most probable candidates for the role of their precursors.