The free nerve endings in fish epidermis

Electron micrographs are presented to show the appearance of nerve fibres in the epidermis of teleost fish, most of which are believed to come to free endings. Nerve fibres are wrapped for part of their course in the borders of epithelial cells. There is little morphological change in the nerves as they run in the epidermis, but their fibrillar structure becomes less organized as the end is approached. Many of the nerve fibres are varicose, with mitochondria accumulated in the varicosities. Many fibres contain vesicles, and some contain bodies with an electron‐dense core. Nerve fibres have not been seen to reach to the surface of the epithelium, although they may reach to within half a micrometre of the surface in some places. Most of the superficial nerve fibres run between or below the outer layer of epithelial cells.