The structure of teleost epidermis with special reference to new qualitative and quantitative data from the guppy, Poecilia reticulata Peters.

Scales from the midlateral body region of adult male guppies, Poecilia reticulata Peters, were investigated morphometrically by light and electron microscopy. The epidermis consists of one superficial layer and, in general, two basal layers of filament-containing cells and a number of mucous cells. There are scattered chemosensory cells and unmyelinated nerve fibres. Superficial cells are flattened and form apical ridges in a fingerprint-like arrangement. The volume density of mitochondria, granular endoplasmic reticulum, and numerical density of dictyosomes are higher in superficial cells than in basal cells. The superficial cells are secretorily active. Small electron dense vesicles are transported from the dictyosomes to the body surface and yield the glycocalyx material, which is not identical with the slime produced by the mucous cells.