A longitudinal, oblique or transverse depression in the cephalic epidermis, sometimes very deep, lined by a ciliated epithelium which normally lacks gland cells; the furrows are paired and their distribution on the head may be of taxonomic importance; typically, although not always, the cerebral sensory organs open into the furrows.

Alternative forms for cephalic furrow : cephalic furrows, cephalic groove, cephalic grooves, cephalic slit, cephalic slits, slits.