Hypocephalus was a disk of bronze or painted linen found under the heads of Greco-Roman mummies found in Egypt. It was inscribed with magical formulas and divine figures, and its objective was probably to secure warmth for the corpse. There is frequently depicted upon such amulets a scene showing cynocephalus apes adoring the solar disk seated in his boat. A.G.H.
Spence, Lewis, An Encyclopedia of Occultism, New York, Carol Publishing Group Edition, 1996, p. 222