Modius
A dry measure unit of grain (approx. 6.7 kg.) symbolizing the fertility and bounty of the earth. Worn as a headdress by Sarapis to symbolize his association with Hades and the underworld. Some coins depict Persephone, daughter of Zeus and Demeter, spouse to Hades on the side of the modius.
Milne 1558 Hadrian
Curtis(1990) p. 188 coin 75