The four deities who were associated with the protection of the internal organs removed during the embalming procedure and placed in canopic jars or packages. They were originally represented as human figures, but by the New Kingdom, three of them had acquired animal heads. Imsety, in human form, protected the liver; Hapy, with a baboon head, guarded the lungs; Duamutef, with a jackal head, safeguarded the stomach; and Qebehsenuef, with a hawk head, watched over the intestines. The gods appear as heads on canopic jars and on amulets placed on the mummy.
See also Religion.
Historical Dictionary Of Ancient Egypt by Morris L. Bierbrier
Ancient Egypt. A Reference Guide. EdwART. 2011.