They believe that bulls belong to Epaphus,Epaphus is the Greek form of Apis or Hapi, the bull-god of Mit Rahina [31.25,29.85] (inhabited place), Giza, Upper Egypt, Egypt, AfricaMemphis; for bulls cf. Mair's Oppian (L.C.L.) Cyn. II. 86, note. and for this reason scrutinize them as follows; if they see even one black hair on them, the bull is considered impure.

One of the priests, appointed to the task, examines the beast, making it stand and lie, and drawing out its tongue, to determine whether it is clean of the stated signs which I shall indicate hereafter.Hdt. 3.28 He looks also to the hairs of the tail, to see if they grow naturally.

If it is clean in all these respects, the priest marks it by wrapping papyrus around the horns, then smears it with sealing-earth and stamps it with his ring; and after this they lead the bull away. But the penalty is death for sacrificing a bull that the priest has not marked. Such is the manner of approving the beast; I will now describe how it is sacrificed.