The Grææ, who acted as servants to their sisters the Gorgons, were also three in number; their names were Pephredo, Enyo, and Dino. In their original conception they were merely personifications of kindly and venerable old age, possessing all its benevolent attributes without its natural infirmities.
They were old and gray from their birth, and so they ever remained. In later times, however, they came to be regarded as misshapen females, decrepid, and hideously ugly, having only one eye, one tooth, and one gray wig between them, which they lent to each other, when one of them wished to appear before the world. When Perseus entered upon his expedition to slay the Medusa, he repaired to the abode of the Grææ, in the far west, to inquire the way to the Gorgons, and on their refusing to give any information, he deprived them of their one eye, tooth, and wig, and did not restore them until he received the necessary directions.
From: Berens, E.M. The Myths and Legends of Ancient Greece and Rome. New York: Maynard, Merril, & Co., 1880. Text in the public domain.