Faustus

A son of Saturn and Entoria. and the brother of Janus, Hymnus and Felix.

From Parallela Graeca et Romana purported to be by Plutarch:

The story of Icarius who entertained Dionysus: Eratosthenes in his Erigonê.

Saturn, when once he was entertained by a farmer who had a fair daughter named Entoria, seduced her and begat Janus, Hymnus, Faustus, and Felix. He then taught Icarius the use of wine and viniculture, and told him that he should share his knowledge with his neighbours also. When the neighbours did so and drank more than is customary, they fell into an unusually deep sleep. Imagining that they had been poisoned, they pelted Icarius with stones and killed him; and his grandchildren in despair ended their lives by hanging themselves.

When a plague had gained a wide hold among the Romans, Apollo gave an oracle that it would cease if they should appease the wrath of Saturn and the spirits of those who had perished unlawfully. Lutatius Catulus, one of the nobles, built for the god the precinct which lies near the Tarpeian Rock. He made the upper altar with four faces, either because of Icarius's grandchildren or because the year has four parts; and he designated a month January. Saturn placed them all among the stars. The others are called harbingers of the vintage, but Janus rises before them. His star is to be seen just in front of the feet of Virgo. So Critolaüs in the fourth book of his Phaenomena.

From A New System; or, an Analysis of Ancient Mythology. Volume II By Jacob Bryant

The priests likewise upon their bonnets had the representation of serpents. The antients had a notion, that when Saturn devoured his own children, his wife Ops deceived him by substituting a large stone in lieu of one of his sons, which stone was called Abadir. But Ops, and Opis, represented here as a feminine, was the serpent Deity, and Abadir is the same personage under a different denomination. Abadir Deus est; et hoc nomine lapis ille, quem Saturnus dicitur devorâsse pro Jove, quem Græci βαιτυλον vocant.—Abdir quoque et Abadir βαιτυλος. Abadir seems to be a variation of Ob-Adur, and signifies the serpent God Orus. One of these stones, which Saturn was supposed to have swallowed instead of a child, stood, according to Pausanias, at Delphi. It was esteemed very sacred, and used to have libations of wine poured upon it daily; and upon festivals was otherwise honoured. The purport of the above history I imagine to have been this. It was for a long time a custom to offer children at the altar of Saturn: but in process of time they removed it, and in its room erected a στυλος, or stone pillar; before which they made their vows, and offered sacrifices of another nature. This stone, which they thus substituted, was called Ab-Adar, from the Deity represented by it.