E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
Horn of Plenty [Cornu-copia].
Emblem of plenty.
Cers is drawn with a rams horn in her left arm, filled with fruits and flowers. Sometimes they are being poured on the earth from the full horn, and sometimes they are held in it as in a basket. Diodorus (iii. 68) says the horn is one from the head of the goat by which Jupiter was suckled. He explains the fable thus: In Libya, he says, there is a strip of land shaped like a horn, bestowed by King Ammon on his bride Amalthæa, who nursed Jupiter with goats milk.
When Amaltheas horn
Oer hill and dale the rose-crowned Flora pours,
And scatters corn and wine, and fruits and flowers.