Today's Quintilian: 8.6.23

XXIII. Nec procul ab hoc genere discedit metonymia, quae est nominis pro nomine positio, [cuius vis est pro eo quod dicitur causam propter quam dicitur ponere] sed, ut ait Cicero, hypallagen rhetores dicunt. Haec inventas ab inventore et subiectas res ab optinentibus significat, ut "Cererem corruptam undis", et "receptus terra Neptunus classes aquilonibus arcet".

23. From synecdoche, metonymy is not very different. It is the substitution of one word for another, and the Greek rhetoricians, as Cicero observes, call it ὑπαλλαγή (hypallage). It indicates an invention, by the inventor, or a thing possessed, by the possessor. Thus Virgil says,

Cererem, corruptam undis,

Ceres by water damaged,
and Horace,

receptus
Terra Neptunus classes Aquilonibus arcet,

Neptune, received
Within the land, from north winds shields the fleets.