"The quadriga with the basket of grain-ears shows the procession of the calathus of Ceres, sung by Callimachus in his hymn [to Demeter]: it had already appeared on the coins of the moneyers of Augustus in 17 B.C. (cf. BMC 38). It is unmistakably derived form Alexandria, and suggests the importance of Egypt as the granary of Rome, even beside any endeavors of the Emperor to revive Italian agriculture." -- Mattingly, p. xlii of BMCRE Vol. 2