Here you go:

Antoninus Pius AE Sestertius.
Obv: ANTONINVS AVG PIVS P P (IMP II), laureate head right
Rev: T R POT XXI COS IIII, Annona standing left, holding rudder on prow & corn ears over modius; S-C across fields.
RIC 981, rated common. 157-158 AD
You'll have to verify that the legends match. I'm pretty sure this is it though - legend matches positioning on the example shown and theres no other matching coin with a modius and a rudder - other coins with Modii have a prow/galley to the right.