Caracalla, Rome mint, 217 AD.,
Antoninianus (23-24 mm / 4,47 g),
Obv.: ANTONINVS PIVS AVG GERM , radiate, draped cuirassed bust right, frontal view.
Rev.: P M TR P XX - COS IIII P P , Serapis, wearing modius on head, standing facing, head left, leaning on scepter and holding wreath of corn ears.
RIC IV, I, 255, 289e (scarce for the type) .
RIC does not indicate this special bust type.
Curtis Clay 7/5/2010:
"A rare bust type for Caracalla, presumably introduced only shortly before his death in April 217, since it only occurs on coins of his final tribunician year (TR P XX), and since the same bust type then became one of the commonest under Macrinus.
Another antoninianus of Caracalla with this bust type, same rev. type, different dies: BMC 187, pl. 72.17. Aurei of TR P XX with the same bust type: BMC pl. 72.20, pl. 73,2-3, pl. 73.6. The same bust type also occurs on rare denarii with the same date, and on a unique sestertius."