Countermark

https://rpc.ashmus.ox.ac.uk/countermark/513 
GIC 393
caduceus head
but might have been applied at Tarsus 

Coins with this countermark

Number Image TypeNumber CoinNumber VolumeNumber
RPC IV, 5031 (temporary) Show 1039 9 4.3
RPC IV, 5813 (temporary) Show 1032 3 4.3
RPC IV, 4994 (temporary) Show 1026 15 4.3
RPC IV, 5031 (temporary) Show 1039 11 4.3
RPC IV, 4994 (temporary) Show 1026 10 4.3
RPC IV, 4994 (temporary) Show 1026 9 4.3