Istros AR drachm, 5.86 g, 4th Century BC. 

Two facing male heads, the left inverted.
ISTRIH, sea-eagle standing left on dolphin.
Theta beneath eagle's wing, S beneath dolphin.

Unpublished symbol combination. CNG 54, 30.

With permission of cngcoins.com, auction 54, Lot 30, Dec. 2002.