Watch List notes:

Parthian Kingdom. Mithradates II. 121-91 B.C. AR drachm (21 mm, 3.95 g, 12 h). Ekbatana, ca. 119-109 B.C. Diademed and draped bust of Mithradates II left; behind, monogram / archer seated right on omphalos, holding bow. Cf. Sellwood 26.10 (form of monogram); cf. Shore 81 (same). Very light porosity. Monogram erased(?) from die. Very fine.

The monogram behind the bust of Mithradates II on Sellwood 26.10 is composed of a Δ with central pellet atop an M-shape. Her it appears to have been mostly erased from the die, but it is still sufficiently legible to tell that it is lacking the Δ with central pellet.